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Smaller parts count should account for something on an engine that is bound to be made in many thousands in a country that has problems with securing a good deal of raw materials. Granted, a 9 cyl can work - perhaps short-stroke the BMW 132 or Bramo 323 (sorta "German Mercury"), down-rate it so it can use lower octane fuel and be done with that? A bespoke 7 or 9 cyl might be even better, or copy the Americans with the R-985 or 975? Or a bigger A-S Cheetah?
Liquid cooled engines were in theory better able to take advantage of the high octane fuel.
For the Germans, however it seems like the BMW 801 was no worse in this regard than the DB engines (German engines were not taking all of the advantage of the very high rich rating of the C3 fuel anyway, per British reports; C3 rich rating being noted as better than on the Allied 130 grade fuel as war progressed). Eg. the BMW 801C gained ~300 HP vs. 1943 801D, despite the increased CR of the 801D (compare with the small V-1710 making 700-800 HP more on 130 grade vs. 91 octane, but also against the DB 605 gaining ~200 HP, and the 601 being worse still). Engine is supposed to actually withstand the increased stress that over-boosting brings along.
The German air cooled V-12s used the same cylinders, heads, pistons and con rods (?) as the Hirth V-8s. They used the same cylinders, heads, pistons as Hirth $ and 6 cylinder engines.s for the small radial - making 30000+ of 7 cyl radials of 20L and 500-600 HP should've been easier on the German budget, manhours and raw material supply than making the same number of V12 air cooled engines.
Pick two, not threeA simple, cheap robust radial engine for LW might've looked like the Ha 41/109 series by Nakajima, or as Kasei by Mitsubishi (perhaps even short-stroke Kasei so it is more compact) - each of these engines were very light when compared with BMW 801. No-nonsense engines, and were able to run on Japanese fuel that was in it's best day of 91-92 octane
Interesting, any idea what is behind this effect?
Anyway, if so, one could argue from this perspective it would have made sense for Germany to focus more on air cooled engines than they historically did?
The Cheetah is too small (13.7 liters). Also at 7 cylinders it may cause problems.Cheetah is probably quite close to what's wanted, if we want a cheap and robust radial as a replacement for the Argus air cooled V-12. A down-rated 132 or 323 is probably a bit heavy, as they're considerably larger engines at close to or around 550 kg vs around 300 kg for the Argus, Cheetah and the R-985.
Yes, German engineers were probably spending so much time trying to get their engines running reliably with their critical material shortages that they never were able to leverage their designs to take advantage of better fuels. So Germany is probably a poor example for studying the performance improvement from higher octane gasoline.
In engine/fuel terms air cooled engines (high performance) were considered as "severe" duty engines. The air cooled engines were more prone to isolated hot spots in the cylinder heads while the water cooled engines averaged the temperatures better, not saying that were not hot spots. The Air cooled engines were running closer to the detonation limits.It probably had a lot to do with water being better at removing the extra heat generated in small amount of time, than air it was capable for.
Not sure about this. P&W was working on a large 18 in 1936 of 2600 cu in until they found out that the new Wright engine was a 2600. Being a bit later in timing P&W went to 2800 to "one up" Wright. Both companies had both civilian (airliner) and military sales in mind and knew that the commercial market was not interested in liquid cooled engines. Once it looked like Military sales might pick up both companies tried to come up with liquid cooled engines and in both companies the programs came to no useable hardware.Much like R-2800 was a cushion against the hi-per engines non-materializing (in sense of actually having them for service) in the USA.
The big Ha-42 making plenty of power on low-octane fuel. Japanese 14 cyl engines (bar the smallest ones, like Sakae and Zuisei) were also very powerful for the accompanying weight and bulk. BMW 801 was probably over-built, however.
End result might be a working Fw 190 in service months before it was the case historically, and be in use in Russia and in Africa by early 1942 instead of in late '42.
Let me reformulate.Not sure about this. P&W was working on a large 18 in 1936 of 2600 cu in until they found out that the new Wright engine was a 2600. Being a bit later in timing P&W went to 2800 to "one up" Wright. Both companies had both civilian (airliner) and military sales in mind and knew that the commercial market was not interested in liquid cooled engines. Once it looked like Military sales might pick up both companies tried to come up with liquid cooled engines and in both companies the programs came to no useable hardware.
The Germans have to come up with the similar size engine and then develop it faster than the Japanese did. The Engine in the Ki-44 II didn't show up the 2nd half of 1942 and was about 100hp down compared to the BMW 801D used the FW 190A-3 (?).
And again, what was the engine life like for the Japanese engines?
In engine/fuel terms air cooled engines (high performance) were considered as "severe" duty engines. The air cooled engines were more prone to isolated hot spots in the cylinder heads while the water cooled engines averaged the temperatures better, not saying that were not hot spots.
Compared with BMW 801s of 1941-42 - engine life was wonderful.
The eventual Ford GAA had 100 more horsepower than the the wright radial in the Sherman and was more reliable.
That's not setting the bar particularly high, is it?
P&W was lead by Mead in the late 30s and unfortunately he drank of the sleeve valve cool-aid and started two liquid cooled 24 cylinder projects. They didn't do much with the smaller one but did make the larger one even bigger. Mead was in ill health by 1939/40 and Hobbs took over and pretty much canned the Sleeve valve project/s to concentrate on the air cooled engines. At the time of the cancelations the R-2800 was to some extend unproven engine of 1850hp, Testing was indicating more.R-2800 also ended up as an insurance vs. the hi-per engines over-promising and under-delivering.
Radials don't have to be vertical.Can we put a radial in Germany's tanks? No cooling system, though there is the Sherman-like height issue.
(in)famous for being known as Screaming Jimmys( GM ) from the high rpms they had to operate at, annoying/deafening to the Truckers that had them under the hood, and from the crankcases being pressurized to feed the cylinders, called 'Green Leakers' from the engine color and ability to mark its territory wherever they were parked.the basic design was so good the 71 series remained in production until (per wiki) 1995
They were working on air cooled diesels, Porsche was working on the X-16 SLA 16, and Tatra had prototypes for air-cooled V-8 and V-12 diesels. AFAIU the motivation behind air cooling wasn't power/weight, but ruggedness, better tolerance for battle damage, and no issues with the coolant freezing in the Russian winter or boiling off in the African desert.
The first Sla 16 engine was tested in late 1944 and produced 770 hp (574 kW) at 2,200 rpm without the cooling fans. It took around 95 hp (71 kW) to drive the cooling fans, which reduced the engine's output to 685 hp (511 kW).