# RAF daylight strategic bombing campaign results



## wiking85 (Feb 22, 2015)

How would the RAF have faired if they had gone for a daylight strategic bombing campaign from 1941 on? Let's say the choice to go for a daylight campaign means they adopt the long range Spitfire variant for service as a escort. In 1941-42 the Luftwaffe was only fielding two Wings of fighters in the West, though I imagine the night fighters would have ended up as daylight bomber destroyers without a night campaign. Do the British go for high altitude bombing too? 

Jagdgeschwader 26 - Wikipedia, the free encyclopedia


> In 1941 most of the fighter units of the Luftwaffe were sent east to the Eastern Front, or south to the Mediterranean Theater of Operations, thus leaving JG 26 and Jagdgeschwader 2 Richthofen as the sole single-engine fighter Geschwader in France. For the next two years these two Geschwader were the main adversaries to the Royal Air Force's (RAF) day offensives over Occupied Europe. The two Jagdgeschwader maintained around 120 serviceable Bf 109 E and F’s to face the increasing number of aggressive RAF Fighter Command sweeps conducted to wear down the Luftwaffe in a war of attrition and so relieve pressure on the Eastern Front.


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## tomo pauk (Feb 22, 2015)

> Let's say the choice to go for a daylight campaign means *they adopt the long range Spitfire variant* for service as a escort.



This is the key. 
No escort = LW racks up the score. Escorts = yes, RAF will get bloody nose sometimes, but will grind down what LW has in the West. LW can/will call back fighter units from Soviet union or/and MTO, but that worsens the situation on those fronts. 
Bombers will have easier time to navigate to their targets and to hit something other than field, or meadow, or wrong part of Europe. However, the heavy Flak will have had an easier task during the day than during the night, especially in 1941 with so few fire-control radars. 
A determined 'push' towards escorted daylight campaign should also mean more internal fuel in up-coming fighters, like Spitfires with 2-stage engines and Typhoon. Another interesting thing might be a greater emphasis on the Mustang to get wing racks ASAP, shortly followed by a better engine (not yet a 2-stage Merlin, though).


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## wiking85 (Feb 22, 2015)

tomo pauk said:


> This is the key.
> No escort = LW racks up the score. Escorts = yes, RAF will get bloody nose sometimes, but will grind down what LW has in the West. LW can/will call back fighter units from Soviet union or/and MTO, but that worsens the situation on those fronts.
> Bombers will have easier time to navigate to their targets and to hit something other than field, or meadow, or wrong part of Europe. However, the heavy Flak will have had an easier task during the day than during the night, especially in 1941 with so few fire-control radars.
> A determined 'push' towards escorted daylight campaign should also mean more internal fuel in up-coming fighters, like Spitfires with 2-stage engines and Typhoon. Another interesting thing might be a greater emphasis on the Mustang to get wing racks ASAP, shortly followed by a better engine (not yet a 2-stage Merlin, though).



Would this result in a heavier loss rate for the RAF to the point that it becomes unsustainable? Would it affect bombing impact if its harder to get through and loss rates are higher than they were at night?


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## tomo pauk (Feb 22, 2015)

That would depend on how great the loss rate is for the RAF, and how great is the loss rate of LW (that would roughly determine how many days the RAF will be sustaining increased losses). Eg. if the RAF can trade a fighter and a bomber per each LW fighter they kill, say during a couple of weeks, the LW is loosing the battle, since it is less numerous after June 1941. RAF sending 250 LR fighters and 500 bombers, supported by 250 fighters on 'ingress' and 'egress' is bound to put LW in problems. Not just of numerical nature (that is a big problem on it's own), but it mandates the LW to kill bombers, meaning they left the initiative to the RAF fighter escort. If LW decides to kill escorts, it is still a fight vs. a big numerical superiority, and the bombers are free to do as they are pleased. 
With the fighters based in France and Netherlands occupied with daylight bombers escorts, that leaves whole shore, stretching from Netherlands to Spain, without meaningful fighter protection, so Coastal Command can have an easier time to interfere with subs their harbors, drop mines etc.


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## nuuumannn (Feb 22, 2015)

The answer to this is already well known and you only need to look at Sholto Douglas' 'Leaning into France' to witness RAF losses over the continent at that time. It was a roundly criticised campaign with high losses for Fighter Command at the hands of mainly Bf 109Fs, which were superior to Spitfire Vs. The appearance of the Fw 190 compunded the problem. Night bombing offered protection against German fighters, until the Nacht Jagd became numerous and effective enough.


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## pbehn (Feb 22, 2015)

To bomb in daylight you need to escort a formation, the RAF didnt have a fleet of bombers to make such a formation for much of the war. Even in 1944 the Halifa and Lancaster were dissimilar and so the formation must be all of one type or perform at the level of the worst.
The first 1000 bomber raid on Cologne 30/31 May 1942 had the following aircraft

Resources committed[8]
No. and type of aircraft	Number of aircraft Total
No. 1 Group RAF	156 Wellington medium bombers 156
No. 3 Group RAF	134 Wellington
88 Stirling heavy bombers 222
No. 4 Group RAF	131 Halifax heavy bombers
9 Wellington mediums
7 Whitley medium bombers 147
No. 5 Group RAF	73 Lancaster heavy bombers
46 Manchester medium bombers
34 Hampden medium bombers 153
No. 91 (Operational Training) Group	236 Wellington
21 Whitley 257
No. 92 (Operational Training) Group	63 Wellington
45 Hampden 108
Flying Training Command 4 Wellington 4

Info from Wiki

As a daylight formation that would be ariel comedy


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## Shortround6 (Feb 22, 2015)

British didn't actually have a whole lot of bombers for most of 1941 compared to what they had later. The first 1000 bomber raid wasn't until May of 1942. They had 88 Stirlings, 73 Lancasters, 46 Manchesters and 131 Halifaxes. The Bulk of the planes were Wellingtons. 79 Hampdens were used. And a dribble of Whitleys. 
These early British heavies also leave a _LOT_ to be desired from the defensive armament perspective. Not all had top turrets and the ones that did had, for the most part, two gun turrets (two .303s). Belly turrets were already on the way but could be fitted for daylight use ( at the cost of speed, none too great to begin with).

Unless you go hog wild redesigning the Spitfire, any 1941/42 long range variant is going to be doing good to escort to the Ruhr.

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## wiking85 (Feb 22, 2015)

nuuumannn said:


> The answer to this is already well known and you only need to look at Sholto Douglas' 'Leaning into France' to witness RAF losses over the continent at that time. It was a roundly criticised campaign with high losses for Fighter Command at the hands of mainly Bf 109Fs, which were superior to Spitfire Vs. The appearance of the Fw 190 compunded the problem. Night bombing offered protection against German fighters, until the Nacht Jagd became numerous and effective enough.



To be fair that was because the Germans were able to pick their battles and only fight when it was favorable, because they didn't care if British bombers hit France; the question is how would it have been had the RAF been hitting Germany instead, forcing them to fight to stop the bombers?


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## nuuumannn (Feb 22, 2015)

I don't see the result being any different, to be honest, Viking. There's a reason why Bomber Command switched to night bombing in the first instance.


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## pbehn (Feb 22, 2015)

Bombers such as the Stirling were vulnerable to flak at night in daylight I doubt Germany would need much in the way of fighter defence, they flew very low and slow. A US Bomber group without escort briefly was exposed but not completely defenseless. Bombers such as the Wellington and Hampden were completely defenseless to a beam attack or anywhere underneath.


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## nuuumannn (Feb 22, 2015)

> Bombers such as the Stirling were vulnerable to flak at night in daylight I doubt Germany would need much in the way of fighter defence, they flew very low and slow.



True, in that time period however, German night fighter arm was not as effective as it was to become, so switching to night bombing was the only real option for keeping losses at acceptable levels. Also, German industrial targets were not as heavily defended in 1941 as they were to become later. Comparatively, Stirlings weren't all that 'slow' compared to other bombers of the era, but of course against fighters its another story. They did have a reputation of being surviveable and also able to withstand violent manoeuvres in order to evade fighter attacks. Again, however, you have to ask what option the RAF had and what is going to minimise losses using the equipment at hand. Defensive armament wise, British bombers were better off than anyone else's (apart from the Hampden). Look at the guns of the He 111, Do 17, Ju 88, SM-79, G4M etc. They were no more surviveable against fighter attack than British bombers. Only the British had power operated turrets on their principal heavy bombers in 1941 (although the Do 217E had one); a far superior means of tracking and accurately shooting at enemy fighters than free mounted guns at that time and from 1942 on, turrets were mandatory on heavy bombers.


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## Shortround6 (Feb 22, 2015)

You have to have _enough_ escorts to get that idea to work. It is also around 250-300 miles from practical British bases to much over the German border. Forget Bremen, Hanover or Frankfort. Even for a raid on the Ruhr you are going to need 3 sets of fighters. One to escort the bombers in, one to rendezvous with the bombers near the target and the last set to rendezvous with the bombers after they drop bombs and get them home. For 1941 and a lot of 1942 that means long range MK V Spitfires. There were only 4 squadrons of MK IXs at Dieppe in Aug of 1942 ( and the kill to loss ratio on that operation was none too good.)

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## nuuumannn (Feb 22, 2015)

> You have to have enough escorts to get that idea to work.



I doubt even then that is going to make much of a difference to the end result, SR, but I support your point. Certainly, until more bombers are available, such raids would be pointless and a waste of resources. Harris had the right idea with the 1,000 bomber raids, despite the polyglot of aircraft types; the raids were a propaganda triumph and did much to restore public and military confidence in Bomber Command's performance in the war to date, which was at a real low before him. Ludlow Hewitt, ever the realist and pessimist was not the man for the wartime Bomber Command and Peirse was out of his depth. Harris injected new life and vigour into Bomber Command.


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## nuuumannn (Feb 22, 2015)

The biggest hindrance to escort fighters in the RAF wasn't the aircraft designs, but Portal, https://en.wikipedia.org/wiki/Charles_Portal,_1st_Viscount_Portal_of_Hungerford who strenouously resisted attempts to introduce long range escort fighters into the RAF, Why? Who knows, but he got into arguments with seniors about it on occasion. His argument was that fighters would not be able to match the performance of interceptors over the target areas (I have quotes, but my books are packed away since I'm moving house). Harris was all for the idea and used to flick pointed memos to Portal on a regular basis about all kinds of things, which Portal got to the point of ignoring, rather than dealing with the issues Harris was raising.


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## wuzak (Feb 22, 2015)

A couple of the daylight Lancaster raids in '42 were done at low level. There was the Augsburg raid, which wasn't very successful and another, the target I can't recall, which was quite successful, including a side raid by Guy Gibson and a couple others to destroy a transformer, or some such.

The advantages of low level raids for Lancaster include the reduced range of detection by radar and the underside is protected from attack due to the proximity from the ground, the upper, front and rear areas being covered by the three turrets.


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## pbehn (Feb 22, 2015)

nuuumannn said:


> True, in that time period however, German night fighter arm was not as effective as it was to become, so switching to night bombing was the only real option for keeping losses at acceptable levels. Also, German industrial targets were not as heavily defended in 1941 as they were to become later. Comparatively, Stirlings weren't all that 'slow' compared to other bombers of the era, but of course against fighters its another story. They did have a reputation of being surviveable and also able to withstand violent manoeuvres in order to evade fighter attacks. Again, however, you have to ask what option the RAF had and what is going to minimise losses using the equipment at hand. Defensive armament wise, British bombers were better off than anyone else's (apart from the Hampden). Look at the guns of the He 111, Do 17, Ju 88, SM-79, G4M etc. They were no more surviveable against fighter attack than British bombers. Only the British had power operated turrets on their principal heavy bombers in 1941 (although the Do 217E had one); a far superior means of tracking and accurately shooting at enemy fighters than free mounted guns at that time and from 1942 on, turrets were mandatory on heavy bombers.


I agree on every point, Stirling pilots were happy that they could out turn a Ju88 (presumably without bombs). Short Sunderlands made many heroic actions and took out many twin engined fighters being free to maneuver, however a formation of bombers gives up that possibility. You cannot start taking violent evasive action in a formation. I think the Stirling bombed within reach of 20mm fire?


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## nuuumannn (Feb 22, 2015)

And in the Lancaster the RAF had the aircraft with which it could conduct the kinds of raids that the command required. It was flexible enough for the job, but in 1942, the type was just entering service in useful numbers. The Halifax had yet to find its mojo (in the Mk.III, which was still a year or so away) and was still suffering numerous issues and a diffident array of variants all with differences to each other. That leaves the Stirling, Wellington, Whitley, Hampden and Manchester to carry the can for the interim.

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## nuuumannn (Feb 22, 2015)

{quote]You cannot start taking violent evasive action in a formation.[/quote]

Generally not adviseable, but night formations were looser than during the day.


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## pbehn (Feb 22, 2015)

nuuumannn said:


> {quote]You cannot start taking violent evasive action in a formation.
> 
> Generally not adviseable, but night formations were looser than during the day.



Agreed, night missions were with a bomber stream not so tight but some did collide. On the later larger missions no one wanted to be flying against the stream, 1000 bombers hit the target in a very short space of time.


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## stona (Feb 23, 2015)

nuuumannn said:


> Generally not adviseable, but night formations were looser than during the day.



Not as loose as sometimes imagined. Hundreds of aircraft passed over the target in minutes. It was a vital prerequisite of a successful area raid that the bombing be concentrated both in space and time. Nonetheless, an attacked or coned bomber would make the most violent evasive manoeuvres.

Even returning the stream was supposed to be maintained. I remember one late war account in which the teller was terrified, on receiving orders for the returning bombers to turn on navigation lights due to visibility problems, to see just how many and how close his colleagues were. This on return when many more experienced crews did not maintain the stream. Some of the Canadians gained something of a reputation for arriving home unfeasibly early with dubious explanations.

If a bomb aimer missed his run in for any reason the aircraft was supposed to go around and try again. Some did, but many did not, well aware of the risk of flying across or against the incoming stream.

A lot of statistical analysis was done to estimate the probability of collisions and the risk was deemed acceptable. Aircraft were also struck by bombs dropped from aircraft above them over the target. The true number of aircraft lost to these causes will never be known.

Cheers

Steve


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## Glider (Feb 23, 2015)

As a general observation I agree that a daylight raid has to have the same type of aircraft or the performance difficulties make the whole thing impractical. Its clear that fighter escort is a requirement for there to be any chance of success but that aside I doubt that the Lancaster and Halifax III would have less success than the B17/B24 combination as used in the USAAF. On daylight raids when attacked by fighters the bomber being targeted was encouraged to evade down and then use any manoeuver they wanted in particular the corkscrew. This was directly different from the US practice of holding formation and shooting it out with the fighters.

RAF bombers were encouraged to evade down below the main formation as it gave a number of advantages.
1) the most accurate shots tend to be the first and if you can get out of the stream of fire then its likely that you will receive fewer hits.
2) The fighter was drawn into the fire of the other bombers
3) A corkscrewing heavy bomber is a difficult target to hit whatever fighter your flying
4) This bought the bomber time helping the escort to intervene 
5) If nothing else it took the fighter away from the other bombers, taking it out of the fight.

I believe that the loss ratios for RAF daylight raids were very similar to the USAAF as each force played to the strengths of the aircraft they had

At night there was no formation flying at all sa its impossible to fly formation if you cannot see the others that were supposed to be in the formation. Each bomber had their own timings, altitude way points etc. which kept the bomber stream tight .


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## stona (Feb 23, 2015)

It's difficult to compare loss ratios for USAAF and RAF raids. The RAF's heavies (meaning Lancasters and Halifaxes) only operated in daylight and in a way comparable to their US counterparts, with few exceptions, after the Luftwaffe day fighter force had been effectively neutralised, almost entirely by those Americans.
Early war daylight efforts by Bomber Command bore no resemblance to even the earliest USAAF raids after the Americans finally arrived.
Cheers
Steve


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## tomo pauk (Feb 23, 2015)

Maybe to add to the discussion - the cruising speeds in mph at 15000 ft (at most economical speed vs. at max weak mixture power): 
-Wellington IA - IC (Perseus): 165 - 195 
-Hampden (with external bombs; I don't have other data): 155 - 200
-Whitley VII (Merlin X): 165 - 195
-Blenheim I: 165 - 200


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## wiking85 (Feb 23, 2015)

tomo pauk said:


> Maybe to add to the discussion - the cruising speeds in mph at 15000 ft (at most economical speed vs. at max weak mixture power):
> -Wellington IA - IC (Perseus): 165 - 195
> -Hampden (with external bombs; I don't have other data): 155 - 200
> -Whitley VII (Merlin X): 165 - 195
> -Blenheim I: 165 - 200



And we know what happened to the Blenheim over Europe...


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## pbehn (Feb 23, 2015)

wiking85 said:


> And we know what happened to the Blenheim over Europe...



The wellington Hampden and Lancaster suffered disastrous losses in daylight raid(s) also.


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## tomo pauk (Feb 23, 2015)

Any 'usual' bomber of ww2 will suffer against a decent fighter opposition. The only help can come out from friendly (preferably long range) fighters providing escort.


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## davebender (Feb 23, 2015)

If RAF build large numbers of long range bomber escorts in addition to historical short range fighter aircraft the Luftwaffe will take notice and Germany will change production priorities. 

Obvious example.
October 1935. Genshagen DB601 engine plant was supposed to receive RM 50 million for construction. Historical RLM reduced this to RM 20 million which eliminate any chance for Heinkel to build fighter aircraft as there weren't enough engines. It also eliminate any chance for mass production of Fw-187. That won't do as Germany must have more fighter aircraft to combat the greater aerial threat.


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## stona (Feb 23, 2015)

davebender said:


> That won't do as Germany must have more fighter aircraft to combat the greater aerial threat.



In 1935? German defensive strategy was based more on the theories of men like Felmy and Rudel (Gunther) which was far more reliant on flak of all types than interceptors. It was only in 1935 that the flak forces were subordinated to the Luftwaffe.

Point number two of the 1935 'conduct of aerial warfare' makes roles quite clear:

_'From the start of the conflict the air forces bring the war to the enemy...

The anti- aircraft artillery directly protects the homeland. Its primary mission is the defence of the homeland in cooperation with the fighter forces....'_

I think you are applying hindsight to a question which arose four years before the war and only shortly after the Nazis came to power.

Cheers

Steve


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## tomo pauk (Feb 23, 2015)

Appearance of the RAF's long range fighter in 1941 means that Germany must act different in 1941/42, not in 1935.


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## Glider (Feb 23, 2015)

pbehn said:


> The wellington Hampden and Lancaster suffered disastrous losses in daylight raid(s) also.



Wellington and Hampden yes, Lancaster no. There were some raids that paid a heavy price certainly, but there were others which did very well. On the 17th October 1942 94 Lancaster's bombed Le Creusot in a daylight raid without any escort and one was lost. On the 24th October 1942 88 Lancaster's did another unescorted daylight raid on Milan and four were lost.


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## Shortround6 (Feb 23, 2015)

The British had trouble with the whole "forward lean" tactic/strategy in 1941/42. Trying to move the targets 100-125 miles further inland and use a lower number of fighters to bombers ratio doesn't sound like a recipe for success. Yes the Luftwaffe _may_ come up and fight but can the British sustain the losses in 1941/42? Until the Summer of 1942 you are pretty much relying on some sort of MK V Spitfire with extra tankage for your "escort fighter" and MK V Spitfires had trouble with 109Fs and early Fw 190s as it was without trying to fly to and from the Germany border/Rhine valley. Germans don't have to slaughter the bombers, just shoot down around 10% or better and the campaign becomes unsustainable pretty quickly. And the losses can be from the combined efforts of Flak and fighters.


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## Denniss (Feb 23, 2015)

British heavies in daylight raids would have a major problem - their limited ceiling in the low 20ks, in the optimum operational altitude for german fighters. They would need a hell lot of escorts if the Luftwaffe was on strength and active.


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## Shortround6 (Feb 23, 2015)

The 17th October 1942 94 Lancaster raid on Le Creusot in a daylight was a special thing and doesn't prove much one way or the other. It is less than 500 miles from the British based used to Le Creusot in a straight line and yet the flight path was 1700 miles. Le Creusot was just over the "border" from Vichey territory. A dog leg flight path might have avoided whatever fighter fields were in Northern France. Photo shows planes over Montrichard which is near Tours. Altitude to target was under 1000ft. 

17th October 1942: Operation Robinson hits Le Creusot works


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## pbehn (Feb 23, 2015)

Glider said:


> Wellington and Hampden yes, Lancaster no. There were some raids that paid a heavy price certainly, but there were others which did very well. On the 17th October 1942 94 Lancaster's bombed Le Creusot in a daylight raid without any escort and one was lost. On the 24th October 1942 88 Lancaster's did another unescorted daylight raid on Milan and four were lost.



The raids on Italy showed the complete disdain for defence in Italy

https://books.google.co.uk/books?id...v=onepage&q=1942 lancaster raid milan&f=false


The le creusot raid saw no enemy AC defense and little flack flown at low level overland it was a surprise attack not possible against Germany.


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## bobbysocks (Feb 23, 2015)

how early would they have realistically been able to get the mustang mk1?


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## pbehn (Feb 23, 2015)

bobbysocks said:


> how early would they have realistically been able to get the mustang mk1?



Much quicker if they had ordered it instead of the A 36 Apache. As I have read the Mustang was put into production and service ASAP but its altitude performance limited it to Tactical Recon for the RAF. The US budget for fighters was used up so it was ordered as a "dive bomber" With an Allison engine it would struggle as an escort.


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## davebender (Feb 23, 2015)

As a complete surprise? How does peacetime (1930s) Britain fund such a massive project complete with production facilities for engines and airframes without it becoming public knowledge? Not even Stalin's Soviet Union could prevent other nations from monitoring construction of his military industrial complex.


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## tomo pauk (Feb 23, 2015)

The Mustang I will not be available before early 1942, as historically; even that is quite a feat. The A-36 entered production after Mustang I and Ia (version with 4 cannons; us nomenclature P-51), and before Mustang II (P-51A).



> The US budget for fighters was used up so it was ordered as a "dive bomber"



Indeed. 
Maybe change the orders for the P-40 - let Curtis add dive brakes to the P-40 and produce 500 of 'A-40', that would free the 'fighter funds' for 500 Mustangs? Even so, the Mustang will not be a major player before 1943.



> With an Allison engine it would struggle as an escort.



Probably. Installing a V-1710-81 will help with altitude capability, the wing racks are a must (originally not installed on Mustang I and Ia, A-36 got them 1st). Again, it will be 1943 until those Mustangs are deployed in ETO MTO.


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## tomo pauk (Feb 23, 2015)

davebender said:


> As a complete surprise? How does peacetime (1930s) Britain fund such a massive project complete with production facilities for engines and airframes without it becoming public knowledge? Not even Stalin's Soviet Union could prevent other nations from monitoring construction of his military industrial complex.



Britain funded Beaufighter, Mosquito, Typhoon, Whirlwind, plus a host of 2-engined bombers, while starting out with 4-engined types. I'm not sure those caused any uproar in LW circles (bar Mosquito). 
The long range fighter is not a massive project, what would might be called 'massive' was the prejudice and opposition to it.


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## wiking85 (Feb 23, 2015)

davebender said:


> As a complete surprise? How does peacetime (1930s) Britain fund such a massive project complete with production facilities for engines and airframes without it becoming public knowledge? Not even Stalin's Soviet Union could prevent other nations from monitoring construction of his military industrial complex.



The long range spitfire just added an extra fuel tank behind the pilot seat


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## davebender (Feb 23, 2015)

> long range spitfire just added an extra fuel tank behind the pilot seat



If it was that easy it would have happened historically and there would have been no Mustang designed for British service.


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## Shortround6 (Feb 23, 2015)

davebender said:


> If it was that easy it would have happened historically and there would have been no Mustang designed for British service.



The Mustang was NOT designed to be a long range escort. It was designed to be a _better_ P-40. The British Mustangs were NOT designed as an alternative to a long range Spitfire. 

For Spitfires the behind the seat tank, aside from photo recon-planes, did not become common ( and even that is stretching things) until the two stage supercharged engines showed up. CG issues may very well have put the kibosh on (stopped) behind the seat tanks on single stage Merlin powered planes. 
Ferry use and even photo-recon flights are a lot different than air to air combat flights. 

Timing, as always, is everything and while the Mustang was one of the record setters both in shortness of design period and going into production it was still a late comer and the initial factory was in Southern California. Initial delivery's were made by ship through the Panama canal. First Mustangs don't show up in England until the Oct 24th 1941. By the time they are fitted with British guns, radios and equipment and test flown it is Jan 1942. First _real_ (as in more than a handful at a time) operational use was at Dieppe Aug 18th 1942 (British have 4 squadrons, the same number of squadrons equipped with Spitfire MK IXs.) 

Using Allison powered Mustangs as escorts is still going to require Spitfires to fly top cover for both the Mustangs and the bombers.


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## gjs238 (Feb 23, 2015)

Now if we can only get those 9.60:1 supercharger gear ratios in the V-1710 a bit earlier......


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## gjs238 (Feb 23, 2015)

Shortround6 said:


> The 17th October 1942 94 Lancaster raid on Le Creusot in a daylight was a special thing and doesn't prove much one way or the other. It is less than 500 miles from the British based used to Le Creusot in a straight line and yet the flight path was 1700 miles. Le Creusot was just over the "border" from Vichey territory. A dog leg flight path might have avoided whatever fighter fields were in Northern France. Photo shows planes over Montrichard which is near Tours. Altitude to target was under 1000ft.
> 
> 17th October 1942: Operation Robinson hits Le Creusot works



From the article:
_It is believed that the transformer and switching station was destroyed, thus depriving the works completely of electrical power. It is known that there is a great shortage of transformers in France and Germany, so much so that they are believed to be virtually irreplaceable under existing conditions. - See more at: Page not found_

If true, perhaps these components of the electrical grid could have/should have been given greater emphasis for future raids?


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## Edgar Brooks (Feb 24, 2015)

wiking85 said:


> The long range spitfire just added an extra fuel tank behind the pilot seat


Too simplistic by far, since there was too much effect on the CoG; the Mark V could only have the tank fitted if the aircraft was using the 170gal ferry tank. Even the Mk.IX generally kept to the same arrangement (e.g. direct deliveries from Gibraltar to Malta.) 
In 1944, the Air Ministry wanted to fit the tank in every Spitfire, but the C.O. of 11 Group fought against it (and won,) since it affected manoeuvrability, height and rate of climb, and he had to consider the possibility of combat with jets. The only Mark to have the tank as a permanent feature was the XVI (and that had to have metal-covered elevators and paved runways,) and its use was banned as soon as the war was over.


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## kool kitty89 (Feb 24, 2015)

gjs238 said:


> Now if we can only get those 9.60:1 supercharger gear ratios in the V-1710 a bit earlier......


Or arrange things to get those V-1650-1s going to the P-40F and L ended up in Mustangs instead. Or divert them from american merlins that would otherwise be earmarked for british bombers or Hurricanes.

Not an easy task in terms of politics ... but we're talking hypotheticals here. (one could point to just using british built engines entirely, but that'd make for more of a real logistical mess rather than just a political one -ie shipping airframes without any engines installed)

On the other hand ... if those 9.6:1 V-1710s were out sooner, I wonder if they'd have been considered for possible Merin XX alternatives for bomber applications or the hurricane perhaps. (weaker altitude performance, but maybe good enough to make the improved low RPM, leaner fuel economy be a bigger advantage or close enough of a wash to be more useful as a bomber engine than on fighters)

Hell, with the Hurricane doing plenty of low-alt fighter-bomber work, even the common 8.8 supercharged V-1710s might have made sense to allocate there instead. (free up the pool of Merlin XXs needed for bombers and US V1650-1s for Mustangs, leaving P-40s and Hurricanes with V-1710s)

Come to think of it, with the performance penalty of the sand filters on tropicalized Spits and Hurricanes, both of those types might have fared comparably well with V-1710s. (which seemed to do well enough with the screens already in use for US Army requirements to not need additional bulky filters)

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## pbehn (Feb 24, 2015)

Discussion of long range escorts seems to centre around the world being blind to the obvious. No one believed a long range escort was needed, no one believed a long range escort was possible. Until very late on the US went for more defensive armament on the bombers and eventually special "fighter versions" which carried no bombs at all.

To design a long range fighter in 1939/40 you must predict that they are needed, you must see the speed and economy of the Mustang before it is built and you must have available merlin engines that were produced in 1944. The mustang was a great design by a small manufacturer and had a charmed or even fated existence. Few saw the need of a long distance escort and even fewer saw the Mustang as that aeroplane. If the merlin did not slot in readily where the Allison had been it would never have happened.

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## Shortround6 (Feb 24, 2015)

The Merlin Mustang prototypes were being worked on _before_ Dieppe or before Mustang was used in full squadron numbers.

Almost 200 Mustngs were built _before_ American Merlins became available in quantity and while fitting a V-1650-1 would be easier than fitting the 2 stage engine it is still not going to be done in a couple of weeks.
You also have the problem of _who's_ engines are you going to use. The American's got 1/3 of initial Packard production and those were the engines that went into American P-40s. The British allocation engines went into bombers and Canadian Hurricanes. Sticking American owned engines into British owned ( bought and paid for) air frames is going to call for a bit of creative negotiations.

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## pbehn (Feb 24, 2015)

Shortround6 said:


> The Merlin Mustang prototypes were being worked on _before_ Dieppe or before Mustang was used in full squadron numbers.
> 
> Almost 200 Mustngs were built _before_ American Merlins became available in quantity and while fitting a V-1650-1 would be easier than fitting the 2 stage engine it is still not going to be done in a couple of weeks.
> You also have the problem of _who's_ engines are you going to use. The American's got 1/3 of initial Packard production and those were the engines that went into American P-40s. The British allocation engines went into bombers and Canadian Hurricanes. Sticking American owned engines into British owned ( bought and paid for) air frames is going to call for a bit of creative negotiations.



I think that as soon as the Mustang was test flown its speed and large internal fuel was appreciated by the test pilots, its poor high altitude performance immediately begged the question "would a merlin fit there" and this was done on both sides of the pond. The P51/Mustang was all about creative negotiations fate and luck.

If Curtiss could manufacture all the P40s the UK wanted =no mustang
If the British insisted on NA making P40s = no Mustang
If the Vulture Sabre worked = need for huge numbers of Merlins = no P51
If the merlin was not able to be developed to circa 1750HP = no P51 
If the A36 was not ordered to keep production going probably no P51

A massive amount of luck resulted in a plane that could hardly be designed better for a job it was never actually designed for. It was so good that it is now easy to say the Brits were remiss in not designing one sooner but the Spitfire was designed around a 850HP engine, how would a Mustang/P51 perform with only 850HP?


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## tomo pauk (Feb 24, 2015)

I'm not sure that Spitfire was designed around the 850 HP engine - the Merlin gave 1000+ from the get-go. 
The story of the Mustang would be even a greater delight had the USAF put more emphasis on the XP-51 once it arrived the Wright Field, on Aug 24th. Another XP-51 arrived on December 16th. The 1st tests started on March 1st 1942!!

re. Spitfire V with rear tank - the fuel from that tank can be used up for warming up, take off and initial climb, then switch to drop tank until entering the combat. The difference is that, once drop tank is gone, whole main fuel tankage (84 gals) will be there, vs. the 'normal' Spitfire that will have around 60 gals after dropping the tank. 25 imp gals mean another 20-30 min of cruise, or another 100-150 miles greater combat radius.


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## pbehn (Feb 24, 2015)

tomo pauk said:


> I'm not sure that Spitfire was designed around the 850 HP engine - the Merlin gave 1000+ from the get-go.
> The story of the Mustang would be even a greater delight had the USAF put more emphasis on the XP-51 once it arrived the Wright Field, on Aug 24th. Another XP-51 arrived on December 16th. The 1st tests started on March 1st 1942!!


Easy to get into an argument about nothing of importance here. The Merlin when accepted for service produced 1000HP but even while Spitfires first flight was made, in march 1936 the Merlin was failing tests at that power output.

Merlin E
Similar to C with minor design changes. Passed 50-hour civil test in December 1935 generating a constant 955 horsepower (712 kW) and a maximum rating of 1,045 horsepower (779 kW). Failed military 100-hour test in March 1936. Powered the Supermarine Spitfire prototype.[17]

All engines (especially the Sabre) have massive claimed bench outputs it is a different matter how much they can safely be used at, the merlin II 
Merlin G (Merlin II)
Replaced "ramp" cylinder heads with parallel pattern heads (valves parallel to the cylinder) scaled up from the Kestrel engine. 400 Hour flight endurance tests carried out at RAE July 1937; Acceptance test 22 September 1937.[18] It was first widely delivered as the 1,030-horsepower (770 kW) Merlin II in 1938, and production was quickly stepped up.[17]

Work on the Merlin started in 1933 it was in service with 1030HP in 1938 but the Spitfire had to be designed and built around what was known, Supermarine couldnt say to the AM in 1936 it will be a great plane in 1938 when the engine is sorted.


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## Shortround6 (Feb 24, 2015)

tomo pauk said:


> re. Spitfire V with rear tank - the fuel from that tank can be used up for warming up, take off and initial climb, then switch to drop tank until entering the combat. The difference is that, once drop tank is gone, whole main fuel tankage (84 gals) will be there, vs. the 'normal' Spitfire that will have around 60 gals after dropping the tank. 25 imp gals mean another 20-30 min of cruise, or another 100-150 miles greater combat radius.



A Merlin 45 _could_ use 50 gallons an hour at 2400rpm and 3 3/4 lbs boost for 310mph true at 20,000ft. 

We have been over this before, and an extra 25-30 gallons of Fuel in a Spitfire MK V _might_ make it possible to "escort" bombers as far as Essen/Dusseldorf. Cologne _may_ be out of reach. 
This is hardly a comprehensive bombing campaign and depending on how fast the Germans catch on to the limited target area and concentrate their fighters (and AA guns) to cover it the British have a rather limited time window to do anything.


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## tomo pauk (Feb 24, 2015)

pbehn said:


> Easy to get into an argument about nothing of importance here. The Merlin when accepted for service produced 1000HP but even while Spitfires first flight was made, in march 1936 the Merlin was failing tests at that power output.
> 
> <snip>


No hard feelings, I was merely trying to point out that Merlin was delivering considerably more than 850 HP, even on non-military rating. 



Shortround6 said:


> A Merlin 45 _could_ use 50 gallons an hour at 2400rpm and 3 3/4 lbs boost for 310mph true at 20,000ft.



Thanks - extra 25 gals would then suffice for 155 miles on fairly fast cruise. 



> We have been over this before, and an extra 25-30 gallons of Fuel in a Spitfire MK V _might_ make it possible to "escort" bombers as far as Essen/Dusseldorf. Cologne _may_ be out of reach.
> This is hardly a comprehensive bombing campaign and depending on how fast the Germans catch on to the limited target area and concentrate their fighters (and AA guns) to cover it the British have a rather limited time window to do anything.



Essen/Duesseldorf means Ruhr area, plus the targets from Ruhr to Channel. Should make for a much more comprehensive campaign than wandering around Germany and ocupied W. Europe while not being able to hit anything in a reasonable percentage (not taking anything from the brave crews).
Don't think that removing the LW fighter Flak force away from area west of Rhine in 1941/42 would've been done, unless at the verge of defeat.


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## wiking85 (Feb 24, 2015)

If they could reach the Ruhr they could do some serious damage; Tooze cites the damage done during 1943 to the Ruhr that stopped German armaments expansion. If the British could afford the losses they could really do something significant in 1941-43 during the day against the Ruhr and divert major German aerial power to defend this pressure point.


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## Shortround6 (Feb 24, 2015)

tomo pauk said:


> Thanks - extra 25 gals would then suffice for 155 miles on fairly fast cruise.



And you _need_ the fast cruise to keep from becoming a target. 



> Essen/Duesseldorf means Ruhr area, plus the targets from Ruhr to Channel. Should make for a much more comprehensive campaign than wandering around Germany and ocupied W. Europe while not being able to hit anything in a reasonable percentage (not taking anything from the brave crews).
> Don't think that removing the LW fighter Flak force away from area west of Rhine in 1941/42 would've been done, unless at the verge of defeat.



Not really, the Germans don't have to shift _anything_ from west of the Rhine. Once they figure out that the daylight attacks with escorts _can't_ reach Hamburg, Hanover, Frankfort, Stuttgart, etc air defensed from those areas (and further east) can be moved to the Ruhr area. 

Unless the British try for a dual campaign, night and day, but they don't have enough bombers for that.


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## Koopernic (Feb 24, 2015)

The disadvantage of the Allison engine of the P-51A (RAF parlance Mustang I roughly) for escort use is moistly a *non problem.* for the following reasons.

1 The Stirling, Manchester, Lancaster, Halifax and Wellington don't have high altitude engines any better than the Allison apart from maybe the Lancasters two speed Merlin. I'm assuming that RAF mission won't exceed 20,000ft and would generally be less. Hence the Allison engine Mustang has little need to exceed its comfort zone of 15000ft by much.

2 Historically the two stage Merlin 61 engine Spitfire IX(perhaps a little latter), The Me 109G1 and the Mustang I all fly their first service missions around May 1942.

The Germans are dependant on the Me 109F, Me 110F and Fw 190A3 (June 1942 for the A4).

The air distance from London to Berlin (the far side of Germany) is about 550 miles which gives and idea of the missions required. I believe a mission to Berlin would be disasterous for the RAF and it would need to focus on shorter ranged missions say to the Ruhr.

A Spitfire has a range of about on internal fuel of at most 400 miles, with drop tanks released before combat the range is likely to be curtailed to just over 600 suggesting a practical combat escort radius of no more than 250 miles.

The Mustang I P-51A essentially has the same range as the P-51D with tail tank (the Allison is less thirsty) so an RAF daylight mission looks like heavy escorts by spitfires to 250 miles with the Mustang I/P-51A taking over from there.

I would suggest the missions go no deeper than 400 miles. They will be at below 20000ft due to limitations in bomber power plants and to keep the P-51A not too far above its critical altitude. In the 15000-20000 band the P-51 is about as fast as a Me 109G1 and the lower it goes the more the P-51 advantage grows.

Of course long range missions in 1941 with escorts are essentially impossible unless the Spitfire V is properly prepared. The Spitfire carried around 90 Imp gallons of fuel in tanks behind the engine which gave a range of around 400 miles. Historically 2 smaller tanks were fitted in the wing leading edges (4 in all) which increased internal fuel tankage by around 33% and range of some marks of Spitifre VII and VIII by around 50% (600 miles) over the Spitfire IX which lacked it. This suggests to me escort radii with drop tanks of around 400-450 miles. Historically many spitfires also had tail tanks which tended to be regarded as ferry tanks only due to their destabilising effects in combat. However if only 10 gallons (instead of 44-50 gallons) I'm sure the effect would be minimal and further range increases would be possible.

Of course the RAF lacked such a spolicy and Supermarines rang such a program only as a sideline.


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## tomo pauk (Feb 24, 2015)

LW from late June 1941 has a grand total of ~40 (~ forty) Bf 109s in Germany and Denmark.



Koopernic said:


> The disadvantage of the Allison engine of the P-51A (RAF parlance Mustang I roughly) for escort use is moistly a *non problem.* for the following reasons.



The P-51A is the Mustang II, it has better altitude capability than Mustang I (the P-51 would be the Mustang Ia - 4 cannons). Problem - the Mustang II will not go in combat before 1943, even if it is produced instead of A-36.


> 2 Historically the two stage Merlin 61 engine Spitfire IX(perhaps a little latter), The Me 109G1 and the Mustang I all fly their first service missions around May 1942.



Mustang and two stage Merlinized Spitfire will be too late for 1941 and much of 1942.



> The air distance from London to Berlin (the far side of Germany) is about 550 miles which gives and idea of the missions required. I believe a mission to Berlin would be disasterous for the RAF and it would need to focus on shorter ranged missions say to the Ruhr.



Yep, Berlin is way too far for years to come.



> The Mustang I P-51A essentially has the same range as the P-51D with tail tank (the Allison is less thirsty) so an RAF daylight mission looks like heavy escorts by spitfires to 250 miles with the Mustang I/P-51A taking over from there.



That is another problem - the Mustang I does not have drop tanks. Introduced with A-36.



> I would suggest the missions go no deeper than 400 miles. They will be at below 20000ft due to limitations in bomber power plants and to keep the P-51A not too far above its critical altitude. In the 15000-20000 band the P-51 is about as fast as a Me 109G1 and the lower it goes the more the P-51 advantage grows.



Problem with going too low is that gives the defended the altitude advantage, and even the Flak might interfere.



> Of course long range missions in 1941 with escorts are essentially impossible unless the Spitfire V is properly prepared. The Spitfire carried around 90 Imp gallons of fuel in tanks behind the engine which gave a range of around 400 miles. Historically 2 smaller tanks were fitted in the wing leading edges (4 in all) which increased internal fuel tankage by around 33% and range of some marks of Spitifre VII and VIII by around 50% (600 miles) over the Spitfire IX which lacked it.



Leading edge tanks were 2 x 12.5 imp gals, the Spitfire VII and VII have had 120 imp gals total, since one of the fuselage tanks was enlarged, too. The rear fuselage tank of 29 imp gals was used in 1941, albeit just for ferry purposes.


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## Shortround6 (Feb 24, 2015)

wiking85 said:


> If they could reach the Ruhr they could do some serious damage; Tooze cites the damage done during 1943 to the Ruhr that stopped German armaments expansion. *If the British could afford the losses* they could really do something significant in 1941-43 during the day against the Ruhr and divert major German aerial power to defend this pressure point.



That is the big question. 
Could the British mount a _big enough_ campaign, _soon enough_and with _acceptable losses_. 

In 1941 production of bombers is a fraction of what it would be later. 
For example they built 10 Lancasters in 1941 and 688 in 1942. in 1944 they _averaged_ over 250 Lancasters a month. 

It took until June of 1942 to get _ten_ Squadrons equipped with Halifaxes. 

As for the Stirling. "Within five months of being introduced, 67 out of the 84 aircraft delivered had been lost to enemy action or written off after crashes." Now maybe there would be fewer crashes in daylight but operating Stirlings in daylight does _not_ sound like the best idea. At their _peak_ of bomber service Stirlings equipped 13 squadrons. 

Now you are down to the twin engine aircraft and only the Wellington has any business at all over enemy territory in daylight even with escorts.


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## Shortround6 (Feb 24, 2015)

Koopernic said:


> The disadvantage of the Allison engine of the P-51A (RAF parlance Mustang I roughly) for escort use is moistly a *non problem.* for the following reasons.
> 
> 1 The Stirling, Manchester, Lancaster, Halifax and Wellington don't have high altitude engines any better than the Allison apart from maybe the Lancasters two speed Merlin. I'm assuming that RAF mission won't exceed 20,000ft and would generally be less. Hence the Allison engine Mustang has little need to exceed its comfort zone of 15000ft by much.
> 
> ...



This rather flies in the face of the reality of the BoB. Very few of the German bombers flew at over 20,000ft. Yet British fighters and some German "escorts" often flew at 25-30,000ft. If your escorts are flying at 15-18,000ft they can be bounced from above by what, on the level, would be slower aircraft. The faster climbing 109Fs and Gs can _evade_ upwards compared to the Allison powered P-51s. The faster climbing German aircraft can also easily (at least somewhat) re-position themselves for 2nd and 3rd attacks from above the high performance _zone_ of the Allison Mustangs. 

You _could_ use Allison Mustangs for escorts but you better have Spitfires flying top cover in that 25,000ft area. And Spitfire Vs are already in trouble against Late model 109Fs and Early 109Gs without carrying several hundred pounds more in fuel and fuel tank weight.


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## pbehn (Feb 24, 2015)

They mounted the first 1000 bomber raid in May 1942, daylight bombing is only better than night without cloud cover which is common in the Ruhrgebiet. Escorting bombers needs huge numbers of fighters. We didnt have the bombers or fighters to do it, sadly.


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## tomo pauk (Feb 24, 2015)

FWIW, here is the 'what and where' for the assets of the LW, for several dates of ww2:

Luftwaffe Orders of Battle 24 June 1941, 27 July 1942, and 17 May 1943

Wondering just how many fighters and bombers the RAF have had in Britain.


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## Shortround6 (Feb 24, 2015)

Some sources state that the Stirling was pulled from service at the end of 1943 due to losses from flak being higher than the losses suffered by the Lancaster and Halifax. 
Flying them by daylight means higher losses _before_ radar shows up and/or restricting bomb load to try to gain altitude. 

There is little question the Luftwaffe fighter forces were stretched thin at this point in time but so were the British bomber forces. The Cologne 1000 bomber raid used several hundred planes manned by instructor and student pilots with planes drawn from training command. Worked OK for a *publicity stunt* but as an ongoing campaign it would fall into the same trap the Germans fell into. To few adequately trained pilots/crews coming in as replacements.
Shifting Luftwaffe AA assets is certainly do-able even if fighter assets are scarce.


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## wiking85 (Feb 24, 2015)

Shortround6 said:


> Some sources state that the Stirling was pulled from service at the end of 1943 due to losses from flak being higher than the losses suffered by the Lancaster and Halifax.
> Flying them by daylight means higher losses _before_ radar shows up and/or restricting bomb load to try to gain altitude.
> 
> There is little question the Luftwaffe fighter forces were stretched thin at this point in time but so were the British bomber forces. The Cologne 1000 bomber raid used several hundred planes manned by instructor and student pilots with planes drawn from training command. Worked OK for a *publicity stunt* but as an ongoing campaign it would fall into the same trap the Germans fell into. To few adequately trained pilots/crews coming in as replacements.
> Shifting Luftwaffe AA assets is certainly do-able even if fighter assets are scarce.



Yeah, but you don't need 1000 bombers to hit specific industrial targets instead of incinerating cities.


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## tomo pauk (Feb 24, 2015)

Stirling was introduced just in time to face the fire-control radars the German Flak arm introduced. Hence the altitudes, once perhaps recognized as 'safe from Flak', suddenly become dangerous. In 1941 the fire control radars are few and far between, but the daylight operations still mean that Flak will be a problem.


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## stona (Feb 24, 2015)

wiking85 said:


> Yeah, but you don't need 1000 bombers to hit specific industrial targets instead of incinerating cities.



Yes you do using WW2 technology and bombing by night in 1942/3. The original development of Bomber Command's large raid strategy was to ensure the destruction of such targets, though this soon became a pretence to cover the real objectives. By the time technology and tactics had developed to a point where accuracy was increased, in favourable conditions, such industrial targets were no longer the real objectives. Harris went on the record rating acreages of housing destroyed as more important than factories destroyed, but that was later.
Cheers
Steve


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## Shortround6 (Feb 24, 2015)

How many do you need?
That raid was a publicity stunt as much as anything else and is best viewed as a snapshot of what the RAF could muster for operational bombers on a given date. Tossing out the trainers and the more obsolete types and you have 292 four engine bombers including 88 Stirlings. You have an additional 46 Manchesters. Number of Wellingtons with Hercules engines is ?????

Now instead of a once a month or every coupe of weeks maximum effort try flying 2-3 missions a week with the approximately 400 first line aircraft available in the spring of 1942. Less said about the 1941 the better. 

Weather conditions in the Ruhr valley were often not good. Modern day terminology would be _SMOG_. The coal fired industrial powerplants adding to the general confusion, purpose built smoke generators could also be brought into play. 

And if you can see the ground then then guns on the ground can see the bombers. The Americans didn't do all that well with daylight bombing either. Granted it was higher up and therefor less accurate but it did cut down on exposure to the AA guns.


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## Shortround6 (Feb 24, 2015)

tomo pauk said:


> Stirling was introduced just in time to face the fire-control radars the German Flak arm introduced. Hence the altitudes, once perhaps recognized as 'safe from Flak', suddenly become dangerous. In 1941 the fire control radars are few and far between, but the daylight operations still mean that Flak will be a problem.



And there you have a big part of trying to conduct daylight bombing with medium altitude planes in 1941/42.* IF * you can see the ground to bomb accurately, the AA guns can see the bombers and don't _need _ radar (although it helped) unlike night bombing were the AA guns either fired blind or tried to pick-out planes illuminated by searchlights. Some early radars guided the search lights. 

You are only going to catch the defenses napping (un ready) a certain amount of times so individual raids are not a guide line for a campaign.


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## stona (Feb 24, 2015)

pbehn said:


> Escorting bombers needs huge numbers of fighters. We didnt have the bombers or fighters to do it, sadly.



Nor did the Americans when they started, at least according to Lemay:







From 'Battles With the Luftwaffe - The Bomber Campaign Against Germany 1942-45'. Theo Boiten and Martin Bowman.

Cheers

Steve


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## Shortround6 (Feb 24, 2015)

There were major holes in theory as can be seen by the specifications issued. 
B-26 and B-25 were _supposed_ to carry 3000lbs of bombs 2000 miles and have top speed of over 300mph. They failed to meet the specification which was issued in the Spring of 1939 but it took a long, long time to get a single engine fighter to fly 2000 miles. 
The 4 engine bomber specs really show how far off the idea of an escort fighter was. 

_Theory_ might have said there should be escort fighters but even the US didn't actually put out specifications for an escort fighter until around 1943.


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## tomo pauk (Feb 24, 2015)

Re. LeMay excerpt - yes, it was a surprise, a rude one. The non-installation (prior mid-1943) of combat-worth drop tank installation in a 2000 HP fighter, that is going to be mass produced in three factories, is a reminder for the surprise. The lack of second source of the only long range fighter is another reminder. RAF Spitfires (and USAF Spitfires?) escorting the 8th AF bombers is yet another reminder for the surprise.
The USAF did not abolished attack aircraft either, the A-20 was produced, along the A-24 (granted, that one would've ill fared in the ETO, esp. without escort). However, attack aircraft will not be able to do Flak suppression 500 miles away from base.


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## stona (Feb 24, 2015)

Shortround6 said:


> How many do you need?
> That raid was a publicity stunt as much as anything else and is best viewed as a snapshot of what the RAF could muster for operational bombers on a given date.



It was very much a propaganda raid, all the 'millenium' raids were. Nonetheless they were a portent of things to come. The later raids comprising a few hundred Lancasters (and Halifaxes) delivered far more bomb tonnage than the earlier raids precisely because of the disparate and sometimes obsolete types employed.

To hit an average sized warehouse, given the aerodynamics and other factors contributing to the CEP of the iron bombs dropped required several hundred bombs *if they were dropped from the right place*. To be sure of hitting such a structure once navigational factors are added required literally thousands of bombs. All these calculations were made at the time, and that's why such large bombing forces were developed, even though the true objective of British bombing did change.
I can't give the exact figures and statistics as I'm away from home, someone else may have them.
Cheers
Steve


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## Shortround6 (Feb 24, 2015)

True but getting back to the original premise of the thread we have, in 1941,
Only a few hundred bombers at a time suitable for daylight operations _even *if*_ escorted. 
Escorts of short range, Ruhr valley is the _BEST_ that can be hoped for. Even tweaking the Spitfire well beyond historical limits. 
Bombers of rather low altitude capabilities leaving them vulnerable to visually aimed flak. Or the carriage of significantly lighter bombloads and higher altitudes which means many more sorties to get results. 
Things improve the further into 1942 you get but not quickly. 

One can look at the Lockheed Ventura raids of late 1942 and early 1943 to get an idea of what the likely results might have been. The Ventura was faster than any British bomber short of the Mosquito and these raids were against coastal targets, not 120-150 miles inland.


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## stona (Feb 24, 2015)

Shortround6 said:


> True but getting back to the original premise of the thread we have, in 1941,
> Only a few hundred bombers at a time suitable for daylight operations _even *if*_ escorted.
> Escorts of short range, Ruhr valley is the _BEST_ that can be hoped for. Even tweaking the Spitfire well beyond historical limits.
> Bombers of rather low altitude capabilities leaving them vulnerable to visually aimed flak. Or the carriage of significantly lighter bombloads and higher altitudes which means many more sorties to get results.
> Things improve the further into 1942 you get but not quickly.



The inability of bombers designed in the 1930s to operate as planned in daylight came as a surprise to everyone, including the Germans. 'Bombing, States and Peoples in Western Europe 1940-1945' (Baldoli, Knapp, Overy) devotes several pages to what the Germans expected and the various ARP measures undertaken to protect the civilian population. 

Cheers

Steve


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## bobbysocks (Feb 24, 2015)

wiking85 said:


> The long range spitfire just added an extra fuel tank behind the pilot seat



how big was this tank? and what part of the flight characteristics suffered due to its installation. anytime you mess with an AC's center of gravity you risk something. as in the case with the mustang you didnt want to do certain maneuvers or get into a dogfight with the fuse tank full ( which surprises me how well the guys at Y-29 did when attacked ). did the spitfire suffer the same way?


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## Edgar Brooks (Feb 24, 2015)

Koopernic said:


> Of course long range missions in 1941 with escorts are essentially impossible unless the Spitfire V is properly prepared. The Spitfire carried around 90 Imp gallons of fuel in tanks behind the engine which gave a range of around 400 miles. Historically 2 smaller tanks were fitted in the wing leading edges (4 in all) which increased internal fuel tankage by around 33% and range of some marks of Spitifre VII and VIII by around 50% (600 miles) over the Spitfire IX which lacked it.


As Tomo Pauk says, the VII, VIII XIV had a single tank in each wing. Two extra tanks (in the strengthened wings) were not fitted before the 20-series Spitfires.


> Historically many spitfires also had tail tanks which tended to be regarded as ferry tanks only due to their destabilising effects in combat.


Only the XVI, in wartime, had a permanent fuselage tank; the removable 29-gallon tank could only be used with the 170 gallon ferry tank.


> However if only 10 gallons (instead of 44-50 gallons) I'm sure the effect would be minimal and further range increases would be possible.


Totally wrong, and made worse by this apparent dream that we had loads of 170 gallon tanks that we could cheerfully chuck away, over France, a dozen at a time. When the ferry tanks were first used to get Spitfires to Malta (without the fuselage tank) pilots were told to avoid dropping them at all costs (except if combat was looming,) since they had to be returned to Gibraltar for re-use.


> Of course the RAF lacked such a spolicy and Supermarines rang such a program only as a sideline.


Wrong on both counts, since the Air Ministry spent a lot of time and effort getting droptanks into service, and Supermarine (like all companies, especially during a war) did as they were told. They did not, in fact, make the tanks, which were made by a different company entirely. Supermarine manufactured the necessary plumbing, etc., to accommodate the tanks, that's all.
As well as the incorrect idea of the numbers of tanks available, there are some other pipedreams which need to be dispelled:-
1/. With the ferry tank in place, the pilot was restricted to straight and level flight, and gentle manoeuvres; if bounced, and he could not switch over the fuel flow, and drop the tank in time, he was dead. 
2/. With the extra fuel, the Spitfire needed a larger oil tank, which was only available on tropical aircraft, with the Vokes filter (therefore extra drag.) Malta complained about just such a situation, with their deliveries, but were told it was that, or nothing. 
3/. The extra fuel meant extra weight, which overloaded the airframe, so all guns and ammunition had to be removed, so what sort of fight are your "escorts" going to put up?


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## Shortround6 (Feb 24, 2015)

Fuel tank weights are all over the map due to shape (surface area) and construction. I have no idea what the 29 gallon tank in a Spitfire weighed, but the forward 37 US gallon tank in a P-40 weighed just about 100lbs _empty_. P-39s were about the worst and their tanks weighed almost 300lbs to hold 120 US gallons of fuel. British tanks may be a bit lighter due to different self-sealing set up? 

British _tried_ a number of different tank set ups on the Spitfire. Including the 40 gallon tank out on one wing, I am certainly not in love with the two small tanks in the wing set up as the more switching of tanks a pilot has to do the more chances of something screwing up. But the Supermarine engineers thought that was better than a single tank in the rear of the plane *and* that was on the planes with a much heavier engine and propeller than many here are proposing.


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## kool kitty89 (Feb 24, 2015)

pbehn said:


> To design a long range fighter in 1939/40 you must predict that they are needed, you must see the speed and economy of the Mustang before it is built and you must have available merlin engines that were produced in 1944. The mustang was a great design by a small manufacturer and had a charmed or even fated existence. Few saw the need of a long distance escort and even fewer saw the Mustang as that aeroplane. If the merlin did not slot in readily where the Allison had been it would never have happened.


Or to just not ignore designs with potential for such a role ... or fail to emphasize development of them for longer range. Granted, that even goes as far as shorter range aircraft (and pretty much all aircraft) lacking drop-tank support early on.

From the 1939/1940 standpoint, there were many fighters in development or even in service that could have developed into a long-range role. In England you had Gloster's F.9/37 twin engine fighter that had plenty of potential for the multirole/long-range fighter category, and possibly derivatives of a single-seat Defiant as well.

The US had the P-38, P-47, and F4U in development, all of which could have had more emphasis put on escort capabilities. Though none would have been really combat ready for 1941. (plus the P-38 had a whole list of problems, P-47 took a while to get large enough pressurized drop tanks and/or wing pylons, and the Corsair wasn't being persued for the USAAF) Hypothetically though, the F4U seems like it might have been the erliest really practical escort fighter for the US. Accelerate development without Naval specific requirements and it might have entered service sooner. Good medium altitude performance, decent high alt (especially compared to contemporaries) good enough for US high alt bomber alts, and certainly at British bomber heights. (not P-47 turbo level power ceiling, but also lighter and more maeuverable)

There's an argument for the F4U making a better fighter-bomber than the P-47 too, but that's not pertanent here. 

Germany had the likes of the Fw-187 on their hands too, though with most bombing ranges they worked with, drop-tank capable Bf-109s would have been good enough.


And, of course, Japan had heavy empahsis on exceptional long range capabilities pre-war, though achieved that in part by emphasizing lightweight construction, no self-sealing tanks, and no armor on top of large fuel capacity and fuel efficient engines.

On that note, the F2A Buffalo might have actually fit in reasonably well as a long-range fighter. Certainly the only pre-way US/British/German fighter in service witha range exceeding 1000 miles, let alone 1500. (technically, the P-40B could manage >1000 miles at minimum cruise, but that was slightly later and not in the same range class as the Buffalo)
The problem being that the performance was a bit mediocre ... manufacturing issues aside, between the lower rated refurbished engines on the Export models the British worked with and the heavier F2A-3, they'd have been ill suited to escorting bombers over Europe by the time the allies moved on to large scale offenssive raids.
That said, in the 1939/1940 context, it was probably the only thing remotely close to a serviceable single-engine escort fighters that the allies had, and performance wasn't far off from a similar vintage Hurricane. (and similarly up-armmed and armored, and more maneuverable -especially roll rate- along with lacking negative G fuel flow issues)

The F4F-3 with drop tanks might have been useful in this role too. (could go from F2A+F4F early war to F4U once it comes online)


Perhaps a P-40 derivative with cowl guns retained and wing guns reduced or elliminated in favor of more fuel would have been a useful early-war stop-gap too? (2x synchronized .50s is a bit weak, but strictly against other fighters it might have been marginally acceptable when nothing else could manage the range) That's assuming the gun bays were useful for holding fuel cells. (or that engineering space for wing tanks wouldn't be more difficult than the space for 6x .50s in the P-40D)

But really, once the Corsair hit the scene, that plane alone (in sufficient numbers) seems like it could have adapted to pretty much every role Allied fighters/fighter-bombers were called upon for in the ETO/MTO ... maybe not the super long-range capabilities of the P-38J/L exploited in the PTO, at least not without further expanded fuel. (perhaps a P-47N style wing redesign) Well that or some specific capabilities of the Beaufighter and especially Mossie.





pbehn said:


> A massive amount of luck resulted in a plane that could hardly be designed better for a job it was never actually designed for. It was so good that it is now easy to say the Brits were remiss in not designing one sooner but the Spitfire was designed around a 850HP engine, how would a Mustang/P51 perform with only 850HP?


The P-40 was adapted from the P-36 initially working with considerably weaker engines than the Merlin, yet expanded into a significantly longer-range aircraft than the Spitfire in spite of being closer to the Hurricane in original engineering date. (and flying slightly earlier)

I suppose that luck argument could apply to the P-36/P-40 too, though, given how well it developed ... and given Crutis's own difficulties in actually engineering something more capable than the existing airframe worked out to be.


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## tomo pauk (Feb 25, 2015)

> Hypothetically though, the F4U seems like it might have been the erliest really practical escort fighter for the US.



That would certainly be the P-38? Very much feasible already in 1941. Few things might help out with P-38, though, like having a second source of production - for example, the P-47 was to be produced in 3 factories, ditto the F4U. Not crashing the XP-38 might've also helped to accelerate the testing, development production.


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## Shortround6 (Feb 25, 2015)

kool kitty89 said:


> Or to just not ignore designs with potential for such a role ... or fail to emphasize development of them for longer range. Granted, that even goes as far as shorter range aircraft (and pretty much all aircraft) lacking drop-tank support early on.



For an escort fighter to work it has to be able to engage the interceptor fighters one a _somewhat_ even level. Just getting a non-bomber with some guns along side the bombers doesn't work well. Germans found that out with Bf 110s trying to fly close escort. 

A Mystery was the lack of drop tank support as many US fighters of teh late 20s and 30s used drop tanks and German Hs 123 used an external tank even if not often dropped. 



> From the 1939/1940 standpoint, there were many fighters in development or even in service that could have developed into a long-range role. In England you had Gloster's F.9/37 twin engine fighter that had plenty of potential for the multirole/long-range fighter category, and possibly derivatives of a single-seat Defiant as well.



We also have theory and intention hitting the brick wall of reality. The P-38 _started_ with 400 US gallons in unprotected tanks, Fitting self-sealing tanks dropped fuel capacity to 300US gallons. The F.9/37 held 190 IMP gallons for it's two engines and more than likely the tanks were unprotected at that time. Fitting protected tanks will decrease capacity and increase weight, fitting more tankage increases weight. 190 IMP gallons _might_ have worked for low powered engines in a light aircraft over short distances. It was nowhere near enough for escort work, think about it. A P-47 (early) carried 254 Imp gallons and that was nowhere near good enough. I rather doubt that the F.9/37 had less drag than the P-47 what with it's twin engines and bigger wing. Usefulness of the Defiant _seems_ to be based of an estimate of an unflown proposal. Installation of the Merlin XX was not all that it could be in practice??



> The US had the P-38, P-47, and F4U in development, all of which could have had more emphasis put on escort capabilities. Though none would have been really combat ready for 1941. (plus the P-38 had a whole list of problems, P-47 took a while to get large enough pressurized drop tanks and/or wing pylons, and the Corsair wasn't being persued for the USAAF) Hypothetically though, the F4U seems like it might have been the erliest really practical escort fighter for the US. Accelerate development without Naval specific requirements and it might have entered service sooner. Good medium altitude performance, decent high alt (especially compared to contemporaries) good enough for US high alt bomber alts, and certainly at British bomber heights. (not P-47 turbo level power ceiling, but also lighter and more maeuverable)



We have been over this a number of times. F4U starts out carrying much less fuel inside than a P-47, has little or no advantage in drag and has to work it's engine harder even at 18-24,000 ft in high speed cruise than the P-47 does. Remenber that it doesn't really matter if the bombers are flying at 16,000ft or 24,000ft if the German interceptors are flying at 24-28,000 feet before diving down on the bombers. The escorts _have_ to engage the interceptors _before_ the interceptors are in a gun run. Shooting them down _after_ the y make firing passes at the bombers means a lot of shot down bombers. 



> And, of course, Japan had heavy empahsis on exceptional long range capabilities pre-war, though achieved that in part by emphasizing lightweight construction, no self-sealing tanks, and no armor on top of large fuel capacity and fuel efficient engines.



And we know how that worked out in the long run. 



> On that note, the F2A Buffalo might have actually fit in reasonably well as a long-range fighter. Certainly the only pre-way US/British/German fighter in service witha range exceeding 1000 miles, let alone 1500. (technically, the P-40B could manage >1000 miles at minimum cruise, but that was slightly later and not in the same range class as the Buffalo)
> The problem being that the performance was a bit mediocre ..



Once again, an escort _fighter_ needs to be able to *fight*. Not just show up. F2A-3 began to come out of the factory in Jan 1941, about the time the First Bf 109Fs were showing up. F2As would have been in trouble against 109Es, against 109Fs in the summer of 1941 they would have been just so many more targets. Granted they may have saved bombers by having the 109Fs use up their ammunition shooting them down but sacrificial lambs is not a good long term strategy. 




> Perhaps a P-40 derivative with cowl guns retained and wing guns reduced or elliminated in favor of more fuel would have been a useful early-war stop-gap too? (2x synchronized .50s is a bit weak, but strictly against other fighters it might have been marginally acceptable when nothing else could manage the range) That's assuming the gun bays were useful for holding fuel cells. (or that engineering space for wing tanks wouldn't be more difficult than the space for 6x .50s in the P-40D)



A stop gap has to actually work, at least somewhat. P-40s _needed _Spitfires flying top cover in order to survive in North Africa. If you escorts need escorts that doesn't leave you much range for the bombing mission. And BTW "2x synchronized .50s is a bit weak" it was more than a bit weak. The US .50 probably took to synchronizing the worst of any gun that was successfully synchronized. British tests report a rate of fire of under 500rpm. One wing gun could fire almost 90% of the rounds that cowl guns could. Also you have to figure out which P-40 you are using. The D/E/F used engines that shifted the prop shaft upwards 6in. Maybe cowl guns would still fit, maybe they would need bumps/bulges to fit. Then you have to play games with the oil tank and CG. P-36s had the oil tank behind the engine and in front of the guns, ammo boxes. P-40-40C had the oil tank behind the behind the seat fuel tank. P-40D/E/F had the oil tank behind the engine near where the guns had been. This may have been in part to balance the plane. P-40 was 3 feet longer than the P-36, all due to engine but it means that 330lb (roughly) prop was 3 feet further in front of the CG than a P-36. You can't always just stick stuff where you want. 

More later


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## Shortround6 (Feb 25, 2015)

kool kitty89 said:


> But really, once the Corsair hit the scene, that plane alone (in sufficient numbers) seems like it could have adapted to pretty much every role Allied fighters/fighter-bombers were called upon for in the ETO/MTO ... maybe not the super long-range capabilities of the P-38J/L exploited in the PTO, at least not without further expanded fuel. (perhaps a P-47N style wing redesign) Well that or some specific capabilities of the Beaufighter and especially Mossie.



The F4U will not handle the long escort mission as well as a P-47, let alone the P-51. We have had threads on this before and with less fuel in the F4U and a higher fuel burn at the speeds and altitudes used it just isn't going to work.
You may want to look at the British twins again. They were very good at what the did do but that was NOT daylight air to air combat against high performance fighters.
American fighters were stressed for 12 G ultimate load at normal gross weight. British single engine fighters were stressed for 10 G. Mosquito was stressed for 6 G. Even if the controls will permit it you are going to break them trying to fling them about like a Spitfire or 109.


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## tomo pauk (Feb 25, 2015)

For the F4U to work as a long range fighter, it will need to have a drop tank facility much earlier than historically. The 1st F4U with single fuselage rack plumbed for fuel tank was accepted by USN at October 4th 1943. That would make 237 gals of protected fuel, 124 gals of non-protected fuel in 2 wing tanks total, and up to 175 gals in the drop tank. *IF* the F4U can warm up, take off, climb and cruise some time on wing fuel alone, that would mean it has all of the protected fuel available before entering combat.

Compared to that, the early P-47D has 305 gals of protected fuel, and can carry a tank under belly. Problem is the size of belly tank - mostly it was used the 75 gal, or 110 gal tank there, due to ground clearance. Seem that the 1st people that managed to get a pressurized belly tank of bigger volume were at 5th AF of Gen Kenney, the tanks produced in Brisbane by Ford of Australia.
The combat radius for the such P-47D with 75 gal tank was 340 miles, per AHT; with 110 gal DT instead it will do ~375 miles of combat radius. The F4U will probably not be able to better those values. Once the P-47 is plumbed for wing drop tanks, it will do 425 miles of combat radius, per USAF table via AHT. Unless the F4U gets much more of protected internal fuel and second drop tank, it won't come close. And, an escort fighter of under 400 miles of radius will not going to do the trick for the USAF in last 24 months of ww2.

The P-47D of early 1944, with 370 gals of protected fuel in fuselage, really outdistances the F4U as an escort fighter with 600 miles of combat radius. All figures for the P-47 are for USAF requirements - 25000 ft cruise, 20 min combat, ~310 mph TAS.


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## tomo pauk (Feb 25, 2015)

Another thing that would've plagued the, presumably, hi-alt operations needed by 8th AF: compressibility. Prom America's hundred thousand, pg. 517:


> - August '43: Navy Squadron VF-17, in testing out their new Corsairs, dives them from high altitude and encounters some compressibility problems; they are shedding elevator fabric and loosing control in the dives . Vertical dives from above 20000 feet are banned in Squadron VF-17



The wing profile was 23018 at root, ie. thickness was 18% of chord. That is one thick wing (even the P-38 was at thinner percentage with 23016 profile at root), and with the 'classic' NACA 230 series it will be entering compressibility quick - meaning LW fighters will have no problems to disengage with split-S when needed.


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## kool kitty89 (Feb 25, 2015)

Shortround6 said:


> You may want to look at the British twins again. They were very good at what the did do but that was NOT daylight air to air combat against high performance fighters.


Hence why I didn't refer to any British twin that actually reached operational status. (though I mentioned the Mosquito would have a tough time due to G-limits and maneuverability)




Shortround6 said:


> I rather doubt that the F.9/37 had less drag than the P-47 what with it's twin engines and bigger wing. Usefulness of the Defiant _seems_ to be based of an estimate of an unflown proposal. Installation of the Merlin XX was not all that it could be in practice??


I'm not thinking of something exceptional, but something closer to an indiginous British P-40 possibly with a bit more room for growth in internal tankage. (the P-40 itself was much better in the long-range role than the Spitfire or Hurricane ... just not good enough to manage the extreme ranges heavy Bombers were pushing over Europe)

So perhaps not potential to be a deep penetration fighter capable of staying with the bombers on their longest routes, but a hell of a lot closer than anything else the British had in production.

And the F.9/37 was more in terms of potential growth ... it might not have worked out, but given the dimensions and design of the airframe (and provisions for a second crewman), it seems a fair bet that it had lots of potential for expanded internal fuel tankage (unlike the Whirlwind) while being a more practical day fighter than the Mosquito (G-limits among other things).
Modified Mosquitos MIGHT have made sense too, but between maneuverability and stress limits of the airframe, it seems less likely.




> We have been over this a number of times. F4U starts out carrying much less fuel inside than a P-47, has little or no advantage in drag and has to work it's engine harder even at 18-24,000 ft in high speed cruise than the P-47 does.


Faster level flight, acceleration, and climb rates at low/mid altitudes than early P-47s (prior to boost limits being raised), lower weight, greater roll and turn rates, and I'm assuming use of the wing tanks. (and replacement with self-sealing tanks on later models rather than deletion) 




> Once again, an escort _fighter_ needs to be able to *fight*. Not just show up. F2A-3 began to come out of the factory in Jan 1941, about the time the First Bf 109Fs were showing up. F2As would have been in trouble against 109Es, against 109Fs in the summer of 1941 they would have been just so many more targets. Granted they may have saved bombers by having the 109Fs use up their ammunition shooting them down but sacrificial lambs is not a good long term strategy.


True, and by the time the F2A-3 arrived, better aircraft were on the horizon anyway ... and drop-tank eqipped F4Fs probably would have fared better. (barring hypotheticals like an F2A fitted with the 2-stage R-1830 of the Wildcat)
Even so, with equal pilots, the F2A-3 may have fared better than the Hurricane at least. (similar speed and climb, but more maneuverable -especially at high speeds)

The 1939/1940 argument is a bit limited here since allied bombing wasn't really significant until after that point, so the really early fighters with the necessary range are only really relevant when there was no serious need for them. (one could argue for the Germans being better off with F2As or especially P-40s during the battle of brittian, but drop-tank equipped Bf-109Es would have been perfectly suited to the short ranges involved there ... albeit P-40s, Buffalos, and Wildcats ... and P-39s for that matter all made better fighter-bombers due to range/fuel load compared to contemporary 109s)




> A stop gap has to actually work, at least somewhat. P-40s _needed _Spitfires flying top cover in order to survive in North Africa. If you escorts need escorts that doesn't leave you much range for the bombing mission. And BTW "2x synchronized .50s is a bit weak" it was more than a bit weak. The US .50 probably took to synchronizing the worst of any gun that was successfully synchronized. British tests report a rate of fire of under 500rpm. One wing gun could fire almost 90% of the rounds that cowl guns could. Also you have to figure out which P-40 you are using. The D/E/F used engines that shifted the prop shaft upwards 6in.


Like the Buffalo and F4F, I'm speaking mostly very early war (before the P-38, P47, or F4U could be ready) so it'd be P-40B/C/Tomahawk. (the C is actually a bit too late for the early-war requirement) But the allusion to the P-40 D/E wing did imply later use as well, so those factors are valid from that standpoint. 

As to the armament, nose guns have concentration of fire, lack of convergence zone limits, and effectiveness round per round over wing mounting. (both the British and Americans seemed to actively ignore/decry this advantage when the Soviets, Germans, and Finns seemed to recognize it much more -including Soviets removing the P-39 wing guns and Finns noting the nose mounted .50 brownings of the F2A were more efficient than the wings in spite of the much lower RoF -and opted for 4x nose mounted .50s in their indiginous fighter development -while the P-51 had its pair of nose guns deleted -or removed in the field on the A-36- ... as did the F4F)
Nose guns are pretty definitively more affected, but realistically (looking at historical US/British doctrine/tendencies) this argument is largely compromised if for no other reason than due to preference over utility.

That whole argument may be superfluous anyway if the P-40's wing was ill suited for fuel in/around the gun bays. (just keep the wing guns ... or even consider adding the nose guns to later models if possible -again ... doctrine/preference seems to nix that idea regardless of technical feasibility)


It's also worth noting that compared to the 8 gun Spitfire and Hurricane, 2 500~600 RPM .50 BMGs still managed better than half the firepower of 8x .303 brownings. (and the 4x .30-06 brownings + 2x .50s had more firepower than the 8 gun british fighters) At very least using these metrics for firepower The WWII Fighter Gun Debate: Gun Tables
(in fact roughly 130% the firepower of an 8-gun spit/hurricane)




There's also one other thing relating to the P-51, especially relevant when comparing the P-40 to Spitfire and 109. Not only was it a 'lucky' design to fit the long range category, but was just an exceptional all around performer lucky enough to NOT have the enemy challenge it with a similarly advanced short-range interceptor. (As the spitfire and 109 were to the P-40) Unless you count the jets but those came too later and too few to matter.


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## kool kitty89 (Feb 25, 2015)

tomo pauk said:


> The wing profile was 23018 at root, ie. thickness was 18% of chord. That is one thick wing (even the P-38 was at thinner percentage with 23016 profile at root), and with the 'classic' NACA 230 series it will be entering compressibility quick - meaning LW fighters will have no problems to disengage with split-S when needed.


According to The Incomplete Guide to Airfoil Usage the F4U's wing root was a 23015. The critical mach number figures for the F4U I've seen (.73 mach in wind tunnel tests) also correspond more to 15% chord than 18%. 

http://www.ww2aircraft.net/forum/flight-test-data/ww2-fighter-critical-mach-speed-802.html
I recall there being a more recent thread to bring this up too, but the F4U's mcrit discussed there is higher than the P-47's. (granted, critical mach alone doesn't say how detrimental the high speed handling is -buffeting, loss of control, shift in center of lift -extreme on the P-38, etc)




tomo pauk said:


> For the F4U to work as a long range fighter, it will need to have a drop tank facility much earlier than historically. The 1st F4U with single fuselage rack plumbed for fuel tank was accepted by USN at October 4th 1943. That would make 237 gals of protected fuel, 124 gals of non-protected fuel in 2 wing tanks total, and up to 175 gals in the drop tank. *IF* the F4U can warm up, take off, climb and cruise some time on wing fuel alone, that would mean it has all of the protected fuel available before entering combat.


Drop tank is going to be the big bottleneck there. It's going to need 300+ gallons externally AND the internal wing tanks to be really useful. Better than the existing P-47 prior to wing mounted drop tanks, but that's about it.

This argument mostly hinges on the F4U being able to receive belly racks for drop tanks quickly ... more quickly than the P-47 got wing pylons and certainly more quickly than the late P-47D's expanded internal fuel capacity. (upgrading to protected wing tanks on the F4U would have been significant too, but less so than being able to cary half its fuel externally)

Further, the more general point on the F4U being (potentially) the only fighter the US needed over Europe also hinges on featuring ALL of those elements. (internal fuel capacity, drop tank capacity, plus bomb and rocket capacity for the fighter-bomber role) The historical USN/USMC F4U-1 in 1942/43 would NOT have been that plane. (but I'll maintain that the F4U design would have been more capable in covering the P-38/47/51's historical roles than any ONE of them would -not better than where those other A/C excelled, just good enough to be a better multi-role machine than them ... perhaps sans the P-38 -unless maybe you took more cost effectiveness into account ... but then simplified turbo-less fighter-bomber derivatives might mitigate some of that too, so lots of variables)

(more detailed argument below)





tomo pauk said:


> That would certainly be the P-38? Very much feasible already in 1941. Few things might help out with P-38, though, like having a second source of production - for example, the P-47 was to be produced in 3 factories, ditto the F4U. Not crashing the XP-38 might've also helped to accelerate the testing, development production.


Maybe. Looking at the P-38, P-47, and F4U stricly from a USAAF long-range fighter point of view:

P-38 needs to solve cockpit heating issues (not QUITE as extreme at RAF bomber heights), terminal dive control issues, maneuverability issues, turbo/intercooler issues, and be drop-tank capable. (the latter was pretty straightforward, and lacking cockpit heating could arguably be lived with -but compromise health/awareness of pilots, especially on such long flights- the engine performance and maneuverability were critical for being adequate in fighter vs fighter combat, and the dive issues could be avoided by a good pilot and the emergency dive-flap/break solution probably could have been applied much earlier without need of extensive research -it IS a reasonable interim solution, unlike actually trying to solve the buffeting and pitch-down+heavy stick issues aerodynamically -the former solved by carefully designed wing/body fillets, the latter never cured only better avoided)

There's not that many quick fixes on the P-38 that'd get it working well as a high-altitude escort fighter. (it COULD reasonably have been optimized in the short-term as a more effective and more cost effective low/medium altitude fighter/fighter-bomber by deleting the turbos and streamlining the design for low/mid-alt roles -lighter, more power at low alt compared to pre-J models, warm enough for cockpit heating issues to be ignored, warmer denser air avoiding high mach number dives, and easier to maintain)

The P-47 was primarily limited (once service ready) by lack of high capacity drop tanks. If they'd been able to carry around 300 US gallons of external fuel on the belly shackle, things would have been very differnt. I'm not sure there's a quick fix here, but I suppose heavy emphasis on the need of the P-47 as an escort fighter would have accelerated development of larger capacity pressurized tanks. (limited internal fuel capacity was an issue too, but not the primary bottleneck until after it could carry over 200 gallons of fuel externally)
It wasn't until the P-47 was carrying 300+ US gallons on wing pylons that the early models actually showed their limitations due to internal fuel capacity. (and slightly more so due to added drag from the pylons -plus added weight increase if comparing the C to early D models)

The F4U mostly just needed to be drop tank equipped and possibly have the wing tanks replaced with self-sealing fuel cells. (likely closer to 50 gallons each) Similar to the P-47, the ability to carry 300 US gallons externally would have been the big factor. (the higher clearange of the F4U's centerline would have allowed a much greater variety of tanks to be employed, making fitting the actual pylons+plumbing to the F4U the main limiting factor rather than sheer availability of suitable tanks) I may be mistaken, but I think the F4U's belly pylons also affected performance less than the P-47's wing+belly pylons.

I do realize that you need fuel for warmup, time to target, combat, and time home+landing, and am not expecting a full half of range to be covered by external fuel, but half of total FUEL is not the same as half the total range. (external stores burned off first would get the worst fuel efficiency due to weight and bulk adding to drag, so the ability to carry significantly more than half your total fuel stores externally might not be useful for combat, but the ability to carry close to or exactly half your total fuel externall IS significant) Likewise the P-38's ability to carry a pair of 150 gallon drop tanks was significant, while its added ability to carry a pair of 300 gal tanks wasn't particularly combat relevant. (more relevant for the late models, but still a bit overkill aside from ferry flights) 
Fuel consumption increase due to weight and higher engine output on later models is also a factor. (though improvements to cruise efficiency sometimes come into play too)


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## tomo pauk (Feb 26, 2015)

> kool kitty89 said:
> 
> 
> > According to The Incomplete Guide to Airfoil Usage the F4U's wing root was a 23015. The critical mach number figures for the F4U I've seen (.73 mach in wind tunnel tests) also correspond more to 15% chord than 18%.
> ...


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## Edgar Brooks (Feb 26, 2015)

Shortround6 said:


> . I have no idea what the 29 gallon tank in a Spitfire weighed,


According to the A.P., the 30-gallon droptank, when made of vulcanised fibre instead of tinned steel, weighed 40 pounds. As the 29 gallon tank was flexible (otherwise it would never have gone into the fuselage,) it's possible that it was the same material, and therefore weight.


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## Koopernic (Feb 28, 2015)

RAF daylight shallow penetration missions into German airspace (The Ruhr eg Dusseldorf) means a range of 300-350 miles. No RAF fighter can achieve this, the Allison Mustangs don't become available for combat til mid 1942. Hence daylight bombing campaign requires engineering. In a What if hindsight scenario what might have plausibly been achieved with simple basic "sheet metal" engineering that didn't require advances in fuels, engines and aerodynamics.

Assume that the RAF had a daylight bombing strategy that had come to accept 'lessons learned' from analysis of what happened to their enemy, the Luftwaffe, over the Battle of Britain.
1 Bombers will be intercepted in force due to the defenders use of radar
2 and that the Germans had good radar. (Seems to have been somewhat of a problem)
3 Long Range Escorts are necessary.
4 Night bombing was unacceptable. (Assume Lindeman didn't exist)

This means decisions to produce an interim long range escort are made by October 1940, near the end of the BoB. Specifications are issued then. Priority is given.

I see only two options:

1 Improve the capacity of the Spitfire III and V by essentially introducing the "C" wing early. Historically the C wing is introduced on the Mk V and is used on the Mk IX but it is only the MK VII, VIII and latter Griffon variants that receive the wing with an in built 15-18 gallon fuel tank. The basic spitfire has a 85 gallon tank increased to 95 gallons.

The 85 Imperial gallon internal capacity in two fuselage tanks, one above the other. Range described as "allowed for take-off, a climb to altitude, 1.65 hours cruising and 15 minutes combat at full bore". 

A later re-design of these internal tanks increased their capacity by 10 gals. Installation of wing tanks added a total of 36 gals capacity. 
Internal tankage capacity for the latest Mks was therefore 85 + 10 +36 = 131 gallons.


The tail tanks I think can be ignored due to their destabilising effects unless only a very small tail tank is added (say 10 gallons, 42L enough for 6 minutes of full bore combat) 

2 Take the P-40 and overcome its power to weight ratio problem and its Allison engines low critical altitude by fitting the single stage Merlin 20 series with two speed supercharger.
Main tank 50 gallons [62.5 gal U.S] 
Fuselage tank 47 gallons [58.75 U.S.] 
Reserve tank 33 gallons [41.25 U.S.] 
Total 130 gallons [162.5 U.S.] (Note some sources state 134 gallons) 

Historically such an aircraft was built, the P-40F with Packard Merlin V-1650-1 but only in 1943. The two speed Merlins were available pre was and production was being wasted on the Hurricane in 1941.

Combined with drop tanks a substantial range can be achieved to reach more than 50% of German airspace.

I think its worth noting that the only nation which had a passable long escort fighter in 1939,1940 and 1941 was Germany with the Me 110. The exchange ratio against RAF Hurricanes and Spitifires was in fact slightly favourable.


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## Glider (Feb 28, 2015)

The rear tank on the Spitfire was an option. I recognise that it didn't do the handling any favours but by using it first the handling issue would have gone before combat was reached. The other comments re the earlier introduction of the C wing I agree with. 
The P40 was outclassed by the 109 and no matter what you do with it that will not be altered. The earlier comment about the F2A apply here, it has to be able to take on the defending fighters on equal or near equal terms to work, just turning up will not suffice.
The Me110 was not up to taking on equivalent single engine fighters, that was proven many times in combat.


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## tomo pauk (Feb 28, 2015)

I'm not the greatest fan of the P-40F as an escort fighter that would be able to go against LW and do very much. 1st delivered on January 1942, it was at least 40 mph slower than LW fighters of same era.


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## Balljoint (Feb 28, 2015)

Glider said:


> The P40 was outclassed by the 109 and no matter what you do with it that will not be altered. The earlier comment about the F2A apply here, it has to be able to take on the defending fighters on equal or near equal terms to work, just turning up will not suffice.



The up-engined P-40 might be useful if the LW interceptors were tasked with avoiding the escorts and stopping the bombers. And, with the bleeding the LW was suffering, their pilot losses would be much more important.


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## Shortround6 (Feb 28, 2015)

Balljoint said:


> The up-engined P-40 might be useful if the LW interceptors were tasked with avoiding the escorts and stopping the bombers. And, with the bleeding the LW was suffering, their pilot losses would be much more important.



P-40 is always about a step behind the 109. P-40s are being built when the 109E was, P-40Cs are being built when 109Fs are coming into service. P-40Es start coming out of the Factory when 109-F-4s start showing up in service units (P-40s have to shipped 3,500-6000 miles to service theaters). P-40Fs start to roll out of the factory when 109Gs start to show up. 

Granted in takes a number of months to see large numbers of a new type to really appear in service but trying to depend on P-40s to take on 109s doesn't look good. 

*IF* you have other fighters that can force the 109s _down_ to the better altitudes for the P-40 the P-40 could (and did) give a better account of itself but that is NOT what is being talked about here. 

And I _repeat_, the escort fighter used *has to* be able to prevent, or at least interrupt, attacking fighters from diving on the bombers from 3-8,000 ft above.


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## Glider (Feb 28, 2015)

Balljoint said:


> The up-engined P-40 might be useful if the LW interceptors were tasked with avoiding the escorts and stopping the bombers. And, with the bleeding the LW was suffering, their pilot losses would be much more important.



The P40 was never as good as the Me109 and as pointed out was always at least a generation behind the Me109 and FW190. 
In the C Shores book Fighters over Tunisia there is a section where a number of allied fighter pilots were asked which were the best allied fighters of the period. There was almost unanimous agreement that went Spit IX followed by Spit V and P38, followed by P40 and Hurricane. Most people agree that the Fw190 was as good as the Spit IX and the Me109G2 was of a similar class. There is no way that the P40 could make such a leap in performance.


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## kool kitty89 (Mar 1, 2015)

Balljoint said:


> The up-engined P-40 might be useful if the LW interceptors were tasked with avoiding the escorts and stopping the bombers. And, with the bleeding the LW was suffering, their pilot losses would be much more important.


Up-engined to what? The 9.6 supercharger geared Allison or Merlin?

P-40 needed more fuel to get the range needed for full penetration escort in Germany and would have been outperformed in most aspects. (aside from range and dive/high speed maneuverability performance)

Aerodynamically it might have been in the same class as the spitfire, 109, or 190, but to manage that range AND be a competent (not just marginal) fighter against those contemporaries, it needed to be able to perform well in SPITE of being capable of more than double the combat radius. (or maybe not quite that extreme compared to the 190 with drop tanks)

With the P-51 B/C/D's engine and fuel expanded wherever practical, it might have gotten by well enough ... a turbocharged P-40 might have managed that too if they could somehoe figure out how to cram a turbo+intercooler AND enough fuel into the ship. (granted, turbo improves fuel efficiency somewhat, potentially, but you'd still need more fuel than the P-40E/F/M carried)


At British bomber alts, the V-1650-1 or 9.6 supercharged Allisons might have been adequate too, but more fuel is still needed.





Shortround6 said:


> P-40 is always about a step behind the 109. P-40s are being built when the 109E was, P-40Cs are being built when 109Fs are coming into service. P-40Es start coming out of the Factory when 109-F-4s start showing up in service units (P-40s have to shipped 3,500-6000 miles to service theaters). P-40Fs start to roll out of the factory when 109Gs start to show up.


From the P-40 through P-40E (aside from WER at low alt), performance of the P-40 consistently DECREASED compared to earlier models due to gains in weight and drag without much/any improvement in engine performance. (figures for the prototypes and acceptance trials show some speed gains in the E over the B/C, but actual service performance figures show a much more consistent degradation in top speed and climb)

Of course, the P-40 was more akin to the very early war Spitfire/Hurricane/109E lacking self sealing tanks and pilot armor and the B wasn't as heavily armored as the C (and lacked the bomb/drop tank rack).

Besides that, as above, the P-40 always carried much more fuel than the 109 or Spitfire, though closer to the 190. And aside from being built heavier, also had to deal with (often) carrying more weight in armament and using similar or lower performance engines. (P-40F with reduced armament and fuel might be reasonably close to Spitfire V and early 109Gs, P-40M probably slightly worse, N perhaps slightly better ... probably close in top speed, weaker in climb, and better controlled at high speeds)



With any given engines available, the P-40 as a basic airframe would be more paractical to configure with enough fuel to be a useful escort fighter compared to the Spit or 109 ... maybe better than the 190 maybe similar hard to tell. (put the 109's engine in the 190 and try to cram in more fuel if there's practical space for tanks without hurting CoG and it might manage it too -likely won't manage it with the BMW in there)




With equal technology, intercepting fighters are always going to have superior performance to escorting ones, aside from short-range low/medium altitude tactical escorts. You need significantly superior technology in a long-range escort fighter to manage combat on equal or better terms ... on a one to one basis. (granted, tactical advantage of managing to drop on intercepting fighters from above and maintain a good bit of zoom energy and take advantage of coordination and numerical superiority -even if 1:1 performance is weaker- could make marginally adequately performing long-range fighters good enough)


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## Shortround6 (Mar 1, 2015)

Has anybody established an 'actual' desired timeline or date here? 

1941-42 is pretty squishy as by the end of 1941 there had only been 138 Mustangs built and due to shipping distance the British don't even test fly one at Boscombe Downs until Jan 1942. They have four squadrons in service in Aug 1942 and 15 squadrons in service in Jan 1943. There are only going to be enough Mustangs to support a daylight bombing campaign in the last few months of 1942. 
And that is with historic production, _no_ modifications, _no_ waiting for better/different engines. 

_Stripper_ P-40s, as done historically are useless. One of the mods was yanking *out* a fuel tank. While yanking the #5 and 6 guns may have been a good idea, limiting the remaining guns to 200-201 rpg isn't such a good idea for an escort fighter. 

The P-40 with a pair of .50cal guns in the cowl with 200rpg and one .30cal in each wing with 500rpg, no armor, no self sealing tanks, grossed 6800lbs. Spitfire II grossed 6172lbs, 109E-3 was 5875 and a 109F-2 was 6173lbs(?)
The P-40 weighed 5357lbs empty (no guns, no trapped oil, no gun sight, no oxygen equipment), unless you cut structure you can't get a P-40 light enough by just leaving out equipment.


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## Freebird (Mar 2, 2015)

nuuumannn said:


> The answer to this is already well known and you only need to look at Sholto Douglas' 'Leaning into France' to witness RAF losses over the continent at that time. It was a roundly criticised campaign with high losses for Fighter Command at the hands of mainly Bf 109Fs, which were superior to Spitfire Vs. The appearance of the Fw 190 compunded the problem. Night bombing offered protection against German fighters, until the Nacht Jagd became numerous and effective enough.



And when the "real" combat losses vs enemy aircraft were tallied it went from high losses to extreme.
The RAF Fighter Command under Douglas and Leigh-Mallory overclaimed g German losses by an astounding 7-1


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## Balljoint (Mar 2, 2015)

Glider said:


> The P40 was never as good as the Me109 and as pointed out was always at least a generation behind the Me109 and FW190.
> In the C Shores book Fighters over Tunisia there is a section where a number of allied fighter pilots were asked which were the best allied fighters of the period. There was almost unanimous agreement that went Spit IX followed by Spit V and P38, followed by P40 and Hurricane. Most people agree that the Fw190 was as good as the Spit IX and the Me109G2 was of a similar class. There is no way that the P40 could make such a leap in performance.



Just what an up-engined P-40 could be is a bit nebulous. And, with enough fuel to get home, so is performance. But the P-40 could well be superior in the vertical in that it maintained rather good roll rate ate high speeds while ME-109 had high roll control forces and suspect structural integrity at speed. Thus the P-40 might well be able to reach more favorable altitudes for escape or combat. 

Overall, the P-40 had been bypassed regarding performance. But, with select tactics taking advantage of the LW fixation on the bombers, the P-40 would have been better than no help at all during the early days.


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## kool kitty89 (Mar 3, 2015)

Shortround6 said:


> _Stripper_ P-40s, as done historically are useless. One of the mods was yanking *out* a fuel tank. While yanking the #5 and 6 guns may have been a good idea, limiting the remaining guns to 200-201 rpg isn't such a good idea for an escort fighter.


Modest weight saved by omitting a single pair of guns would probably be the only practical compromise there, yes. (similar armament to P-51A/B/C)



> The P-40 with a pair of .50cal guns in the cowl with 200rpg and one .30cal in each wing with 500rpg, no armor, no self sealing tanks, grossed 6800lbs. Spitfire II grossed 6172lbs, 109E-3 was 5875 and a 109F-2 was 6173lbs(?)
> The P-40 weighed 5357lbs empty (no guns, no trapped oil, no gun sight, no oxygen equipment), unless you cut structure you can't get a P-40 light enough by just leaving out equipment.


Could the Spitfire or 109 be practically modified to carry enough fuel to be competitive with the P-40 range-wise? And could it do so in a manner that was reasonably stable in flight? (degradation to speed and climb/turn rate is unavoidable, but actual handling characteristics in terms of stability are still critical -an overweight but stable A/C can at least rely on dive and zoom tactics to gain an advantage)

And equally importantly, could a 109 or Spitfire carry a large enough drop tank to have that cover for close to 1/2 the range.

For the 1941/42 period, in the context of British daylight raids, modified long-range Spitfire Vs might have been adequate ... but that's only IF they could safely carry enough fuel.


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## Shortround6 (Mar 3, 2015)

in reverse order. 



> For the 1941/42 period, in the context of British daylight raids, modified long-range Spitfire Vs might have been adequate ... but that's only IF they could safely carry enough fuel.



MK V Spits were getting hammered on the "lean into France" missions. That is attacking targets or escorting planes attacking targets in coastal areas. Asking them fly to targets another 100-125 miles inland is certainly not going to help things. Especially if the "long range planes" are heavier. 



> Could the Spitfire or 109 be practically modified to carry enough fuel to be competitive with the P-40 range-wise? And could it do so in a manner that was reasonably stable in flight? (degradation to speed and climb/turn rate is unavoidable, but actual handling characteristics in terms of stability are still critical -an overweight but stable A/C can at least rely on dive and zoom tactics to gain an advantage)
> 
> And equally importantly, could a 109 or Spitfire carry a large enough drop tank to have that cover for close to 1/2 the range.



The problem is NOT getting *in.* It is getting *out.* A few 109 recon planes carried a tank under each wing (usually without wing guns?) Spit might carry a 90 gallon drop tank (might go larger, 170 gallon ferry tank is out), both planes may/would need larger oil tanks. 
For a mission profile on the way in you have engine warm up and take off taking up fuel plus climb to altitude and forming up. SPits could top off fuselage tanks I think. Pump and piping would solve problem for 109 if not already fitted. 
That solves getting IN. Getting OUT has the combat allowance (how many minutes at combat power, how many minutes at max continuous or max climb or? ) and a high enough cruise speed back to the coast to _help_ keep from being bounced. For a Spit V using 16lbs of boost in combat every minute was worth 5 minutes at most economical cruise.
Us planners figured how much fuel was needed to get back after dropping tanks, that was the _practical_ radius and _then_ they figured how to get enough external fuel on the planes to get to the radius distance. Plane limitaions sometimes got in the way on early planes. Please note that the external 52 gallon tank on the P-40 (and the under fuselage tank on the P-39) were to _restore_ fuel capacity _after_ fitting self sealing tanks. 



> Modest weight saved by omitting a single pair of guns would probably be the only practical compromise there, yes. (similar armament to P-51A/B/C)



Modest weight savings won't get you want you want/need. And while the armament is similar at first glance P-51Bs carried more ammo. 250 rounds for the inboard guns and 350 rounds for the outboard guns. Stripper P-40s carried 201 ( why the 01?). Regular P-40s carried a total of 1410 rounds. (235 per gun but I don't know if all guns had the same amount.) .50 cal ammo is about 30lbs per 100 rounds so adding ammo back in for a 4 gun version can quickly use up the weight savings. Some P-51Ds pulled the center gun of the three(?) and increased ammo. Some planes carried 500rpg (not always filled?) for 4 guns and others (later ones changed ammo trays) to 400 for inboard gun and 500 round for outboard gun.


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## Koopernic (Mar 3, 2015)

The original poster, Viking, wanted to examin daylight raids from 1941 onwards. To me that means January 1941.

If the RAF wants to run precision daylight raids into Germany proper it needs an escort fighter. The only aircraft that is available that can do the Job is the Curtiss P-40B (Tomahawk IIA) and it most certainly can do the job being the first P-40 with acceptable armour and protection. The P-40B is available from May 1941.

It has a range of 730 miles on internal fuel, 1270 if throttled back. That is 75% more than the Me 109F or Spitfire III or V. With a 75 gallon drop tank it has even more range.

The aircraft is over maligned. It can out dive both the Me 109 and the Spitfire by a substantial margin, it can out roll both by a substantial margin, particular at speed. It can out turn the Me 109 at low altitude and could probably give the Spitfire a run for its money. A well trained pilot has some strengths he can play to. The P-40 made aces against all the axis power, Clive Callwell being one.

The P-40's problem is that its larger airframe and relatively weak Allison V-1710 engine gave it an inferior power to weight ratio to the Spitfire and Me 109F2 which was worsened by the relatively low full throttle height of the Allison.

A power to weight ratio problem can be fixed by fitting a more powerful engine, such an engine was the Merlin, which was easy to fit. The Merlin XII, Merlin 45 and Merlin XX are all available in 1941 (the XX which had a two speed supercharger and was latter know as the 20 series) Historically the P-41F with Packard built V-1650-1 "Merlin 20" became available a scant 8 months latter in Jan 1942. The Merlin would improve the power to weight ratio of the P-40B by between 10% to 20%.

The RAF can have an even more effective escort fighter before mid 1941 by bringing forward the installation of the Merlin into the P-40 by 9 months. Having said that I believe that Allison engine P-40/Tomahawk IIA would have been effective in substantially protecting the bombers by diverting the Luftwaffe's interceptors. It has to be remembered the Luftwaffe is stretched then as well.

The main opponent would be the Me 109F2 with its 1270hp DB601N which at 369mph is slightly faster but able to climb much faster. The Allison is producing 1040hp, latter in 1941 1140hp, about 10% less with lower critical altitude. German C3 fuel is only rated at 92/110 in this period, raising to perhaps 93/115 in that year. Latter in 1941 the Me 109F4 appears with the more powerful DB601E engine (running on lower grade B4 87 octane fuel) but with substantially more power due to variable length inlet ports and the Me 109F4 with a speed of 380 to 390 mph for a short time perhaps even eclipses even the Spitfire V.

The Allies have a substantial fuel advantage with their fuel rapidly jumping from octane/PN 100, 100/110, 100/125, 100/130 by 1942. The German fuel lagged, not even reaching 100/130 even by mid 1944 though close enough (but then the allies were using 100/150.

The Middle of 1942 sees the early Allison P-51A Mustang I/II come into service. This is an incredibly fast aircraft below 15000ft that outclasses all other fighters but at 20000ft its speed is 380mph versus the Me 109G1 400mph. Again the Merlin 20 ie Packard V1650-1 would close of this gap.

There is one further possibility. Wikipedia states that in 1938 Supermarine was told to develop suspended 20mm canon for the Spitfire. Joe Smith objected and the guns were built into the wing. However had he not done so the leading edge tanks used in the Reconnaissance Spitfires (which added 66 gallons each wing) could have been used on the fighter spitfires with a pair of suspended 20mm Hispano's.

We know that a pair of suspended canon "gondola guns" on the Me 109G impacted speed less than 1%. (See Kurfurst.org) and so I argue that the impact on spitfire speed would have been negligible since the guns were being moved (not added as in the German case).

Such a Spitfire would substantially out range even the P-51D with tail tank.


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## Glider (Mar 3, 2015)

The P40 was significantly outclassed by the Me109 and suffered heavy losses when they met in combat, any analysis of the actions in the Mediterranean area will prove that. The P40 had no speed advantage over the 109F, dive advantage was marginal and to be of use you have to have a height advantage which is a major problem with the P40, as compared to the 109F it has a miserable climb performance. It was also poorly armed. The LMG were of little effect against the 109 and the 0.5 had their rate of fire significantly reduced as they had to fire through the propeller.

The quickest and simplest way of giving the RAF a decent long range fighter in this period was to develop drop tanks for the Spitfire. At Malta they installed 2 x 45 gallon drop tanks under the fuselage of the Spit V (they were cast offs from those fitted to Hurricanes) and with a bit of imagination this could have been developed.

However I do agree that the Spit V was outclassed by the FW190 and losses would have been heavy. That said all fighters of the period were outclassed by the FW as it was by far the best fighter of the period anywhere. Nothing is going to get around that.


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## Shortround6 (Mar 3, 2015)

A problem when trying to compare P-40s is that they change a lot in the early ones. 

_IF_ you could get a P-40 to go 730 miles on internal fuel it was an early one _without_ self-sealing tanks or tanks with a crude sealing applied outside, capacity 160 US gallons. Getting one to go 1270 miles if throttled back requires a real leap of faith. 3 times the range of a Spitfire or 109 on 60% more fuel? Those P-40Bs must have been one slick ship 
P-40D/E was rated for 700 miles on 120 US gallons (100imp) remaining with 28 US (23imp) used for warm up and take-off at 173-188mph indicated depending on altitude, sea level to 15,000ft. I am not sure you want to throttle back any more than that. Max endurance is often NOT max range. 
At a more useful 229mph indicated at 15,000ft range for the 120 US gallons was 425 miles. Fuel burn was in the 70-80 gallon an hour range depending on altitude. 

Some the early performance numbers are a little suspect. this test report has some very good numbers. Trouble is it gives the gross weight of the plane at 6835lbs which is either a misprint or there is a whole lot of "stuff" not in the airplane. 

A P-40B with full internal tanks, full ammo and NO external tank could go 7624lbs. A P-40C with external tank could go just over 8000lbs. 

http://www.wwiiaircraftperformance.org/P-40/P-40B_41-5205_PHQ-M-19-1227-A.pdf

Some of the P-40s 'success' in North Africa and with the AVG came from over-boosting the engines in service. This only worked at low altitudes and could not be used at the altitudes the bombers were flying (the supercharger simply would NOT supply the higher pressure at those altitudes.) 

P-40s climb, unless being over boosted (or running light, ie little ammo or fuel) at low altitudes is best described as mediocre and falling to dismal at higher (in this case 15,000ft and above) altitudes. 

A lot is made of speed and while I don't subscribe to the view that is as unimportant as some do it, others focus on it to exclusion of rate of climb. Rate of climb, while not linear, is an indication of acceleration and/or the excess power available to to sustain speed through maneuvers. The Bf 109 gun boats lost very little speed it is true, but they lost rate of climb (and losses in rate of climb tend to carry through to the higher altitudes. a 10% loss in rate of climb at sea level is often a 15-20% loss in rate of climb in the 20-30,000ft range) and turning ability. 

An equipped, loaded P-40B at 15-20,000ft is no match for a 109. And you can't escort bombers flying at 12-15,000ft by flying at 6-9,000ft. 


and as always, _drop tanks are for getting you in, internal fuel is for getting you out_. adding drop tanks but not adding internal fuel doesn't do a lot for radius past a certain point.


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## Glider (Mar 3, 2015)

Balljoint said:


> Just what an up-engined P-40 could be is a bit nebulous. And, with enough fuel to get home, so is performance. But the P-40 could well be superior in the vertical in that it maintained rather good roll rate ate high speeds while ME-109 had high roll control forces and suspect structural integrity at speed. Thus the P-40 might well be able to reach more favorable altitudes for escape or combat.


The P40 had a very poor climb and would never win in a vertical combat. It was also poor at altitude.


> Overall, the P-40 had been bypassed regarding performance. But, with select tactics taking advantage of the LW fixation on the bombers, the P-40 would have been better than no help at all during the early days.


Overall the P40 had been bypassed in performance and would have been at a serious disadvantage, remember the defenders have the fixation with the bombers, to protect them


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## stona (Mar 3, 2015)

Glider said:


> The P40 had a very poor climb and would never win in a vertical combat. It was also poor at altitude.
> Overall the P40 had been bypassed in performance and would have been at a serious disadvantage,



It certainly would. It was seriously out classed in North Africa, and the Luftwaffe rarely had more than 30-40 serviceable Bf 109s in the entire theatre at any given time. It also had serious limitations on fuel and an inability to complete the training of new pilots arriving from the schools. Despite this it wreaked havoc on the Hurricanes and P 40s of the RAF whenever they were encountered. Flying a defensive circle is not an option for escorts protecting bombers. The situation in NW Europe would have been rather different and much the worse.

The real answer to the question is that without some serious alteration in thinking before the war the RAF simply didn't have, nor could it acquire, a suitable aircraft to act as an escort to daylight bombers in 1941. It must have been something considered at the time with the resultant switch to night time operations.

I certainly wouldn't fancy flying a 1941 P-40 against the Bf 109 F, I'd just about consider myself having a chance in a Spitfire V. The arrival of the Fw 190 late in 1941/early 1942 only makes things a lot worse.

Cheers

Steve


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## gjs238 (Mar 3, 2015)

So early in the war, certainly in the southern hemisphere, allied pilots had difficulty letting go of great war tactics (in general), (others such as the AVG figured this out.)

Were MTO pilots also slow to adapt?


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## Glider (Mar 3, 2015)

gjs238 said:


> So early in the war, certainly in the southern hemisphere, allied pilots had difficulty letting go of great war tactics (in general), (others such as the AVG figured this out.)
> 
> Were MTO pilots also slow to adapt?



I admit to not understanding this


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## pbehn (Mar 3, 2015)

An escort fighter that has good dive performance but poor climb is in a poor situation doing what it is supposed to do. In my opinion the advantage lies with the escorts, they dont have to win inm a dogfight just stop the enemy getting to the bombers however hard to do if you have a speed and performance at altitude disadvantage.


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## Shortround6 (Mar 3, 2015)

You are correct. The escorts don't have to be superior to the defenders but they have to be _good enough_ to stop the majority of the attackers from reaching the bombers (gaining good firing positions). They also have to be _good enough_ not to loose too many of the escorts per mission. This is a campaign and not a single raid or series of a few raids. Loose too many escort fighters too quickly and the campaign will be stopped or suspended. 

Defenders, if they have superior (enough superior) climb/altitude performance, can use altitude and trade it for speed on the attack runs, They don't have to do steep dives, just trade altitude for speed. A poor climbing escort is going to be in trouble trying to counter it.


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## pbehn (Mar 3, 2015)

Shortround6 said:


> You are correct. The escorts don't have to be superior to the defenders but they have to be _good enough_ to stop the majority of the attackers from reaching the bombers (gaining good firing positions). They also have to be _good enough_ not to loose too many of the escorts per mission. This is a campaign and not a single raid or series of a few raids. Loose too many escort fighters too quickly and the campaign will be stopped or suspended.
> 
> Defenders, if they have superior (enough superior) climb/altitude performance, can use altitude and trade it for speed on the attack runs, They don't have to do steep dives, just trade altitude for speed. A poor climbing escort is going to be in trouble trying to counter it.


As I see it the escorts just have to stay in the fight, almost regardless of the A/C involved it is impossible to shoot down a bomber with a fighter on your tail, I believe that eventually was the main philosophy on US missions. The defensive fire of the formation coupled with escorts made the Germans job difficult to almost impossible.


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## gjs238 (Mar 3, 2015)

gjs238 said:


> So early in the war, certainly in the southern hemisphere, allied pilots had difficulty letting go of great war tactics (in general), (others such as the AVG figured this out.)
> 
> Were MTO pilots also slow to adapt?



Don't get into a turning fight.
Use boom and zoom - energy fighting tactics.


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## stona (Mar 3, 2015)

gjs238 said:


> Don't get into a turning fight.
> Use boom and zoom - energy fighting tactics.



How is a P-40B/Tomahawk II going to do that against a Bf 109 (F would be the 1941 model) which has much superior altitude performance. The Germans could decide whether or not to initiate combat and need only do so on favourable terms. They could also disengage vertically whenever they chose. The P-40 has little chance of preventing the bombers being attacked and should the Luftwaffe fighters turn on it, little chance of doing anything to survive that they didn't try historically. In North Africa this was usually a defensive circle, just as another unsuccessful escort, the Bf 110, had done a year previously during the BoB. 

I've read first hand accounts of the frustration of Merlin powered Hurricane pilots watching Bf 109 Es (not Fs) leaving contrails several thousand feet above them, completely safe with their altitude advantage.

Cheers

Steve


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## gjs238 (Mar 3, 2015)

stona said:


> How is a P-40B/Tomahawk II going to do that against a Bf 109 (F would be the 1941 model) which has much superior altitude performance. The Germans could decide whether or not to initiate combat and need only do so on favourable terms. They could also disengage vertically whenever they chose. The P-40 has little chance of preventing the bombers being attacked and should the Luftwaffe fighters turn on it, little chance of doing anything to survive that they didn't try historically. In North Africa this was usually a defensive circle, just as another unsuccessful escort, the Bf 110, had done a year previously during the BoB.
> 
> I've read first hand accounts of the frustration of Merlin powered Hurricane pilots watching Bf 109 Es (not Fs) leaving contrails several thousand feet above them, completely safe with their altitude advantage.
> 
> ...



???
I never said it could.
I was asking if MTO allied fighter pilots were getting hammered due in any way to dated tactics?



gjs238 said:


> So early in the war, certainly in the southern hemisphere, allied pilots had difficulty letting go of great war tactics (in general), (others such as the AVG figured this out.)
> 
> Were MTO pilots also slow to adapt?





Glider said:


> I admit to not understanding this





gjs238 said:


> Don't get into a turning fight.
> Use boom and zoom - energy fighting tactics.


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## Shortround6 (Mar 3, 2015)

pbehn said:


> As I see it the escorts just have to stay in the fight, almost regardless of the A/C involved it is impossible to shoot down a bomber with a fighter on your tail, I believe that eventually was the main philosophy on US missions. The defensive fire of the formation coupled with escorts made the Germans job difficult to almost impossible.



Yes, it is hard to shoot down a bomber with a fighter on you tail _but_ if the interceptor _starts_ several thousand feet above the escort fighter and can use the height advantage as a speed advantage. It is hard to stay on a fighters tail if it is doing 30-60mph faster than than the plane chasing it. If attacking from above the attackers can also use a modified boom and zoom. After going through the fighters (don't stop and get in a turning fight with them) hit the bombers (one pass) and then do a curved climb back to a higher altitude. The plane with a good climb rate can both turn (not sharp but enough to make a pursuer face a defection shot) and climb. A poor climber can do one or other. 
The escort fighter _has_ to be close in performance to the interceptors, just showing up is not enough.


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## stona (Mar 4, 2015)

gjs238 said:


> ???
> I never said it could.
> I was asking if MTO allied fighter pilots were getting hammered due in any way to dated tactics?



The allied pilots tried to fight to the advantages of their aircraft. In the MTO neither the P-40 nor the Hurricane could compete with the 'Friederich' using so called boom and zoom tactics. A slow, horizontal, turning fight was their best bet, if the German pilots would oblige, hence the defensive circle.

The escort fighters shouldn't find themselves in the position of the 'fighter on the tail' of an aircraft attacking the bombers. Their job was to prevent the interceptors getting into a position from which they could launch an attack, ideally by breaking up the intercepting formation with their own attack(s). The idea that P-40s could do this in the face of a determined effort by Bf 109 Fs doesn't wash with me. I believe losses would have been prohibitive.
The close escort implied in the 'fighter on the tail' scenario was repeatedly shown not to work. I wouldn't fancy being the US fighter on the tail of a Luftwaffe fighter attacking a formation of Boeings and exposing myself to their defensive fire in the same way as the German aircraft. Typically air gunners fire at anything that appears a threat, certainly anything that points its nose in their direction, friend or foe, and there are numerous accounts of precisely this from 8th AF fighter pilots. Escorting fighters stayed well out of the range of their bomber formation. Even formatting on a straggler, to offer it protection, could be dangerous

Cheers

Steve


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## pbehn (Mar 4, 2015)

Shortround6 said:


> Yes, it is hard to shoot down a bomber with a fighter on you tail _but_ if the interceptor _starts_ several thousand feet above the escort fighter and can use the height advantage as a speed advantage. It is hard to stay on a fighters tail if it is doing 30-60mph faster than than the plane chasing it. If attacking from above the attackers can also use a modified boom and zoom. After going through the fighters (don't stop and get in a turning fight with them) hit the bombers (one pass) and then do a curved climb back to a higher altitude. The plane with a good climb rate can both turn (not sharp but enough to make a pursuer face a defection shot) and climb. A poor climber can do one or other.
> The escort fighter _has_ to be close in performance to the interceptors, just showing up is not enough.



Agreed, just keeping the attacking planes up near maximum speed is a help, it took an average of 25 hits to take down a US bomber IIRC not so easy to do at maximum speed with someone following you.


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## stona (Mar 4, 2015)

pbehn said:


> Agreed, just keeping the attacking planes up near maximum speed is a help, it took an average of 25 hits to take down a US bomber IIRC not so easy to do at maximum speed with someone following you.



Can anyone provide a single instance in which an intercepting fighter was shot down, by an escort, off the tail of a bomber formation? I can't recall one. These battles (Luftwaffe/USAAF which is the only concerted daylight campaign we have for reference) took place over miles of air space, not hundreds of yards. There seems to be a misunderstanding about how escort fighters operated successfully.
Once and if the interceptors could evade or break through the defending escorts they only had to worry about the bombers defensive fire. I'd recommend Boiten and Bowman's 'Battles with the Luftwaffe' which tells the story of the US strategic bombing offensive in Europe from both sides.

Cheers

Steve


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## kool kitty89 (Mar 4, 2015)

Shortround6 said:


> The problem is NOT getting *in.* It is getting *out.* A few 109 recon planes carried a tank under each wing (usually without wing guns?) Spit might carry a 90 gallon drop tank (might go larger, 170 gallon ferry tank is out), both planes may/would need larger oil tanks.
> For a mission profile on the way in you have engine warm up and take off taking up fuel plus climb to altitude and forming up. SPits could top off fuselage tanks I think. Pump and piping would solve problem for 109 if not already fitted.
> That solves getting IN. Getting OUT has the combat allowance (how many minutes at combat power, how many minutes at max continuous or max climb or? ) and a high enough cruise speed back to the coast to _help_ keep from being bounced. For a Spit V using 16lbs of boost in combat every minute was worth 5 minutes at most economical cruise.
> Us planners figured how much fuel was needed to get back after dropping tanks, that was the _practical_ radius and _then_ they figured how to get enough external fuel on the planes to get to the radius distance. Plane limitaions sometimes got in the way on early planes. Please note that the external 52 gallon tank on the P-40 (and the under fuselage tank on the P-39) were to _restore_ fuel capacity _after_ fitting self sealing tanks.


This is all what I intended to imply before. Internal fuel capacity is critical, and if the Spitfire couldn't be expanded to have competitive (clean) range to the P-40 (or P-39 for that matter), there's no way it could have been a competent penetration/escort fighter.

On the allied end of things, especially in a 1941 scenario, things are pretty damn limited. 1942 somewhat less so, but still pretty tight.

Even if you include prototypes on the scene early enough to be considered for the role, it's still fairly limited. (and the Miles M.20 managed longer range than the Spit/Hurricane but was closer to the contemporary P-40 in weight class on top of lower speed)
British twin-engine fighter development might have had more promise had it gone in the long-range direction, but neither Gloster nor Westland's early war designs progressed in that direction ... or even entered production.

Had the export lightning not been botched/crippled (not just the turbo issue, but general mediocre conversion/optimization for non-turbo engines) they might have been compelling early-war options, especially for the somewhat lower alts RAF bombers were operating at.

Prior to the P-51 becoming available in numbers (with any engine), there's not too many options. And service ready P-47s or F4Us (hypothetically) wouldn't really be there much/any earlier either. (get into 1942/43 and you've got a lot more potential hypotheticals we've already been over -from Merlin XX powered mustangs to F4Us to P47s with earlier access to larger drop tanks, etc)







Koopernic said:


> If the RAF wants to run precision daylight raids into Germany proper it needs an escort fighter. The only aircraft that is available that can do the Job is the Curtiss P-40B (Tomahawk IIA) and it most certainly can do the job being the first P-40 with acceptable armour and protection. The P-40B is available from May 1941.
> 
> It has a range of 730 miles on internal fuel, 1270 if throttled back. That is 75% more than the Me 109F or Spitfire III or V. With a 75 gallon drop tank it has even more range.


The P-40C/Tomahawk IIB's performance degraded due to the protection on the P-40B being felt to be inadequate (at least by american planners). More advanced (and limited capacity) self-sealing tanks were introduced along with increased armor (including armor glass for the windshield) along with the belly shackle.

So climb/turn performance dropped significantly, speed dropped more modestly.



> The P-40's problem is that its larger airframe and relatively weak Allison V-1710 engine gave it an inferior power to weight ratio to the Spitfire and Me 109F2 which was worsened by the relatively low full throttle height of the Allison.


The V-1710's good specific fuel consumption at cruise was part of the key to the longer range on US aircraft (on top of aerodynamics and -mostly- fuel capacity) So some of the range advantage would be lost by using a merlin ... even in a hypothetical 1940/41 export model using British built engines. (or some other hypothetical like the UK licensing the hawk airframe several years earlier and developing it independently around the Merlin ... or just an indepdently developed British design for a similar goal -focus on escort isn't necessary, just some sort of long range duties from intruder to fighter bomber ... I suppose an argument for Hawker focusing on a more advanced faster/longer range Merlin-powered direct successor to the Hurricane -opposed to the Typhoon- could be relevant too)

The higher fuel capacity is still going to be a major advantage, though.



> Having said that I believe that Allison engine P-40/Tomahawk IIA would have been effective in substantially protecting the bombers by diverting the Luftwaffe's interceptors. It has to be remembered the Luftwaffe is stretched then as well.


For 1941 I'd still have to agree that ... inadequate or not, of existing aircraft available to the British, the Tomahawk IIA and IIB were the closest things to esxort fighters they had on hand. But inadequate escort fighters are not going to cut it either. (marginally adequate could manage though ... and it's unclear whether modified Spit Vs might have crammed in enough internal fuel to fit the bill there in the interim -let alone hypothetical long-range Spit IX's in 1942)

Or ... maybe ... maybe the Typhoon could have been converted into the medium alt escort role if it had enough internal fuel and drop tanks capacity added.

That or, again, better luck with the P-38 export model development. (and showing enough promise to make procurement over more export P-40s and P-39s more attractive ... particularly to the point of meriting second-sourcing the P-38)



> We know that a pair of suspended canon "gondola guns" on the Me 109G impacted speed less than 1%. (See Kurfurst.org) and so I argue that the impact on spitfire speed would have been negligible since the guns were being moved (not added as in the German case).
> 
> Such a Spitfire would substantially out range even the P-51D with tail tank.


Hmm ... that's a more interestion suggestion, but do remember the Hispano was a larger/heavier weapon than the MG-151. (the underwing pods on the P-39Q would probably be more comparable than hispano gun pods)

Did the recon spits even use self sealing tanks for the extended range? (that'd be a major issue to consider)





Shortround6 said:


> Yes, it is hard to shoot down a bomber with a fighter on you tail _but_ if the interceptor _starts_ several thousand feet above the escort fighter and can use the height advantage as a speed advantage. It is hard to stay on a fighters tail if it is doing 30-60mph faster than than the plane chasing it. If attacking from above the attackers can also use a modified boom and zoom. After going through the fighters (don't stop and get in a turning fight with them) hit the bombers (one pass) and then do a curved climb back to a higher altitude. The plane with a good climb rate can both turn (not sharp but enough to make a pursuer face a defection shot) and climb. A poor climber can do one or other.
> The escort fighter _has_ to be close in performance to the interceptors, just showing up is not enough.


With similar technology, you're going to pretty consistently have superior 1 to 1 performance for short range interceptors over long range escort fighters. 

So you NEED a technological edge to manage competent escort fighters (or long range roaming intruders/penetration fighters) that are relatively close to even terms with enemy interceptors.


Short range escort is another matter entirely and doesn't skew performance requirements nearly as much.


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## Vincenzo (Mar 4, 2015)

HoHun calculations sustained turn rate
109F-4 
S.L. 21.5°/sec, 3 km 17.5°/sec, 6 km 13°/sec, 9 km 7.5°/sec
P-40C (44" Hg)
19°/sec, 15.5°/sec, 11.5°/sec, 6°/sec
P-40E (44" Hg)
17°/sec, 12.5°/sec, 7°/sec, too high
Hurricane IIB (+12/9 lbs)
22°/sec, 18°/sec, 13°/sec, 8°/sec
Spit VC (+16 lbs)
21.5°/sec, 18°/sec, 12.5°/sec, 7°/sec


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## pbehn (Mar 4, 2015)

stona said:


> Can anyone provide a single instance in which an intercepting fighter was shot down, by an escort, off the tail of a bomber formation? I can't recall one. These battles (Luftwaffe/USAAF which is the only concerted daylight campaign we have for reference) took place over miles of air space, not hundreds of yards. There seems to be a misunderstanding about how escort fighters operated successfully.
> Once and if the interceptors could evade or break through the defending escorts they only had to worry about the bombers defensive fire. I'd recommend Boiten and Bowman's 'Battles with the Luftwaffe' which tells the story of the US strategic bombing offensive in Europe from both sides.
> 
> Cheers
> ...



During the Battle of Britain a hurricane pilot was about to shoot at a bomber when the bomber took cannon hits from a 109 trying to down the Hurricane. Even during the BoB which was a short distance in comparison the object of Park was to strip away the escorts, just the presence of an escort formation makes foring up for the attack difficult.


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## stona (Mar 4, 2015)

pbehn said:


> During the Battle of Britain a hurricane pilot was about to shoot at a bomber when the bomber took cannon hits from a 109 trying to down the Hurricane.



The Luftwaffe escorts in the BoB, unlike their 8th AF counterparts in the strategic offensive against Germany were 'tied' to the bombers in a tactically limiting (some would later say idiotic) close escort role. Galland later said that it was this denial of freedom to manoeuvre to which he was referring with his famous 'give me a squadron of Spitfires' quip. Rather than being allowed to range ahead of the bombers, attacking and breaking up RAF formations they were forced to fly close to, usually above, the bombers and attempt to protect them at relatively close quarters. 

Apart from that this example illustrates my point. Not only did the escort fighter manage to inflict damage on the bomber it was supposed to be protecting, it could have been the victim of the defensive fire of the 'friendly' bomber too.

Luftwaffe interceptors later had only to evade or defeat the escorts to get a run at the bombers. Easier said than done. Earlier I said they then needed only to worry about the bombers defensive fire, but they also braved 'friendly' flak.

Cheers

Steve


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## Glider (Mar 4, 2015)

gjs238 said:


> Don't get into a turning fight.
> Use boom and zoom - energy fighting tactics.



Thanks for the clarification. If the main advantage of your aircraft is in its general agility then play to your strengths. If your aircraft has the advantage in dive and climb, then again play to your strengths. The trick is not getting confused when considering who your fighting. 

In Europe the RAF normally had the advantage in agility over the Luftwaffe but when they tried it against the IJAAF they came seriously unstuck. In the Far East the RAF normally had the advantage in boom and zoom, in Europe the Luftwaffe had that advantage


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## Greyman (Mar 4, 2015)

stona said:


> Can anyone provide a single instance in which an intercepting fighter was shot down, by an escort, off the tail of a bomber formation? I can't recall one.



Your overall point is sound but the sort of incident you describe happened all the time.

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## stona (Mar 4, 2015)

Greyman said:


> Your overall point is sound but the sort of incident you describe happened all the time.



Any first hand accounts? I'm referring to the US daylight campaign and interceptions by the Luftwaffe. As I said, I can't recall a single example. I've read tens (maybe even hundreds) of combat reports and many published recollections and memoirs of this campaign. 

My memory is not infallible but to say that this sort of incident occurred all the time simply doesn't fit the facts. The facts are that most US escort combats with the Jagdwaffe's would be interceptors took place literally miles away from the bomber formations. Stragglers or damaged bombers might receive a 'close' escort. Close in this context meaning within maybe 1,000 yards.

Cheers

Steve


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## Greyman (Mar 4, 2015)

The later US daylight campaigns aren't my area of 'study' whatsoever. A quick look over at wwiiaircraftperformance turned up this combat report.

Having said that, what comparatively little I've read on that portion of the air war - the tools and tactics used by the USAAF certainly seems to have made it a far less common occurrence as compared to, say, the Battle of France.

EDIT: spending a couple more minutes looking at the combat reports on that site and I'm seeing many cases.

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## pbehn (Mar 4, 2015)

I said this

*Agreed, just keeping the attacking planes up near maximum speed is a help, it took an average of 25 hits to take down a US bomber IIRC not so easy to do at maximum speed with someone following you.
*



stona said:


> Can anyone provide a single instance in which an intercepting fighter was shot down, by an escort, off the tail of a bomber formation? I can't recall one. These battles (Luftwaffe/USAAF which is the only concerted daylight campaign we have for reference) took place over miles of air space, not hundreds of yards. There seems to be a misunderstanding about how escort fighters operated successfully.
> Once and if the interceptors could evade or break through the defending escorts they only had to worry about the bombers defensive fire. I'd recommend Boiten and Bowman's 'Battles with the Luftwaffe' which tells the story of the US strategic bombing offensive in Europe from both sides.
> 
> Cheers
> ...



I didnt say that the interceptor was on the tail of the bomber I said the escort was on the tail of the interceptor. In the case a bomber or group was caught without escorts they would attack from the above and behind or from the beam as they saw fit. The job of the escort is to get the bombers to the target and back, the job of the interceptor is to eventually get the bombers. Dogfights between the fighters almost regardless of losses are a victory for the escorts so long as you can keep it up throughout the mission.

Here is some gun cam film of a Bf110 attacking a B17, the Bf110 was withdrawn as it coulnt survive in the presence of S/E escort fighters just as it couldnt perform as an escort itself in the BoB.


_View: https://www.youtube.com/watch?v=iyJAlsJAbZw_


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## pbehn (Mar 4, 2015)

stona said:


> The Luftwaffe escorts in the BoB, unlike their 8th AF counterparts in the strategic offensive against Germany were 'tied' to the bombers in a tactically limiting (some would later say idiotic) close escort role. Galland later said that it was this denial of freedom to manoeuvre to which he was referring with his famous 'give me a squadron of Spitfires' quip. Rather than being allowed to range ahead of the bombers, attacking and breaking up RAF formations they were forced to fly close to, usually above, the bombers and attempt to protect them at relatively close quarters.
> 
> Apart from that this example illustrates my point. Not only did the escort fighter manage to inflict damage on the bomber it was supposed to be protecting, it could have been the victim of the defensive fire of the 'friendly' bomber too.
> 
> ...



The massed raids of the LW during the BoB were short lived, the escorts were ordered by Goering to stay with the bombers during the daylight raids on London handing the tactical advantage to the RAF, the only role the Bf 100 served was being easier to down than a bomber, Goering sacrificed all its plus points. Attacking and breaking up RAF formations is exactly what I was referring to. 

If the US did not have long range escorts and the Germans had a plane like the Mosquito it could just cruise up behind the bombing formation and pick the bombers off out of range of 0.5" Mg defensive fire but within range of 20mm cannon. No one would send mosquitos out to face a bomber force with escorts but with no escorts they would be devastating, more so than the Bf110 was.


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## Shortround6 (Mar 4, 2015)

pbehn said:


> If the US did not have long range escorts and the Germans had a plane like the Mosquito it could just cruise up behind the bombing formation and pick the bombers off out of range of 0.5" Mg defensive fire but within range of 20mm cannon. No one would send mosquitos out to face a bomber force with escorts but with no escorts they would be devastating, more so than the Bf110 was.



Nice theory but wouldn't actually work. Effective range of the .50cal and most 20mm guns was actually about the same. Some 20mm guns actually had less effective range. 

Now a twin engine fighter carrying a heavy battery of 20mm guns might very well be more effective than several different gunners each trying to direct 2 guns apiece onto the same target but there was no safe zone/range where a fighter could _sit_ and fire at a bomber.


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## kool kitty89 (Mar 5, 2015)

Glider said:


> Thanks for the clarification. If the main advantage of your aircraft is in its general agility then play to your strengths. If your aircraft has the advantage in dive and climb, then again play to your strengths. The trick is not getting confused when considering who your fighting.
> 
> In Europe the RAF normally had the advantage in agility over the Luftwaffe but when they tried it against the IJAAF they came seriously unstuck. In the Far East the RAF normally had the advantage in boom and zoom, in Europe the Luftwaffe had that advantage


One addition to the previous mentioned of the AVG's success with the P-40 that I forgot to mention was that they fairly routinely pushed the engines beyond officially accepted operating limits, pushing the early V-1710-33s into almost 1300 HP both overboosting and overspeeding the engines for higher power and higher FTH and suffering higher mechanical wear rates as a consequence. I'm not sure on the use of that on their later P-40s and post-peral harobor operation of the Flying Tigers, but I suspect they similarly pushed the aircraft. (granted, other units in the far east and MTO were known for overspeeding and overboosting V-1710s too ... and it likely shortened the engine life but the Allison did seem to tolerate being pushed beyond spec more than contemporary merlins -albeit that may in part have been due to more conservative ratings and slower rate of official WER clearance -despiration during the BoB probably drove some of that experimentation on the Merlin end)

Would have been interesting if the British had had enough Tomahawks during the BoB to make them worth pressing into service as interceptors. (longer endurance would have made roaming patrols more feasible too)





Vincenzo said:


> HoHun calculations sustained turn rate
> 109F-4
> S.L. 21.5°/sec, 3 km 17.5°/sec, 6 km 13°/sec, 9 km 7.5°/sec
> P-40C (44" Hg)
> ...


I remember a discussion that pointed out a number of the examples of P-40s showing turning (or other performance) advantages over the 109s in the MTO were at low altitude with engine overboosting employed. (not 'stripper' P-40s, but just pushing the engine beyond spec)




Shortround6 said:


> Nice theory but wouldn't actually work. Effective range of the .50cal and most 20mm guns was actually about the same. Some 20mm guns actually had less effective range.
> 
> Now a twin engine fighter carrying a heavy battery of 20mm guns might very well be more effective than several different gunners each trying to direct 2 guns apiece onto the same target but there was no safe zone/range where a fighter could _sit_ and fire at a bomber.


Against RAF bombers sporting .303 turrets they could be beyond range ... or same for actual mosquitos vs German bombers sporting rifle caliber and heavy machine gunes. (possibly 20 mms too given the longer range and shorter slight time of the hispano)

Against .50 BMGs, the Germans only had the Mk-103 and 15 mm MG-151 to out-range them, but the former was too heavy/high recoil for most aircraft (or not worth the trade in Mk-108 firepower -possibly the case on the Me-262) and the latter was too weak to be really affective against heavy bombers ... probably. (would have been interesting to see how 4x MG-151/15 fared on the Fw-190 with HEI/API type ammo)


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## stona (Mar 5, 2015)

"Agreed, just keeping the attacking planes up near maximum speed is a help, it took an average of 25 hits to take down a US bomber IIRC not so easy to do at maximum speed with someone following you."

Some have been suggesting, including one perfectly valid example given from the BoB, albeit in a different tactical situation, that it was commonplace for escorts to shoot down interceptors off the bombers tails. I do not believe this to be the case, as I haven't seen any evidence for this being a common occurrence.
For an escort fighter, pursuing a Luftwaffe fighter into the defensive fire of a US bomber box would be as dangerous for it as the interceptor. As the interceptors made their final attack on the bombers they would not usually have 'someone following' them

US escort fighters tried to engage the Luftwaffe interceptors well before they attacked the bombers. Luftwaffe interceptors tried to avoid the escorts, not fight them. Interceptors fighting escorts was a victory for the attackers.
The sky is a big place. These confrontations took place over many miles. 

Cheers

Steve


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## gjs238 (Mar 5, 2015)

kool kitty89 said:


> One addition to the previous mentioned of the AVG's success with the P-40 that I forgot to mention was that they fairly routinely pushed the engines beyond officially accepted operating limits, pushing the early V-1710-33s into almost 1300 HP both overboosting and overspeeding the engines for higher power and higher FTH and suffering higher mechanical wear rates as a consequence. I'm not sure on the use of that on their later P-40s and post-peral harobor operation of the Flying Tigers, but I suspect they similarly pushed the aircraft. (granted, other units in the far east and MTO were known for overspeeding and overboosting V-1710s too ... and it likely shortened the engine life but the Allison did seem to tolerate being pushed beyond spec more than contemporary merlins -albeit that may in part have been due to more conservative ratings and slower rate of official WER clearance -despiration during the BoB probably drove some of that experimentation on the Merlin end)



I remember reading here that the Soviets were notorious for pushing the American engines (some crew chiefs would surely say abusing)


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## gjs238 (Mar 5, 2015)

stona said:


> Interceptors fighting escorts was a victory for the attackers.



By that you mean, Interceptors fighting escorts was a victory for the *defenders*. (i.e., the escorts)?


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## pbehn (Mar 5, 2015)

Who suggested that attackers were routinely shot off the tail of bombers?


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## stona (Mar 5, 2015)

gjs238 said:


> By that you mean, Interceptors fighting escorts was a victory for the *defenders*. (i.e., the escorts)?



Yes I did....slip of the senses.

The Luftwaffe declined to intercept US escorts close to the European coast, forcing them to jettison drop tanks, something the Americans expected them to do, for precisely this reason.

Cheers

Steve


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## gjs238 (Mar 5, 2015)

stona said:


> Yes I did....slip of the senses.
> 
> The Luftwaffe declined to intercept US escorts close to the European coast, forcing them to jettison drop tanks, something the Americans expected them to do, for precisely this reason.
> 
> ...



Wonder if single-engine fighters intercepted the escorts early in their flight, forcing them to jettison drop tanks, if that would have freed up twin-engine fighters to better intercept the bombers unmolested by escorts?


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## stona (Mar 5, 2015)

gjs238 said:


> Wonder if single-engine fighters intercepted the escorts early in their flight, forcing them to jettison drop tanks, if that would have freed up twin-engine fighters to better intercept the bombers unmolested by escorts?



Generaloberst Weisse (commanding 'Befehlhaber Mitte') suggested in November 1943, as the US escorts were significantly increasing their range, that single engine types should engage the US escorts allowing heavy fighters/destroyers to engage the bombers. He also suggested that some heavy fighter squadrons should convert to single engine types to provide an escort to the heavy fighters. One officer suggested that the entire fighter force should convert! Finally Weisse conceded that the only aircraft available to escort the heavy fighters (he recognised that they could not survive alone) were Hermann's 'wild boar' fighters.
The problem was a lack of aircraft and pilots to fly them. It was General Schmid who finally turned down Weisse's proposal, saying that there were simply not enough single engine fighters available to 'hold off' the US escorts whilst the heavy fighters engaged the bombers. 

About a month later, in December, Galland and the staff of Jagdkorps I issued a report explaining why the Germans were failing against these new, escorted, US formations.

a) the weather

b) the considerable inferiority of German strength.

c) the impossibility of gathering sufficient strength in an area because of time and distance limitations; result: weak and dispersed fighter attacks.

The report didn't mention the increasing unwillingness of the Luftwaffe fighters to even attempt an attack on heavily escorted formations. The US escorts often did their job just by being there.

Cheers

Steve


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## Glider (Mar 5, 2015)

kool kitty89 said:


> One addition to the previous mentioned of the AVG's success with the P-40 that I forgot to mention was that they fairly routinely pushed the engines beyond officially accepted operating limits, pushing the early V-1710-33s into almost 1300 HP both overboosting and overspeeding the engines for higher power and higher FTH and suffering higher mechanical wear rates as a consequence. I'm not sure on the use of that on their later P-40s and post-peral harobor operation of the Flying Tigers, but I suspect they similarly pushed the aircraft. (granted, other units in the far east and MTO were known for overspeeding and overboosting V-1710s too ... and it likely shortened the engine life but the Allison did seem to tolerate being pushed beyond spec more than contemporary merlins -albeit that may in part have been due to more conservative ratings and slower rate of official WER clearance -despiration during the BoB probably drove some of that experimentation on the Merlin end)
> 
> Would have been interesting if the British had had enough Tomahawks during the BoB to make them worth pressing into service as interceptors. (longer endurance would have made roaming patrols more feasible too)



I have never heard of the RAF pushing the Merlin beyond its normal operating limits with the exception of 12lb boost being used for longer than five minutes. That did happen a number of times.

As for the P40 in the BOB it was never going to happen being nine months too late for the battle. Even then it lacked climb, performance, protection, agility and altitude performance. The engine only produced 1040hp the 12lb boost Merlin was looking at 1,300hp a significant difference. A P40B could hold its own up to approx. 15,000ft but above that forget it and I think that only made service in mid 41..


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## tomo pauk (Mar 5, 2015)

The 1st production P-40 was delivered at June 1940, the 1st Tomahawk I was delivered (still it is in the USA) at Sept 1940. Production-wise, they might qualify for the BoB, but obviously not when we count in the training and logistic needs.
The early P-40 will climb better than any subsequent P-40, being far lighter. With 120 US gals, the P-40 was at 6800 lbs and doing 357-360 mph tests. 
Their engines were making 1040 HP at ~13500 ft; at 16300 ft it was good for 980 HP vs. 1030 HP of the Merlin III. The Db 601A (with newer supercharger version) was doing 1006 HP at 14746 ft (1020 PS at 4.5 km); makes ~960 HP at 16300 ft. Version with older SC was worse by some 1500 ft (500 m) in the altitude power.

Protection of 1940 BoB fighters was not equal with what fighters carried in 1941, let alone, say, in 1943.


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## Shortround6 (Mar 5, 2015)

The P-40s big problem was weight. A P-40B with 120 US gallons of fuel went almost 7200lbs. A Spitfire I or II was under 6200lbs. 
The P-40 is going to need 16% more power just equal the Power to weight ratios of the Spitfires and that is if you stuck A Merlin in it. Over revving the Allison at altitudes above 13-14,000ft is NOT going to get you 16% more power. The P-40 also had a higher wing loading. Unless you have anti-gravity paint the P-40 is NOT going to come close to a Spitfire for altitude performance.


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## Glider (Mar 5, 2015)

I admit that I only have the figures on the N Williams site but they seem to give the Tomahawk I 1020hp at 11,600ft and performance is poor. This is considerably less power than the then current Merlin. . Naturally the protection of a 1941 fighter is less than a 1943 fighter but the protection was often sufficient against the LMG and I understand that the Tomahawk I of 1940 had no protection and only 2 x HMG and 2 x LMG.


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## tomo pauk (Mar 5, 2015)

The Spitfire is not the only aircraft that fought during the BoB. Early P-40 does have it's shortcomings, but it's performance was closer to the Spit and 109E, than to the Hurricanes and Bf 110.


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## Balljoint (Mar 5, 2015)

The P-40 didn’t have the appropriate engine early in the war. However, like the successor P-51, it had an airframe that would do the job with a better engine. 

P-40 Performance Tests

If it was employed, the improvements would come …maybe.


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## Shortround6 (Mar 5, 2015)

> I admit that I only have the figures on the N Williams site but they seem to give the Tomahawk I 1020hp at 11,600ft and performance is poor.



That power seems low and the altitude seems low. 

There were a variety of Tomahawks and not all corresponded _exactly_ to a particular P-40 model (and you had P-40s, P-40Bs, and P-40Cs), The very early ones, American, ex-French and early British (?) had NO protection let alone equal protection to late 1940 British or German fighters. I am not sure how many single gun in each wing Tomahawks the British got because I believe the ex-french aircraft had two guns in each wing.


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## Koopernic (Mar 5, 2015)

kool kitty89 said:


> snip
> 
> The P-40C/Tomahawk IIB's performance degraded due to the protection on the P-40B being felt to be inadequate (at least by american planners). More advanced (and limited capacity) self-sealing tanks were introduced along with increased armor (including armor glass for the windshield) along with the belly shackle.
> 
> ...



The Spitfire had a "D" section wing structure whereby thick skins of the leading edge and main spar formed the primary load carrying structure. Reginald Mitchell and Supermarines had long recognised that this provided an exceptionally large storage space for fuel and had intended to use this on several other designs.

"despite having a proposed wingspan of 97 feet, it nevertheless was to make use of a single spar wing supported by torsion-resistant leading edge boxes on a similar principle to that developed for the Spitfire; and, unusually for its time, fuel was to be carried in these leading edges, thereby saving weight, and with the tanks adding to the rigidity of the wing. Behind this spar component, the structure allowed sufficient room for the main stowage of bombs, thus avoiding the need for conventional tiered bomb stowage which would have substantially increased the fuselage cross-section and its drag component – another example of Mitchell ingenuity."






From Drawing 31600 Sheets 5/6 supermarine 318 to air ministry B.12/36 showing leading edge tanks and stowage of 27x500 lb/29x250 lb bombs.
R J Mitchell and Supermarine: R. J. Mitchell’s Bomber and his death.

Nevertheless its interesting to note that many of the engineering decisions made by RJ Mitchel and J Smith over ruled the possibility of using the full wing for fuel storage. For instance Mitchell did not like the idea of synchronised cowling machine guns or a motor gun because it inevitably 'thickened' the fuselage. Had weaponry been mounted on the cowling, between the V block or in the wing roots (as in the Fw 190, He 112 and several Soviet aircraft) the wings might have been left clear. There were no doubt other issues such as lack of a suitable guns, the inability of Merlin engine propeller combination to take this without re-engineering. The US 0.5" Browning with hydraulic hydrostatic interrupter gear in the wing roots seems the easiest to me. Likewise the rejection of 'gondola' hispano weapons on the Spitfire by J Smith.

It seems neither man was motivated by the Air Ministry to increase the range of their aircraft. 

Somewhat more puzzling is the lack of a long range escort specification by the RAF unless once considers the Typhoon and its teething problems. 

H Dowding Watson Watt came up with Radar and a grand plan for defence of their island as early as 1934 having developed and deployed a completely integrated defence system by 1939. Couldn't someone see that the enemy could do the same and that their B.12/36 specification (Stirling, Halifax BI, Supermarine 317 or 318 etc) would be similarly vulnerable? I suspect had they looked at this possibility the supermarine 318 would have been the clear winner over Stirling and Halifax due to its much higher speed (330mph), a speed while not as fast as a German fighter, would have made interception in force less likely or of less duration and simplified the task of any escort fighter.

The Germans have an excuse since radar in Germany was an invention of the signals branch of the Germany navy who applied ideas on sonar to radio, they didn't go out of their way to inform the Luftwaffe and tried to lock their suppliers into exclusivity.

The range of the P-51 it seems to me came down to 'serendipity' of the NA sales and engineering team. Using the laminar profiles and their large capacity, keeping the radiators and their plumbing away from using space in the wings.


My understanding is that the Tomahawk IIA (P-40B) carried 131 Imp Gallons (160 US Gallons) but that later versions dropped down to 120 Imp gallons) This is still well above the Spitfire III/V's 85 gallons and similar for P-39.

While I of course accept the altitude limitations of the Allison P-40B I suspect the two speed Merlin XX would have given the power, altitude power and competitive cruise capability to the Allison to be acceptable in say a P-40B or P-40C airframe. I would imagine that the LF gear on the Merlin XX would also aid cruising ability at altitude.

While the Merlin P-40B or C would never have the power to weight ratio of the Spitfire V I note that the Allies did have a technological advantage and that is superior fuel and that the Performance of the DB601/605 series always lagged the Merlin by 15%-20% AFAIK. The later Me 109F4 and 109G1 are impossible to match with a single stage Merlin/p40 but there is a window between mid 1941 to early 1942 where a Merlin XX P-40B+ could be in the game against the Me 109 and Me 110 types enough to reduce bomber losses. The appearance of the Me 109G and the Fw 190A3/A4 would end that, I would think decisively, in the Luftwaffe's favour. However mid 1942 also might have allowed a hypothetical Merlin XX/ Packard V-1650-1 powered Mustang or long range Spitfire VII or VIII to partially take over (they had the "C" wing and thus wing tanks, the IX had the "C: wing but lacked the wing tanks)

I see these missions as not being too deep into Germany and escorted by the shorter ranged Spitfires 2/3rds of their Journey.


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## Greyman (Mar 5, 2015)

stona said:


> I'm referring to the US daylight campaign and interceptions by the Luftwaffe.



Outside of what you were referring to - but I thought these images were pretty striking:

Bf 109 on a Spitfire on a Ju 88
Mustang on a Fw 190 on a Lancaster






*EDIT:* ten months later - new image (P-51 on a Bf 109 on a B-17)

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## kool kitty89 (Mar 6, 2015)

Glider said:


> I have never heard of the RAF pushing the Merlin beyond its normal operating limits with the exception of 12lb boost being used for longer than five minutes. That did happen a number of times.
> 
> As for the P40 in the BOB it was never going to happen being nine months too late for the battle. Even then it lacked climb, performance, protection, agility and altitude performance. The engine only produced 1040hp the 12lb boost Merlin was looking at 1,300hp a significant difference. A P40B could hold its own up to approx. 15,000ft but above that forget it and I think that only made service in mid 41..


I meant that the Battle of Britan (and prior action in France) forced the RAF and Rolls Royce to put more aggressive engine testing/experimentation in place, developing emergency ratings on engines years before the US did. Same engines ... all a matter of testing in the factory and in the field.

At normal 3000 RPM, the V-1710-33 was officially limited to only 37.2 mm Hg manifold pressure at 14,500 ft (that's +3.5 psi boost). 
If overboosted to 46" Hg (just shy of +8 psi boost), it could pull 1,280 hp at 9,000 ft (same as the Merlin I's FTH for 1,300 hp )
That's without resorting to overspeeding to boost supercharger output. (3200 RPM makes the 8.8:1 gearing act like an effective 9.4:1 supercharger ratio would at 3000 RPM)




tomo pauk said:


> The 1st production P-40 was delivered at June 1940, the 1st Tomahawk I was delivered (still it is in the USA) at Sept 1940. Production-wise, they might qualify for the BoB, but obviously not when we count in the training and logistic needs.
> The early P-40 will climb better than any subsequent P-40, being far lighter. With 120 US gals, the P-40 was at 6800 lbs and doing 357-360 mph tests.


Unless you count intial climb on some loadouts for later P-40s in WER power ... definitely the fastest climber on mil power. 



> Protection of 1940 BoB fighters was not equal with what fighters carried in 1941, let alone, say, in 1943.


I think the P-40B was fairly close to late model Spitfire Mk.Is maybe closer to Mk.IIs. P-40Cs got the totally redesigned fuel system using self-sealing cells rather than conventional tanks with sealing material applied to the exterior. (Cs also added armor glass to the windshields as standard)




tomo pauk said:


> The Spitfire is not the only aircraft that fought during the BoB. Early P-40 does have it's shortcomings, but it's performance was closer to the Spit and 109E, than to the Hurricanes and Bf 110.


Roll rate, overall control weights at high speeds, stall characteristics, and dive acceleration would be useful characteristics too. (plus lack of negative G problems) Then there's the higher fuel capacity and good fuel economy allowing a more flexible mission profile than the spit/hurri/109. (longer endurance, longer loiter time ... roaming patrols might be logistically difficult though -that range/endurance would have made it more interesting for the Germans as an escort or fighter-bomber compared to the 109)

The level speed the P-40 managed in spite of being heavier with lesser engine performance seems to point to it being a cleaner airframe than the Spitfire or 109 as well, and while that might not mean too much on the whole it does imply better dive acceleration than any of the BoB fighters. (the one place that higher weight becomes an asset)

Rear visibility is a bit better on the P-40 too, with the hollowed out and glazed fuselage section immeditately rear of the cockpit.

Power to weight ratio might have been worse than the Hurricane, but the P-40B's climb rate figures seeem to compare favorably to the Hurricane Mk.I, though sustained turn-rate was worse. Quite possibly a better interceptor than the Hurricane, though not the Spitfire. (ironically, the 109E's performance and armament best fit the bomber interception role of the lot)








Koopernic said:


> Nevertheless its interesting to note that many of the engineering decisions made by RJ Mitchel and J Smith over ruled the possibility of using the full wing for fuel storage. For instance Mitchell did not like the idea of synchronised cowling machine guns or a motor gun because it inevitably 'thickened' the fuselage. Had weaponry been mounted on the cowling, between the V block or in the wing roots (as in the Fw 190, He 112 and several Soviet aircraft) the wings might have been left clear. There were no doubt other issues such as lack of a suitable guns, the inability of Merlin engine propeller combination to take this without re-engineering. The US 0.5" Browning with hydraulic hydrostatic interrupter gear in the wing roots seems the easiest to me. Likewise the rejection of 'gondola' hispano weapons on the Spitfire by J Smith.
> 
> It seems neither man was motivated by the Air Ministry to increase the range of their aircraft.


The .50 browning or (if they'd taken an interest) .50 vickers (might have had better synronized RoF too and lighter and more compact -2 wing root guns plus 2 cowl guns would have been decent even with the lower powered vickers rounds).
Mounting hispanos in underwing pods was suggested too. Use fuel tanks in the wings and a pair of 20 mm underwing and it might have been useful. (depends just how much drag the installation added)

Tony Willaims has a couple articles pointing out the realistic potential for the hispano to be made synronization capable too. I'm not sure about engine-mounting it though, that'd depend on the Merlin's design. (the V-1710's supercharger arrangement didn't allow this ... neither did the propeller hub positioning used on the C series V-1710s) It might have been a possibility though. A mix of HMGs and nose cannon would have been pretty useful too ... and allowed WORKING cannon-armmed single engine fighters during the BoB. (1 20 mm plus 2 or 4 HMGs is a pretty useful fighter armament)




> Somewhat more puzzling is the lack of a long range escort specification by the RAF unless once considers the Typhoon and its teething problems.


The Typhoon's range hardly fit the requirements for that role either, even without teething troubles.





> My understanding is that the Tomahawk IIA (P-40B) carried 131 Imp Gallons (160 US Gallons) but that later versions dropped down to 120 Imp gallons) This is still well above the Spitfire III/V's 85 gallons and similar for P-39.


The P-40C carried tanks of 134 US gal (111.7 Imp), but the P-40E expanded that to 157 gallons (130.7 Imp). The P-40N reduced that to 122 US gallons. (on a side note, if the same proportions are applied for the 160 gal vs 134, the P-40E's configuration might have allowed some 187 US -156 imp- gallons with P-40B style tanks)


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## Shortround6 (Mar 6, 2015)

The main trouble with all (or most) of the P-40s "advantages" is that they only apply to altitudes that are too low to be useful in the BoB or for an escort fighter over Europe in 1941-42. 

And it seems a lot of the "book" figures for the P-40B were done at a rather unrealistic weight for the proposed duties.

http://www.wwiiaircraftperformance.org/P-40/P-40B_Official_Summary_of_Characteristics.jpg

Performance figures are for 6835lbs. The "normal" gross weight of 7326lbs has the plane holding 120 US gallons of gas, not the 160gal over load condition. 

Getting rid of 490lbs of useful load means ripping out guns and armor and/or fuel/oil ( the pilot has to stay). You only had 720lbs of fuel to make 120 gallons. Performance with 38.33 gals of fuel on board is rather useless. 

We can do the easy thing first and ditch ammo. 
Cut wing guns from 500rpg to 350rpg will save 36lbs =6 gallons
Cut fuselage guns from 380rpg to 200rpg will save 108lbs (.50 cal ammo is heavy)= 18 gallons. 
If we aren't going to use full fuel tanks we don't need a full oil tank. If we pull 42lbs of oil (roughly 1/3rd) we can get another 7 gallons of gas. 

We are now up to 69.33 US gallons (maybe 57.7Imp) gallons? 

Put the pilot on a diet??

P-40 is NOT going to perform to book figures with a "normal" load let alone the 160 gallon overload. 
Unless you over-rev the engine _any_ improvement in performance from increased boost will be at under 13,000-14,500ft. And with 109s coming over the top of Hurricanes during the BoB that doesn't look so good. 



> The .50 browning or (if they'd taken an interest) .50 vickers (might have had better synronized RoF too and lighter and more compact -2 wing root guns plus 2 cowl guns would have been decent even with the lower powered vickers rounds).
> Mounting hispanos in underwing pods was suggested too. Use fuel tanks in the wings and a pair of 20 mm underwing and it might have been useful. (depends just how much drag the installation added)



.50 cal Browning is a lot of weight for not a lot of result in synchronized mountings. The Vickers .303 gun was subject to an amazing variety of jams and was NEVER placed were the pilot or crewman could not get to it to working the charging handle/lever and/or beat on it with a gloved hand. A lot of schemes were _proposed_ for the Hispano, it turned out the Hispano _liked_ fairly rigid mountings and had a higher tendency to jam in less rigid mountings. Under wing guns place the guns with a longer lever moment in relation to the aircraft's CG and can cause even more "dip" on firing. One explanation for the six .303s in the Beaufighter was that the four 20mm guns in the bottom of the nose caused the plane to dip and go off target. True or not???? 

And once again, weight is more important at times than drag. the 109 gunboats were still fast but climb, turn and roll all suffered to the point where they needed non-boats to handle the opposing fighters.

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## pbehn (Mar 6, 2015)

Greyman said:


> Outside of what you were referring to - but I thought these images were pretty striking:
> 
> Bf 109 on a Spitfire on a Ju 88
> Mustang on a Fw 190 on a Lancaster
> ...



The thread is about RAF daylight raids, a photo of an Fw 190 being shot at while attacking an RAF Lancaster is completely on topic, I dont know how the discussion was turned around to exclude lightly armed German and British bombers and made to exclusively consider USAF deep penetration raids. The Lanc was the RAFs frontline strategic bomber, it applies to this thread.


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## kool kitty89 (Mar 6, 2015)

Shortround6 said:


> The main trouble with all (or most) of the P-40s "advantages" is that they only apply to altitudes that are too low to be useful in the BoB or for an escort fighter over Europe in 1941-42.
> 
> And it seems a lot of the "book" figures for the P-40B were done at a rather unrealistic weight for the proposed duties.
> 
> ...


Performance for pretty much any actual service-test aircraft tended to be significantly below the factor/aproval tests. The P-40D/E/F/L/M/N usually failed to meet their specified level speed if not climb performnace as well. Same is true for the Hurricane and Spitfire (some models more than others). Propellers used could make a big difference too, even aside from early examples of fixed-pitch ones.



> Getting rid of 490lbs of useful load means ripping out guns and armor and/or fuel/oil ( the pilot has to stay). You only had 720lbs of fuel to make 120 gallons. Performance with 38.33 gals of fuel on board is rather useless.
> 
> We can do the easy thing first and ditch ammo.
> Cut wing guns from 500rpg to 350rpg will save 36lbs =6 gallons
> ...


Ditching the wing guns entirely might be better in that case ... depending on how much weight you put in nose mountings and concentrated fire being superior. (even with the low RoF of the .50s when synched)
Plus it's 50 vs 30 cal performance here. If you're dealing mostly with light/fragile structured opponents, the 4x .30s might be preferable to using the .50s at all. (with decent armor and strong structures, the .30s would be much less useful anyway)

Also depends if you're talking intercept or escort duty. (against small fighters, the lighter armament would be more acceptable)



> .50 cal Browning is a lot of weight for not a lot of result in synchronized mountings. The Vickers .303 gun was subject to an amazing variety of jams and was NEVER placed were the pilot or crewman could not get to it to working the charging handle/lever and/or beat on it with a gloved hand.


I'm not sure the .50 vickers gun had those same problems, the tests I've seen show it to be fairly reliable ... but it never entered RAF service, so there's no field experience to go by for aircraft use.
The guns and ammo were both significantly ligher than the Browning though.

And aside from all that, there's still the issue of concentration of fire vs rate of fire. (the former is less useful if you're a poor shot though, 'shotgun' effect of more guns with staggered convergence would be preferable there)




> And once again, weight is more important at times than drag. the 109 gunboats were still fast but climb, turn and roll all suffered to the point where they needed non-boats to handle the opposing fighters.


If we were talking Spitfires with nose armanets on the level of the 109, then yes, that'd be worth exploring, but I was suggesting a REDUCED armament compared to the Spit V/IX though more potent than the 8-gun early marks. (a single pair of underwing cannons or even faired close and half-burried in the wings -with the feed mechanism totally internal still, occuping the rear of the wing but freeing up the leading edge boxes for fuel.)

Now the added FUEL would still be an issue of adding weight, but that's always going to be a factor for escort fighters. The P-51 could hardly escape those problems itself. (a long range spit might have been significantly ligher than the P-51 too, though certainly slower in level speed using similar engines)


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## Glider (Mar 6, 2015)

pbehn said:


> The thread is about RAF daylight raids, a photo of an Fw 190 being shot at while attacking an RAF Lancaster is completely on topic, I dont know how the discussion was turned around to exclude lightly armed German and British bombers and made to exclusively consider USAF deep penetration raids. The Lanc was the RAFs frontline strategic bomber, it applies to this thread.



I totally agree with this statement and as an aside note that the Lancaster is clearly evading. Its a great photo


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## Shortround6 (Mar 6, 2015)

kool kitty89 said:


> Performance for pretty much any actual service-test aircraft tended to be significantly below the factor/aproval tests. The P-40D/E/F/L/M/N usually failed to meet their specified level speed if not climb performnace as well. Same is true for the Hurricane and Spitfire (some models more than others). Propellers used could make a big difference too, even aside from early examples of fixed-pitch ones.



It is one thing to miss the test numbers with service aircraft, it is another to use a test weight that is hundreds of pounds lower than the actual service weight. 




> Ditching the wing guns entirely might be better in that case ... depending on how much weight you put in nose mountings and concentrated fire being superior. (even with the low RoF of the .50s when synched)
> Plus it's 50 vs 30 cal performance here. If you're dealing mostly with light/fragile structured opponents, the 4x .30s might be preferable to using the .50s at all. (with decent armor and strong structures, the .30s would be much less useful anyway)



Your synched _pair_ of .50 cal guns are lucky if they are firing 16 rounds a second. The MG 151 cannon was firing 10-12 rounds per second. 
four .303 Brownings (or .30 cal) were firing 72-80 rounds per second.

The pair of .50 cal guns weighed 150.5 lbs and even 200rpg added about 120lbs or 270lbs total. 
the four .30 cal guns weighed 95lbs and using the full 500rpg added 127.4 lbs or 222.4lbs total. 




> I'm not sure the .50 vickers gun had those same problems, the tests I've seen show it to be fairly reliable ... but it never entered RAF service, so there's no field experience to go by for aircraft use.
> The guns and ammo were both significantly ligher than the Browning though.



The .303 Vicker's gun was pretty near unbreakable, which is a different form of reliability ( British Paratroopers were using a few in Aden in 1960, years after it was "officially" retired.) That didn't mean the gunners manual didn't list 27 different possible jams. Usually diagnosed by the position the crank handle stopped at. Most jams (at least in ground guns) could be cleared fairly easily. Since the .5in gun was pretty much just a scaled up .303 gun it is hard to believe it wouldn't have pretty much the same characteristics. 
A Browning sized to take the British .5in cartridge would certainly be interesting however. A British version of the Japanese Ho-103.


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## kool kitty89 (Mar 7, 2015)

Shortround6 said:


> The .303 Vicker's gun was pretty near unbreakable, which is a different form of reliability ( British Paratroopers were using a few in Aden in 1960, years after it was "officially" retired.) That didn't mean the gunners manual didn't list 27 different possible jams. Usually diagnosed by the position the crank handle stopped at. Most jams (at least in ground guns) could be cleared fairly easily. Since the .5in gun was pretty much just a scaled up .303 gun it is hard to believe it wouldn't have pretty much the same characteristics.
> A Browning sized to take the British .5in cartridge would certainly be interesting however. A British version of the Japanese Ho-103.


The pre-war .50 browning was showing higher rates of stopages than the vicker's too, from what I recall ... but the vicker's gun wasn't developed further, and the browning was. With that it's broad speculation to suppose the vicker's gun would have improved substantially. We know the browning did and we know it converted well to the .50 vickers round (lighter and faster firing than the existing vickers guns or italian guns using that ammunition).

The Japanese also developed the .303 vicker's further, pushing it to 900 RPM, but I have no idea if they improved the jamming problems. 

Japanese developments certainly showed the further potential the basic browning design had though from 12.7 mm to 20 mm to 30 mm to 37 mm ... a shame (and quite odd) that the US didn't pursue further development. (I've seen some claims about .60 cal browning guns -unrelated to the MG-151 derived guns aside from possibly using the same ammunition- but very little information on them)


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## stona (Mar 7, 2015)

Shortround6 said:


> the 109 gunboats were still fast but climb, turn and roll all suffered to the point where they needed non-boats to handle the opposing fighters.



Indeed they were.

There is a generally cavalier attitude expressed on forums like this today towards alterations to aircraft (I am most definitely not aiming this at SR, though I've quoted him above). People seek to add fuel and/or tanks, auxiliary tanks and make alterations to armament etc as if these were simple things to do. If the were places like the A&AEE would not have been needed.

As an example I just read elsewhere that one of Australia's greatest fighter pilots, Clive Caldwell, experimented with a Spitfire VIII armed with four cannon (Morotai, 1945). It was an effort to up the hitting power of the Spitfire in a close support role. He concluded that the handling of the aircraft was so degraded by the addition of the two cannon that it would be dangerous for the average pilot to fly such an aircraft at low level. The idea was subsequently abandoned.


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## kool kitty89 (Mar 7, 2015)

stona said:


> As an example I just read elsewhere that one of Australia's greatest fighter pilots, Clive Caldwell, experimented with a Spitfire VIII armed with four cannon (Morotai, 1945). It was an effort to up the hitting power of the Spitfire in a close support role. He concluded that the handling of the aircraft was so degraded by the addition of the two cannon that it would be dangerous for the average pilot to fly such an aircraft at low level. The idea was subsequently abandoned.


Hmm, more degraded than the Hurricane IIC? Though with the hurricane already being a heavier and higher drag airframe, the percentage of performance loss might have been less dramatic. (similar might have been true comparing a 6 gun P-40E/F/L/M with a re-armmed 4 hispanos)


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## kool kitty89 (Mar 8, 2015)

pbehn said:


> The thread is about RAF daylight raids, a photo of an Fw 190 being shot at while attacking an RAF Lancaster is completely on topic, I dont know how the discussion was turned around to exclude lightly armed German and British bombers and made to exclusively consider USAF deep penetration raids. The Lanc was the RAFs frontline strategic bomber, it applies to this thread.


In this line of thinking, what would be the combat range or radius requirements for a useful escort fighter? Drop tank equipped spitfires could range decently far into France. Let alone with modifications for more modest internal tankage expansion. (and more emphasis on 100+ gallon drop tanks earlier)

In that context, the P-39/P-400 Aracobra would have been more appealing than the P40 too. Decent enough range, significantly better speed, dive, and climb rate. (deleting the wing guns probably would have been a reasonable move as well)
Same altitude problems as the P-40, but bigger edge in level speed, dive, and not as weak in climb or turn rate.

The P-39N brought the higher alt 9.6:1 blower engine too ... though that would have been around the same time the Mustang was available anyway. (and even without drop tank provisions, the Mustang Mk.I and II would have managed longer combat radii than the Spitfire or Aracobra with drop tanks -the MkII/P-51A had better altitude performance than the similarly engined Aracobra too, at least in level speed -climb defeats RAM performance)

A Merlin 60 series spitfire with expanded fuel capacity may have made a better escort than an allison powered P-51 though. Hypothetical V-1650-1 powered P-51s might have had an advantage (certainly over Spit Vs). Once Mustang IIIs become available they're the obvious choice for escort.


The altititudes for the bombers in question also matter here. That includes medium altitude heavy bomber runs and potentially reducing bombload and pushing higher cruise altitudes.


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## stona (Mar 8, 2015)

kool kitty89 said:


> Hmm, more degraded than the Hurricane IIC? Though with the hurricane already being a heavier and higher drag airframe, the percentage of performance loss might have been less dramatic. (similar might have been true comparing a 6 gun P-40E/F/L/M with a re-armmed 4 hispanos)



The problem wasn't so much performance loss as it was the detrimental effect on handling. Many of the 'solutions' and fixes so lightly proposed (fuselage tanks being a good example) had serious effects on the Spitfire's stability. It's all very well saying that once the tank was emptied the handling and stability would return to more normal parameters, but by then a less able pilot might have killed himself and destroyed the aircraft. 
During a war some measures unthinkable in peace time might be and were allowed, but service aircraft, with very few exceptions, had to be flyable by the least able pilots, not just the best. Caldwell was well aware of this.

The Lancaster was considered an easy aircraft to fly, with benign handling. Due to Bomber Command/Harris' reluctance to allow its use at the Heavy Conversion Units many accidents occurred and many lives were lost due to lack of familiarity with the type. Coming from a Halifax or Stirling did not make flying a Lancaster a simple thing. 
Training, training and more training was required and many WW2 pilots didn't get it. The idea that most of them could handle any aircraft in which modifications had caused some instability or malicious handling characteristics is silly.

Cheers

Steve


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## Shortround6 (Mar 8, 2015)

kool kitty89 said:


> Hmm, more degraded than the Hurricane IIC? Though with the hurricane already being a heavier and higher drag airframe, the percentage of performance loss might have been less dramatic. (similar might have been true comparing a 6 gun P-40E/F/L/M with a re-armmed 4 hispanos)



It is not the "performance loss" that mattered, at least in this case. Handling refers to things like roll response and pitch response. Even IF you can keep the CG the same (balance) the inertia may change with the added weights causing the response to change. And this is different than peak rolling rate or peak pitch response. 
take a yard stick and place a 2 0z weight at both 17 and 19 in. hold at the 18in mark and wobble it left and right (ends go up and down). Now move the weights to 12in and 24in and try again and then to 0in and 36in and try. Same weight, same balance but very different responses. 
An anecdote told to me by my brother-in-law. He owned for a few years a Mudry Cap 10




Not this one.
One day he met with some old collage buddies who suggested that he take them up in a rented Cessna 172. He suggested he needed to take a check ride in a 172 since he had not flown one in several years. He went up for 1/2 hour with an instructor and upon landing told his friends it wouldn't be safe for him to fly the 172. He was consistently _under_ controlling the 172 since it needed much higher effort control inputs to get anything to happen than he was used to with the Cap 10. 
The reverse killed a _lot_ of pilots in WW I and a fair number in WW II. Going from sedate and forgiving trainers to fast responding (and some unforgiving) fighters caused many low time would-be fighter pilots to over-control their aircraft and crash.
One reason duel control (or at least dual cockpit) conversion trainers were finally put into use. 

Please remember that *EVERY* Spitfire from the MK Vc onward had the _capability_ of being fitted the four Hispano guns. The gun bays were there, the holes in the leading edge spar were there, the space for the ammunition tray/box was there. 
Shortage of guns, problems heating four cannon, loss of climb rate and turning have all been put forward as reasons why the four gun setup was not used very much but there seem to be darn few (if any) conversions done in the field.

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## Edgar Brooks (Mar 8, 2015)

kool kitty89 said:


> Hmm, more degraded than the Hurricane IIC?


The Hurricane IIC had just the four 20mm cannon; the Spitfire VIII was designed to carry four cannon AND four .303" Brownings. The R.A.A.F. were expected to intercept nimble Zeros at above 20,000', and Caldwell knew perfectly well the VIII, with 8 guns, would never do it.


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## Glider (Mar 8, 2015)

Edgar Brooks said:


> The Hurricane IIC had just the four 20mm cannon; the Spitfire VIII was designed to carry four cannon AND four .303" Brownings. The R.A.A.F. were expected to intercept nimble Zeros at above 20,000', and Caldwell knew perfectly well the VIII, with 8 guns, would never do it.


This is new to me \I admit, can you supply something to support this idea


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## kool kitty89 (Mar 9, 2015)

stona said:


> The problem wasn't so much performance loss as it was the detrimental effect on handling. Many of the 'solutions' and fixes so lightly proposed (fuselage tanks being a good example) had serious effects on the Spitfire's stability. It's all very well saying that once the tank was emptied the handling and stability would return to more normal parameters, but by then a less able pilot might have killed himself and destroyed the aircraft.
> During a war some measures unthinkable in peace time might be and were allowed, but service aircraft, with very few exceptions, had to be flyable by the least able pilots, not just the best. Caldwell was well aware of this.


Yes, this is also why I was focusing more on the potential leading edge wing tanks on the spitfire than the rear tank. That placement seems like a less problematic location for degrading CoG positioning. (plus issues with being nose-heavy usually caused fewer problems with stability -and especially stall/spin characteristics than being tail heavy)

Managing good, stable handling would have been a more important consideration for the suggestion of underwing cannon pods too. If those couldn't be installed without degraded handling characteristics (compared to in-wing mountings), it would be an unacceptable compromise. That suggestion was also posed in the context of having 2 wing cannons be the ONLY armament and intended mainly for escort duties and fighter v fighter combat. Or at least that was one of the contexts it came up in. (along with the suggestion for nose armaments and motor cannon mountings)



> Training, training and more training was required and many WW2 pilots didn't get it. The idea that most of them could handle any aircraft in which modifications had caused some instability or malicious handling characteristics is silly.


Training and actual knowledge of the aircraft's characteristics. Some handling problems were less officially known than others. The CoG specific stability issues on the P-39 were noted in the field before officially documented at Bell. (and specific to being nose-light/tailheavy)

Tail heavy conditions seem to be one of the biggest problems for stability, at least in single-engine aircraft ... especially fighters. (which are inherently less stable for maneuverability needs)

I haven't seen that many specific claims on this issue, but handling characteristics seem to be one of the more definitive advantages of the P-40 over the P-39. (in terms of ease of stability and ease of flying, less so compared to actual turn/roll performance ... similar to comparing the hurricane to the spitfire in some respects, except not the same gap in performance)


And taking a step back: 


stona said:


> Indeed they were.
> 
> There is a generally cavalier attitude expressed on forums like this today towards alterations to aircraft (I am most definitely not aiming this at SR, though I've quoted him above). People seek to add fuel and/or tanks, auxiliary tanks and make alterations to armament etc as if these were simple things to do. If the were places like the A&AEE would not have been needed.


I mostly try to think in terms of reasonable hypothetical thinking/foresight (not hindsight) of engineers and planners from the period. (ie choices that made sense to them ... even if they didn't make them historically)

In terms of altering the Spitfire's loadout it's mainly a question of trying to figure out SOME acceptable escort fighter for Brittain to use. If the Spitfire could be configured to allow similar or longer range to the P-40 (or even P-39) without irreparably degrading performance and/or handling characteristics (and performing better than the P-40 itself), then that would have been worth persuing.

Discussion of USAAF style long range penetration bombing runs skewed the discussion a bit further, but for shorter range missions, more modest modifications may have been reasonable. (that and potentially using Mustangs without drop tanks ... or hypothetical British P-38s)

Hmm ... shifting the topic a bit, but still somewhat relvant: in terms of similar manufacturing cost/resources, would ordering more early model P-38s (or modified turbo-less ones) have been more useful than similar resources going into P-39 and/or P-40 production? (this includes potential use as a medium altitude escort fighter)


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## stona (Mar 9, 2015)

Edgar Brooks said:


> The Hurricane IIC had just the four 20mm cannon; the Spitfire VIII was designed to carry four cannon AND four .303" Brownings. The R.A.A.F. were expected to intercept nimble Zeros at above 20,000', and Caldwell knew perfectly well the VIII, with 8 guns, would never do it.



Not in 1945. The Aussies understood that they would be carrying out a close support role in support of the Americans which is why they were looking at flying four 20mm cannon and why Caldwell carried out the unofficial trials.

Spitfires fitted with four cannon are as hard to find as rocking horse poop. I believe it was you that said the four cannon set up was used to ferry weapons to Malta, but this wasn't an intended operational configuration even there, though who knows what happened short term in the chaos of that island? I know of a few pictures of four cannon Spitfires, supposedly on Malta.






Interesting wheel chocks 

Cheers

Steve


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## Greyman (Mar 9, 2015)

Definitely used over Malta. Luftwaffe reported them in action as well.


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## kool kitty89 (Mar 9, 2015)

I'm sure it's been suggested before too, but in the previous discussion on Merlin 20 series (V-1650-1) powered Mustangs, particularly on the issue of actually proposing/testing such a prototype, the suggestion of acquiring a British manufactured Merlin for said testing didn't arise. Given the fact that it was being designed and manufactured to a British order (and the fact that both the XP-40L and the later experimental Merlin 60 powered Mustang used British manufactured engines for testing) it would have made plenty of sense for this to have been done. More so if the British themselves had requested such a configuration and supplied a test engine.

Such a request might have been the most likely way for an V-1650-1 powered Mustang to actually make it into production. (granted, with the timing of V-1650 production, the initial run of mustangs would still have to start with Allison powered models ... or have British Engines allocated to them -rather unlikely)

Hell, if they'd proposed that back during the NA-73 prototype design and construction phase, a Merlin engine might have been allocated to the project before the American V-1710 was even available. (due to US production allocation priority delays for the V-1710) Granted, that would be earlier than than the P-40 flew with a Merlin ... but rather less crazy than the likes of what the British later did reguarding jet developments. (admittedly different context, but as far as radical decisions, sacrificing the two flight worthy Goblin engines -and a third ground-test only one- was a much greater risk than providing a Merlin XX for testing in 1940, a couple months after the initial Hurricane Mk.II prototypes had received theirs)

Testing that early would still mean having to wait until late 1941 before V-1650s were available, or allocating british-built merlins to Mustangs ... which would also complicate logistics. (either shipping British engines to be installed in the US or shipping engineless airframes to the UK -removing the possibility of ferry flights)


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## Shortround6 (Mar 9, 2015)

kool kitty89 said:


> Hmm ... shifting the topic a bit, but still somewhat relvant: in terms of similar manufacturing cost/resources, would ordering more early model P-38s (or modified turbo-less ones) have been more useful than similar resources going into P-39 and/or P-40 production? (this includes potential use as a medium altitude escort fighter)



Perhaps but then you would have needed a crystal ball. Because of the crash of of the XP-38 and delayed testing it wasn't ordered as soon as the P-40 and P-39 which means in 1940 they built 1 P-38, 13 P-39s and 778 P-40s. In 1941 they built 207 P-38s, 926 P-39s and 2248 P-40s. P-38 production catches up (sort of) in 1942 with 1479 P-38s compared to "only" 1932 P-39s. P-40s were 3854. 
Loosing a number of months production of either the P-39 or P-40 at that stage of the war would have had a serious impact on the American forces.


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## Koopernic (Mar 9, 2015)

i do not think we have entered the realm of cavalier conjecture in this case though we've had some crazy propositions, I appreciate however much needs consideration, increase the weight and its not just C of G but tail plane incidence that might need adjustment. Historically PRU reconnaissance Spitfires did carry full span 66 gallon wing tanks on each wing. Spitfires Mk 21,22,24 all entered service with 4 x 20mm Hispano's, these were fully length Hispanos except on the Mk 24. This was of course with the "new" or "revised" wing. In General increases in weights may need redistribution of equipment to achieve a satisfactory centre of gravity, the Spitfire needed bob weights to add control force in pull-outs and so forth. 

Below is the Spitfire "C" wing first introduced on the Mark V.

Each wing had two positions just outside the propeller arc which could take either a US 0.5 inch Browning or 20mm Hispano. Although two Hispanos could be fitted in each wing it was usual to carry only one and either a 0.5 inch Browning in the adjacent station or that station was simply plugged. In the case that the station was plugged the 0.303 Browning's in the outboard wings were carried.

As can be seen there is an 18 Imperial gallon tank inboard of the guns (used for some reason only on some variants such as the long range Mk VIII the Australians used in the Pacific).
The two heavy gun stations occupy prime real estate in that it looks like a another 18+ gallon tank could be fitted there. IE 36 gallons in each wing instead of only 18 and more like 40 if the common sidewall is considered. Such a Spitfire would match the P-51 without tail tank but would only be able to carry 4 x 0.303 guns in its outboard stations. Is that enough to deter fighters?

To me it look like a 0.5 inch Browning with ammunition could be fitted between ribs 1 and 2 or 3 and 4 to be synchronised hydraulically. There might be plumbing there to the radiators that would have to be moved.

The revised wing spitfires could also carry small fuel tanks of about 6 gallons in the outer wing stations, their 0.303 guns being of little use. 

Underwing armament I think would do the trick since there is not extra weight being added, the guns are only being moved.


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## tomo pauk (Mar 9, 2015)

The LE tanks were offering 2 x 13 imp gals per aircraft, used on Mk.VII/VIII (also for MTO) and Mk.XIV. Installing any armament inboard of the main wheel wells will be next to impossible due to radiators taking a lot of volume there.
FWIW, here is my take. Two guns next to the wheel well; possibilities for the extra fuel tankage are in front of the main spar (outboard of the guns); behind the main spar; area marked with '?'.


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## kool kitty89 (Mar 10, 2015)

tomo pauk said:


> The LE tanks were offering 2 x 13 imp gals per aircraft, used on Mk.VII/VIII (also for MTO) and Mk.XIV. Installing any armament inboard of the main wheel wells will be next to impossible due to radiators taking a lot of volume there.
> FWIW, here is my take. Two guns next to the wheel well; possibilities for the extra fuel tankage are in front of the main spar (outboard of the guns); behind the main spar; area marked with '?'.


Hmm, perhaps 4x .50 guns or a single pair of 20 mm cannons? (the latter would be lighter depending on the ammunition load, granted 2x .50s and 2x 20 mm would work too, or allowing all 3 configurations ... which I suppose they already did -4 .50s was possible, just not really used)

Given the compact placement of the inner 4 gun points, I'm not sure the earlier suggestion of resorting to under-wing pods would be all that useful. There's SOME leading edge space to be gained, but not a whole lot. (so more a question of the added drag being worth the added fuel -even if you keep weight down by limiting armament to a single pair of cannons, and embed the guns as flush to the wing as possible, keeping ammunition boxes within the wings themselves still, since only the leading edge wing space would be used for fuel)


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## Edgar Brooks (Mar 10, 2015)

Koopernic said:


> To me it look like a 0.5 inch Browning with ammunition could be fitted between ribs 1 and 2 or 3 and 4 to be synchronised hydraulically. There might be plumbing there to the radiators that would have to be moved.]


You might need to land and take off without undercarriage, too, since the oleo legs go across that area.


> This is new to me \I admit, can you supply something to support this idea


In January 1944, the Air Ministry finally settled on the armament of 1 x 20mm + 2 x .303", but only on the V IX. For those two Marks (only) there was a modification "To introduce the single blister door called for under mod 683 as a retrospective item." Mod 683 was to standardise the armament as above.
However, on 15-12-43, another mod (769) was "To introduce a cannon gun door having two small blisters in place of the existing single large blister," and that was solely for the Mk.VIII; two small blisters would only be needed for two cannon. There had been talk of fitting the short-barrelled Mk.V Hispano in the VIII, but that came to nothing (maybe the Tempest had priority.)


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## Koopernic (Mar 10, 2015)

Edgar Brooks said:


> You might need to land and take off without undercarriage, too, since the oleo legs go across that area.
> 
> In January 1944, the Air Ministry finally settled on the armament of 1 x 20mm + 2 x .303", but only on the V IX. For those two Marks (only) there was a modification "To introduce the single blister door called for under mod 683 as a retrospective item." Mod 683 was to standardise the armament as above.
> However, on 15-12-43, another mod (769) was "To introduce a cannon gun door having two small blisters in place of the existing single large blister," and that was solely for the Mk.VIII; two small blisters would only be needed for two cannon. There had been talk of fitting the short-barrelled Mk.V Hispano in the VIII, but that came to nothing (maybe the Tempest had priority.)



There might still be room there (ribs 3/4 or 2/3) for a smaller weapon since these ribs are inboard of the wing attachment.









Obviously the 4 gun armament was achieved on the Spitfire Mk 21/22/24 with its revised wing however the "Super Spitfire" Mk XVIII, which was a backup design to the Mk 21, and essentially an improved Mk XIV Using stainless steel stringers for strength) didn't carry this armament.

It seems to me there were control and stability issues that still needed to be solved.


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## Glider (Mar 10, 2015)

A couple of observations. 
Weight is a key factor and anything that adds weight has to be of value or it isn't worth the impact on the aircraft as a whole.

Any weapon less than 0.5 after mid 1943 is almost useless in the west, as the Luftwaffe were well protected against the LMG. As has been noted almost any spit from the Mk Vc onwards could carry 4 x 20mm and there is little doubt that this impacted its climb but had little impact on its speed or agility. There were no control or stability issues to be resolved.

Note summary of the Test Results of the Spitfire Vc with 4 x 20mm cannon:- 
(i) The maximum rate of climb is 2,900 feet/minute at 13,400 feet. The time to 20,000 feet is 7.4 minutes, and the estimated service ceiling is 36,400 feet. 
(ii) The top speed is 374 m.p.h. at 19,000 feet. 
iii) There is no noticeable difference between the handling characteristics of this aeroplane and other Spitfire V types. 
Spitfire Mk V Performance Testing

However against the aircraft they had to fight, the standard weapons of 2 x 20mm and 4 x LMG or 2 x 0.5 was more than sufficient

90 gallon drop tanks were routinely carried on the Spit IX on combat missions in the Med/Italian campaign without any issues

The Spitfire could easily carry the Hispano V if they were available and the Seafire III carried them as a standard fitting. Indeed the Hispano II and the Hispano V were interchangeable as they used the same mountings

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## wuzak (Mar 10, 2015)

kool kitty89 said:


> I'm sure it's been suggested before too, but in the previous discussion on Merlin 20 series (V-1650-1) powered Mustangs, particularly on the issue of actually proposing/testing such a prototype, the suggestion of acquiring a British manufactured Merlin for said testing didn't arise. Given the fact that it was being designed and manufactured to a British order (and the fact that both the XP-40L and the later experimental Merlin 60 powered Mustang used British manufactured engines for testing) it would have made plenty of sense for this to have been done. More so if the British themselves had requested such a configuration and supplied a test engine.
> 
> Such a request might have been the most likely way for an V-1650-1 powered Mustang to actually make it into production. (granted, with the timing of V-1650 production, the initial run of mustangs would still have to start with Allison powered models ... or have British Engines allocated to them -rather unlikely)
> 
> ...



Rolls-Royce suggested fitting either the Merlin XX or Merlin 61 in the Mustang. The former wasn't done, though it was discussed, while the latter was built as the Mustang X.

There was also some discussion that the Mustang X would be put in production - airframes would be shipped from the US to Britain where a Merlin 61 would be fitted and any airframe modifications performed.


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## kool kitty89 (Mar 11, 2015)

wuzak said:


> Rolls-Royce suggested fitting either the Merlin XX or Merlin 61 in the Mustang. The former wasn't done, though it was discussed, while the latter was built as the Mustang X.
> 
> There was also some discussion that the Mustang X would be put in production - airframes would be shipped from the US to Britain where a Merlin 61 would be fitted and any airframe modifications performed.


For the Merlin XX example to be worthwhile, procurment and testing of such would really have needed to take place much earlier than the Mustank X (or parallel developments with the Merlin 60 powered P-51 prototypes in the US) to be worthwhile. Namely before the first production Mustang examples were even being shipped to the UK.


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## Edgar Brooks (Mar 11, 2015)

Koopernic said:


> It seems to me there were control and stability issues that still needed to be solved.


Perhaps you might like to elaborate on that?


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## Neil Stirling (Mar 11, 2015)

Koopernic said:


> _Using stainless steel stringers for strength) didn't carry this armament.
> _
> 
> Huhh? Where do you get this from?
> ...


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## drgondog (Mar 12, 2015)

The questions to be addressed to make daylight bombing by RAF feasible start with escort capability, or with airframe capability to outrun fighter interceptors.

The fact that LF3 with JG 2 and 26 was the primary defense is irrelevant - that is all that was required, Had RAF incursions during daylight become dangerous, the Luftwaffe would have drawn re-enforcements' from other fronts as required - just as they did beginning mid 1943 vs 8th AF.

The RAF defensive capabilities against fighter were less than B-17E/F/G or B-24D/H/J or B-26B/C capability - all of which required fighter escort to survive - at the target and all along the way.

The RAF bombers did not have turbo superchargers, limiting bomb ceilings below 20,000 feet which introduces another threat at a more dangerous threshold than their US counterparts - Flak. AAA is increasingly effective from the large caliber guns as the altitudes lower, and the additional 'small' flak such as 20/37/40mm flak becomes lethal below 10,000 feet.

Escort combat radius is influenced by two separate factors. First and most important is the internal capacity of fuel. Based on exhaustive American experience, the return range profile must account for a.) dropping external tanks, b.) engaging at full Military Power for up to 20 minutes, c.) returning in a straight line at optimal cruise speed, and d.) providing 30 minutes of loiter time as a contingency prior to landing.

If you use the Spitfire, the comparable internal fuel storage to escort RAF bombers to Berlin in 1941 would require approximately as much (actually more) as a P-51B with 85 gallon aft fuselage tank = 269 gallons. The 'more' factors include drag of the airframe as it relates to maximum miles per gallon at the operational bomber altitudes plus 0 to 5,000 feet, and capacity of external fuel storage as it affects both capacity and additional drag. The slipper tank design, if capable of the same 75 or 110 US gallon capacity could move the needle back slightly.

If you wish speed as the strategic alternative there is only one choice and that is the Mossie. IMO that selection points toward single or two ship formations to limit the intercept tracking and stretch German defenses. Single large formations, having no defensive firepower, seems foolish and in any case the loss rate will still be high. More effective? I don't see why the Mossie ability to deliver a bomb load better than a Halifax - on target - is improved unless the Mossie drops to the deck and makes its bomb run from there. In addition, Low altitude tactics influence fuel storage vs bomb load vs range calculations.

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## gjs238 (Mar 12, 2015)

drgondog said:


> *The RAF bombers did not have turbo superchargers*, limiting bomb ceilings below 20,000 feet which introduces another threat at a more dangerous threshold than their US counterparts - Flak. AAA is increasingly effective from the large caliber guns as the altitudes lower, and the additional 'small' flak such as 20/37/40mm flak becomes lethal below 10,000 feet.



Could they have implemented 2-stage supercharging?


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## Shortround6 (Mar 12, 2015)

They could have. They did on some late war Lancasters or Lincolns. 

However the two stage engines only show up in small numbers part way through 1942 and you need them for the fighters. There were four squadrons of Spitfires with two stage engines at the time of Dieppe in Aug of 1942. Packard built 5 two stage engines in 1942. They built 7250 single stage engines. Obviously RR was making them first but you won't have enough to do anything until the very end of 1942. 

Forget Berlin. It is about 360-370miles from Norwich to Hamburg and about the same from Norwich to Frankfurt. A P-51 with 184 US gallons internal and 150 gals in drop tanks was rated at a 460 mile radius. With 269 US gallons internal and no drop tanks it was rated at 375 miles. Now can you get enough fuel into a MK V Spit (not a IX or VIII although you can use the same tanks) with it's Merlin 45 engine *AND* have enough performance to fight the interceptors? 
That is what you have in 1941-42. 
Even an Early Mustang with the Allison swapped for a Merlin XX may have trouble. Even with just four .50 cal guns it could go 7300lbs or more with full internal tanks. About 800lbs heavier than a MK V Spitfire. It may be faster but climb and turn won't be as good. ANd MK V Spitfires weren't good enough in 1941/42.

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## Edgar Brooks (Mar 12, 2015)

Can we get one thing clear? The lack of supercharging had nothing, whatsoever, to do with bombing from 18,000', it was a deliberate policy of the Air Ministry. 
Flying above 20,000' (and the Lancaster I could go to 23,000') brings the aircraft into the zone of contrails, and four white trails in the glare of moonlight, would have been (as the Air Ministry put it ) like fingers beckoning to every nightfighter within range, and a certain death sentence.
The two-stage Merlin was originally planned for bombers (in daylight,) but became unnecessary at night, hence the availability for the Spitfire.

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## Glider (Mar 12, 2015)

Is there any reason why people have such a hang up about bombing Berlin, when the industrial areas such as the Rhur would be at least as important


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## Milosh (Mar 12, 2015)

Is that 23,000ft for a bomb laden Lancaster or a Lancaster with no bombs?


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## pbehn (Mar 12, 2015)

Glider said:


> Is there any reason why people have such a hang up about bombing Berlin, when the industrial areas such as the Rhur would be at least as important



I think purely because of the distance it represents, the Rhur could be bombed fairly accurately by night using the gee system from beginning 1942. Hamburg was target more easily identified at night, the problem was with targets deep in Germany away from the coast. These targets however are as hard to find by day under normal European cloud as they are at night. By the time the US became successful at daytime raids they had a huge recon capability which wasnt there in 1941/2.


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## Greyman (Mar 12, 2015)

Milosh said:


> Is that 23,000ft for a bomb laden Lancaster or a Lancaster with no bombs?



Fully loaded.


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## wuzak (Mar 12, 2015)

drgondog said:


> If you wish speed as the strategic alternative there is only one choice and that is the Mossie. IMO that selection points toward single or two ship formations to limit the intercept tracking and stretch German defenses. Single large formations, having no defensive firepower, seems foolish and in any case the loss rate will still be high. More effective? I don't see why the Mossie ability to deliver a bomb load better than a Halifax - on target - is improved unless the Mossie drops to the deck and makes its bomb run from there. In addition, Low altitude tactics influence fuel storage vs bomb load vs range calculations.



Low altitude bombing does improve accuracy, but for the Mosquito it did have a couple of other benefits. 

One, the German radar would not pick the intruders up as quickly, if at all. 
Two, the Mosquito's performance at low level compared very well with the German fighters - Bf 109 and Fw 190.
Three, the Mosquito's great blind spot to the rear and below was not exposed.

The third is also applicable to the Lancaster and Halifax, as their defences did not cover beneath very well.
The downside was, of course, range is lessened.

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## kool kitty89 (Mar 12, 2015)

Shortround6 said:


> Even an Early Mustang with the Allison swapped for a Merlin XX may have trouble. Even with just four .50 cal guns it could go 7300lbs or more with full internal tanks. About 800lbs heavier than a MK V Spitfire. It may be faster but climb and turn won't be as good. ANd MK V Spitfires weren't good enough in 1941/42.


You've still got basically the same set of trade-offs seen comparing the Mustang III/P-51B/C to the Spitfire IX. (range, level speed, dive acceleration, diving speed, energy retention at high speeds, roll rate)

Except compared to a Spit V, you'd have some modest advantages at low level with the MS gear of the Merlin XX. Possibly a slightly higher FTH due to ram performance too.




Edgar Brooks said:


> Can we get one thing clear? The lack of supercharging had nothing, whatsoever, to do with bombing from 18,000', it was a deliberate policy of the Air Ministry.
> Flying above 20,000' (and the Lancaster I could go to 23,000') brings the aircraft into the zone of contrails, and four white trails in the glare of moonlight, would have been (as the Air Ministry put it ) like fingers beckoning to every nightfighter within range, and a certain death sentence.
> The two-stage Merlin was originally planned for bombers (in daylight,) but became unnecessary at night, hence the availability for the Spitfire.


If there was a need to push altitudes a bit higher still while still working with Merlin XX level manufacturing/components capacity, wouldn't a 2-speed merlin with FS gear similar to the high-alt Merlin 47 be pretty feasible? (not 2-stage level performance, but enough to raise the ceiling a bit) Change in propellers for higher alt optimized performance might be useful as well.





pbehn said:


> I think purely because of the distance it represents, the Rhur could be bombed fairly accurately by night using the gee system from beginning 1942. Hamburg was target more easily identified at night, the problem was with targets deep in Germany away from the coast. These targets however are as hard to find by day under normal European cloud as they are at night. By the time the US became successful at daytime raids they had a huge recon capability which wasnt there in 1941/2.


I thought one of the points of this thread's premise was also considering the employment of precision bombing over area bombing. (one of the main reasons to even risk flying daylight missions) So ease of identifying area targets isn't as useful.





wuzak said:


> One, the German radar would not pick the intruders up as quickly, if at all.
> Two, the Mosquito's performance at low level compared very well with the German fighters - Bf 109 and Fw 190.
> Three, the Mosquito's great blind spot to the rear and below was not exposed.
> 
> ...


Would the .303 guns on the British heavy bombers even be much use as defensive armaments from any position by 1942 or 43?

If .50 cal gun arrangements couldn't be adopted, optimization for unarmed, faster flying heavy bombers might be more practical as well. (and as with any unarmmed bombers, drop the tight formations in favor of dispersion as individual or very small formations)


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## Edgar Brooks (Mar 13, 2015)

kool kitty89 said:


> If there was a need to push altitudes a bit higher still while still working with Merlin XX level manufacturing/components capacity, wouldn't a 2-speed merlin with FS gear similar to the high-alt Merlin 47 be pretty feasible? (not 2-stage level performance, but enough to raise the ceiling a bit) Change in propellers for higher alt optimized performance might be useful as well.


I hope I don't appear rude, but you don't seem to be listening. Until Bomber Command returned to daylight raids, at the end of the war, the Air Ministry didn't want them to fly any higher than 18,000'. Here, there seems to be an obsession, at times, with aircraft/engine performance, while the authorities, here (contrary to the "Butcher" Harris title) did make efforts to keep their crews alive.


> Would the .303 guns on the British heavy bombers even be much use as defensive armaments from any position by 1942 or 43?


I recommend you read "Gunning For the Enemy," the story of tail/mid-upper gunner "Wally" Macintosh, who shot down 8 plus one probable. 
Once "Village Inn" plus infra-red recognition and the gyro gunsight came into use, making tracer redundant (so the fighter pilot didn't know he was being fired at until too late,) things changed massively. This also increased the usefulness of the .5", hence the "Rose" turret.


> If .50 cal gun arrangements couldn't be adopted, optimization for unarmed, faster flying heavy bombers might be more practical as well. (and as with any unarmmed bombers, drop the tight formations in favor of dispersion as individual or very small formations)


Already being done with the Mosquito, which could plant a 4000lb "cookie" onto Berlin twice per night.


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## Shortround6 (Mar 13, 2015)

The original premise of this thread was:

"How would the RAF have faired if they had gone for a daylight strategic bombing campaign from 1941 on? Let's say the choice to go for a daylight campaign means they adopt the long range Spitfire variant for service as a escort. In 1941-42 the Luftwaffe was only fielding two Wings of fighters in the West, though I imagine the night fighters would have ended up as daylight bomber destroyers without a night campaign. Do the British go for high altitude bombing too?"

Now lets say, to follow up on this, that the Air Ministry has a change of heart/mind in late 1940/early 1941.and look at the technical aspects of trying to implement this tactic/policy. We may find that the air Ministry made the right decision. 
1. It is too late to design a new fighter. Anything you start working on in Dec 1940/Jan 1941 won't show up in squadron service until the beginning of 1943 at best. That leaves you with modifying existing designs. Spitfire is the only with a hope of making 1941( and that would be summer or fall of 1941).
2. Without using a time machine to alter development schedule you have pretty much historic engines with historic deployment, no making hundreds of 2 stage Merlins in 1941.
3. With said time machine you have pretty much Historic bomber production. That is for numbers, maybe you can add a turret here and/or take a turret from there but no, you can't have 500 Lancasters in the spring of 1942. 7 Factories built Lancasters during the war but only 3 were doing it in 1942 and one of them (Armstrong Whitworth) only started in Sept of 1942 and built 30 aircraft by the end of the year. By the end of October 1942 they had built 493 Lancasters total. 
4. People are confusing individual aircraft performance with formation performance. A Lancaster might very well have been able to fly at 23,000ft loaded with bombs, that doesn't mean A, that it could cruise at that height. B, that you could fly a large formation (even a squadron) at that height. 
A. 23,000ft is the height at which it could still climb at 100ft per minute using 2850rpm and 9lbs boost. Max cruise (rich) was 2650rpm and 7lbs boost. Max lean was ????
B. In formation flying you have to plan speeds/altitude for the worst performing plane in the group/formation to be on the outside of a turn and a using it's max performance to stay in formation while the planes closer to the center of the turn use less power. 

Not picking on the Lancaster, just using it as an example. NOBODY flew bombers (or fighters) in formation at their service ceilings. And if you don't fly the bombers in formation they are much harder to escort and much easier to shoot down. 

More later.

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## drgondog (Mar 13, 2015)

Shortround6 said:


> They could have. They did on some late war Lancasters or Lincolns.
> 
> However the two stage engines only show up in small numbers part way through 1942 and you need them for the fighters. There were four squadrons of Spitfires with two stage engines at the time of Dieppe in Aug of 1942. Packard built 5 two stage engines in 1942. They built 7250 single stage engines. Obviously RR was making them first but you won't have enough to do anything until the very end of 1942.
> 
> ...



I agree that the Mark I/IA with Merlin XX would not have the same combat maneuverability as the Spit V but to me that suggests higher fighter vs fighter loss rate against the Fw 190/Bf 109 than achieved with the B but the I/IA w/Merlin XX loses in climb comparison but not much else. As an example it should turn better than the heavier P-51B even if climb 500 fpm less.

Having said that, the production tooling for mass manufacturing of any version of the P-51 wasn't acquired until mid 1943. 

With a crystal ball and greater recognition of potential, a separate track for the XP-51 would have been to install a XX/1650-1 in parallel to the Allison. The bottleneck would still be the ability of Packard to generate enough engines to meet demands of RAF BC and P-51 production... suggesting that the Merlin engined MKI/IA still wouldn't be available in squadron level force until mid to late 1942.


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## Shortround6 (Mar 13, 2015)

Drgondog, no quibble from me on P-51 radius with max fuel. Just trying to show that with less than max fuel even the Mustang was only good for roughly 1/2 way into Germany.
So even if you could get 150 imp gal into a Spitfire AND hang 120imp gallons outside you get a radius of around 400-410miles (drag 10% worse than Mustang?). Now what hoops had to be jumped through to get 150gal imp into the Spitfire and what is it's performance like with a Merlin 45 or XX?
It just doesn't look like a viable project.
Jumping through larger hoops closer to the ground (300 mile radius) is easier and leaves the plane with more performance but a much more restricted target set. This makes defence for the Germans easier.

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## Shortround6 (Mar 13, 2015)

Going back to the bombers, the Lancaster was the highest flying bomber the British had (Mosquito excepted) with many of the others operating thousands of feet lower than the Lancaster. Stirlings, Manchester's and Whitleys all being rather low flyers unless operating at well below gross weight.
Whitley was always a night bomber, even before the war. Flying at 10-14,000ft in daylight against visually aimed AA guns wasn't a good idea even with fighter escort.
The bulk of the British bomber force in 1941/early 42 was Wellingtons with a lot of Pegasus engines. 
Even if you had escorts the bulk of the British bombing force in 1941/42 wasn't really suited for daylight raids. Too low flying or too slow or both. Without totally revamping production lines (and starting that in 1940) the British are not going to get any sort of daylight bombing force (not counting token raids) until sometime in 1943.
Maybe those guys in the air ministry knew something after all


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## Greyman (Mar 13, 2015)

Shortround6 said:


> Going back to the bombers, the Lancaster was the highest flying bomber the British had (Mosquito excepted) with many of the others operating thousands of feet lower than the Lancaster. Stirlings, Manchester's and Whitleys all being rather low flyers unless operating at well below gross weight.



For what it's worth the Wellington VI had a ceiling of 36,700 feet at max weight -- 266 mph cruise at 35,000 feet.


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## Balljoint (Mar 13, 2015)

While it wouldn’t matter during 1941, if both the AAF 8th and BC were later daylight bombing the LW would have been much more effective in defense. Night fighters and day interceptors are have different requirements. The initial efforts to support both was a bit beyond the LW and industries capability and pushed Hitler to specify FLAK that, while inefficient, was more universal.

The American experience during 1943 was a tragic failure save for lessons learned. The RAF seemingly didn’t have the mindset or equipment during 1941 for a better outcome.


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## stona (Mar 13, 2015)

Balljoint said:


> The RAF seemingly didn’t have the mindset or equipment during 1941 for a better outcome.



Historically, in 1941, the RAF had already tried daylight bombing and found the cost unsustainable. It was developing the aircraft, tactics and technologies that would enable it, eventually, to launch a devastating night time campaign. It was not developing the aircraft, in the form of long range fighters, that would enable it to carry out another daylight campaign.
It proved late in the war that a blunt night time instrument could also be a very sharp daylight one, but only after the Luftwaffe was defeated.
Cheers
Steve

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## kool kitty89 (Mar 13, 2015)

Shortround6 said:


> 1. It is too late to design a new fighter. Anything you start working on in Dec 1940/Jan 1941 won't show up in squadron service until the beginning of 1943 at best. That leaves you with modifying existing designs. Spitfire is the only with a hope of making 1941( and that would be summer or fall of 1941).
> 2. Without using a time machine to alter development schedule you have pretty much historic engines with historic deployment, no making hundreds of 2 stage Merlins in 1941.


A greater emphais on higher altitude Merlin XX derivatives (or possibly even Hercules variants) should still have been practical in this timeframe. Again, not 2-stage performance, but enough to get operational combat ceilings a bit higher.

Puting an emphasis on turbochargers at that stage might have been useful, but unless the US's own policies for export (and turbo volume production) changed that'd mean setting up domestic British turbocharger manufacturing which probably wouldn't be available any sooner than the 2-stage merlin derivatives anyway. (perhaps more useful mated with Hercules engines, if a greater emphasis on supercharging alone didn't supplant the need there as well)




> 4. People are confusing individual aircraft performance with formation performance. A Lancaster might very well have been able to fly at 23,000ft loaded with bombs, that doesn't mean A, that it could cruise at that height. B, that you could fly a large formation (even a squadron) at that height.
> A. 23,000ft is the height at which it could still climb at 100ft per minute using 2850rpm and 9lbs boost. Max cruise (rich) was 2650rpm and 7lbs boost. Max lean was ????
> B. In formation flying you have to plan speeds/altitude for the worst performing plane in the group/formation to be on the outside of a turn and a using it's max performance to stay in formation while the planes closer to the center of the turn use less power.


Yes, so any shift in doctrine to emphasize day bombing not only would need suitable escorts, but also developing/configuring bombers in a feasible manner. (in tersm of speed and especially altitude)

That would include managing practical loaded weights for the needed cruise altitude as well as using appropriate engines (and allotting said engines accordingly) ... and adapting aircraft to accept the most suitable engines as well.

And along with all that, followon plans for replacing obsolecent interim escorts and bombers with more capable ones.






Shortround6 said:


> Drgondog, no quibble from me on P-51 radius with max fuel. Just trying to show that with less than max fuel even the Mustang was only good for roughly 1/2 way into Germany.
> So even if you could get 150 imp gal into a Spitfire AND hang 120imp gallons outside you get a radius of around 400-410miles (drag 10% worse than Mustang?). Now what hoops had to be jumped through to get 150gal imp into the Spitfire and what is it's performance like with a Merlin 45 or XX?


A side note on fuel carring capacity that I keep avoiding, but: would experimenting with wing-tip fuel tanks (fixed or expendable) have helped issues? They became common post-war and usually performed well aerodynamically, often reducing drag and even improving roll rate (at least when empty). Winglets might not have been understood during the period, but the so-called 'end plate effect' improving the effective aspect ratio of airfoils was at least known.

A clipped wing spitfire with fixed tip tanks seems light it might have been a useful development. (honestly this thought mainly occurred in the context of the P-39 some time back)




Shortround6 said:


> The bulk of the British bomber force in 1941/early 42 was Wellingtons with a lot of Pegasus engines.
> Even if you had escorts the bulk of the British bombing force in 1941/42 wasn't really suited for daylight raids. Too low flying or too slow or both. Without totally revamping production lines (and starting that in 1940) the British are not going to get any sort of daylight bombing force (not counting token raids) until sometime in 1943.
> Maybe those guys in the air ministry knew something after all


Would focus on re-engining (and shifted performance envelope targets for new marks entering production) make the Wellington situation any better?

Aside from that ... before the Mosquito hits volume production, a fast-bomber update to the Bleinheim might be useful in a similar role. A more direct Merlin (or possibly Hercules) powered conversion of the existing bomber than the heavier (and delayed) developments that the Beaufighter experienced. Admittedly a more limited bombload than the mosquito.


Fast bombers (be it early or late war) would be tougher to escort given the high cruise speeds and impact on range of escorting fighters ... but one of the major points of fast bombers is not using escorts as such at all. So focusing escort support on slow heavy/medium bombers in need of such (and possibly even allowing the fast-bombers to target beyond practical escort range) would make sense.

Any bombers simply too vulnerable to even practically escort (including sheer vulnerability to flak) would need to fall back to night raids. (but this could still have been a short-term tactic with emphasis on shifting strategies as soon as viable)




Greyman said:


> For what it's worth the Wellington VI had a ceiling of 36,700 feet at max weight -- 266 mph cruise at 35,000 feet.


With 2-stage merlins.

To manage anything approximating an earlier counterpart to that (but still lower altitude and unpressurized), you'd need some earlier higher altitude tuned engines. Single stage merlins (or maybe hercules) might have done the job well enough to get into the >20,000 ft cruise altitude range.






stona said:


> Historically, in 1941, the RAF had already tried daylight bombing and found the cost unsustainable. It was developing the aircraft, tactics and technologies that would enable it, eventually, to launch a devastating night time campaign. It was not developing the aircraft, in the form of long range fighters, that would enable it to carry out another daylight campaign.
> It proved late in the war that a blunt night time instrument could also be a very sharp daylight one, but only after the Luftwaffe was defeated.
> Cheers
> Steve


Puting Emphasis on flak (and divided development resources) might still have occurred with bombing concentrated at lower 'high' altitudes and medium altitudes, let alone combinations of day and night bombing and fast+unarrmed/unescorted and slow+armmed+escorted arrangements.

Plus it doesn't just depend on what the RAF are actually planning/executing, but the predictions the Germans made regarding expected tactics. (granted, their own experiences with day and night bombing during the BoB probably would have been a reasonable yardstick there ... depending what LW and RLM officialls you actually look at)


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## Denniss (Mar 14, 2015)

Greyman said:


> Fully loaded.


Nope, according to Air Ministry data sheets it was 20k at max weight.

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## Shortround6 (Mar 14, 2015)

kool kitty89 said:


> A greater emphais on higher altitude Merlin XX derivatives (or possibly even Hercules variants) should still have been practical in this timeframe. Again, not 2-stage performance, but enough to get operational combat ceilings a bit higher.



Not really. There is a limit to what you can do with single stage supercharger and they were running into it. A Merlin 46/47 was rated at 1100hp at 22,000ft at 9lbs boost. So you picked up about 3500ft of altitude over a Merlin XX. Because of the single speed you _lost_ about 100hp at take off. Granted with a two speed drive you can get some that back but you are still going to have less take of power than a Merlin XX _or_ a mighty big dip in the power between low gear and high gear. 



> That would include managing practical loaded weights for the needed cruise altitude as well as using appropriate engines (and allotting said engines accordingly) ... and adapting aircraft to accept the most suitable engines as well.



A climb chart from a B-17 shows the plane pretty much leveling out at bit above 36,000ft at a take off weight of 40,000lbs and needing over 240 gal and 130 miles to make the climb. At which point it pretty much has to turn around a land. At 50,000lbs it can make it to 35,000ft using about 440 gallons and 210 miles. 55,000lbs means About 33,000ft, 520 gallons of fuel and 250 miles. 65,000lbs means a bit over 28,000ft, 680 gallons burned and about 325 miles covered during the climb. A B-17 could pull 1000hp per engine for climb all the way to 27,000ft (it actually varied a bit from inner engines to outer because of different intake ducts). There is more than one reason for the US bombing from under 25,000ft. 
Chart for a Lancaster at 65,000lbs show a climb rate of 300fpm at 19,000ft dropping to 100fpm at 22,000ft. plane would take 15 minutes to climb those 3,000ft. You can get a Lancaster to fly thousands of feet above 222-23,000ft, you just have to leave most of the bombs at home. 
In 1941/42 the most suitable engine _is_ the Melrin XX. At least if you want raids by more than a handful of bombers at a time. 



> Would focus on re-engining (and shifted performance envelope targets for new marks entering production) make the Wellington situation any better?



Probably not. They were re-engining the Wellinton at this time. They were sticking Hercules engines in them instead of the Pegasus. It takes time to replace hundreds of bombers in the bomber force and the Pegasus powered planes were shuffled off to coastal command and training units although a number were brought back for the 1000plane raid on Cologne which rather tells you haw many better bombers were actually in service in the Spring of 1942.
Performance targets are going to depend on available engines, you can spec anything you want but if what you have (or can get) are 1600hp engines and not 1900hp engines where are you??



> Aside from that ... before the Mosquito hits volume production, a fast-bomber update to the Bleinheim might be useful in a similar role. A more direct Merlin (or possibly Hercules) powered conversion of the existing bomber than the heavier (and delayed) developments that the Beaufighter experienced. Admittedly a more limited bombload than the mosquito.



I kind of like the Blenheim but it was a rather limited airplane. 
View attachment 287238

The big pipes under the outer wings are the fuel dump outlets. The long nose planes had long rang tanks in the outer wing the short nose planes did not have. In the event of an emergency early in the flight the plane could NOT safely land at the same weight it could take off at and the fuel in the outer tanks had to be dumped before landing. 
Makes putting in bigger/ heavier engines a bit of a problem. The MK V Blenheim was beefed up for extra weights. 
You also don't have an unlimited supply of engines. Perhaps a Merlin powered Blenheim _might_ have been more useful but then what Merlin powered planes _don't_ get built? They built 220 Twin Wasp powered Wellingtons in addition to the 400 Merlin powered ones due to shortages of Merlins and Hercules engines. 




> Fast bombers (be it early or late war) would be tougher to escort given the high cruise speeds and impact on range of escorting fighters ... but one of the major points of fast bombers is not using escorts as such at all. So focusing escort support on slow heavy/medium bombers in need of such (and possibly even allowing the fast-bombers to target beyond practical escort range) would make sense.



The first part is a mistaken premise. The escorts _cannot_ cruise at the speed of the bombers or slightly above or they will not be able to respond in a timely fashion to the attackers. The US escort fighters in 1943/44 routinely cruised at over 300mph weaving back and forth over the 180-200mph bombers. It can take a fighter doing 200-220mph over two minutes to accelerate to full speed. In two minutes a fighter doing 360mph can cover 12 miles. By the time a slow cruising fighter gets up to combat speed it is too late. For the second part, nobody has really figured out _how fast is fast enough_. A-20s that could do over 300mph were't fast enough, Mosquitoes were. where is the dividing line? 



> Any bombers simply too vulnerable to even practically escort (including sheer vulnerability to flak) would need to fall back to night raids. (but this could still have been a short-term tactic with emphasis on shifting strategies as soon as viable)



Which is pretty much any and all bombers the RAF could field in practice in 1941/42 except for the Mosquito. 




> To manage anything approximating an earlier counterpart to that (but still lower altitude and unpressurized), you'd need some earlier higher altitude tuned engines. Single stage merlins (or maybe hercules) might have done the job well enough to get into the >20,000 ft cruise altitude range.



Again, only if you leave most of the bombs home. At which point it starts to become _why bother._


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## Greyman (Mar 14, 2015)

Denniss said:


> Nope, according to Air Ministry data sheets it was 20k at max weight.



The data sheets are for the Lancaster Mk.I/III drawn up in 1945. This is after the myriad of changes made to the type in the preceding three years (new engines, new engine limits, new equipment, new propellers, etc.)

The earlier Lancaster I (which I feel is more applicable to this thread and the one Edgar Brooks was probably referring to) used Merlin XX engines and at that time the maximum take-off weight was 60,000 pounds - compared to the data sheet Lancaster I/III at 68,000 pounds.

An A&AEE test of Lancaster I R5546 (4 x Merlin XX) at the maximum take-off weight of 60,000 pounds shows a service ceiling of 23,000 feet and an absolute ceiling of 24,500 feet.

In 1943 the maximum take-off weight was increased to 63,000 pounds. At Boscombe Down, Lancaster I W4963 (4 x Merlin XX) was tested and gave a service ceiling of 21,400 feet.

In 1945 they tested Lancaster I PD435 (4 x Merlin 24) at 72,000 pounds and had a service ceiling of 20,100 feet.

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## Greyman (Mar 14, 2015)

Shortround6 said:


> Again, only if you leave most of the bombs home. At which point it starts to become _why bother._



I'm not necessarily disagreeing with any of your points but I just want to bring up the fact that - compared to the Lancaster, the Fortress _did_ 'leave most of the bombs home', and the USAAF certainly still bothered.


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## pbehn (Mar 14, 2015)

I think some consideration should be given to how many bombers could be massed into a raid. Bomber command on night time raids wished the bomber stream to pass over flak belts and targets as quickly as possible to minimise losses. The same applied to night fighter opposition, even if a night fighter gets into the bomber stream there is a limit of time, fuel and ammunition to restrict losses. For d. Its OK to speculate about the Mosquito but that oisaylight escorted raids you need a large mass of bombers to destroy the target, to provide covering fire and to overwhelm flak and fighter opposition. The RAF was not in any position to mount raids of 500 single type raids with Halifax and or Lancaster until late in the war. Its Ok to speculate about what could have been done with hundreds (thousands) of mosquito bombers but in fact only a few hundred of each variant were built. The Mosquito performed well against defenses set up to repel massed day and night raids, if it was the only bomber then I am sure things would be very different.


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## Glider (Mar 14, 2015)

The RAF were in a position to mount large daylight raids with the Lancaster and Halifax from 1943 onwards but chose not to, they concentrated on night raids as didn't have a suitable long range escort. In fact no one (incl USAAF) was able to operate effectively by daylight without suffering heavy unsustainable casualties unless they had escorts. Once escorts arrived then the USAAF became really effective and I do not doubt that the RAF could have made the switch with similar results but chose not to as they had become effective at night bombing and would have been second in the queue for escorts anyway.
Tempests were a very effective escort for RAF bombers and could escort raids to the Rhur which is an important target but other things called V1's caused a diversion of resources. To many demands and not enough Tempests was a problem.


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## Shortround6 (Mar 14, 2015)

Greyman said:


> I'm not necessarily disagreeing with any of your points but I just want to bring up the fact that - compared to the Lancaster, the Fortress _did_ 'leave most of the bombs home', and the USAAF certainly still bothered.



A lot of this depends on the mission flown and mission planing. It is quite true that the Fortress did have a rather restricted bomb bay that limited the amount of bombs carried. The Lancaster could and did carry more bombs further than the Fortress but the difference may not be quite as much as is commonly supposed.
According to the end of the war data sheet for the Lancaster I/III (at 68,000lbs) it could carry 10,000lbs for 2250 miles using 2150 IMP gallons (2582 US gal) with 270 gallons being allotted for the "allowance" ( warm up, take-off, climb to height, reserve, etc) and 7,000lbs for 2680 miles using 2550 imp gal ( 3082 US gallons) with the same allowance. Ceiling at the 68,000lbs was supposed to be 20,000ft. 
http://www.wwiiaircraftperformance.org/Lancaster/Lancaster_I_III_ADS.jpg

The manual (pilot's notes) for the B-17F G _shows_ a range chart for a B-17 at 64,200lbs and carrying 6,000lbs as over 3000 (as much as 3200 miles) miles using 2812 US gallons at 25,000ft. Range changes with speed but the max range was at about 215mph true. Trouble with this is that it is a calculated range using NO ALLOWANCES. Actual range using similar allowance to the British might have been 10-20% shorter. Same manual but different chart shows the B-17 at 64,000lbs using 300 US gallons to climb to 20,000ft and using 110 miles. to get to 24,000ft from 20,000ft required _another_ 120 gallons and another 60 miles. 

Range chart : http://zenoswarbirdvideos.com/Images/B-17/17TRC.pdf

The different flight profiles and mission seriously affect *practical* range. British bombers may not have stooged around for anywhere near as long after take-off like the Americans did while getting all the planes into formation. They might not have spent as much time climbing to altitude _before_ setting course for Europe (first way point). Americans may have very well been climbing to operational cruise heights after forming up but while crossing the Channel or North Sea. The outer wing tanks (Tokyo tanks?) may have been a fire/explosion hazard and not used unless really needed? 

If Lancasters had tried flying the same type missions (or mission profile) as the B-17 they might not have carried the same bomb load either. Mission "profile" being take-off, then spend a 1/2 hour (or more) getting into formation and climbing to an intermediate altitude. Then set out for first way point on a course that includes several dog legs (nobody flew direct to target) and climbing to "operational" altitude by the time the formation crossed over land (or at least by first know flak concentration.)
Difference in "ceiling" between a B-17 at 55,000lbs and one at 64-65,000lbs was around 4,000ft. If you want the Lancaster to cruise at 23-24,000ft how may thousands of pounds of bombs/fuel are you going to have to leave behind? 

The Lancaster will carry more bombs further than the B-17 but even with a 4-5000 difference in altitude the difference is not as much as it might seem.


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## Glider (Mar 14, 2015)

I am sure that I have seen stats that showed on average the RAF Lancaster's and Halifax's averaged a 50% increased payload compared to the B17/24.


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## Shortround6 (Mar 14, 2015)

That may very well be but then they weren't flying quite the same mission. They weren't flying in formation which uses more fuel than flying independent even if in a bomber stream. They weren't spending several hundred gallons circling around waiting for the last planes of the formation to take-off. By flying several thousand feet below their "service" ceiling they saved another 100-200 gallons of fuel. Add it all up and there were several thousand pounds they could use for bombs that the Americans were using for fuel. 
This is assuming the same target distance. If you want to use Lancasters and Halifax's on daylight raids using close formations for defense you have to take the bad with the good, and the bad means hundreds more gallons of fuel used per mission which cuts into the bomb load on all the medium and long range missions.


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## Milosh (Mar 14, 2015)

There was also the problem of fitting many LARGE bombs into the B-17/24.


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## pbehn (Mar 14, 2015)

The Sterling was rather good at leaving bombs at home but not so good at getting the crew back there.


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## Shortround6 (Mar 14, 2015)

True.

Please, I am not claiming the B-17 or B-24 was the equal of the Lancaster when it came to lugging bombs over distance, just that difference isn't really as great as is sometimes reported because the reports/stories aren't comparing quite the same thing. Lancasters and Halifaxes didn't burn much fuel chasing planes like this around for 1/2 hour to two hours (?) before heading for Germany. 

http://www.ww2aircraft.net/forum/aircraft-pictures/story-17-a-19761.html


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## pbehn (Mar 14, 2015)

Shortround6 said:


> True.
> 
> Please, I am not claiming the B-17 or B-24 was the equal of the Lancaster when it came to lugging bombs over distance, just that difference isn't really as great as is sometimes reported because the reports/stories aren't comparing quite the same thing. Lancasters and Halifaxes didn't burn much fuel chasing planes like this around for 1/2 hour to two hours (?) before heading for Germany.
> 
> http://www.ww2aircraft.net/forum/aircraft-pictures/story-17-a-19761.html



I dont disagree with the point but o heavy BC raids the crews were given a take off time and coordinates and times to make rendezvous for the bomber stream, one navigator used to take a route across England almost into Wales and then back instead of stooging around over the North Sea. The US bombers were mainly in East Anglia while Bomber command in Lincolnshire and Yorkshire/Durham. Maybe the US forces would have been better further north to allow a smoother forming up?


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## Koopernic (Mar 14, 2015)

Edgar Brooks said:


> I hope I don't appear rude, but you don't seem to be listening. Until Bomber Command returned to daylight raids, at the end of the war, the Air Ministry didn't want them to fly any higher than 18,000'. Here, there seems to be an obsession, at times, with aircraft/engine performance, while the authorities, here (contrary to the "Butcher" Harris title) did make efforts to keep their crews alive.
> 
> I recommend you read "Gunning For the Enemy," the story of tail/mid-upper gunner "Wally" Macintosh, who shot down 8 plus one probable.
> Once "Village Inn" plus infra-red recognition and the gyro gunsight came into use, making tracer redundant (so the fighter pilot didn't know he was being fired at until too late,) things changed massively. This also increased the usefulness of the .5", hence the "Rose" turret.
> ...



The poster is right to query as to whether a high altitude impellor and gear ratio could be introduced for Lancaster's Merlin in 1941. The topic is RAF *daylight* strategic bombing campaign results around 1941. RAF concerns about contrails above 18000ft disclosing their bombers in moonlight are irrelevant during the *daylight.*

18000ft is in effective range of the widespread 8.8cm FLAK 37. Go higher and only the far less common 10.5cm and 12.8cm FLAK can reach.

June/July 1941 marks a major advance in radar with the introduction of the Wurzbug D and its big brother the 7m dish Wurzburg-Riesse radar. The Wurzburg-D featured conical scan and could track a target to within 0.3 degrees. The larger 7m dish Wurzburg-Riesse was twice as accurate again. It had accurate ranging to 25m and could transfer directly into the Kommandogerät 40 FLAK predictor which would provide a full firing and fuse setting solution. The Kommandogerät 40 featured its own tracking optics and a long base coincidence range finder but the combination of optical tracking plus radar ranging was very synergistic. Deployment was rapid since the Wurzburg C and Wurzburg A had been in production for nearly a year.

The point being that a target could now be accurately located and targeted through cloud and night. The angular accuracy was a little less than desired but in daylight quick glimpses of the target through cloud could provide a very accurate update of elevation/azimuth while the radar provided accurate range.

Degrading accuracy of FLAK now meant relying more on *altitude* to induce the natural dispersal of projectiles at range rather than on instrument errors in the coincidence range finders.

In 1941 to at least mid 1942 it would seem it was the Germans that had the superior high altitude engines so flying lower to benefit an allied escort might be advantageous from the escorts point of view but not the point of view of avoiding FLAK.

The deployment of a new generation of technically advanced German gun laying radars was suppressed by the collapse of the Reich in 1944 so the RAF was able to rely on the jamming of many of the older radars thus giving the Lancaster a chance.


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## wuzak (Mar 15, 2015)

Koopernic said:


> The poster is right to query as to whether a high altitude impellor and gear ration could be introduced for Lancaster's Merlin in 1941. The topic is RAF *daylight* strategic bombing campaign results around 1941. RAF concerns about contrails above 18000ft disclosing their bombers in moonlight are irrelevant during the *daylight.*




Contrails were very much a factor during teh daylight







Perhaps more than during the night.


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## wuzak (Mar 15, 2015)

The people of England could see the contrails during the Battle of Britain


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## kool kitty89 (Mar 15, 2015)

Glider said:


> The RAF were in a position to mount large daylight raids with the Lancaster and Halifax from 1943 onwards but chose not to, they concentrated on night raids as didn't have a suitable long range escort. In fact no one (incl USAAF) was able to operate effectively by daylight without suffering heavy unsustainable casualties unless they had escorts. Once escorts arrived then the USAAF became really effective and I do not doubt that the RAF could have made the switch with similar results but chose not to as they had become effective at night bombing and would have been second in the queue for escorts anyway.
> Tempests were a very effective escort for RAF bombers and could escort raids to the Rhur which is an important target but other things called V1's caused a diversion of resources. To many demands and not enough Tempests was a problem.


Would the Typhoon be at all more favorable for conversion to escort range capability than contemporary Spitfires or would its teething troubles make that moot? The cannon bays take up a lot of space that seem prime for fuel (along with potential leading edge space with no cannon barrel punching through it), so omitting 2 of the cannons might be enough to faciliate long range combat radius.

Typhoons might also make better matches for intercepting Fw-190s in the 1942 timeframe.







Shortround6 said:


> The first part is a mistaken premise. The escorts _cannot_ cruise at the speed of the bombers or slightly above or they will not be able to respond in a timely fashion to the attackers. The US escort fighters in 1943/44 routinely cruised at over 300mph weaving back and forth over the 180-200mph bombers. It can take a fighter doing 200-220mph over two minutes to accelerate to full speed. In two minutes a fighter doing 360mph can cover 12 miles. By the time a slow cruising fighter gets up to combat speed it is too late. For the second part, nobody has really figured out _how fast is fast enough_. A-20s that could do over 300mph were't fast enough, Mosquitoes were. where is the dividing line?


I meant more that with fast bombers cruising close to 300 MPH, fighters would be forced to fly even faster to allow a decent escort perimeter and scout around for interceptors. (otherwise resort to flying static top cover formations, which might help fighter range a bit -straight line cruising- but hurt ability to bounce enemy fighters)



> Which is pretty much any and all bombers the RAF could field in practice in 1941/42 except for the Mosquito.


The differnce being that it would be an interim measure until precision bombing capabilities were actually combat feasible.



> Again, only if you leave most of the bombs home. At which point it starts to become _why bother._


What would be the minimum cruising altitude for bomber formations to practically avoid daytime flack well enough that enemy interceptor vs escort abilities become the deciding factor? Would 20,000 ft be enough?

With the lighter configurations of the earlier models of bombers themselves, pushing it a bit higher might have been more feasible in some respects too (without heavier modifications to engine performance envelope -supercharger and reduction gearing- or propellers used) but a different shift in long-term strategy and Bomber Command doctrine could have meant follow-on changes that kept the bombers high altitude capable as they got heavier.




Koopernic said:


> The poster is right to query as to whether a high altitude impellor and gear ration could be introduced for Lancaster's Merlin in 1941. The topic is RAF *daylight* strategic bombing campaign results around 1941.


The more practical counter-point is whether shifting production from historical merlin XX levels (along with propellers in use at the time) would have been practical if indeed they actually made a notable difference at altitude.

The Merlin XX series already cruised well enough in the 20,000 ft range, but having enough power to climb beyond 20,000 ft in a reasonable manner is more the problem.


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## Shortround6 (Mar 15, 2015)

kool kitty89 said:


> Would the Typhoon be at all more favorable for conversion to escort range capability than contemporary Spitfires or would its teething troubles make that moot? The cannon bays take up a lot of space that seem prime for fuel (along with potential leading edge space with no cannon barrel punching through it), so omitting 2 of the cannons might be enough to faciliate long range combat radius.
> 
> Typhoons might also make better matches for intercepting Fw-190s in the 1942 timeframe.



Beside the teething troubles there weren't enough to much of anything until the end of 1942.
First batch of 250 Mk 1a and 1b delivered between September 1941 and June 1942.
Second batch of 250 Mk 1a and 1b delivered between June 1942 and September 1942.
Third batch of 700 Mk1b delivered between September 20th 1942 and May 5th 1943.

Depending on how far you want to go into Germany you need 2 or 3 sets of escorts in relays to cover one set of bombers. 



> I meant more that with fast bombers cruising close to 300 MPH, fighters would be forced to fly even faster to allow a decent escort perimeter and scout around for interceptors. (otherwise resort to flying static top cover formations, which might help fighter range a bit -straight line cruising- but hurt ability to bounce enemy fighters)



you aren't going to get 300mph bombers (cruise) in 1941/42 due to the power of the engines available. 

If somebody has a data Sheet for a Mosquito MK IV??

Mosquito MK XVI with Merlin 72/73 engines could cruise at 311/321mph (with/wo stores under wing) but using such speeds cut the range to 850-1156 miles depending on bomb load and fitting of underwing or bombay tanks. Slowing the plane down extended the range. Cutting several hundred horsepower from each engine is going to lower the 'cruise' speed. 




> The differnce being that it would be an interim measure until precision bombing capabilities were actually combat feasible


.

Interim measures seldom produce good results. The whole "lean forward into France" campaign was sort of an interim measure and it was a disaster. Less known at the time but with post war records of actual German losses the British were big losers just trying to bomb (and suck the Luftwaffe up to fight) coastal Belgium, France, and Holland. 




> What would be the minimum cruising altitude for bomber formations to practically avoid daytime flack well enough that enemy interceptor vs escort abilities become the deciding factor? Would 20,000 ft be enough?



Hard to say what the dividing line is. Definitions change with time. British figured (in 1944) _effective _ ceiling for an AA gun was the Ceiling at which a 300mph flying directly over the gun could be engaged (fired at) for 20 seconds. Not sure what the Germans used for a definition or if definitions had changed from 1941/42. German early 88s were good for (new gun/not worn) a _max_ ceiling of almost 32,500ft and had an _effective_ ceiling of just over 26,000ft. In 20 seconds an 88 could fire 5-6 shells. A 200 mph bomber gives 50% more firing time. The lower the bomber flies the more firing time and the more accurate the fire is. The further to the side of the gun the less firing time the gun has. Due to times of flight of the shells a short engagement time leaves little room for correction, several shells are in the air before the first one/s burst to give gunners any indication if corrections need to be made to the sight settings. 



> With the lighter configurations of the earlier models of bombers themselves, pushing it a bit higher might have been more feasible in some respects too (without heavier modifications to engine performance envelope -supercharger and reduction gearing- or propellers used) but a different shift in long-term strategy and Bomber Command doctrine could have meant follow-on changes that kept the bombers high altitude capable as they got heavier.


It goes back to what you had for available bombers and try to compare them to the American bombers of 1942/43. The American bombers had engines with turbos that would give 1000hp max continuous to 27,000ft or above and they weren't good enough to keep 4 engine bombers doing 200+mph at altitudes over 20,000ft in large formations. Mainly because by the time you get to max cruise *lean* you are down to around 750hp. The Melrin XX wasn't much different. Max lean cruise was around 725-760hp depending on altitude (and without the turbo that was down around 18-20,000ft). Problem for the Melrin XX is that as you go above 18-20,000ft the cruise power drops. The B-17 could hold 750hp cruise to 35,000ft. Makes cruising at 24-26,000ft a breeze. 

So the interim solution seems to be, use bombers that have lousier gun defense than the Americans used, bombers that can't fly any faster, bombers that can't fly as high, and bombers that can't (if you try for high altitudes) carry much more than the American bombers. And use escort fighters that had trouble matching the German fighters over the coastal areas _without_ being burdened with long range fuel tanks. Why the panic over getting MK IX Spits in service? Because the MK Vs couldn't to the job and yet somehow adding several hundred pounds of tanks and fuel will _improve_ the combat results? 




> The Merlin XX series already cruised well enough in the 20,000 ft range, but having enough power to climb beyond 20,000 ft in a reasonable manner is more the problem.



See above.


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## Greyman (Mar 15, 2015)

Shortround6 said:


> Beside the teething troubles there weren't enough to much of anything until the end of 1942.
> If somebody has a data Sheet for a Mosquito MK IV??



Cruising Speed at 15,000 feet according to data sheet
Mosquito IV (Merlin 21) economical: 265 mph - max weak mix: 320 mph


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## stona (Mar 15, 2015)

pbehn said:


> I think some consideration should be given to how many bombers could be massed into a raid. Bomber command on night time raids wished the bomber stream to pass over flak belts and targets as quickly as possible to minimise losses. The same applied to night fighter opposition, even if a night fighter gets into the bomber stream there is a limit of time, fuel and ammunition to restrict losses.



The idea of a bomber stream was to overwhelm the flak defences. There are only so many aircraft that the flak and searchlights could track. 

Similarly the stream overwhelmed the then current night fighter system. When the stream was introduced the night fighters still operated under Kammhuber's original system. Each fighter operated in an area of sky (a 'Himmelbett') from which it could not exit. It couldn't track or follow the stream, the ground interception radar and control system did not allow it. The Germans were eventually forced to change the system, making it more flexible.

Additionally the stream could concentrate the bombing _in time and space _, absolutely essential to a successful, incendiary, area raid.

Cheers

Steve


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## Koopernic (Mar 15, 2015)

kool kitty89 said:


> ?....
> 
> Typhoons might also make better matches for intercepting Fw-190s in the 1942 timeframe.
> 
> ...



I don't think higher than 20000ft is needed in 1941/42 in fact if only Allison engined escorts are available I was thinking as low as 15000ft for bombers since fighters could provide top cover at about 20000ft before being forced down to 15000ft where the bombers they were protecting were (Allison's full throttle height). At 15000ft bombers are more vulnerable to FLAK but the numbers of guns and numbers of radar was nowhere near as high as it would become and fighters are far more dangerous.

They would have been capable of some very accurate bombing over the highly industrialised Ruhr in the summer and fall of 1941. 

If the Merlin XX is available for the escorts then Attack altitude over 20000ft would seem to be practical.

When English Electric purchased Napiers in December 1942 the Sabre engine problems were still prevalent. The Typhoon certainly would make a capable escort as its range was greater than the Spitfire V or IX. The Fw 190s engine issues were generally regarded as solved by then.

There are often throw away statements that the typhoon out performed the Fw 190 but the charts on ww2 perform org show no such thing. They were about even.


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## stona (Mar 15, 2015)

But in 1941 15,000 ft was considered 'lethal' by Bomber Command due to flak. It was flak that forced the Americans (later) to bomb from such high altitudes.

Cheers

Steve


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## Glider (Mar 15, 2015)

Shortround6 said:


> That may very well be but then they weren't flying quite the same mission. They weren't flying in formation which uses more fuel than flying independent even if in a bomber stream. They weren't spending several hundred gallons circling around waiting for the last planes of the formation to take-off. By flying several thousand feet below their "service" ceiling they saved another 100-200 gallons of fuel. Add it all up and there were several thousand pounds they could use for bombs that the Americans were using for fuel.
> This is assuming the same target distance. If you want to use Lancasters and Halifax's on daylight raids using close formations for defense you have to take the bad with the good, and the bad means hundreds more gallons of fuel used per mission which cuts into the bomb load on all the medium and long range missions.



Fair point. The RAF didn't use formation ships or wait until the last aircraft took off. On daylight mission the norm was to set course at a slower speed until the others caught up. Also they didn't fly in such tight formation which in turn saved them fuel along the way. That said your point is a good one and flying in formation of any kind does use more fuel up than being an individual


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## Glider (Mar 15, 2015)

kool kitty89 said:


> Would the Typhoon be at all more favorable for conversion to escort range capability than contemporary Spitfires or would its teething troubles make that moot? The cannon bays take up a lot of space that seem prime for fuel (along with potential leading edge space with no cannon barrel punching through it), so omitting 2 of the cannons might be enough to faciliate long range combat radius.
> 
> Typhoons might also make better matches for intercepting Fw-190s in the 1942 timeframe.



I admit that I hadn't thought about it. On the face of it the Typhoon would be a respectable escort for the bombers and I know it was often used to escort Mosquito bombers. It had a decent range but obviously not in the league of the P51, as for the P47D it had a shorter range but by how much I am not sure. I am confident that others know more than me about this.

It was roughly equal of the Fw190A and that would be the major threat to the Bombers. Numbers would be the problem in 1942 and reliability


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## Shortround6 (Mar 15, 2015)

What "range" on the Typhoon?

It can go further on 154 imp gallons than a P-47 can on 254imp gallons????

http://www.wwiiaircraftperformance.org/typhoon/typhoon-ads.jpg

You put on the drop tanks (assuming they are available in 1942) you fly _IN_ 400 miles, drop the tanks and fight for 15 minutes. You now have 385 miles of fuel left at most economical. The 610 mile range at most economic minus the 3 X 75 miles/5min combat allowance=225 miles. Hope you ended the fight at something over 15,000ft instead of well under because you are going to see how well a Typhoon glides. 
This is assuming there are no headwinds on the trip back or you may be testing the dingy. 

If you want the pretty much standard 30 min reserve to take care of navigation errors, head winds, clouds over home airfield, etc you need to save 20-25imp gallons or about 125 miles worth of range _after_ dropping the tanks. 

Basically the _practical_ radius of a standard typhoon was closer to 250 miles if you count the combat allowance and provide a decent reserve.


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## drgondog (Mar 15, 2015)

To contemplate low level attacks from RAF Bomber command is to ask:

1.) How far into Germany before bombers reported by ground observers all along the penetration route? And how much easier to plot return routes and deploy day fighters along the probable routes home or attach a recon Ju 88 or Me 110 to shadow the returning bombers?
2.) How survivable is a Lancaster vs a B-24 against fighter attack - or against flak of all calibers?
3.) Is there any reason to expect better results with low level Lancaster attacks than the August 1, 1943 Tidal Wave attacks on Ploesti?
4.) How easy is it to flood approach routes to key targets with 20mm flak? 

As to escort strategy? If we are selecting 1941 as the opening of RAF daylight bombing campaign, even given not enough production to offset 10% attrition MIA and 10-20% Class A/B battle damage, then RAF have to have the 'feasible' design in mind in 1939 to get through trials and into serial mass production. The Spitfire is the only airframe with escort potential but the NOTION of long range escort was deemed impossible by RAF, as well as USAAF, through 1941.

The Mustang was an Accident, not clever planning, and forever linked to the idea of "P-40 replacement" for low to medium altitude utility fighter. The Wing Rack and Fuel drop tank ideas first originated with the notion of keeping the NAA Mustang line (and plant and workers) employed by slipping the A-36 procurement into available AAF Dive Bomber funding in early 1942. The notion of Merlin engine modification originated with RR in the last days of April, 1942.

So, the Mustang in numbers to perform medium altitude escort could not begin until late summer of 1943, and immediately subordinated to the P-51B in early fall, 1942 after the RR/RAF results were surfacing.

The Notion of Ferry Tanks on the sly, for the P-38 and P-47 is what stimulated NAA to incorporate the fuel pump and pressurization feed to/from external tanks via vacuum pump - which was mid 1942 - attributed to Ben Kelsey, who was still behind the knowledge curve on P-51 potential as long range escort. The A-36/51A wing tank (external) beat the P-47D by nearly a year - but still two years after RAF BC needs daylight escorts.

So, IMO the Spitfire design team has to have the resources and funding and foresight to design a long range wing for the Spit starting in early 1939, have it operational in mid 1940 and in squadron deployment by late summer 1940 for the RAF to contemplate daylight strategic bombing.

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## pbehn (Mar 15, 2015)

drgondog said:


> As to escort strategy? If we are selecting 1941 as the opening of RAF daylight bombing campaign, even given not enough production to offset 10% attrition MIA and 10-20% Class A/B battle damage, then RAF have to have the 'feasible' design in mind in 1939 to get through trials and into serial mass production. The Spitfire is the only airframe with escort potential but the NOTION of long range escort was deemed impossible by RAF, as well as USAAF, through 1941.



It is common to quote losses in percentages. However losses are in aircraft which have to be replaced. I doubt that any group of 10 bombers (4 engined heavies) trying to raid deep into Germany at any time during the war in daylight would suffer less than 60% losses and would probably be 100% more often than not. You need a massive number of bombers and escorts to keep the losses down to 10%. The UK had just staggered through the BoB in 1940 , I think it is very very fanciful (as some have) to think about forces of 500 x 4 engined bombers and escorts in 1941 when we were struggling to cope with defence of the UK plus N Africa.

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## Shortround6 (Mar 15, 2015)

Quite right, see the link for Lancaster production;
LancasterMonlty Production

For most of 1942 they were building around 50 Lancaster a month getting up to about 100 a month the last two months of the year. Most of 1943 saw around 150 a month and by late summer of 1944 they were over 250 a month. 

Lancasters were not the only arrow in the quiver but some of the other arrows were a bit bent or needed new fletchling if you were going to try to use them as day bombers.


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## pbehn (Mar 15, 2015)

SR6 it is easy to quote the successes of mosquito raids, those raids were conducted while other mass raids were being performed, if they were the only raids they would have met much more resistance. Of the main British bombers available in any numbers in 1941 I can hardly think of any that could form a "group" Sterling Hampden Halifax Wellington? The lanc didnt even appear until 1942 in service.

Some raids had success at low level but operating at low level increases accidents, knocking an engine out at 20,000 ft gives the pilot a problem but knocking an engine out at 50ft is a kill in most cases.


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## mhuxt (Mar 16, 2015)

Of the Mosquito-only raids, the majority took place when the heavies were at home. Any number of Mossies came home "on one", can't agree that the ones that didn't account for most cases. During the daylight raids of '42-'43, overall Mossie loss rates dropped appreciably when they went low-level. Losses to flak went up slightly - if the loss rate to flak had stayed even, the Mossie squadrons could have expected to lose 11.5 aircraft, when in fact they lost 13.


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## kool kitty89 (Mar 16, 2015)

Shortround6 said:


> It goes back to what you had for available bombers and try to compare them to the American bombers of 1942/43. The American bombers had engines with turbos that would give 1000hp max continuous to 27,000ft or above and they weren't good enough to keep 4 engine bombers doing 200+mph at altitudes over 20,000ft in large formations. Mainly because by the time you get to max cruise *lean* you are down to around 750hp. The Melrin XX wasn't much different. Max lean cruise was around 725-760hp depending on altitude (and without the turbo that was down around 18-20,000ft). Problem for the Melrin XX is that as you go above 18-20,000ft the cruise power drops. The B-17 could hold 750hp cruise to 35,000ft. Makes cruising at 24-26,000ft a breeze.


Perils P40 Archive Data

The V-1650-1 is listed at econimical cruise of 2650 RPM 725 hp, low blower, auto-lean at 20,000 ft. (not too much less than the max cruise power at 2320 RPM ... but I suspect British and american standards for maximum cruise might differ a bit)

Also odd that the minimum specific consumption on the merlin is at high RPM, it's certainly not the case on the allison. (granted, minimum specific consumption and most economical power settings for a given aircraft are different matters, but still that's much different from the cruise figures for the V-1710) ... and reading the figures more closely shows 'maximum cruise' at 2,320 rpm high blower 18,000 ft having significantly more power and LOWER fuel consumption than at 2,650 20,000 ft ... so the labeling of those cruise power settings seem a bit odd.

The USAAF chart also leaves a big gap between 20k and 30k ft, but given 20k is still in low blower (while 30k is in high if only 580 hp) that still implies a bit of room for variables there. (though running at lower RPM in high supercharger gear seems to make the most sense in the 20,000 ft range too)



> So the interim solution seems to be, use bombers that have lousier gun defense than the Americans used, bombers that can't fly any faster, bombers that can't fly as high, and bombers that can't (if you try for high altitudes) carry much more than the American bombers. And use escort fighters that had trouble matching the German fighters over the coastal areas _without_ being burdened with long range fuel tanks. Why the panic over getting MK IX Spits in service? Because the MK Vs couldn't to the job and yet somehow adding several hundred pounds of tanks and fuel will _improve_ the combat results?


How much does this comparison differ from the experiences with Luftwaffe precision day bombing during the BoB? (aside from them having no real heavy bombers, though several of the medium bombers were higher performing and/or better armmed)

Hmm, actually the He-111H series with 7 defensive guns during the BoB seems better covered than the british heavies, let alone the later H models with improved armaments. (given the relative sizes, more akin to the B-17's defensive arrangement ... or B-25's )

Lack of waist and ventral guns on british heavies leaves a lot of open spots. (wellington too)







Koopernic said:


> I don't think higher than 20000ft is needed in 1941/42 in fact if only Allison engined escorts are available I was thinking as low as 15000ft for bombers since fighters could provide top cover at about 20000ft before being forced down to 15000ft where the bombers they were protecting were (Allison's full throttle height). At 15000ft bombers are more vulnerable to FLAK but the numbers of guns and numbers of radar was nowhere near as high as it would become and fighters are far more dangerous.
> 
> They would have been capable of some very accurate bombing over the highly industrialised Ruhr in the summer and fall of 1941.
> 
> If the Merlin XX is available for the escorts then Attack altitude over 20000ft would seem to be practical.


Mustang IIs (9.6 supercharged allisons) might have been good enough to provide top cover for bombers cruising at 20,000. Or ... better than overweight spitfire Vs (spit IXs with extended fuel capacity would be another matter). Speed was the big disadvantage of the Spitfire V next to the 190s, and the P-51A fared much better there even at 20,000 ft.

But ... historical Mustang IIs (and P-51As) came too late to be useful anyway and too few with the Mustang III coming online very soon after. (a hypothetical V-1650-1/Merlin XX powered mustang I alternative is another matter though)

But aside from that, long-range spitfire models with expanded fuel and streamlined armaments seem the most practical option. Merlin powered P-40s were too heavy and also a bit late into service anyway ... and arguably worse than the historical Mustang I/Ia even with the limited power at altitude.





pbehn said:


> It is common to quote losses in percentages. However losses are in aircraft which have to be replaced. I doubt that any group of 10 bombers (4 engined heavies) trying to raid deep into Germany at any time during the war in daylight would suffer less than 60% losses and would probably be 100% more often than not. You need a massive number of bombers and escorts to keep the losses down to 10%. The UK had just staggered through the BoB in 1940 , I think it is very very fanciful (as some have) to think about forces of 500 x 4 engined bombers and escorts in 1941 when we were struggling to cope with defence of the UK plus N Africa.


Wouldn't this be another argument in favor of focusing on shorter/medium range bombing objectives? (more like the RAF already was, just with the shift to daylight precision bombing)




drgondog said:


> The Mustang was an Accident, not clever planning, and forever linked to the idea of "P-40 replacement" for low to medium altitude utility fighter. The Wing Rack and Fuel drop tank ideas first originated with the notion of keeping the NAA Mustang line (and plant and workers) employed by slipping the A-36 procurement into available AAF Dive Bomber funding in early 1942. The notion of Merlin engine modification originated with RR in the last days of April, 1942.


A lot of this was also just looking for middle ground though. Not something as good as the mustang, just something closer to what the P-47C, P-40, or even P-39 could manage in 1941/42. (except not the P-47 since it wasn't combat ready yet, let alone in sufficient numbers) Or for that matter, similar to the P-38 or P-51/Mustang I's combat radius without drop tanks.

The RAF didn't need a 'long' range fighter in the USAAF sense for this scenario ... just a normal/medium range one rather than the short range aircraft they actually had in force.






Shortround6 said:


> Basically the _practical_ radius of a standard typhoon was closer to 250 miles if you count the combat allowance and provide a decent reserve.


Yes, which is why I brought it up with the specific context of expanding internal fuel capacity as well.
And given the timing of the Mustang and Spitfire IX, a medium/long range Tempest might still have been useful. (Spitfire IX with expanded fuel capacity would probably the main target though)


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## wuzak (Mar 16, 2015)

2,650rpm, +7psi boost was the maximum continuous (cruise) power of later Merlins.


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## Shortround6 (Mar 16, 2015)

> knocking an engine out at 20,000 ft gives the pilot a problem but knocking an engine out *at 50ft is a kill in most cases*





> Any number of Mossies came home "on one", can't agree that the ones that didn't account for most cases.



Mossies are NOT most cases. Try loosing an engine on a Blenheim, Hampden, or Wellington at 50ft and see what the odds of surviving are. And those three aircraft made up the bulk of bomber Commands aircraft in 1941 and for a good part of 1942. 
Hopefully nobody was thinking of sending Whitleys on low level missions, the other 1941 mainstay. 

Some (many) of the early twins didn't have feathering propellers so a 'dead' engine was real problem. Prop could only be set to max pitch (if the prop control worked) and pilot/crew hoped for the best.


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## Greyman (Mar 16, 2015)

kool kitty89 said:


> Hmm, actually the He-111H series with 7 defensive guns during the BoB seems better covered than the british heavies, let alone the later H models with improved armaments.
> 
> Lack of waist and ventral guns on british heavies leaves a lot of open spots. (wellington too)



The Wellington (Ia) had a retractable mid-under turret (though it was quite unsatisfactory) and a port/starboard .303 in each side (Ic on).

The firing arcs of the mid-upper turrets of the four-engined heavies were capable of covering the sides.

Mid-under turrets were fitted to the Stirling, Halifax and Lancaster - but these didn't last long as they weren't very useful at night.

The German bombers' defensive armament had a few shortcomings - one can't merely count the barrels.

 hand-held on gimbal mountings: much more difficult to fire steady, accurate bursts than weapons mounted in a powered turret
 magazine-fed: every 75 rounds the gunner has to change magazines, as opposed to the 500 to 2,500 rounds belts the British turrets used
 ring-and bead sights


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## Shortround6 (Mar 16, 2015)

kool kitty89 said:


> How much does this comparison differ from the experiences with Luftwaffe precision day bombing during the BoB? (aside from them having no real heavy bombers, though several of the medium bombers were higher performing and/or better armmed)
> 
> Hmm, actually the He-111H series with 7 defensive guns during the BoB seems better covered than the british heavies, let alone the later H models with improved armaments. (given the relative sizes, more akin to the B-17's defensive arrangement ... or B-25's )



You have *got* to be joking? 
Most He-111s were lucky they had six guns let alone seven. The idea that a single gun (1000rpm) with a 75 round magazine manually aimed on a pivot mounting was the equal of 2 or 4 guns (11-1200rpm) with belt feeds and powered mountings is quite a stretch. That fixed gun in the tail of the He 111 did a to of good too. Mostly for morale of the bomber crew. Didn't stop others from trying it. He 111 didn't get a powered (if you could call it that) top turret until 1942. 



> Lack of waist and ventral guns on british heavies leaves a lot of open spots. (wellington too)



British tail turrets had a pretty wide field of fire, usually much larger than most early US tail positions. 

The best (easiest to aim) firing position was dead astern. the more around to the sides you get the more deflection (lead) was needed and the more difficult the firing solution became. 

But basically it comes down to if the American bombers with 9-13 .50 cal mounts with 2-4 powered mounts couldn't defend themselves then how does 6-10 .303 guns with 2-3 powered mounts look like it's going to work? 




> Mustang IIs (9.6 supercharged allisons) might have been good enough to provide top cover for bombers cruising at 20,000. Or ... better than overweight spitfire Vs (spit IXs with extended fuel capacity would be another matter). Speed was the big disadvantage of the Spitfire V next to the 190s, and the P-51A fared much better there even at 20,000 ft.



Speed only counts for so much, once you have done a couple of 180 turns speed and/or altitude has bled off considerably. Now you need acceleration/climb to get back in the game. This is one reason the British passed on the P-40s in late 1940 and early 41 compared to the Hurricane. They were faster but once speed was bled off in the first few maneuvers they were headed for being sitting ducks.


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## mhuxt (Mar 16, 2015)

Shortround6 said:


> Mossies are NOT most cases.



That's fair enough - I had thought the reference was specifically to >twitch< Mosquitos >twitch<


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## pbehn (Mar 16, 2015)

mhuxt said:


> Of the Mosquito-only raids, the majority took place when the heavies were at home. Any number of Mossies came home "on one", can't agree that the ones that didn't account for most cases. During the daylight raids of '42-'43, overall Mossie loss rates dropped appreciably when they went low-level. Losses to flak went up slightly - if the loss rate to flak had stayed even, the Mossie squadrons could have expected to lose 11.5 aircraft, when in fact they lost 13.




I am not twisting your tail mhuxt and I am a great admirer of the Mosquito. From when the Mosquito was introduced BC had already switched to night bombing. The mossie made many famous precision raids but total production for all types was 7,781 compare to 7377 Lancasters 6176 Halifaxes. To use the Mosquito as a strategic weapon may have been possible in hindsight but only in hindsight, to use the Mossie in such a role would need the decision to be made before the aircraft was even designed. I know many mosquitos came home on one engine, many four engined AC came home on three or even two but they didnt lose the engine while under fire 50ft from the ground. If the RAF had committed to a force of mosquito types then the LW would have committed to a response. Many of the famous mossie raids were against places like Oslo, Copenhagen and a Berlin Radio station and a French prison. I am not knocking the raids or the people involved at all but it was a different matter to hit properly defended targets. I doubt if the LW considered Gestapo headquarters or prisons to be targets at all or at least until a few were hit.

The thread is about RAF daylight bombing in 1941/42 the mosquito could hardly figure in any meaningful sense until 1943, my original comments concerned RAF bombers other than the mosquito used in low level raids. I had in mind the Lancaster raid on Augsburg April 1942 which was heavily hit by interceptors and flak and never repeaded because a Lanc is not a mosquito.


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## mhuxt (Mar 16, 2015)

pbehn said:


> I am not twisting your tail mhuxt



No worries, heheheh my post was mostly Pavlovian: "Gack! Discussion mentioned Mosquito! Must ... post ..."

Reactions: Like Like:
1 | Like List reactions


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## wuzak (Mar 16, 2015)

The low level raid against Augsburg by Lancasters was a disaster, but the raid against Cruesot was successful.

As posted earlier in the thread: 17th October 1942: Operation Robinson hits Le Creusot works

It maybe the size of the attack had some bearing - the Augsburg raid was smaller.


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## Greyman (Mar 16, 2015)

wuzak said:


> The low level raid against Augsburg by Lancasters was a disaster, but the raid against Cruesot was successful.
> 
> It maybe the size of the attack had some bearing - the Augsburg raid was smaller.



I think it was because there was a navigation/planning error and a portion of the Augsburg formation flew directly over a Luftwaffe fighter base.


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## pbehn (Mar 16, 2015)

wuzak said:


> The low level raid against Augsburg by Lancasters was a disaster, but the raid against Cruesot was successful.
> 
> As posted earlier in the thread: 17th October 1942: Operation Robinson hits Le Creusot works
> 
> It maybe the size of the attack had some bearing - the Augsburg raid was smaller.



I agree but Augsburg is in Germany Le Creusot is in Central rural France.


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## pbehn (Mar 16, 2015)

Greyman said:


> I think it was because there was a navigation/planning error and a portion of the Augsburg formation flew directly over a Luftwaffe fighter base.



There were diversionary raids to support the attack, some LW aircraft returning to base saw the Lancs trying to sneak through. That was bad luck bu just a couple of LW fighters created havoc.


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## Shortround6 (Mar 16, 2015)

I believe the this was mentioned earlier in the thread. Le Creusot was just a few miles from Vichy France and part of the flight path may have crossed Vichy France. I am don't know what the flight path was but there is a photo of the formation flying over a small town near Tours which certainly suggests a roundabout route. Which is a perfectly good tactic, it just doesn't tell us how well that would have worked over Germany.


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## stona (Mar 17, 2015)

The rout took the Lancasters around Brittany and over the sea down the Atlantic coast of France before they turned inland, crossing the coast north of La Rochelle. This meant that they only flew over a relatively narrowl tongue of the occupied zone that extended south to the Spanish border (to include France's important Atlantic ports and Bordeaux) before continuing the flight eastwards over Vichy France. The last way point, from which the climb to bombing height began, was Nevers. The raid was timed so that much of the return flight was made under cover of darkness.
It was quite a different operation to the attack on Augsburg, six months earlier. The British had learnt their lesson from that one. The next day light target was Milan, not Berlin 
Cheers
Steve


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## kool kitty89 (Mar 17, 2015)

Greyman said:


> The Wellington (Ia) had a retractable mid-under turret (though it was quite unsatisfactory) and a port/starboard .303 in each side (Ic on).
> 
> The firing arcs of the mid-upper turrets of the four-engined heavies were capable of covering the sides.
> 
> ...





Shortround6 said:


> You have *got* to be joking?
> Most He-111s were lucky they had six guns let alone seven. The idea that a single gun (1000rpm) with a 75 round magazine manually aimed on a pivot mounting was the equal of 2 or 4 guns (11-1200rpm) with belt feeds and powered mountings is quite a stretch. That fixed gun in the tail of the He 111 did a to of good too. Mostly for morale of the bomber crew. Didn't stop others from trying it. He 111 didn't get a powered (if you could call it that) top turret until 1942.



I'd actually been thinking more in terms of the B-17D's configuration when comparing the He-111 ... somewhat off topic given the 1941 British heavy bombers had much more stable gun placements, even if lighter guns. (and the turret equipped medium bombers) Not to mention nearly identical to the B-17C's armament, and the Fortress I didn't fare very well in RAF service. So the British were actually a good bit ahead in that respect.


But the Fortress I does remind me of another issue I keep forgetting to comment on: bombing accuracy. If the day bombers can't actually manage to hit precision targets on day raids, even if not shot down, that's a huge problem too. Bombing at higher and higher altitudes becomes problematic there, and the bombsights in use would be one of the deciding factors.



> But basically it comes down to if the American bombers with 9-13 .50 cal mounts with 2-4 powered mounts couldn't defend themselves then how does 6-10 .303 guns with 2-3 powered mounts look like it's going to work?


The comments on armament are more towards 'being good enough to allow the escorts to be effective.' So limiting the options for attacking interceptors (and especially close-up attacks). 

If the existing armament on 1941/42 heavy bombers (or medium bombers for that matter) could manage that, and manage a high enough altitude to avoid unsustainable losses from flack alone, and they could manage accurate bomblaying, then the deciding factor would be escorts.


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## Shortround6 (Mar 17, 2015)

And there you pretty much have your answer/s.



> The comments on armament are more towards 'being good enough to allow the escorts to be effective.' So limiting the options for attacking interceptors (and especially close-up attacks).



RAF/Bomber Command pretty much turned away from Daylight attacks after the Fall of 1939 when they lost a number of planes trying to attack the German Warships in home ports. Granted the early Wellingtons did not have self sealing tanks and the early gun positions, while powered, didn't have the range of motion of the later turrets and the the tail position was only 2 gun. The 4 gun tail turret was introduced at some point in 1941 with somewhere between 1000-2000 (correction welcome) Wellingtons built with 2 gun tail turrets. For 1941 they would be the bulk of available bombers.



> If the existing armament on 1941/42 heavy bombers (or medium bombers for that matter) could manage that.


The heavy bombers don't really show up until 1942. and then some are rather late. Lancaster, which seems to be every-bodies favorite had a total of 290 planes by the end of July 1942. That is NOT the number issued to units. that lags a few weeks or a few months. 
There were only 202 Manchesters built and the less said about that the better. 
The first several hundred Halifaxes had Merlin X engines. and this for performace;
http://www.wwiiaircraftperformance.org/Halifax/Halifax_I_ADS.jpg
There were under 150 Halifaxes built by the end of 1941.
One of the two main 4 engine type in 1941 and early 1942 was the Stirling. 2 gun turret in nose, 2 gun dorsal turret, two gun retractable belly turret and 4 gun tail turret. There was some variation between belly turrets, waist guns and top turrets on the very early planes. 
And "Main" may give a wrong impression as it took until Early 1942 for a 3rd squadron to become operational on Stirlings. 



> and manage a* high enough altitude* to avoid unsustainable losses from flack alone


The Manchester, Stirling and early Halifax and most of the twin engine bombers were quite incapable of flying at anything near a high enough altitude _while carrying *both* a high bomb load and large amount of fuel._ Few of these planes had a service ceiling of over 20,000ft in full loaded condition and could only make 22-23,000ft by lightening the plane by around 10,000lb for the heavies.

Neil Stirling was kind enough to post some links to RAF data Sheets for many RAF twin engine bombers a while back.

Her are the links again. 

http://www.ww2aircraft.net/forum/re...s://dl.dropbox.com/u/93074546/RAF%20Twins.rar

http://www.ww2aircraft.net/forum/re...dl.dropbox.com/u/93074546/RAF%20twins%202.rar

This should provide a base for estimating what could and could not be done by running planes light or changing engines to some extent (Hercules III s instead of Pegasus, etc)
Data cards for Halifax and Lancaster are at Spitfire performance. Short Stirling may be among the missing?


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## EKB (May 23, 2015)

Koopernic said:


> Of course long range missions in 1941 with escorts are essentially impossible unless the Spitfire V is properly prepared. The Spitfire carried around 90 Imp gallons of fuel in tanks behind the engine which gave a range of around 400 miles. Historically 2 smaller tanks were fitted in the wing leading edges (4 in all) which increased internal fuel tankage by around 33% and range of some marks of Spitifre VII and VIII by around 50% (600 miles) over the Spitfire IX which lacked it. This suggests to me escort radii with drop tanks of around 400-450 miles. Historically many spitfires also had tail tanks which tended to be regarded as ferry tanks only due to their destabilising effects in combat. However if only 10 gallons (instead of 44-50 gallons) I'm sure the effect would be minimal and further range increases would be possible.




Unfortunately there was another unresolved obstacle to flying long distance combat in British fighters. Nearly all Spitfires, including the Mk IX, had no cockpit heating system. 

The canopy frosted up quickly at high altitude, especially during winter months. The pilot’s oxygen tube often froze, causing the pilot to inhale ice crystals. There were more than a few complaints about the guns freezing. Cold weather was a deadly serious problem if the missions were extended from 90 minutes to five hours or more.

The long-range Spitfire PR Mk XI (circa 1944) had no guns and a crude cockpit heater that failed to stop icing and misting.

A good example of icing in the cockpit from Don Caldwell, The JG 26 War Diary: 1939-1942, p.307:

*4th December 1942*
_“ At 1410 the St. Pol Jäfu scrambled three Gruppen on reports that four formations were approaching the coast. These were RAF aircraft on Rodeo No. 115, a sweep of the Pas de Calais by twelve Spitfire squadrons. The all-Canadian Kenley Wing, flying its first mission as a wing, was having difficulty keeping formation, which is probably why it was the only unit seriously engaged. 
Many of the Spitfire’s canopies had frosted up in the minus fifty-degree temperatures, and few of No. 401 Squadron’s pilots, flying as top cover, saw Hptm. Seifert’s Focke-Wulfs dive through them over Marquise to attack No. 402 Squadron just as the wing turned at the end of its sweep. The Spitfires scattered in all directions, and before re-forming over Boulogne and withdrawing to England were attacked by Focke-Wulfs from the other Gruppen. 
The pilots of the Geschwader claimed seven Spitfires; six of these claims were confirmed. The Canadians lost five Spitfires and three pilots; the only loss to the Geschwader was the damage one Third Gruppe FW 190 sustained while landing on Wevelghem with a blown tire. ”_

Casualties from Aircrew Remembered: world's premiere aviation personal history site

BATTERS Sgt Harold Mark From Portage La Prairie, MB, Born in 1921 Served w/ 401 Sqn On 4 Dec 1942 flying Spitfire F.IX BS277 for a sweep over the Pas de Calais, he is s/d by Fw-190 from JG 26 over Guines and KIA.

FIANDER P/O J.W. Served w/ 401 Sqn On 4 Dec 1942 flying Spitfire F.IX BS536 for a sweep over the Pas de Calais, he is s/d by Fw-190 from JG 26 over Guines. Rescued. 

HONEYCOMBE Sgt R.B. USA From Brooklyn NY Served w/ 402 Sqn On 4 Dec 1942 flying Spitfire F.IX BS132 for a sweep over the Pas de Calais, he is s/d by Fw-190 from JG 26 over Guines and KIA.

McGRAW Sgt H.E. Served w/ 402 Sqn On 4 Dec 1942 flying Spitfire F.IX BS450 for a sweep over the Pas de Calais, he is s/d by Fw-190 from JG 26 and KIA. 

NICKEL Sgt B.H. Served w/ 401 Sqn On 4 Dec 1942 flying Spitfire F.IX BS317 for a sweep over the Pas de Calais, he is lost near Audruicq possibly because of Oxygen failure and KIA.

SIMPSON F/O H.A. Served w/ 402 Sqn On 4 Dec 1942 flying Spitfire IX BS309 for a sweep over northern France, he is s/d and crash-lands at Hawkinge.


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## gjs238 (May 23, 2015)

Did any US WWII aircraft not have cockpit heaters?


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## stona (May 23, 2015)

EKB said:


> Unfortunately there was another unresolved obstacle to flying long distance combat in British fighters. Nearly all Spitfires, including the Mk IX, had no cockpit heating system.


 

You might want to check that.

Steve


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## tomo pauk (May 23, 2015)

What Steve said.


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## RCAFson (May 23, 2015)

stona said:


> You might want to check that.
> 
> Steve


paragraph 33 of the Spitfire V PNs:


> Cockpit heating and ventilation.- A small
> adjustable flap on the starboard coaming above
> the instrument panel is provided for ventilation
> of the cockpit. The flap is opened by turning
> a knurled nut underneath the flap.



The same control is available on the Spitfire IX.


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## EKB (May 23, 2015)

RCAFson said:


> paragraph 33 of the Spitfire V PNs:
> 
> 
> The same control is available on the Spitfire IX.





If any heat actually reached the cockpit, apparently it was not noticed by the pilots.


“ I went on a show this afternoon and damn near froze to death. I sure wish the Spitfire had a heater. In fact, my oxygen tube would freeze and when I'd squeeze it, ice crystals would blow up into my mask and slap me in the face. Very refreshing when its about 40 below, very.”

Lee Gover, 
336th Fighter Squadron, USAAF (Spitfire V)



“ the P-47 really shined when it was headed downhill. The dive performance was truly spectacular ... I really liked the cockpit heating system, which kept the pilot reasonably comfortable even at 30,000 feet, where the temperature was minus 60 degrees. The heating system also did a good job of keeping the windshield clear of frost. In a Spitfire, if you made a long dive the windshield would frost over at about 15,000 feet, leaving the pilot blind until it cleared. That didn't happen in the P-47 ”

Lt. Colonel Francis Gabreski
315 Squadron, RAF (Spitfire IX)
63rd Fighter Squadron, USAAF (P-47D)



“ A cramped cockpit at -50 degrees is not not the most comfortable work place. At altitude the heater in the Spitfire or F-5 was not much good ... From April 1944 to October I flew 36 missions in the Spitfire.”

John Blyth
7th Photo Recon Group, USAAF (Spitfire PR XI)


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## EKB (May 23, 2015)

RCAFson said:


> Quote Originally Posted by stona View Post
> You might want to check that.
> 
> Steve
> ...





If any heat actually reached the cockpit, it was apparently not noticed by the pilots.

_“ I went on a show this afternoon and damn near froze to death. I sure wish the Spitfire had a heater. In fact, my oxygen tube would freeze and when I'd squeeze it, ice crystals would blow up into my mask and slap me in the face. Very refreshing when its about 40 below.”_

Lee Gover 
336th Fighter Squadron, USAAF (Spitfire V)



_“ The P-47 really shined when it was headed downhill. The dive performance was truly spectacular ... I really liked the cockpit heating system, which kept the pilot reasonably comfortable even at 30,000 feet, where the temperature was minus 60 degrees. The heating system also did a good job of keeping the windshield clear of frost. In a Spitfire, if you made a long dive the windshield would frost over at about 15,000 feet, leaving the pilot blind until it cleared. That didn't happen in the P-47.”_

Francis Gabreski
315 Squadron, RAF (Spitfire IX)
63rd Fighter Squadron, USAAF (P-47D)



_“ A cramped cockpit at -50 degrees is not the most comfortable work place. At altitude the heater in the Spitfire or F-5 was not much good ... From April 1944 to October I flew 36 missions in the Spitfire.”_

John Blyth
7th Photo Recon Group, USAAF (Spitfire PR XI)


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## Koopernic (May 24, 2015)

Presumably the Mk VI and VII, with their pressurised cockpits, had such. How would one stop condensation on the canopy? This can completely blind a pilots view if changing conditions cause the condensation to freeze.


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## stona (May 24, 2015)

EKB said:


> At altitude the heater in the Spitfire or F-5 was not much good ... From April 1944 to October I flew 36 missions in the Spitfire.”
> 
> John Blyth
> 7th Photo Recon Group, USAAF (Spitfire PR XI)




Well a heater that is "not much good" at 30,000 ft is not the same as no heater. You've rather confirmed what others have written above.

Nobody said that the Spitfire had a good cockpit heater, they just said that you were incorrect to say that it didn't have one at all. Maybe another internet myth nipped in the bud 

Cheers

Steve


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## kool kitty89 (May 25, 2015)

Koopernic said:


> Presumably the Mk VI and VII, with their pressurised cockpits, had such. How would one stop condensation on the canopy? This can completely blind a pilots view if changing conditions cause the condensation to freeze.


Does anyone know if cockpit heating vents were arranged similar to automobile windshield defrosters? This would seem like the most straightforward solution. (Bell took the much more complicated approach of using a double-paned canopy in the P-59, with heated air ducted between the panes -a feature that ended up rather troublesome on the XP-59A given it couldn't be shut off and made the cockpit excessively hot in the desert testing grounds at Muroc)


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## bobbysocks (May 26, 2015)

i remember reading about the early 38s...that either didnt have a heater or it wasnt very effective.


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## kool kitty89 (May 26, 2015)

bobbysocks said:


> i remember reading about the early 38s...that either didnt have a heater or it wasnt very effective.


I believe the early P-38s lacked cockpit heating but featured gun heaters. That on top of the compressibility issues are some of the reasons a non-turbo version would have been relatively attractive. (somewhat cost/complexity reduced and optimized for operations at altitudes where the heating and compressibility problems were much less severe, while having overall superior performance than the P-40 or P-39 and better low alt performance, range and early war bombload than the P-47)

There's the cost to performance/value (survivability included) issue to compete with the cheaper P-40 and P-39, but that isn't even the deciding factor until volume production is actually feasible.


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## Glider (May 27, 2015)

I just read a piece on the American Mosquito's. A navigator from a B24 unit was transferred to fly on the mosquito. He refused to believe that he could stay warm so went up fully dressed in everything and almost passed out he was so hot. The one ting a mosquito lacks is room to get rid of extra clothing.


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## EKB (May 28, 2015)

*25 October 1943*
_" But we had dived in a very short time from the Arctic cold of twenty-five thousand feet, and the moisture from the warmer air below began to cake in solid ice on our windscreen. In a few moments it was opaque, and although by the time we had pulled out of our dive the range had closed to two thousand feet we could see nothing through that sheet of ice."_

25th October 1943: Mosquito night fighter over London AA fire


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## Greyman (May 28, 2015)

There are a lot of anecdotes of Spitfires having problems with windscreens icing up.

After his short stint of operational experience in the Battle of Britain, Jeffrey Quill (Supermarine test pilot) had in his report:

_"Windscreen Condensation. Internal condensation on the bulletproof glass is a very serious defect. Aircraft operate for long periods at high altitude on patrol and then may descend 20,000 ft. in a few seconds. The aircraft is rendered entirely inoperative as a fighting machine by the fact that the windscreen and sighting line become obscured. Immediate steps must be taken to cure this."_


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## kool kitty89 (May 28, 2015)

Is it possible that proper operating procedures for the cockpit heaters in the Spitfire V were improperly briefed, at least in some squadrons?


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## Greyman (May 28, 2015)

It was common enough that I doubt it was due to forgetting any particular procedure. One anecdote I remember but can't recall specifics (so as to find it) told of a Spitfire formation jumping a formation of 190s and the Germans half-rolled and dived for home. As the Spitfires dived after them the author looked left and right at the others in his Section and saw them all scraping their windscreens along with him.

The Spitfire XIV had a de-icing system that sprayed glycol on the windscreen. Many American fighters (Kittyhawk, Lightning, Mustang) had warm air from the coolant radiator blast directly onto the armoured glass.

The Airacobra and some Mustangs also had glycol spray.


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## EKB (May 29, 2015)

Alan Deere wrote that the problem of misted over cockpits was never solved in British aircraft during World War II.


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## Greyman (May 29, 2015)

From what I can tell the Meteor might have been good in this regard. The windscreen used the "dry air sandwich" method, internal moisture was prevented with silica-gel containers, and there was a windscreen de-icing pump.


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## kool kitty89 (May 29, 2015)

Any information on whether the bubbletop P-47s had any trouble with condensation or icing that the razorback versions? (aside from the good cockpit heating, I'm wondering if the canopy geometry had an effect)

Also, I was replying more to the issues of the Spitfire being unbearably cold and without heating than without defrosting/defogging. It's plenty believable that the heating ventilation system wasn't oriented/ducted in a way that facilitated windscreen heating/drying. Having wholely inadequate/nonexistent heating for the pilot is more the issue that confuses me. (post Spitfire II/BoB in particular)


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## tomo pauk (May 30, 2015)

bobbysocks said:


> i remember reading about the early 38s...that either didnt have a heater or it wasnt very effective.




Heating was insuficient. The solution for the problem was provided once second geneartor was installed (early 1944), the greater supply of electric power meant that guns were heated electrically, so the stream of hot air that previously was heating the guns was re-routed to the cockpit.


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## kool kitty89 (May 30, 2015)

tomo pauk said:


> Heating was insuficient. The solution for the problem was provided once second geneartor was installed (early 1944), the greater supply of electric power meant that guns were heated electrically, so the stream of hot air that previously was heating the guns was re-routed to the cockpit.


Hadn't considered it before, but I wonder if they could have added a heater core as part of the intercooler system on the early P-38s ... then again, probably a big engineering pain there too given they were air to air intercoolers. Still, with the radiator cooling lines all routed to the aft portion of the booms, that leaves the turbo/manifold/intercooler ducting and oil coolers as the main sources of heat anywhere close to the cockpit. (without greatly expanding the coolant loop for the radiators)

I suppose air bled off the turbocharger manifold before reaching the intercoolers could work too. Hot, pressurized air ducted and blended into the cockpit ventilation system. That'd probably be much simpler than any sort of expanded heater core arrangement.


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