Escort Spifire

[Shortround6]

You also need to speed up the development of fuel and/or engines.
Spitfire V or Mustang I with single stage Merlin will NOT be competitive with 109Gs or FW 190s over Germany for most of 1942.

 

[stona]

British fighter design was almost entirely devoted to attacking the expected bomber formations and defending British air space. From a period after the end of WW1 and the early thirties it was even more limited, devoted almost entirely to aircraft to defend London.
In the mid 1930s endurance was consciously sacrificed to give better performance in other areas, leading to the conflation of the requirements for zone and interceptor fighters, and producing the Spitfire which is the subject of the debate.

I'm struggling to think of any operational requirement or specification for anything that could be described as an escort fighter between 1919 and WW2. I might have missed something

Webster and Frankland wrote

"More was learnt about the potentialities and limitations of the day bomber formation in a few months of war experience than had been gained from the previous twenty years of theorising on the basis of fragmentary and often obsolete evidence derived from the First World War, Sino-Japanese War and the Spanish Civil War."

Among those lessons learnt (they were not referring to the Americans) may well have been the need to escort bomber formations in daylight, but this was not the path chosen by the RAF, nor by the Luftwaffe, who both chose instead to bomb by night.

Cheers

Steve

 

[tomo pauk]

You also need to speed up the development of fuel and/or engines.
Spitfire V or Mustang I with single stage Merlin will NOT be competitive with 109Gs or FW 190s over Germany for most of 1942.

Mustang with a single stage Merlin of 1941-42 is certainly going to be competitive over Germany vs. either 190 or 109 in 1942.

 

[drgondog]

I am deep into a book on this subject. The absolute milestone on a critical path to getting Merlin 61/P-51 airframe in the UK is a.) combined strain on UK Merlin 61 production ramp up, and b.) Kits and learning curve to modifying Mark I and Mark IA EXISTING airframes to accommodate the Merlin 61. Possibly RAF could have pulled NA-73 from recon force, modified them and returned as Fighters by mid 1943. Earliest.

It would take far too long to set up airframe license deal in UK even if AAF/NAA had been so disposed.

The slightly slower introduction of P-51B-1-NA into AFF was first dependent on the production run for the Packard Merlin 1650-3 - which had its development and test issues in delivering engines to NAA. It took the delivery of the first 1650-3 into the XP-51B 41-37352 for first flight test November 30 - before NAA realized they had a serious Merlin induced issue clogging up the much larger re-designed radiator.

The first 10 P-51-1-NAs were completed and ready for engines in late March 1943 but didn't fly until May 5th, 1943. NAA was building airframes faster than Packard was delivering engines.

Net - the P-51B arrived in ETO in group level numbers September through November from those airframes built and awaiting engines April through May, 1943.

Rolls Royce/Packard were the critical milestones, not the manufacturing processes to make the production P-51B from the lessons learned on the XP-51B.

 

[pbehn]

I don't think you could consider a UK escort fighter unless as a help to the USA which historically they did anyway. The UK did not have the industrial capacity to do daylight raids. Just as the numbers in Bomber Commands bomber stream offered mutual protection by weight of numbers, US daylight raids needed a number of bombers to swamp the defence. The escorts and a bombers own defences worked quite well as they were used, I doubt a raid of ten, twenty or even one hundred bombers to Berlin would have had acceptable losses until t he LW ceased to exist.

If the UK had decided to produce B17Gs when the Lancaster started production how long before a 1000 bomber raid with two to three thousand Spitfires with pilots could be mounted? As far as strategic daylight raids go Germany was in a worse position.

 

[pbehn]

Rolls Royce/Packard were the critical milestones, not the manufacturing processes to make the production P-51B from the lessons learned on the XP-51B.

I have read a few (more than a few probably) of your posts on this subject. What comes out of it is to get the P51 in production in numbers significantly faster than actually happened would need a joining of the USA and UK military production, the identification of the P51 AND the Merlin around 1938/39 as the product of choice and a commitment to daylight bombing of enemy that didn't actually exist at that time. Within that is the certain knowledge of the advances in superchargers and fuels that did happen but were not guaranteed at the time.
You also need a lot of powerful people to consider the possibility of a single engine fighter flying to Berlin and back, something so outrageous that Goering had not considered it and realised the "gig was up" when it happened.

 

[tomo pauk]

The Sabre engine should have been shot, stabbed and strangled while still in the crib. And the remains disposed of well out to sea.

The Griffon was effectively a 2000hp engine. Considering that a single stage Griffon was 700lbs lighter than a Sabre and a two stage griffon was still 500lbs lighter.

It was not Napier's/Sabre's fault that a) Sir Sidney believed wrong people about the aerodynamics of the wing, nor b) that a long range Tempest (192 gals of internal fuel + 2x90 in drop tanks = 1790 miles range) was introduced too late to matter.

 

[Robert Porter]

I would agree that the need for bomber escorts was not "officially" foreseen, but it became self evident almost from the onset of US daylight bombing missions. The loss rates were and remained far higher than projected "acceptable" loss rates from the onset. The USAAF was highly motivated to provide those escorts as fast as possible after the need became obvious. After all a bomber and crew in cold hard numbers was far more expensive and time consuming to replace than several fighters would be. So I honestly think the P-51 was hurried as much as production issues could support. There is some information that says both the RAF in particular and some within the USAAF said all along that unescorted daylight bombing missions would be inherently disastrous in terms of men and equipment well before it was actually proven.

Truly I do not understand the logic behind unescorted deep penetration missions. But that is probably the benefit of hindsight. The B-17, on paper, looked to be a formidable weapons platform for self defense I suppose. But even in more modern conflicts, like Vietnam, the loss rate of bombers declined when accompanied or preceded by Wild Weasel and other suppression fighter escorts.

 

[pbehn]

Truly I do not understand the logic behind unescorted deep penetration missions. .

There was no logic and no proof, when the British had the Wellington some believed that the more the Germans sent up the more would be shot down, an attitude mirrored over the pond with fighter versions of the B17 and B24, bombers with no bombs.

 

[pbehn]

It was not Napier's/Sabre's fault that a) Sir Sidney believed wrong people about the aerodynamics of the wing, nor b) that a long range Tempest (192 gals of internal fuel + 2x90 in drop tanks = 1790 miles range) was introduced too late to matter.

The Sabre was a dog of an engine which was discontinued as soon as was possible. If anyone could have foreseen advances in superchargers and fuels, Napier would have been told to produce the Griffon and Hawkers told to design an engine around it.

If the Sabre carried the whole of a military project with it like the R-3350 then maybe it would have been better but it didn't, so it wasn't.

 

[parsifal]

I cant comment on the technical challenges to near the level of competence you guys are doing. however, I would point out that the allies were excellent at the art of conversion planning and design. Items that come to mind include the Firefly, the MGB/MTB MAS conversions, to name just two.

I have no doubt that had the inclination and the need been seen for a long range escort spitfire , it would have been achieved in record time. the allies were good at that sort of thing.

And in some ways the P-51 conversion to use the merlin engine was an extension of the "long range escort spitfire" concept anyway. it used a British engine married to a US airframe. a marriage made in heaven in my book. Quick, fairly easy and available on the spot. effective. its doesn't get better than that.

 

[Shortround6]

A lot of things were happening at the same time or over the course of about 4 years.
An effective single engine escort fighter was impossible in 1938.
The British hadn't figured out that constant speed props were actually practical and had real advantages (being a bit sarcastic here, but only a bit).
British airfields were small.
Standard fuel was 87 octane (limits take-off power for one thing)
A Fairey battle had an operational radius of somewhere between 300 and 400 miles (range was 1000 miles).
Blenheim was even further and the Whitley (which was always a night bomber but shows the problem) had a radius of over 600 miles.

Trying to get a a fighter with enough fuel to fly those distances out of a 500-600 yd airfield using 87 octane fuel and even a two pitch propeller is going to require a large high lift wing, which is going to have a lot of drag meaning poor performance in combat, that is to say, it won't be effective.
100 octane allowed for more power,both take-off and combat, from similar weight engines. 100/130 allowed even more.
Constant speed props allowed more power to be used at take-off and gave better performace in combat.
AIr fields got larger, allowing even greater loads at take-off even with the greater power of the engine using better fuel and props.
Aerodynamics got better.

I have said it before, for the Americans the B-17C was rated at 2400 mile range with 4000lbs of bombs. Even if you cut the the Radius to 900 miles that is way beyond the capability of any single engine fighter of the time (1940).
Maybe the Americans should have built short range bombers to cover their large coast lines and off shore possessions?

The insistence that single engine escort fighters could not be built in 1942 however doesn't hold up. The Fuel/engines/propellers had advanced to make the possibility very real and the structures and aerodynamics had advanced also.
Now at what point in 1942 it was possible and a what point you could build enough of them to sustain a campaign????

 

[pbehn]

But S/R, to build them in 1942 you have to order them in 1940/41. That is designing a long range escort to fly to Berlin around a 1200 BHP engine.

 

[Shortround6]

It was not Napier's/Sabre's fault that a) Sir Sidney believed wrong people about the aerodynamics of the wing, nor b) that a long range Tempest (192 gals of internal fuel + 2x90 in drop tanks = 1790 miles range) was introduced too late to matter.

Nobody knows (or the ones that did never told) what the cost of the Sabre engine program was. Some people claim the Sabre cost anywhere for 2 to 4 times per horsepower what a Merlin did.
It was planned to power a whole generation of aircraft with Sabre engines. SIngle engine fighters, twin engine fighters, twin engine bombers . As the delays in the Sabre program mounted and delivery of engines amounted to a trickle, program after program tried switching to alternative engines, or was delayed, or out right canceled. In the end only the Typhoon and Tempest used the Sabre in quantities much over a dozen. And the Typhoon was a failure at it's intended job, air superiority fighter.

 

[pbehn]

And the Typhoon was a failure at it's intended job, air superiority fighter.

I would argue that it was replaced by the aircraft it was meant to replace itself, the Spitfire. Not exactly a fault of the airframe but the engine.

 

[Shortround6]

But S/R, to build them in 1942 you have to order them in 1940/41. That is designing a long range escort to fly to Berlin around a 1200 BHP engine.

And that is the problem with most of theses schemes or blaming the generals/air marshals in charge at the time.
Yes Portal held on to the idea it was impossible for too long but it wasn't possible in the early years.

This is why a number of airforces had built twin engine fighters, the Me 110, the K-45, Several French twins, The P-38 (sort of)

and a few others. It turns out that most of them weren't very good escort fighters but shows that most air staffs didn't believe it was possible to build single engine long range escorts.

A P-38 on internal fuel (410 gallons) had an operational radius of 275 miles as outlined above. The P-51B with out rear tank was godd for 150 miles and a P-47 with 305 gals internal was good for 125 mile radius and with 370 internal was good for 225 miles.
Early P-38s without self sealing tanks would hold 400 gallons, the self sealing tanks dropped capacity to 300 gallons and the lat emodels with under engine intercoolers and leading edge tanks went to 410 gallons.
The P-38 was not designed as an escort fighter but as an interceptor with twice the endurance of a single engine interceptor and shows the problems the designers of the time had in providing single engine performance with high endurance/long range.

 

[parsifal]

Unfortunately I disagree with the starting premise here. 'it wasn't possible, if it was it would have been built!" The constraint was NOT technological it was pre-conception that caused the failure.

Why would I say this? Because in the very time frame that people are saying it was not possible to build a long range escort, other nations were doing just that. in 1940 the Japanese were putting the finishing touches on two aircraft, namely their A6M and their Ki-43 that were using small capacity, super fuel efficient engines, running on low grade fuels, and able to outperform just about everything currently available and able to fly all the way from London to Berlin and then some.

Just because WE lacked the imagination to think laterally and solve a fundamental problem does not mean that the problem was not solvable with the means at hand.

 

[pbehn]

Yes Portal held on to the idea it was impossible for too long but it wasn't possible in the early years.
.

I don't believe it was possible for the UK. There is no technical reason why a single engined escort could not be built however it means a doubling (at least) of the number of S/E aircraft in service with the RAF. There were rarely more than 1000 Spitfires in service. A long range raid needed three sometimes four groups of escorts. The whole of the RAFs fighter strength would be needed or more planes and pilots made, an investment similar to that of Bomber Command itself.

 

[Shortround6]

It was NOT possible in a European context. The Japanese fighters (especially the KI 43) were not carrying a European standard of armament (payload) nor were they carrying what would be, after 1940, a European standard of protection (also payload), they were not cruising at a speed needed to either be an effective escort or to help ensure their own survival in defended air space.
It is one thing to make a long/slow/low flight over water (or undefended South East Asia land mass) and face defenders in a very limited target area at the end. It is quite another to fly hundreds of miles into airspace with Flak guns dotting the landscape and the possibility of being bounced by enemy fighters over a period of hours both to and from the target area. Enemy fighters operating from airfields that are local to the flight path followed by the attackers.

It was possible for a Spitfire MK VIII to fly over 1100 miles with a 90 gallon drop tank if it did it slow. But that is not escorting anything and setting itself up as a target over Europe no matter how well it may have worked in the Pacific.

Edit. I would note that a P-40E with a 52 gallon drop tank was, in theory, able to fly 1050 miles at 9,000ft at 220mph true airspeed after subtracting 42 gallons for warm-up, take-off and climb to 10,000ft (used charts) .
US sure goofed up not using it as an escort for B-17s over Europe in 1942 didn't they (sarcasm)

 

[Peter Gunn]

^^^ So much this. I've discussed the issue more than once that distance flying (escort missions) were different in the Pacific than the ETO. Sure a Zeke/Zero could fly escort ranges approaching the Mustang, but in practice it's a non-starter to me. Your first two paragraphs... I couldn't agree more.