a diesel 109 ?

don4331 · Aug 11, 2021

Snowygrouch said:
DB607 was meant for bombers/long distance flight (and not at very high altitudes). The take off power of 1750PS was actually achieved by using Alchohol fuel, so you need
two fuel tanks (I dont have the particulars of how that system worked annoyingly), and the 607 was down to 625PS by 33,000feet altitude (a bog standard 605A at that point was 790PS, a 603A was 950PS and even an old 601E has 700 at 33,000ft). Diesels tend to have high airflow per unit power, as they need to run pretty lean, so this places a higher
demand on the supercharger size, so they dont make brilliant engines for very high altitudes without being turbocharged - which totally counts them out for any
German single seat fighter.

Today because of the more advanced state of turbocharging, it is a possibility again to make a high performance aviation diesel with good altitude performance, with a reasonable
package size and overall weight.

RED Aircraft – Home of the V12

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View attachment 637422

I certainly brought out the big guns, thx.

Thanks for the information on DB 607, wasn't aware that it was to run on alcohol for take off.

While diesels remain functional at very lean mixtures - the old tractor idled at air-fuel ratios of near 100:1, do they need to? The same old tractor made some serious power when injector pump was screwed in. And lots of truckers in Americas make wild power while "rolling coal". I'm having to do some airflow calculations here - the engine rpm differences between the automotive engines - diesel versus gas make direct comparisons challenging.

There's a lot of improvement over past 90 years, not just turbocharging, but some forgotten technology on the gear drives too.

Snautzer01 · Aug 11, 2021

Snowygrouch said:
DB607 was meant for bombers/long distance flight (and not at very high altitudes). The take off power of 1750PS was actually achieved by using Alchohol fuel, so you need
two fuel tanks (I dont have the particulars of how that system worked annoyingly), and the 607 was down to 625PS by 33,000feet altitude (a bog standard 605A at that point was 790PS, a 603A was 950PS and even an old 601E has 700 at 33,000ft). Diesels tend to have high airflow per unit power, as they need to run pretty lean, so this places a higher
demand on the supercharger size, so they dont make brilliant engines for very high altitudes without being turbocharged - which totally counts them out for any
German single seat fighter.

Today because of the more advanced state of turbocharging, it is a possibility again to make a high performance avaition diesel with good altitude performance, with a reasonable
package size and overall weight.

RED Aircraft – Home of the V12

red-aircraft.com

View attachment 637422

Know to you of course but may be of intrest

don4331 · Aug 11, 2021

Wait a minute - MW50 is just water injection (Germans added alcohol to water so it doesn't freeze, but still just water injection) And yes, water injection works on diesel too. Although, I used propane - it cut down on smoke in exhaust better, so dad couldn't tell just how far I had turned up the pump!

Fw.190s had separate MW50 (and often GM1 tanks) so not that different from gas engines.

fastmongrel · Aug 11, 2021

I have often wondered if the Caterpillar D200a tank engine (diesel version of the Wright R1820) was tried in an aircraft.

Shortround6 · Aug 11, 2021

fastmongrel said:
I have often wondered if the Caterpillar D200a tank engine (diesel version of the Wright R1820) was tried in an aircraft.

Why bother?
The tank engine was rated at 450hp at 2000rpm. Granted all tank engines are under rated.
It was supercharged (or at least some sort of distribution fan was used in the intake system) and the compression ratio was 15.5 to 1.

In 1930 you could buy an R-1820E series engine that was rated at 575hp max continuous at 1950rpm that ran on 80 octane fuel.

The M3 Grants and M4 Shermans that used Wright 9 cylinder engines used R-975s of 355-400hp running on 80 octane.
Aircraft R-975s were rated at up to 450hp running on 92 octane fuel.
Guiberson made an R-1020 Diesel version of the R-975 and got 340hp out of it.

Deleted member 68059 · Aug 12, 2021

don4331 said:
Wait a minute - MW50 is just water injection (Germans added alcohol to water so it doesn't freeze, but still just water injection) And yes, water injection works on diesel too. Although, I used propane - it cut down on smoke in exhaust better, so dad couldn't tell just how far I had turned up the pump!

Fw.190s had separate MW50 (and often GM1 tanks) so not that different from gas engines.

Its hard to know what was used on the DB607 exactly, my German document states "Alkohol", not "MW50". Its possible the Allied intel people who made the document above misinterpreted something, but its also possible that it was MW50 and the German document is misinterpreted (although this is an official DB datasheet.... ). Anyway, we certainly know that 1750PS output requires the addition of
some Methanol containing additive. You can also see here that its suggesting that the take off power without it was 1400 PS.

a diesel 109 ?

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