WW2 Strategic Bomber Characteristics

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i've writed the reply to wuzak&parsifal before to read your 52nd post.
AFAIK the Lancaster radius with a 22,000 lbs bomb is 775 miles well beyond Berlin so can do the same with the 14,000 load
 

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Glider said:
a) the pathfinder units were manned by the best and most experienced crews in the RAF and it would make sense to give them the maximum chance of survival.
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I'm afraid that this is something of a myth too.

The Pathfinder crews were drawn from regular squadrons and did not have any special qualifications.The various Groups were supposed to send their best crews but as Bennett noted 4 and 6 Groups loyally did so whilst the AOC's of other Groups were less scrupulous,sometimes simply sending men that they wanted rid of.
They did receive extra training,a two week course at Warboys, and were expected to complete a minimum of 45 rather than 30 missions in order to maximise the benefits of the extra investment.

The vast majority of Pathfinder crews were men who had completed 10-15 missions with Main Force who then either volunteered for,or were drafted into the Pathfinders. They were not otherwise remarkable. A very small number of crews who had shown exceptional promise in training went directly to the Pathfinders. Another minority was men on their second or third tours who were extremly proficient and simply wanted to carry on until the war ended or the grim reaper intervened.
One 44 Sqn crew was "volunteered" for the Pathfinders simply to get the pilot away from the base commanders WAAF driver!
It was not unheard of for tight knit crews to seperate prior to joining the Pathfinder Force. Some men wanted nothing to do with an extended 45 mission tour.

There was much controversy within Bomber Command regarding the Pathfinders. Main Force crews blamed them for bad or incorrect target marking. Max Hastings notes that following the failiure of the Battle of Berlin

"Their [Pathfinder] crews were little better qualified or more experienced than those of Main Force,and were almost as prone to the problem of creep back."

Bennett's response was to claim that 50% of Main Force crews "never troubled to use their bombsight."

Towards the end of the war the Pathfinders of 8 Group and those crews doing the same job in 5 Group (Cochrane's independent air force) had a plethora of sophisticated marking systems,but they could never beat the weather.

Cheers

Steve
 


Your right about the first flight date, thanks, but fail to take into consideration that the contract to build the prototype was not signed until March 1940, andf there were two cancellations, one by Beaverbrook that took out nearly three months development time. moreover, more than a 1/3 of the design team were press ganged by the ministry into other work.

Facts are, the Mosquito as a concept was at least 2 years older than the Stirling, and most of the concept design was completed before the Stirling was even on the drawing board.

You can rely on the data cards if you like (which are different to the ones I have), but that doesnt avoid the fact that the Mosquito had the lowest loss rate of any type. i dont care if you argue that Mosquitoes approached targets at walking pace, you cannot their fantqastically low loss rates away. And, the facts are, Mosquitoes were regulalrly hitting Belin with 4000 lb cookies, and 2000lb internal bombloads (in separate aircraft) and not suffering antwhere near the loss rates of their companions.

I dont understand your range to payload figures. they appear grossly wrong to me. RAAF Mosquitoes were flying from Courallie to northern Borneo, with roughly twice that payload (in fuel and gear) and twice the range at least. The RAE test reults also conflict fundamentally with what you are saying. None of the more qualitifed experts in this place appear to believe you either. Maybe its time for you to re-think your claims
 
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As a category of interest, I like stall speed in max gross weight configuration for strategic bombers. That, together with powerweight determines the take off run (some bombers frequently used up 6000ft runway length, limiting its potential airbase deployment), a lower stall speed allows for more easy approach and landing.
It's often found to be compromised for an edge in the high speed realm but some examples are really weird (the pe2 had jetlike stall speed).
 
I thought the aircraft notes might be of help, and attach them. From my reading of them, Vincenzo is almost certainly quoting IAS figures, which are a gross undersetimation of the true performance figures. When IAS is showing 236 @ 30K altitude for example, the aircraft is actually clocking 376mph (TAS).

The notes show there are two basic cruise configurations, an economical cruise and a max economical cruise. There is little difference between the max cruise fuel consumption rates and normal econmical cruise consumption rates.
The aircraft is better off incidentally not using max economical cruise under most conditions. better range is normally achieved by flying high, with a 7lb boost and betwen 1900 rpm and 2650 rpm. Only where range is at the extreme limit does it become necessary to weaken the mixture right back and fly like a lame duck.

When flying with a cruise speed of around 350mph (you guys need to read the attachment, I am only roughly summarising) the a/c will travel at 330-350mph a distance of 895miles (thats a radius incidentally). Thats for a later mark. Merlin 21 engined types have a greater range, but lower speed. Fuel consumption is around 106 gallons per hour,, and a mossie typically on those long haul missions carried a 540 gallon fule load. Mision specs usually required a 25% reserve to be kept in the tanks, so in a pinch, if you wanted to take the risk, you could go some distance further
 

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which according to the operational performance notes I posted, the max continuous cruising speed was between 285 and 378 TAS depending on the mission profile and loaded condition. These figures are for a mid range weight (20000lb) which is equivalent to a 540 gallon fuel loadout and a 2000lb bombload. More than enough to get you to berlin and back.

Moreover, the notes actually say that travelling at lower speed is less economical thanb travelling with 7lb boost and weak mixture @ 2650 rpm. at those settings you will travel at 30000 feet at more than 350 mph (TAS)
 
parsifal said:
Facts are, the Mosquito as a concept was at least 2 years older than the Stirling, and most of the concept design was completed before the Stirling was even on the drawing board.
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From Wiki, for what it is worth: " In April 1938, performance estimates were produced of a twin Rolls-Royce Merlin powered DH.91, with the Bristol Hercules and Napier Sabre as alternatives."

"Shorts built a half scale version as the S.31 (also known internally as the M4 - the title on the tailfin), powered by four Pobjoy Niagara engines, which first flew on 19 September 1938, piloted by Shorts' Chief Test Pilot J. Lankester Parker."



1/2 scale model flies 5 months after De Havilland proposal is presented. When was work started on both full size and 1/2 scale aircraft?

"On 4 October 1938, for example, De Havilland projected the performance of another design based on the D.H 91 Albatross, powered by two Merlin Xs, with a three-man crew and armed with six or eight forward firing guns, plus one or two manually operated guns and a tail turret."

About the same time (Oct 1938 ) De Havilland did propose an unarmed bomber. It is not until Sept/Oct of 1939 that work begins on the actual DH 98 design.

I guess it depends on what you mean by concept and how close the concept was to the final design.

parsifal said:
And, the facts are, Mosquitoes were regulalrly hitting Belin with 4000 lb cookies, and 2000lb internal bombloads (in separate aircraft) and not suffering antwhere near the loss rates of their companions.
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That is a fact but when did the first raid occur with the 4000lb bomb?

Mosquito (DH 98 )was first planned with 1,280 hp (950 kW) Rolls-Royce RM3SM (experimental designation for what became known as the Merlin 21) engines,. Please note that at this time 100 octane fuel was the best that could be expected in the near future. There was NO MEASUREMENT SYSTEM for ratings or performance over 100 octane at this time. Boost was going to be 12bs at best for while. The discovery that British 100 octane was actually 100/115-120 was still in the future let alone actual 100/130 fuel.

There is abosoulty no doubt that the Mosquito was a VERY amazing plane but too many people are using the performance of late 1943/44 versions to claim that bomber command made a serious mistake in ignoring it in 1940/41. It was a mistake but the first Mosquitos, even with 100/130 octane fuel are down on ceiling, speed, payload and range compared to the later ones. They could have been used to great effect in replacing many of the RAF twin engine bombers much sooner.

How suitable they were for replacing 4 engine bombers is subject to argument, they may have been able to, they may not.
 
That's fine for photo recon or a path finder aircraft but a WWII bomber cannot hit anything from 30,000 feet. What's the economical cruise speed @ 15,000 feet?
 
stona said:
I'm afraid that this is something of a myth too.
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I think we are going to have to disagree on some of this

So two of the groups did what they were asked to do which in itself greatly increased the average quality.

They did receive extra training,a two week course at Warboys, and were expected to complete a minimum of 45 rather than 30 missions in order to maximise the benefits of the extra investment.
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I knew they did the extra training but thought that those who were not up to standard would have been sent back to the main force units.

The vast majority of Pathfinder crews were men who had completed 10-15 missions with Main Force who then either volunteered for,or were drafted into the Pathfinders. They were not otherwise remarkable.
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To survive 10-15 missions was remarkable in my book. Again it significantly increased the average quality of the pathfinder force.

One 44 Sqn crew was "volunteered" for the Pathfinders simply to get the pilot away from the base commanders WAAF driver!
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I would be willing to bet a penny to a pound that this was not the real reason but an explanation to cover up their decision. Its quite a common habit in people to cover up a major decision (of any kind).
It was not unheard of for tight knit crews to seperate prior to joining the Pathfinder Force. Some men wanted nothing to do with an extended 45 mission tour.
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Can you blame some of them for deciding that they had pushed the odd to the limit. Absolutely understandable

I wouldn't often disagree with someone like Max Hastings but we have seen that the average was higher in pathfinders, far from perfect but on average they were more qualified and experienced.

Bennett's response was to claim that 50% of Main Force crews "never troubled to use their bombsight."
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does anyone seriously believe that with the photo evidence available in the last 12-18 months of the war.

Towards the end of the war the Pathfinders of 8 Group and those crews doing the same job in 5 Group (Cochrane's independent air force) had a plethora of sophisticated marking systems,but they could never beat the weather.
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Clearly true but that isn't the point. Its also true that 617 squadron basically did their own pathfinding using a Mosquito and a Mustang. Not exactly the normal kit found in a Lanc squadron

cheers

David
 
Shortround6 said:
...

That is a fact but when did the first raid occur with the 4000lb bomb?
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My question, too

This aircraft data sheet gives, for May 1st 1944, the range of 1450 miles when cruising on 265 mph, or 1000 miles when cruising on 327 mph, with 4000 lbs. Up to that date only 26 aircraft were modified (= bulged bomb bay, some strengthening?) to carry 4000 lbs bomb. Merlin 23 power.

added: Wikipedia gives April of 1943 as the date when the squadron was formed, that would use the cookie-capable Mosquito.


The range was 1620/1360 miles when cruising on 265/320 mph, for 2000 lbs carried by Mosquito, on Merlin 21s. The maximum weight of the plane was 21462 lbs, same as Merlin 23 powered cookie-capable version. Ie. all going on with single stage Merlins - a 1941 technology.
here

How suitable they were for replacing 4 engine bombers is subject to argument, they may have been able to, they may not.
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Not sure they would be able, to bad there was no 4-engined Mossie's stablemates.

Looking at Williams' site, the Mossie Mk.XX (Merlin 32) and XVI ( Merlin 72,73) were able to haul a cookie and wing bombs, but the earliest date is same as above, May 1st 1944.
 
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range was 1620/1360 miles when cruising on 265/320 mph, for 2000 lbs carried by Mosquito, on Merlin 21s
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More or less similiar to Me-410A. Except the German aircraft could dive bomb (50 degree angle), had superior crew protection and a pair of remote control machineguns to provide some defense against rear air attacks. IMO these type aircraft are useful for long range tactical airstrikes but lack the range / payload for attacking industrial targets.

Ju-288 or a similar type Allied aircraft would be an entirely different matter. Speed similiar to Mosquito and Me-410A but range / payload is much greater.
 
Shortround6 said:
That is a fact but when did the first raid occur with the 4000lb bomb?
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From back on page 4:


de Havilland put forward plans for enlarged, 3 seat Mosquitoes, the the D.H 99/101 and D.H 102 but both were felt to be too compromised to be worthwhile:



(Buttler: British Secret Projects Fighters and Bombers 1935-1950 85-86)
 
davebender said:
More or less similiar to Me-410A.
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Of that I am not convinced.

The Me 410 with 2 x 1750hp engines had performance similar to earlier Mosquitoes with 2 x 1250hp engine.



davebender said:
Except the German aircraft could dive bomb (50 degree angle)
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I didn't think dive bombing was all that successful/survivable when it is done without local air superiority. Something that could not be had over Germany (for teh Allies) for most of 1943/44.


davebender said:
had superior crew protection
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In what way? More armour?


davebender said:
and a pair of remote control machineguns to provide some defense against rear air attacks.
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And how effective were those pop-guns? Did their value outweigh their added complexity and the loss of performance (weight, drag)?


davebender said:
IMO these type aircraft are useful for long range tactical airstrikes but lack the range / payload for attacking industrial targets.
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I suppose it depends on how many bombs are required to destroy/damage targets.

Take the first Schweinfurt mission. There was significant damage to the ball bearing factories - not enough to close production completely, but enough to reduce capacity and delay production. This damage was achieved with 80 hits with 1000lb bombs. Over 600 such bombs were dropped to achieve this - so 13%, or less hit the targets.

Now, 80 1000lb bombs = 40 Mosquitoes (they could carry 2 x 1000lb GP or MC bombs). At low level you could say they would achieve 50% accuracy. So now we need 80 Mosquitoes. If we assume 50% losses that would mean we require 160 Mosquitoes. To do the same damage as 230 B-17s.

From early 1944 Mosquitoes could carry 4000lb bombs - either the 4000lb HC "cookie" or the 4000lb MC bomb. These were even better for industrial targets.
 
Shortround6 said:
That is a fact but when did the first raid occur with the 4000lb bomb?
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Another question is when could it have occurred?

Ian Thirsk, de Havilland Mosquito, An Illustrated History, has a picture of Mosquito DZ637, a B.IV series ii. It was sent to Vickers on 24 June 1943 for conversion to carry the 4000lb bomb. This was completed by 2 September 1943, after which the aircraft entered storage. Then in February 1944 it was assigned to 627 Squadron, before being transferred to 692 Squadron some 2 weeks later.

So, there was at least one conversion, not for testing, completed 5 months before the first 4000lb bombs were dropped by Mosquitoes.
 

The performance of B.IVs in daylight operations from late 1942 to early 1943 should have been enough to convince the powers-that-be that the Mosquito was a very valuable and capable bomber.

As in the example above, some Mosquitoes went into storage after completion.

DZ599 sent to Vickers for conversion to carry the 4000lb bomb 28 May 1943. After completion it went into storage, and didn't go to a squadron until February 1944, and not on operations until April 1944.
 

This has nothing to do with the technology. Mostly, it relates to the timing that specifications are issued.

On 8 September 1936, the British Air Ministry issued Specification P.13/36, which called for a twin-engined medium bomber capable of carrying a bomb load of 3,000 pounds (1,400 kg) for 3,000 miles (4,800 km) with a maximum speed of 275 miles per hour (443 km/h) at 15,000 feet (4,600 m); a maximum bomb load of 8,000 pounds (3,600 kg) which could be carried over shorter ranges was also specified. Major aviation firms entered heavy designs with new high-powered engines and multiple defensive turrets, leading to the production of the Avro Manchester and Handley Page Halifax.

In May 1937, as a comparison to P.13/36, George Volkert, who was the chief designer of Handley Page, put forward to the Air Ministry the concept of a fast unarmed bomber. In his 20-page document, Volkert laid out plans for an aerodynamically clean medium bomber that would carry 3,000 pounds (1,400 kg) of bombs at a cruising speed of 300 miles per hour (480 km/h). There was some support for the idea in the RAF and Air Ministry, but they were muzzled ; for example a Captain Liptrot, who was then Research Director Aircraft 3 , appraised Volkert's design, calculating that its top speed would exceed that of the brand new Supermarine Spitfire. There were, however, counter-arguments that, although such a design had merit, it would not necessarily maintain a speed advantage over enemy fighters for long. The Ministry was also considering the use of non-strategic materials for aircraft production, which, in 1938, led to specification B.9/38 and the development of the Albemarle medium bomber, which was largely constructed from spruce and plywood attached to a steel-tube frame. Thus it can be seen that the idea of a small, fast bomber, possibly made out of non-strategic materials, was gaining support but the specifications for its development were at least two years later than those relating to the heavy bombers that Britiain would eventually use in the war. The Mossie even from before its inception was playing catchup, but this had nothing to do with the technology. De Havilland, for example, was years ahead of everyone else in laminar design, dating back to at least his 1931 comet design, The problem was not the technology, it was convincing the decision makers that it could be done.


That is a fact but when did the first raid occur with the 4000lb bomb?
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I believe it was May 1944.



If the mosquito had begun development in say 1938, with squadron delivery in 1939, I dont think there is any argument that these hypothetical Mosquitoes would have been a lot less of a performer compared to the later real world marks. The first real world Mosquitoes with merlin 21s had a top speed of 365 mph, which was still fast enough to virtually gurantee immunity from intercetion. This was because even the earlier marks still had an impressive sustained max cruise speed, and a respecable (ie superior to any other bomber) sustained cruise speed.

If Mosquitoes began entering service in 1939, they may have had a max speed of around 340 mph Im just guessing that number, but if Im even close , thats still more than enough to walk away from any fighter then in existence.

The evolution off the Mosquito design is interesting. i note that this 9and some of the preceding text is in wiki, however wiki has in fact pinched its narrative from a good source, the Point Cook museum.

"After further consideration, in a follow-up letter sent to Freeman on 27 July, de Havilland stated that the P.13/36 specification could not be met by a twin Merlin powered aircraft and that either the top speed or load carrying capacity would be compromised, depending on which was paramount. For example, a larger, slower, turret armed aircraft would have a range of 1,500 miles (2,400 km) carrying a 4,000 lb (1,800 kg) bomb load, with a maximum speed of 260 miles per hour (420 km/h) at 19,000 feet (5,800 m), and a cruising speed of 230 miles per hour (370 km/h) at 18,000 feet (5,500 m). De Havilland believed that such a concept was too much of a compromise, and that getting rid of some surplus equipment would lead to a better design. On 4 October 1938, for example, de Havilland projected the performance of another design based on the D.H 91 Albatross, powered by two Merlin Xs, with a three-man crew and armed with six or eight forward firing guns, plus one or two manually operated guns and a tail turret. Based on a total loaded weight of 19,000 pounds (8,600 kg) it would have a top speed of 300 miles per hour (480 km/h) and cruising speed of 268 miles per hour (431 km/h) at 22,500 feet (6,900 m).

Still believing that this performance could be improved upon, and after examining more concepts based on the Albatross and the new all-metal DH.95 Flamingo, de Havilland settled on designing a completely new aircraft that would be aerodynamically clean, of wooden construction and powered by the Merlin, which offered promise of substantial future development. The new design would be faster than all current or foreseeable enemy fighter aircraft, and could dispense with a defensive armament, which would only slow it down and make interception or losses to anti-aircraft guns more likely. Instead, high speed and good manoeuvrability would make it easier for the design to evade both fighters and ground fire.

Also, the lack of turrets meant that production would be simplified and production time reduced, with a delivery rate far in advance of any competing designs. Without armament, the crew could be reduced to a pilot and a navigator. This was in contrast to contemporary RAF design philosophy, which required well-armed heavy bombers and was much more akin to the German schnellbomber concept" (. However, it also damned the acceptance of the Mosquito to a very rough reception, and a long aceptance perios. it was simply too radical and too much of a departure to be easily accepted for the war winner that it could be).

"During a meeting held in early October 1938 between Geoffrey de Havilland, Charles C Walker (de Havilland's chief engineer) and Air Ministry officials, the latter showed little interest in de Havilland's concept and, instead, asked de Havilland to build wings for other bombers as a sub-contractor.

By September 1939 de Havilland had produced preliminary estimates for both single- and twin-engined variations of light-bomber designs using different engines, while speculating on the effects of defensive armament on their designs. On 20 September, in another letter to Wilfred Freeman, Geoffrey de Havilland wrote "...we believe that we could produce a twin-engine bomber which would have a performance so outstanding that little defensive equipment would be needed." (Those pre-design estimates proved to be prophetically accurate. DeHavilland estimated their design could achieve a top speed of around 360mph, the actual dewsign was found to be 367mph). "By 4 October work had progressed to a twin engine light bomber with a wingspan of 51 ft 3 in (15.62 m), and powered by either Merlin or Griffon engines, with the Merlin being favoured because of its immediate availability."
 


I agree, but I am not trying to promote the early versions as having performance of the 1943-4 types. The issue with Vincenzo was about the FB XVI and the FB40. FB XVI had Merlin 61s and FB40s had Merlin XXX (locally produced Packard Merlins). The early versions could still fly to Berlin, and could drop between 1500 lbs to 2000 lbs. They were still un-interceptabl;e by the LW.

How suitable they were for replacing 4 engine bombers is subject to argument, they may have been able to, they may not.
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The fast light bomber proponents were having exactlly the same arguments in 1936-8. The Light strike Force, when it was finally formed undetook some outstanding precision strikes from 1944. City busting was probably beyond their capability, but then, city busting as a techniques was forced on the RAF out of necessity. If equipped with a bomber like the Mosquito, they may not have needed to rely on brute force
 
davebender said:
That's fine for photo recon or a path finder aircraft but a WWII bomber cannot hit anything from 30,000 feet. What's the economical cruise speed @ 15,000 feet?
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Its in the operational specs I posted, but there is not a great deal of difference. But why would they do that (approach at 15K) if that is less economical?. Why wouldnt they have a Hi-lo-hi mission profile, if that is the most efficient fuel wise?
 
parsifal said:
The issue with Vincenzo was about the FB XVI and the FB40. FB XVI had Merlin 61s and FB40s had Merlin XXX (locally produced Packard Merlins).
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No such thing as the FB.XVI. Do you mean FB.VI? That is the fighter bomber version, which had half its bomb bay taken over by the cannon. That meant a maximum bomb load of 2000lb - 2 x 500lb in the rear of the bomb bay plus 2 x 500lb bombs under the wings. The 1500lb bomb load mentioned would be 2 x 500lb in the bomb bay plus 2 x 250lb under the wings. The FB.40 was the Australian built FB.VI, using Packard Merlins. The FB.26 was the Canadian built version.

The FBs were not at all suitable for strategic bombing, as they had even more limited loads than the bomber versions. Plus, they had lower performance, owing to the flat fighter type windscreen and drag from the gun installations.
 
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