WW2: Germany with no DB-601

parsifal · Sep 12, 2013

no-one has mentioned the possibility of early development of the BMW 801 engine. Not that i know much about german engine development, but the little bit that I do know is that the first BMW 801A's ran in April 1939, only six months after starting work on the design, with production commencing in 1940. It had been delayed by about 12-18 months because of a cooling problem, which was solved very simply by fitting a twelve bladfe fan running about twice the speed of the crank. The actual engine design dates back to about 1935 or so I understand.

Radials were not favoured across Europe in the 1930s, but hostory does show this to be a spurious assumption. The Luftwaffe would have been just as well off with early FW190s as it would with Me 109s.

wiking85 · Sep 12, 2013

parsifal said:
no-one has mentioned the possibility of early development of the BMW 801 engine. Not that i know much about german engine development, but the little bit that I do know is that the first BMW 801A's ran in April 1939, only six months after starting work on the design, with production commencing in 1940. It had been delayed by about 12-18 months because of a cooling problem, which was solved very simply by fitting a twelve bladfe fan running about twice the speed of the crank. The actual engine design dates back to about 1935 or so I understand.

Radials were not favoured across Europe in the 1930s, but hostory does show this to be a spurious assumption. The Luftwaffe would have been just as well off with early FW190s as it would with Me 109s.

First runs are deceptive; this means first bench test, which is very far from being ready. Usually it took 3-4 years from the first bench test to actually be ready. IIRC the Jumo 222 was first tested in 1940 and wasn't ready until mid-1943. Same for the Jumo 213. Overall from first design to reliable service introduction required 5-6 years for WW2 era engines.
Also the first production runs are just sample engines for testing and development, rather than being service engines. The BMW 801 was rushed into service in 1941 with predictable results: the engine wasn't reliable yet and required another year of development, finally being made ready for service in May 1942.

Tante Ju · Sep 12, 2013

JtD said:
Imho there are only two options (outside of water injection co): run it with B4 on unchanged boost, or run it with C3 and increase boost or compression. You just don't use higher quality fuel then necessary.

Increasing boost would be of course possible by the machanics at their own peril, but normally it would require proper testing and clearance, wheter the engine can take the resulting greater load. I agree that higher quality fuel using would be generally unneccesary, but sometimes circumstances demand it, i.e. if there is no supply of lower quality fuel for some reason, or if its much easier to supply only one fuel type.

My understanding is that with C3 fuel, the increased boost and compression of the later engines as used with WEP could be run without immediate engine damage, maybe not for 10 minutes like with MW50, but still possible. So if the premise is the DB605A was running on C3, you would get a short time power output similar to historical MW50 operation with C3 use alone. In case of the A engine, a power boost in the range of 250-300hp.

Yes paper I seen show ca 1700 PS output for DB 605G (this is basically maiden name for A/m version) if only high boost is used for high octane, but no MW.

JtD · Sep 12, 2013

Well, yes. I was talking more about the technical possibilities and development, you're focussing on the practical side. Sure enough, you don't just fill the plane up with a different fuel and off you go with extra power.

davebender · Sep 12, 2013

RLM provided BMW801 engine program with almost unlimited resources. If faster development were possible it would have happened historically. Jumo 211 program also received generous funding.

Daimler Benz V12 engine programs could benefit from greater funding during late 1930s. But that's outside this discussion.

tomo pauk · Sep 13, 2013

If I may:

Tante Ju said:
Increasing boost would be of course possible by the machanics at their own peril, but normally it would require proper testing and clearance, wheter the engine can take the resulting greater load. I agree that higher quality fuel using would be generally unneccesary, but sometimes circumstances demand it, i.e. if there is no supply of lower quality fuel for some reason, or if its much easier to supply only one fuel type.

The story about mechanics over-boosting the V-1710 is a well known one, I guess - mechanics made it feasible to the pilots to override the boost control, hence more power was achieved at lower altitudes. Some pilots used it to the good effect, but, as SR6 says, we never hear about the pilots that wrecked their engines when doing so. Once Allison got aware about that, the didn't liked it, but soon the V-1710 was cleared for the WER, with strict directions about the usage.
Merlin/RR were swiftly to take advantage of the better fuel as it got available, again the new, strengthened versions of the engines were needed to take a full advantage.

Yes paper I seen show ca 1700 PS output for DB 605G (this is basically maiden name for A/m version) if only high boost is used for high octane, but no MW.

Thanks for pointing out to that version, here is the power graph of the 605G (scroll down).

Tante Ju · Sep 14, 2013

Ah, thanks for that, thats where I have seen it!

WW2: Germany with no DB-601

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