Best piston engine(s) for fighters of 1945?

[tomo pauk]

An interesting post made here by D Deleted member 68059 inspired me for this thread.
So between the piston engines of 1945, what ones do you think were the best? Or the best (ie. a singular), for that matter? We're probably looking at the best combination of power at all altitudes vs. the weight and size/drag penalty, with reliability as required for a service engine?
Only the engines that were actually flying back in 1945.

 

[herman1rg]

P-51 Mustang surely?

 

[tomo pauk]

P-51 Mustang surely?

Not an engine, though

 

[Admiral Beez]

For piston radials, top spot for a 1945 fighter goes to the Pratt & Whitney R-2800 Double Wasp. There were later Wasp family engines with more power for bombers, but the R-2800 was the ideal all rounder. Then we have the best of the rest, in no particular order: Bristol Centaurus, Shvetsov ASh-82, Wright R-2600 Twin Cyclone (or R-3350 Duplex-Cyclone), Nakajima Homare, Mitsubishi Kinsei and BMW 801.

For piston inline engines, what's better in 1945 than a Rolls Royce Griffon? Maybe one of the late model RR or Packard Merlins. The Junkers Jumo 213, Daimler-Benz DB 605 and (if reliable) the Napier Sabre should be in the top tier of the also rans.

 

[Shortround6]

Pratt & Whitney R-2800 Double Wasp

Then we have the best of the rest, in no particular order: Bristol Centaurus,...................................................

In 1945 none of the other radials make the cut. They don't make the power to begin with, don't make it at high altitude (bad supercharger?) have crappy overhaul life, or combinations of those factors.

 

[herman1rg]

Not an engine, though

D'oh read the question.............. foolish me.

 

[GregP]

I'd take the P&W R-2800 myself or a late-model Merlin. I'd skip the Griffon just because it turned the wrong way. Of course, so did the rest of the later British engines, so maybe we include the Griffon.

For the Japanese, the Mitsubishi Kasei was a good engine; more reliable than the Hamare. It started about 1,500 hp and got to about 1,850 hp in later versions. It was decently reliable when the build quality was decent.

The ASh-82 was decent for the Russians, and the Centaurus was quite good when operated at normal rpm levels. It was fragile if you git it even 250 rpm too fast.

The best is an opinion.

I'd take a Double Wasp or Centaurus myself for reliability, and would CHOOSE the Double Wasp because it turned the correct direction. But,"the correct direction" is an opinion, so I'd be happy with an R-2800, a Centaurus, or a Griffon. Nothing particularly wrong with a good German engine other than the difficulty in obtaining one in running order from the Germans during the war. The ASh-82 made it hard for a German airplane to live in a Russian sky in 1944 - 1945, so it can't have been all that bad. I have seen a few run here in the states recently, and they seem as good as any raidal I have seen run. That doesn't mean they ARE, just that they appear reliable to the casual observer. Your results may vary.

 

[Admiral Beez]

I'd take a Double Wasp or Centaurus myself for reliability....

The sleeve valves and incredible clockwork of the Centaurus must have made it tricky to produce and maintain. For that reason, it's out.


View: https://www.youtube.com/watch?v=v9IpQeVdDS4

I would have liked to have seen Britain make an eighteen cylinder twin-row radial out of the conventional poppet-valve actuated Bristol Pegasus. If Bristol refused, then give funding to Armstrong-Siddeley or Alvis to create one, from scratch if need be.

 

[bf109xxl]

It seems that I have to repeat again: the M-82 succeeded only because all the efforts of the Design Bureau were concentrated on it. If Shvetsov had been ordered to prioritize the perfection of the M-71, this engine would have been completed in approximately the same period of time, but with significantly better parameters. The M-71 did not have any inherent defect by design - even the long piston stroke cannot be recognized definitely as a drawback. The M-71 had even less problems with overheating being more powerful and in 1941 it was approximately equal to the M-82 in terms of reliability. The improvement of the M-82 continued throughout the war, in 1943 its reliability was still quite low (I can confirm it with references). To call the M-82 "the best" just because it was in mass production is not quite correct if we try to evaluate the design quality. Nevertheless, the M-82 was undoubtedly a success and could achieve even better parameters under conditions of a higher production culture (s. ASh-83). But it is also obvious that the technical level of German, American and British engines (it's not a ranking, the order is random) at the end of the war was superior taking into account both performance and reliability.
I suspect that many (but in no way all!) problems of Soviet engines were caused by the abominable quality of carburetors (most of which were deteriorated copies of the Western ones). Unfortunately there is no opportunity to carry out an in-depth study of the subject, I can only judge from the available publications.

 

[Shortround6]

I suspect that many (but in no way all!) problems of Soviet engines were caused by the abominable quality of carburetors

There may have problems with bearings, piston rings, valves, valve springs, etc.

Engine life of under 100 hours (sometimes well under) are not usually a carburetor problem (running way to rich and washing the oil off the cylinder walls?)

I suspect some rose colored glass in the case of the M-71. Nothing really wrong with it but it might have take a lot more time to straighten out than the M-82.
It might have gained a few hundred KG in weight when they got it straighten out.
Or they may have been happy with less power at the lower weight.
The 970kg for a double Cyclone 9 is too light, Granted Cyclone 9s went from under 475kg to around 595kg (for a G200).
The G-series (1000hp for T-O) went around 540kg. These were the 2200rpm versions.
Not surprisingly the Soviet M-62s went about 560-573kg for engines that reduction gears.

Maybe the book numbers are off.
P&W had built 3 different 14 cylinder engines in the 1930s, the 18 cylinder R-2800 drove them crazy in development with vibration problems.
Adding two cylinders per row was not as easy at it sounds.

 

[tomo pauk]

For my money, Merlin still seems to be holding up very well, even against the more flashy engines.

 

[bf109xxl]

There may have problems with bearings, piston rings, valves, valve springs, etc.

Really? I couldn't even imagine it.

Engine life of under 100 hours (sometimes well under) are not usually a carburetor problem (running way to rich and washing the oil off the cylinder walls?)

1. I never stated, that engine lifetime depends directly on the carburetor quality.
2. Lifetime was not the only problem with Soviet engines. They suffered from underpowering, vibration, smoke emission, etc.

I suspect some rose colored glass in the case of the M-71. Nothing really wrong with it but it might have take a lot more time to straighten out than the M-82.

That's not my opinion. This is the opinion of specialists from TsAGI who published the book "Aircraft Construction in the USSR". Some leading historians of Soviet aviation, such as Vladimir Kotelnikov, also shared the same opinion. I can quote if necessary. The M-72 was accepted for serial production with minimal differences from the M-71. If the resources of the design bureau in early 1941 were concentrated on the M-71, it would have been better finished than the M-82 by the end of the year.

It might have gained a few hundred KG in weight when they got it straighten out.

It is just a hypothesis. If you will find the weight value of the M-72 (I haven't looked so far, but I will), it would help to make a more definite statement.

Maybe the book numbers are off.

Yes, sure. But the M-72 was accepted to serial production...

 

[Shortround6]

I only have this book for a modern reference.

In tables in back the only entry for weight in M-71 series is 970KG for M-71.
No weight given for the M-71TK (turbo)
No weight given for the M-71F (higher power)
No weight given for the M-72 (two speed supercharger).

The ASh-73 with single speed supercharger is listed at 1330kg,
The older M-70 has no weight listed.

In the text section (page 130) it says that the M-72 was boosted version of the M-71 and series production was planned to begin in the third quarter of 1945 at Factory No 19 but an improved M-73 (ASh-73) was introduced into production instead.
The LL-143 flying boat (Be-6 prototype) was powered by the M-72 and a different source says first flight was in March 1945.

The M-71 was supposed to have used M-63 Components. The M-63 was supposed to have weighed 515kg. Apparently the plain M-63 did not use a reduction gear.

 

[bf109xxl]

I know perfectly, what Kotelnikov wrote. I have all these books. But he didn't specify the weight of the M-72, otherwise I wouldn't have asked.

 

[Admiral Beez]

For my money, Merlin still seems to be holding up very well, even against the more flashy engines.

Gotta love the Merlin. If focus can make it earlier and in greater numbers, Britain really only needed this one engine for the entire war. Swap out all the Bristol radials, Napier Sabres, Vultures, even Griffons, etc.... Put a Merlin on everything from the FAA's torpedo bombers and Shagbats to the RAF's transports and trainers. Meanwhile, make the Meteor earlier on and stick it into every British tank asap. Merlins for all until the jet age! So, no Typhoon, Tempest, Swordfish, etc. Everything must be sized to fit a Merlin.

 

[z42]

Gotta love the Merlin. If focus can make it earlier and in greater numbers, Britain really only needed this one engine for the entire war. Swap out all the Bristol radials, Napier Sabres, Vultures, even Griffons, etc.... Put a Merlin on everything from the FAA's torpedo bombers and Shagbats to the RAF's transports and trainers. Meanwhile, make the Meteor earlier on and stick it into every British tank asap. Merlins for all until the jet age! So, no Typhoon, Tempest, Swordfish, etc. Everything must be sized to fit a Merlin.

With the benefit of hindsight, they could have done that. But of course it wasn't obvious back then at the time.

Anyway, for a new prop fighter introduced in 1945 I'd pick either the Griffon or the R-2800. Or maybe the R-3350 instead of the R-2800, though given the engine problems the B-29 had the R-3350 perhaps wasn't really ready then..

 

[SaparotRob]

though given the engine problems the B-29 had the R-3350 perhaps wasn't really ready then..

Was it the engine or cowling/mount?

 

[Shortround6]

Meanwhile, make the Meteor earlier on and stick it into every British tank asap

Trouble is you need a transmission that will handle the power (torque) and the British screwed up the requirement.
You don't need a 600hp engine in a 30 ton tank.
40mph 30 ton tanks didn't work with the existing suspensions and track design.
Now if they had started Centurion production in 1943 things would have made more sense. But they didn't.

Tank Transmissions (and steering gear) can weigh as much as the engines and they take up a fair amount of volume in the armored hull.

 

[z42]

Trouble is you need a transmission that will handle the power (torque) and the British screwed up the requirement.
You don't need a 600hp engine in a 30 ton tank.
40mph 30 ton tanks didn't work with the existing suspensions and track design.
Now if they had started Centurion production in 1943 things would have made more sense. But they didn't.

Tank Transmissions (and steering gear) can weigh as much as the engines and they take up a fair amount of volume in the armored hull.

They could have derated it to suit whichever application it was used for. Mass production of a single good engine model covers a lot of sins in terms of that engine not being perfectly optimal for some applications.

 

[Admiral Beez]

They could have derated it to suit whichever application it was used for.

And cut it down to V8 size for smaller applications. Just like the postwar Meteorite.


View: https://www.youtube.com/watch?v=zsYgXzE61WQ