British escort fighter--what might it have been like?

B

BarnOwlLover2

ACCESS: Confidential
Joined
31 October 2022
Messages
66
Reaction score
72
I know that there'll be some variables here, namely time period and such, but what if the British had their own long range escort fighter? Naturally, it can't really be a Spitfire or a Hurricane since they're too short legged early war (and Spitfire for most of the war). But, from say 39-42, 42-45, what would a single seat, long range high performance escort fighter be like? The biggest thing as far as spec is enough fuel internally to have a 700-800 mile range, and the ability to use drop tanks. It also has to be heavily armed for the period (which from 42-45 basically means 4x20mm cannons), and be a great dogfighter per tactics of the period. This will address one of the few shortcomings of the P-51, given that it was a bit heavy due to being built to outdated USAAF load requirements (largely resolved with the H variant, but that doesn't really count here).

So I'll open the floor to the forum members to discuss.
 
Hi,

BarnOwlLover2 said:
I know that there'll be some variables here, namely time period and such, but what if the British had their own long range escort fighter? Naturally, it can't really be a Spitfire or a Hurricane since they're too short legged early war (and Spitfire for most of the war). But, from say 39-42, 42-45, what would a single seat, long range high performance escort fighter be like? The biggest thing as far as spec is enough fuel internally to have a 700-800 mile range, and the ability to use drop tanks. It also has to be heavily armed for the period (which from 42-45 basically means 4x20mm cannons), and be a great dogfighter per tactics of the period. This will address one of the few shortcomings of the P-51, given that it was a bit heavy due to being built to outdated USAAF load requirements (largely resolved with the H variant, but that doesn't really count here).
Click to expand...

You could have a look at the Standard Aircraft Characteristics sheets here https://www.alternatewars.com/SAC/SAC.htm to have a look at the way the long range escort fighters' range was calculated. Here an example for the P-51H:

F-51H 3 July 1950.jpg

Pick an engine available in the period you're looking at, decide on likely climb and cruise speeds your fighter might have, and you can get an impression of what the range might be.

I'd speculate that at least in 1939 - 1942, the British escort fighter will look like a hybrid between a Westland Whirlwind and a Focke-Wulf Fw 187 (top-of-the-line engines, cross-feeding tanks for full twin-engine redundency, useful amount of fuel), as I'd expect that it will be difficult to fulfill the requirements with a single-engine design and still be competitive against the Luftwaffe defenders.

I don't think that tactics of the day really were based on dogfighting. Even RAF experts advised against turning with the enemy even when it gave the opportunity for the kill, as one is very vulnerable in a continued turn, and zooming up and diving on the enemy again was just as promising at a lower risk for the attacker (see the contemporary treatises on fighter tactics reproduced in "Spitfire Manual" by Dilip Sarkar).

The best bet of the USAAF before the Mustang came along was the Fisher P-75 Eagle, by the way: https://www.secretprojects.co.uk/threads/fisher-xp-75.4523 ... it wasn't successful in the end, but it's worth noting that they came up with a fairly big and as-good-as twin-engined design as well (as the V-3420, though a single engine, essentially was all the parts from two V-1710s united by new crankcase).

In my opinion, you don't really need 4 x 20 mm cannon for an escort fighter as the successful Mustang had just 6 x 12.7 mm, which provides only half that firepower (and it didn't do so bad initially either, when it only had 4 x 12.7 mm ... except for the well-known jamming issues, of course). Settle for 2 x 20 mm and save a lot of weight you can use to carry fuel instead.

Which reminds me ... are you familiar with Breguet's range equation? Might be useful for your question: https://en.wikipedia.org/wiki/Range_(aeronautics)#Cruise/climb_(Breguet_range_equation)

Regards,

Henning (HoHun)
 
I'd say the answer is simply a Spitfire that adds the various additional internal tanks different variants got, but does this all together and earlier. e.g. aft fuselage, centre fuselage, wing LE tanks. You can get much greater range out this way. But it's a heavier aircraft with a bit lower performance and more restrictive CG on take-off. Much like the P-51

Then also disposable drop tanks rather than the slipper tank
 
Westland Whirlwind ? drats, ninja'd by @HoHun

I would say, cut into the number of Battles (who needs 2000+ of those death traps when there are perfectly good and better Blenheims with radials ?). Throw those Merlins at a alternate Whirlwind DESIGNED FOR MERLIN FROM THE DRAWING BOARD (because the OTL Whirlwind was so tightly designed around Kestrels, no bigger engines could be shoehorned into the airframe without creating a whole new aircraft, Welkind, cough, cough)
 
Sadly, per that other thread, the 'design sin' of not allowing 'wriggle room' AKA 'Growth Potential'...
:-(
 
You nailed it ! That's the classic mistake with the Whirlwind "Whirlwind + Merlin = world champion" alas, not so easy. Fact: it was designed tightly around the kestrels to squeeze the last drop of performance out of 885 hp*2 , and it certainly succeeded wildly. Bad luck it also made it an evolutionary dead end.
Now, reel back to the drawing board, and design the Whirlwind from zero, with Merlin I. There, it would have at least some limited growth potential.
 
Glosters twin might have achieved the desired performance.

But I'll agree Spitfire can do it.
 
As far as the Mustang with cannons deal, I did read somewhere (maybe somewhere on this forum) that the USAAF tried to ask NAA to up-gun the P-51H/L/M and maybe also the F-82 to run 4x20mm cannons, but NAA said that they were too far into the design to redesign the wings to house the cannons and their ammo. Not to mention that the war was almost over by then.
 
Hi Zen,

zen said:
But I'll agree Spitfire can do it.
Click to expand...

Here's a contemporary document on the Spitfire Vc that includes range considerations:


I've graphed the range data, using an 88 imperial gallons per hour data point from the Spitfire V Pilot's Notes data point to get fuel consumption at combat power (+9 lbs/sqin, 3000 rpm):

SpitfireVC Range.png

Now the tropicalized Spitfire VC might be a bit more draggy than other subvariants, but the data from the Australian report really assumed ideal conditions otherwise - in particular optimum cruise at 1600 rpm, while the Pilot's Notes consider 1800 rpm the permissible minimum engine speed.

I'm also not sure it's a good idea to cruise at a leisurely 200 knots over Germany ... there's an RAF letter on how to save fuel when not in contested airspeed in order to be able to cruise as fast as possible in contested airspace, which was found to be of great importance when facing the Fw 190 in the Spitfire V (over Northern France).

Still, it's interesting to estimate how much fuel a Spitfire VC might need to have the combat radius to cover various parts of Germany. To be able to escort bombers to Berlin, about 475 nautical miles combat radius would be required. From eyeballing it, I'd say you'd probably need about 250 imperial gallons for that.

Regards,

Henning (HoHun)
 
Hi,

red admiral said:
https://www.aerosociety.com/news/escort-spitfire-a-missed-opportunity-for-longer-reach/

Paul did an article on this a little while ago. He got to a notional 286g internal + 124/180g external. So possible to massively increase radius. But this obviously needs to be worked into a proper variant with sufficient strengthening etc. and priority for doing this
Click to expand...

Hm, I have to admit that I'm not familiar with the name Paul Stoddard. Is he active on this forum?

I find his article slightly confusing as the tables sometimes contain more numbers than the headlines advertise, and I made some attempts to reverse-calculate his numbers which made me think maybe he gave the Mustang a 10 gallon reserve in one case, but not the Spitfire in the same case.

I was also distracted by the comment on both the Spitfire and Mustang "being more economical when carrying drag inducing external tanks than when flying clean". While he goes on to explain that as paradoxical, I'd like to point out that he needlessly created that paradox himself when he decided just to divide nominal range by total fuel capacity and call that "air miles per gallon". Of course that's going to give a wrong impression ... don't do it in the first place, then you don't need to debug that number.

With reard to the total tankage of the Spitfire ... well, considering the escort mission to Berlin, realistically the Spitfire will have to drop its external tanks over Berlin, and then be able to fight unrestrictedly for the allocated time, and still have enough fuel to return to Britain with a sensible reserve. If the rear tanks can't be used in combat because they give the Spitfire a rearward centre of gravity position, they're not available for combat and the return flight. I'm also not convinced that the leading edge tank is viable for combat operations. As a protected tank, it would have a fairly poor weight-to-volume ratio because the walls of the self-sealing tanks were heavy and took up a fair bit of volume themselves, and the ratio of tank wall mass to fuel content mass was not very good for thin elongated tanks. As an uprotected tank, it would probably not available for combat and the return flight either. (The Vought F4U-1 Corsair had unprotected long range tanks in the wings, but these were eliminated in the F4U-1D. I'd guess the reason was that they were more of a liability than an asset.) Oh, and of course you have to be competitive in air combat, and as the Spitfire lacks the speed of the P-51D and is not quite its usual nimble self when weighed down with all that extra fuel, that might be a bit of an extra challenge.

(There's a mention that the Spitfire was stable with 35 gallons used up from the rear fuel tank, but it's not linked to any definite rear tank volume as far as I can tell, and with the very light stick force per G values the Spitfire has, I'm not even sure one would want to fight in a Spitfire that's merely "stable" ... perhaps that's good enough for cruising, but when pulling Gs, predictable and reasonable stick forces would be highly desirable if you want to keep attrition down.)

I also wonder how the Spitfire's take-off performance would be when loaded with all that fuel. Unlike the P-51, it doesn't have camber-changing flaps, but rather simple split flaps that create a log of drag when deployed. Great for landing, not so great when taking off with a heavy load. The RAF throughout the life of the Spitfire always seem to have been somewhat worried about the question of take-off distances ... I always though this a bit exaggerated as the type has fairly good performance, but now we're talking about routine operations at 9,856 lbs take-off weight when the Spitfire IX Pilot's Notes give a maximum of 8,700 lbs with the precautionary notes, "for take-off and gentle manoeuvres only" and "at this weight, take-off must only be made from a smooth hard runway".

Not that I would automatically discount the Spitfire as a long-range escort aircraft in the 1942-45 period specified in the initial post of this thread, but I'm not sure one would get there simply by combining the features some historical Spitfires used anyway. In my opinion, if you need a long-range Spitfire in 1942, you better start designing a purpose-built variant in 1939, but you'll be competing for production capacity with all the interim marks that were historically produced in the original timeline, plus the "definitive" Spitfire VIII which is a bit of an extended-range version itself. For the 1939-41 period, I'd still suggest a Whirlwind/Fw 187 crossover.

Regards,

Henning (HoHun)
 
There was an article in Aviation Historian fairly recently (last year or year before) which studied a what-if concept based on the idea of flying a Mk IXT from the back seat - in essence what would happen if you moved the cockpit back to where the rear IXT cockpit was and fit an additional fuel tank. The article was about a speculative PR version rather than an escort fighter though. I'll dig it out and see what kind of range it was postulating.

I suppose you could pack fuel into a Typhoon but the altitude performance isn't up to snuff for this kind of role I would think.

As an escort fighter would the Mosquito not count?
Maybe clipped outer wings, remove the Brownings and second crewman to save weight, new canopy with reduced framing. It's not quite a Hornet but still pretty potent.
 
1668439142664.png

This is a Mk.IXc (identified as a Mk.210 for some reason*) The caption says:

'Photographed at Wright Field, Ohio, May 1944 where fitted with a 43 gal fuel tank in the rear fuselage, 16.5 gal flexible tanks in the leading edge of each wing and Mustang type 62 gal tanks under each wing. Total fuel load 285 gallons. Early summer 1944 flown across Atlantic via Iceland and went to Boscombe Down for further trials.'

* Spitfire specialist probably has the full story. Dunno if the figures are US or Imperial gallons.

Chris
 
CJGibson said:
Dunno if the figures are US or Imperial gallons.
Click to expand...
I think those would be Imperial gallons. I've seen references to 75 and 110 US gallon P-51 drop tanks, that would be 62 and 91 Imperial gallons respectively.
 
HoHun said:
Not that I would automatically discount the Spitfire as a long-range escort aircraft in the 1942-45 period specified in the initial post of this thread, but I'm not sure one would get there simply by combining the features some historical Spitfires used anyway. In my opinion, if you need a long-range Spitfire in 1942, you better start designing a purpose-built variant in 1939, but you'll be competing for production capacity with all the interim marks that were historically produced in the original timeline, plus the "definitive" Spitfire VIII which is a bit of an extended-range version itself. For the 1939-41 period, I'd still suggest a Whirlwind/Fw 187 crossover.
Click to expand...
Paul is a fairly active member of the RAeS historical group and has published a few articles in TAH recently. More of an analysis insight rather than engineering.

I think my point is that you could make a Spitfire variant with significantly greater range. I think this would probably be a different Mk VIII with more changes than historically, and priority for development and production instead of the Mk IX. It's all trade offs.

I mean UK bomber command was actually night flying and using Beaufighters and Mosquitos as "escort" fighters
 
Were tyhose type not used as intruders at the time? Sorry, probably missinterpretation.
 
Glosters Reaper had a lot of potential. Arguably a better basis for a long range fighter as was the Supermarine Type 320 with twin Merlins.
But Westland's machine was compact, fast and used what seemed like a cheaper engine
 
Hi Zen,

zen said:
Glosters Reaper had a lot of potential. Arguably a better basis for a long range fighter as was the Supermarine Type 320 with twin Merlins.
Click to expand...

Hm, I just looked up the Gloster Reaper and found it listed with 360 mph @ 15000 ft for the Taurus II, but on the other hand, the Taurus II was listed elsewhere with a full throttle height of 5000 ft, which looks like a mismatch.

With the Peregrines, the Reaper apparently could do 330 mph @ 15000 ft, which is good but not great. I'd presume it might have been more suitable to a Merlin conversion than the Whirlwind, though.

Similar figures were posted on this forum, too:


Regards,

Henning (HoHun)
 
I asked a similar question on the ww2aircraft.net forum, and someone did post info about a de Havilland project that may've been what lead to the genesis of the Hornet. It was for a twin engine fighter that weighed about 15,000 lbs, powered by Merlin 60 series engines, and armed with 4x20mm cannons. I'd love to see some speculative drawings on what that might have looked like.

British escort fighter--what might it have been like?

Even when it had long range fighters, there was no milage in reverting to daylight once they had the technical means to blind bomb with high precision, and night still kept the single engined fighters out of it. 153 daylight raids by Bomber Command in 241 days between 27 Aug 1944 & 24 April...
ww2aircraft.net
 
Hi again,

HoHun said:
With the Peregrines, the Reaper apparently could do 330 mph @ 15000 ft, which is good but not great. I'd presume it might have been more suitable to a Merlin conversion than the Whirlwind, though.
Click to expand...

Here's a largely speculative calculation of what Gloster F.9/37 performance with a Merlin might have looked like:

Gloster F9 37_Performance_Comparison.png

It's based on the 330 mph @ 15,000 ft figures for the Peregrine-engined version (assuming this speed was achieved at +9 lbs/sqin boost), with an arbitrary 1000 lbs of extra weight for the Merlin XII engined version, and an additional 500 lbs of extra weight for the Merlin 45 engined version. Both Merlins are assumed to have double jet exhausts, which give a bit less exhaust thrust than the later individual ejectors.

Performance is not bad at all, but even with the Merlin 45 version, I'd not like to come up against Focke-Wulfs over Germany.

Regards,

Henning (HoHun)
 
Hi again,

HoHun said:
Here's a largely speculative calculation of what Gloster F.9/37 performance with a Merlin might have looked like:
Click to expand...

Hm, "tare" weight of the Peregrine Gloster is given as 9222 lbs, and the fuel load as 170 gallons. Assuming that means imperial gallons, these are consumed at 57.5 gallons/hour at maximum cruising (rich mixture) per engine (according to the Whirlwind's Pilot's Notes).

Assuming weak mixture cruise was a bit more economical, say 45 gallons/hour per engine, that would be good for 2 hours of cruise, no allowance for anything, no reserve.

I'd have thought the Merlin would use fuel at a faster rate than the Peregrine, but surprisingly, that might not be the case (comparing to data from the Spitfire V Pilot's Notes):

- Peregrine I, all-out level: 75.5 imp. gal. per hour (at 15000 ft)
- Merlin 45, +9 lbs/sqin, 3000 rpm: 88 imp. gal. per hour

- Peregrine I, max. weak mixture cruise: 57.5 imp. gal. per hour (at 12000 ft)
- Merlin 45, +4 lbs/sqin, 2650 rpm: 56 imp. gal. per hour

Now I don't have the exact figures, but I'm confident that the Merlin yields a lot more power at "all-out", and probably it does the same at maximum weak mixture cruise.

That looks as if the Peregrine really was a very thirsty engine, as far as specific fuel consumption goes. Can this be right? If it is, I really wonder if that was another good reason to discontinue production of this engine ... never heard that mentioned anywhere before.

Regards,

Henning (HoHun)
 

Similar threads

Back
Top Bottom