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

[BarnOwlLover]

As far as my original post, it seems that it wasn't really 100% practical for a single seat, let alone single engine, escort fighter anywhere until at least 1942. That was mostly because the allies could have access to 1500-2000+hp engines to lift the fuel armament, armor and such required of such an aircraft, as well as improvements in aero and such. And the big thing that helped there was two stage supercharging and everything that made that possible.

However, I should note that going from single stage to two stage usually wasn't a simple drop in job. Why did the Spitfire IX/VII/VIII run symmetrical underwing radiators? Why did the two stage Mosquitoes grow under propeller intakes similar to the Merlin P-51's supercharger intake? Speaking of which, why did the Merlin P-51s get a deeper, more pronounced radiator intake vs the Allison powered versions? Two stage supercharging makes more power, but needs more cooling to handle/use that power. Probably an oversimplification, but that's the simple crux of it.

Hence, even if the Mustang used the Merlin from the start, it would've needed a similar redesign to make the most of the two stage Merlins.

As far as something that did get made, what about maybe the Martin-Baker MB5 as a possible British escort fighter? It had the range and performance, but it wasn't a reality until 1944-45, by which time there was the Merlin Mustangs, the Hawker Tempest, and the Hawker Fury/Sea Fury and DH Hornet. Not to mention that though I like it overall, the MB5 was a bit outdated as far as construction (tube frame instead of a monocoque) and, like the Merlin Mustangs that were most produced/used, a bit heavy for the engine power being used. Of course, for the Mustang that was due mostly to outdated US stress and loading standards, for the MB5, I'd argue that using a monocoque fuselage would've saved weight due to better strength to weight ratio.

 

[tomo pauk]

As far as my original post, it seems that it wasn't really 100% practical for a single seat, let alone single engine, escort fighter anywhere until at least 1942.

Japanese didn't get the memo, and made the Zero before 1942.

However, I should note that going from single stage to two stage usually wasn't a simple drop in job. Why did the Spitfire IX/VII/VIII run symmetrical underwing radiators? Why did the two stage Mosquitoes grow under propeller intakes similar to the Merlin P-51's supercharger intake? Speaking of which, why did the Merlin P-51s get a deeper, more pronounced radiator intake vs the Allison powered versions? Two stage supercharging makes more power, but needs more cooling to handle/use that power. Probably an oversimplification, but that's the simple crux of it.

Certainly not a drop-in job, but not the major problem, either. A lot of Spitfire IXs started a life as Mk.Vs.

 

[BarnOwlLover]

Japanese didn't get the memo, and made the Zero before 1942.



Certainly not a drop-in job, but not the major problem, either. A lot of Spitfire IXs started a life as Mk.Vs.

Remember what was said here and elsewhere. The Zero operated in areas where cruising at low speeds was permissible. Between that and it's lack of armor and self sealing fuel tanks, it wouldn't have lasted long in Europe.

And as far as the Spitfire goes, that's true, but it still took some significant modifications to the cooling system, not to mention that the nose on the IX was longer than the V due to the longer engine due to the second supercharger stage. Changing the Ki-100 from the K-61 (radial engine conversion) required new engine mounts, and ballast changes due to engine weight and CG shift. Same applied to the Spitfire and Mustang as well as cooling changes. Of course, such changes were incorporated more "seemelessly" into the Mustang, because time was able to be taken to do so, instead of the Spitfire IX being a necessary expedient, and NAA wassn't based in the UK, which was within range of German strike aircraft.

 

[Deleted member 68059]

'The British built 20,000 spitfires…'

that was over a 10 year period

Meanwhile, NA built 17,000 P-51's in 4 years


Ditto the Merlin - 'The British made 150,000 hand fitted Merlins'

That was over a 14 year period

Meanwhile, Packard built 55,000 production engineered Merlins with gaskets in 4 years
An interesting aside, you could always tell which plane was fitted with a RR vs a Packard Merlin - there were always drip trays under the RR Merlins

Murica! Masters of production engineering.

Data says no. Sorry about that.
Packard didnt even out produce RR until 1944, which (as you can see) was only because RR were already ramping down
production as the end of the war was in sight and they were moving towards turbojet.

Virtually all RR Merlin production was not over 14 years, but 7 years.

 

[tomo pauk]

Remember what was said here and elsewhere. The Zero operated in areas where cruising at low speeds was permissible. Between that and it's lack of armor and self sealing fuel tanks, it wouldn't have lasted long in Europe.

Nobody said that Zero was a perfect long range fighter.
For another angle wrt. long-range fighters on 1939 aerodynamics and engine technology, we can take a look on the Ki-61. It also sported protection for fuel and pilot.

 

[BarnOwlLover]

I thought the Ki-61 wasn't designed until 1941, and didn't enter service in numbers until 1943?

 

[pbehn]

Remember what was said here and elsewhere. The Zero operated in areas where cruising at low speeds was permissible. Between that and it's lack of armor and self sealing fuel tanks, it wouldn't have lasted long in Europe.

And as far as the Spitfire goes, that's true, but it still took some significant modifications to the cooling system, not to mention that the nose on the IX was longer than the V due to the longer engine due to the second supercharger stage. Changing the Ki-100 from the K-61 (radial engine conversion) required new engine mounts, and ballast changes due to engine weight and CG shift. Same applied to the Spitfire and Mustang as well as cooling changes. Of course, such changes were incorporated more "seemelessly" into the Mustang, because time was able to be taken to do so, instead of the Spitfire IX being a necessary expedient, and NAA wassn't based in the UK, which was within range of German strike aircraft.

The Mk IX required more cooling and an additional radiator for the intercooler, but this is probably easier to set up on the P-51 than the Mk IX, it has more space.

 

[tomo pauk]

I thought the Ki-61 wasn't designed until 1941, and didn't enter service in numbers until 1943?

Engine from late 1938, wing profile from 1935.

 

[Shortround6]

For another angle wrt. long-range fighters on 1939 aerodynamics and engine technology, we can take a look on the Ki-61. It also sported protection for fuel and pilot.

I thought the Ki-61 wasn't designed until 1941, and didn't enter service in numbers until 1943?

The Ki 61 didn't use anything from either aerodynamics or engine technology that didn't exist in 1939/40 in the west. No trick airfoils or magic flaps on the wings.
Engine was a licensed DB 601 and not even the one the Germans were building in 1941.

However the Ki 61 was also only armed to a 1939-40 standard and the Japanese were playing catch up for a good part of it's career, this is as a much a supply problem as a design problem but a K-61 built to western standards in 1941-42 might have been a bit heavier.

 

[Shortround6]

Engine from late 1938, wing profile from 1935.

Not sure you want to use a 1938 DB600-601 in a 1941-42 fighter
Maybe my books are old but the Japanese seem to have gotten around 100hp more out of the engine at 4200meters than the early German versions got?
Or they are counting RAM air?

 

[BarnOwlLover]

There was the Ha-140 engine, which was a DB601 improved independent of DB by Kawasaki. Much like the Ha-40, it wasn't particularly reliable.

 

[tomo pauk]

Not sure you want to use a 1938 DB600-601 in a 1941-42 fighter
Maybe my books are old but the Japanese seem to have gotten around 100hp more out of the engine at 4200meters than the early German versions got?

You are right. Bunrin-Do book about the Ki-61 gives 1100 CV (PS) at 4200m, this should be comparable with later 601As (1940?) with improved S/C. So not this, but more like this.
About the using of 1938 DB 601 on a 1941-42 fighter - Japanese used less capable engines on a lot of Ki-43s and Zeros in 1941-42.

Or they are counting RAM air?

I believe those are the 'proper' figures, ie. no ram effect accounted for. Ki-61 speed maxed out at 5800-6000m.

 

[Shortround6]

There was the Ha-140 engine, which was a DB601 improved independent of DB by Kawasaki. Much like the Ha-40, it wasn't particularly reliable.

It was closer to the DB 605 but yes, it stretched the Japanese manufacturing capability a bit beyond it's capacity of the time.
How much of that was shortages of raw materials showing up in 1943 and 1944 I don't know or if the methods used to increase the power level to DB 605 levels were not compatible with the engine. While peak rom may not be that different the engine was running a bit faster, they use of higher compression was a bit lower than the newer German engines but Japanese fuel may not have been a good match for German fuel and the Japanese resorted to water injection to get the numbers they wanted?

 

[Shortround6]

About the using of 1938 DB 601 on a 1941-42 fighter - Japanese used less capable engines on a lot of Ki-43s and Zeros in 1941-42.

Yes they did, and they paid for it in 1942, at least in the last 4 months or so. The Japanese were starting to loose the edge they had from Dec 41 through the summer of 1942.

They were playing catch up for the rest of the war.

 

[tomo pauk]

Yes they did, and they paid for it in 1942, at least in the last 4 months or so. The Japanese were starting to loose the edge they had from Dec 41 through the summer of 1942.

While can put a part of the blame on the engine choice, there is a lot of blame to be laid in front of other parts of Japanese military.

They were playing catch up for the rest of the war.

Agreed 100%.

 

[Shortround6]

While can put a part of the blame on the engine choice, there is a lot of blame to be laid in front of other parts of Japanese military.

Agreed 100%.

 

[GrauGeist]

The British made 150,000 hand fitted Merlins'

Only the early (pre-war) Merlins had some hand-fitted components.

Later, especially once WWII started, Rolls-Royce and Ford manufactured the engine by assembly line.

 

[PAT303]

Two stage supercharging makes more power, but needs more cooling to handle/use that power. Probably an oversimplification, but that's the simple crux of it.

From what I can remember the P51 had four different radiator designs before they got it right, the Spit was the same, other members will know more.

 

[PAT303]

Japanese didn't get the memo, and made the Zero before 1942.

How do you think the Zero would have done over Europe before and after 1942?, my guess there would have been many more Luftwaffe aces.

 

[PAT303]

Only the early (pre-war) Merlins had some hand-fitted components.

Later, especially once WWII started, Rolls-Royce and Ford manufactured the engine by assembly line.

I'm pretty sure we all know this and the myth of the 'mericans showing the British how mass production works has been debunk numerous times but alas the rumour still persists.