Which country designed the best engines for WWII? (4 Viewers)

Which country designed the best aircraft engines for WWII?

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Lets take these one at a time

Merlin
Small but obvious point, without the UK Merlin there wouldn't be a US Merlin. Secondly, the US Merlin used in the P51H was designed by Rolls Royce as the RM 14 SM not by the USA, the UK design increased the power to 2,200 hp without any increase in weight quite an achievement by any standards.

Merlin development in the UK was aimed at the Hornet which had 2000 hp but it also had a much reduced frontal cross section making it a more efficient design for the designers of the Hornet.

Reliability, I do not know the facts but I have never seen anyone call the Merlin unreliable.

Alison V-1710
1) If it was so good, why was it taken out of the P51A?
2) Why did the P38 need all that extra complexity to make it efficient at height something the Merlin didn't need?


R2800
This is without doubt a remarkable engine and I am not going to pretend that anything can top it. However the Centurus did give it a run for its money in the power to weight ratio. The big difference is of course that the Centaurus only just made the war whereas the R2800 was there when it was needed
A clear case of ignorance or opinion trumping facts.
Click to expand...
Now would you care to :-
a) Expand on the ignorance bit re the P51H
b) Supply some awnsers to the questions re the V1710

I await your reply with some anticipation
 
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I should add that one of the keys for making the P51H lighter than the D, was that they used UK standards for design loads not US loads which were more stringent increasing the airframe weight. They based it on the loads used in the Spitfire and Supermarine helped with some of the early calculations. So you can also say that the US owe the UK more than you think for the performance of the P51H.
 
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Radial lazybones stuck around for years post-war primarily due to being work-horse transport mills, being babied/fussed over by dedicated flight engineers -but if flogged they `d let go too, like the Stratoliners coming down on trans-oceanic flights, Merlin engined P-82s could do those distances too, but hi-po liquid cooled mills were for fighters too expensive TBO-wise for commmercial use..

With a type-tested 3055hp in 1945, that in the standard airframe Tempest Mk 6 could do 455mph on only 17lbs boost at 17,000ft or 485mph at that altitude in the Fury airframe,my pick goes to the thoroughbred Napier Sabre... best sound too, even firing multiples of 3 [24 in 2 flat banks of 12] running @ 4,000rpm, sweet...

Bristol sleeve-valve radials were strong smooth too,while running long TBO BMW radials, [like the Bristols] ran proper fighter jock-friendly combined Kommando-gerat synchronised engine management units that let the pilot fly shoot without endless fussing/fettling about like U.S. mills
 

Radials stuck around for years until manufacturers came up with turbine engines that were more economical to operate.


Care to give some SPECIFIC examples of that?
 
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The PT boats used a Packard V12 which was not the Merlin engine.
 
Got to give it to the Americans by a short head:

1) Best radials of the war: not only (mostly) extremely reliable but several key types built in huge numbers by dispersed manufacturing by a range of sub-contractors.

2) V-1710 continually panned but why? Basic design was fine, the single stage versions performed okay and had similar capabilities to the early Merlins. The biggest problem was lack of supercharger development (particularly a two-stage two-speed supercharger) which was largely a by-product of USAAF/USN policies. Otherwise thoroughly reliable.

As for the Sabre? Used by only two operational types during the war and that only after a great deal of grief.
 
Overall, I think the R-2800 was easily the best engine produced during the ww2 era: Pratt Whitney was not unjustified in bragging it was the engine that won the war. On the other hand, I think the Sabre was the most advanced piston engine to reach production, although it was, realistically, strictly an engine for combat aircraft. For this reason, I voted for England (incidentally, in 1940 it should have been referred to as either the United Kingdom or at least Britain; at the time England was no more an independent country than New York). Why the US needed to license build Merlins is, imho, simple: in Europe and Japan, the military drove aircraft engine development, and generals thought (wrongly) that in-lines were "better," in that the installation was lower drag (this was, and is, wrong: cooling drag does not correlate with whether the engine is liquid- or air-cooled; it only correlates with horsepower). In the US, commercial development drove engine development, and liquid-cooled in-lines resulted in aircraft that cost more to operate than did the radials. Even though airlines were subsidized, they were still businesses, and the subsidies were delivered by postal contracts and control of ticket prices, not covering the cost of operating individual aircraft.

"Best" is always a subjective choice, especially when comparing the aircraft engines of a number of countries with significantly different engine and aircraft design philosophies. It's hard to argue with the excellence of P&WA's Twin Wasp -- there were more of them produced (about 174,000) than any other large aircraft engine, and it wasn't because the US aircraft industry was run by sentimental fools.
 
swampyankee said:
Overall, I think the R-2800 was easily the best engine produced during the ww2 era: Pratt Whitney was not unjustified in bragging it was the engine that won the war.
Click to expand...

The war was won 1st by Merlins (BoB), then by Klimovs, Mikulins, Allisons, Again Merlins and Shvetsovs (Eastern front), then by Merlins, Allisons, Bristols, Wrights and P&Ws (but mainly R-1830s; MTO, Asia/Pacific), then again Merlins, Wrights, P&Ws and Bristols (ETO). Allied war effort was far more depenedant on Merlins, Allisons and Klimovs, rather than R-2800s.


Yep, Sabre was a troubled child


Japan was never much into inlines. The drag of liquid cooled engined planes was, of course, far smaller than of the radial engined ones, you're wrong on your assumption. Check P-36 vs. P-40, Fw-190A vs. Fw-190D.


For the much of piston era, USA did not have had inlines to offer to the airlines.


Twin wasp being far more important to the Allied was effort than R-2800?
 
tomo pauk said:
Japan was never much into inlines.The drag of liquid cooled engined planes was, of course, far smaller than of the radial engined ones, you're wrong on your assumption. Check P-36 vs. P-40, Fw-190A vs. Fw-190D.
Click to expand...

It's not an assumption; it's a conclusion based on articles published in the Journal of Aircraft.
 
The drag of a radial can be as small as that of a V engine of the same power (or even less draggy) - but early implementations certainly were more draggy.
 
swampyankee said:
It's not an assumption; it's a conclusion based on articles published in the Journal of Aircraft.
Click to expand...

When?

In the late 30s the inline engine (V-12) had much lower drag, but the air cooled installations were getting better. They eventually matched the liquid cooled engines, for the most part, but it took until the end of the war ( or after) for air cooled radials to match inlines as a general rule. The FW 190 was a big wake-up call. More than one late war (1944-45-46) air cooled installation cut drag just a little too much and cooked the engines under certain flight and climate conditions.

The P-36/P-40 is pretty well documented and shows the swing, both ways. Fitting the Allison engine increased speed by about 40-50mph ( OK,it took several tries to get the radiator sorted out, the first one was slower than the radial engine planes). The XP-40 was a production P-36 pulled off the the line. Later, in 1940 or 41 a P-40 ( letter unknown ? but an early one) was bailed back to P W for engine development. P W fitted it with a two stage R-1830 much like the F4F used and eventually got it up to 386mph I believe, ( at around 22,000ft ?) which makes it faster than any P-40 equipped with a Merlin engine (Allison peak power being at much lower altitudes.) From the photo I have seen it does appear that the company plane was unarmed however. This flight also did not take place until the late summer/fall of 1942. Which is about the time that Evansville began turning out P-47s and Curtiss was about too. It is also within a few weeks of big contracts being placed for P-51s with two stage Merlins. SO it is too late for any practical use, Knowledge gained is put to good use designing other engine installations.
 
We can also note that there were several much better liquid-cooled engine installations than one in bread'n'butter P-40, like wing LE radiators found in Tempest I, Westland and De Haviland planes, then P-51, several annular instalations etc.

The cooling installation of the XP-40Q seem to be better than of the regular P-40?
 
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True, Some designers were better than others even with the same type of engine, Many later air cooled engines used the exhaust gas not only for thrust but to help pull cooling air through the cowling at low speeds ( getting rid of some of the need for a fan).

because of overlapping production it is hard to say if either camp was really ahead at certain points in time but as a very vague general statement the liquid cooled engines were more stream line at the beginning of the war but the air cooled ones pretty much caught up by the end or just post war. Obviously an early war design still in production (B-17, Avro Anson, SBD, etc) got little or no improvement while something like a Hawker Sea Fury had an engine installation much advanced over a 1941 installation.
 
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