Talk:BMW 801/Archive 1

Archive 1

Comments

BMW 801 TJ saw a short production run, as it equipped about 100 Ju-388; I'm not sure about the high altitude ratings for this engine, can anyone give a good source for them?

This source [1] claims that the 801 had only a single intake AND exhaust valve. Looking at the engine and seeing only two pushrods, this doesn't seem so crazy. Any other sources on this? Maury 22:29, 8 November 2005 (UTC)

Every other source that I can find agrees. Changing. Maury 22:37, 8 November 2005 (UTC)

Valves and pushrods

The cylinder heads used one inlet and one exhaust valve with matching pushrods. the cam ring had two rings with four pairs of lobes 90 degrees apart. the cam ring rotated at one eight crankshaft speed. the pushrods were set up so that one cam ring was for exhaust and the other was for the inlet valves. Each pushrod was operated by a roller folloewr. The angle between the pushrods set the timing for the valves operation with the eshust operating first and then the inlet. This design of the cam ring made the grinding of the lobes a simple process. By Mike Nixon @ Vintage V-12's75.38.66.114 03:17, 17 December 2006 (UTC)

The Engine today

At this time there are two of these engines being restored for flight. links can be found at vintagev12s.com Mike Nixon75.38.66.114 03:21, 17 December 2006 (UTC)++

Displacement

The bore and stroke given, 156mm, yield 41,743cc (2547cuin), not the 41.8 or 2502 or 2560 given in the article. AMCKen (talk) 22:08, 12 January 2011 (UTC)

No anti-clockwise versions in service ?

Photos I've seen of two-engined bombers with this engine all show both engines running clockwise. Was there any particular reason why the (to me) simple mod to provide a counter-clockwise engine on twins, and hence theoretically provide smoother takeoffs and general handling, wasn't used in production ? Or did it make so little difference to a bomber that it wasn't worth any effort ? Did it power any high-performance twins where it might have mattered ? 101.117.127.212 (talk) 09:20, 31 January 2014 (UTC)

No idea, maybe they didn't see the need and/or wanted to avoid a complicated replacement/spare parts system. The only german production aircraft to use counter-rotating prop system was the He 177. --Denniss (talk) 11:23, 31 January 2014 (UTC)

Counter-rotation here (separate handed propellers), not contra-rotation (two co-axial propellers).

This was generally not done for any aircraft engines. It doubles the spares situation for major field-replaceable units like engines and propellers. Less obviously, the engines are never a simple mirror of each other.

Should a coolant pump or magneto be made in handed two versions? Or should the gearcase driving the ancilliaries be reversed, so that a counter-rotating crankshaft still drives the ancillaries the same way? A counter-rotating crankshaft has its own problems: desaxe crankshafts would be the wrong way round, as would master-slave connecting rods. Slow-speed marine two-stroke diesels have often been reversible by shifting the camshaft timing or even just cranking them backwards, but these were slow-running and sometimes had limitations on for how long they could be run backwards (often their cooling wasn't working fully in reverse). Another way to reverse an engine is to simply turn it end-for-end and take the output drive from the opposite end. Rolls-Royce did this for their C series post-war industrial diesels, but they had to be designed with a certain amount of symmetry to allow this. I've even heard that the Allison V-1710 did something similar.

In practice, the only paired aero engines I can think of in detail were the Rolls-Royce Merlin 130/131 pair (later the 133/134). These were the same engine, crankshaft and auxiliaries. Reverse rotation was achieved by an extra idler gear in their reduction gearbox. Such engines were needed for the dH Hornet, particularly the carrier-based Sea Hornet, to improve the symmetry of their handling.

The Allison V-1710 was also used handed for a variety of applications, including counter-rotating pairs for the P38 Lightning. These were (AFAIK) counter-rotating crankshafts, however I don't know how this was arranged internally.

In the end, the need for handed propellers in twins was overtaken by the increasing single-shaft power of engines and so the increasing need for contra-rotating propellers, just to handle the amount of power in a reasonable diameter and subsonic tip speed. Once the propellers were contra-rotating anyway, there was no longer a need for counter-rotation across nacelles. Andy Dingley (talk) 15:07, 31 January 2014 (UTC)

I think there were others, not sure. For some reason, the P-61 comes to mind, but I wouldn't swear on it. But there is another way to reverse rotation: just add another gear into the reduction gear. Automatic rotation reversal, but the rest of the engine runs exactly the same. AnnaGoFast (talk) 07:06, 10 March 2016 (UTC)

wrong spec

"Length: 2,006 mm (79 in)" This twin radial engine wasn't even close to this in length. Please someone correct this. Lastdingo (talk) 23:10, 31 October 2014 (UTC)

Jane's Fighting Aircraft of World War II (London. Studio Editions Ltd, 1998. ISBN 0-517-67964-7) gives the overall length as 2,006 mm for the BMW 801A, B, C and L, TQ variant as 2,525 mm and the R variant as 2,741 mm (larger superchargers most likely). All the other figures also agree apart from the weight which is given as 1,055 kg (43 kg heavier). Nimbus (Cumulus nimbus floats by) 04:14, 1 November 2014 (UTC)

1055 kg is the bare engine with some additional equipment, according to manual it's with 6 kg oil and 37 kg for engine bearer/mountings. It does not seem to include an oil cooler and the external engine cover plates. Manual lists 176 kg + 12 kg oil for a complete 801 MA/ML Motoranlage engine system on top of 1010 kg for the A/L engine.--Denniss (talk) 10:08, 1 November 2014 (UTC)

Methanol

  "The D-2 models were tested with a system for injecting a 50-50 water-methanol mixture known as MW50 into the supercharger output to cool the charge, and thereby reduce backpressure."

That's not what methanol-water injection does. Cooling the charge works like an intercooler, increasing density and allowing more air to fit into the cylinder, as well as decreasing the chances of detonation, and reducing exhaust gas temperatures in turbo applications. I don't see what effect it could have on back pressure. AnnaGoFast (talk) 02:57, 11 March 2016 (UTC)

Kraftei

A picture caption says "Kraftei" (literally "force-egg"). That's the nickname of the Me163. Was this term also used for powerplants with cowling fitted? 92.211.144.178 (talk) 21:07, 22 April 2017 (UTC)

See Power-egg. — Preceding unsigned comment added by 95.149.247.125 (talk) 08:58, 22 October 2017 (UTC)

Please stop making stuff up

Not just this article but the radial engine article contains the assertion that radials were generally considered to have too much frontal area for fighter aircraft before and during the time of this engine. That assertion is not just unsupported by any source but soundly refuted by fact as there were fighters in existence and development at the time that used large frontal area radials. For examples, consider just about all of the US Navy fighters in use during WW2. The authors need to at least put in enough effort and discipline to make articles appear as something other than flights of imagination.2600:1700:6D90:79B0:AC0B:BAF:E10:54C7 (talk) 22:18, 23 March 2019 (UTC)

The article actually asserts that "Radial engines were rare in European designs as they were considered to have too large a frontal area for good streamlining and would not be suitable for high speed aircraft." While the above refutation offers US Navy rather than European aircraft as examples to the contrary (and even the article itself in fact specifically singles out naval aircraft as being preferred with radial engines) and one could also mention that all WW2 Japanese fighters both Army and Navy had radials with the single exception of the Kawasaki Ki-61, European air forces also did have radial-engined fighters all through the war but particularly during the early phase. At least 19 different types saw combat, including older biplanes such as the British Gloster Gauntlet and Gladiator and Bristol Bulldog, the Italian Fiat CR 42, and the Russian Polikarpov I-15, I-15bis and I-153. However, all three major Italian monoplane fighters at the beginning of the war -- the Fiat G.50 Frecchia, Macchi MC.200 Saetta and Reggiane M.C.2000 Falco I -- also used radials. The Russians had the Polikarpov I-16 and later the Lavochkin La-5 and La-7, the French had the Bloch MB 150, the Dutch had the Fokker DXXI and the Koolhoven F.K.80, the Poles had the PZL P11 and P11c, the Roumanians had the IAR-80, the Finns built the VL Myrsky late in the war and the Germans of course had the FW 190. The Hurricanes, Spitfires, Dewoitines, Morane-Saulniers, Me 109's and Mustangs as well as the various Russian MiGs, LaGGs and Yaks and the later versions of the Fiats, Macchis and Reggianes may have represented the majority as far as sheer numbers of planes go, but as for types per se, European fighters with radial engines were by no means rare.--Death Bredon (talk) 20:00, 27 September 2021 (UTC)