109 e3b against spitfire II

[Kurfürst]

Originally Posted by Seadog

From what I can gather on the web, the DB601 also had a 100 hr TBO versus 240 for the Merlin. Does anyone have other figures?

TBO for DB 601A-1 was 200 hours. RR TBOs were understood as a figure that 1/3 of the engines could satisfy, and if a single cause of failiure did not amount to more than 2/3 of the cases IIRC.

[TomcatViP]

Originally Posted by CaptainDoggles

In one of Viper's earlier points he argues that if you don't care about emissions and purposely run a bit rich, then minor variations in fuel/air ratio will not cause problems. Temperatures on the downstream side of the supercharger ought to be plenty high enough to cause evaporation of the fuel droplets, particularly if you aren't intercooling.

On a turbocharged, intercooled engine I'd wager that direct injection would be superior since the turbo is already much more thermodynamically efficient than a supercharger. But on a supercharged engine where the supercharger can pull as much as 30% of the crankshaft's power it's a sound engineering decision to try to increase that efficiency foremost.

I think you summed it up.

[TomcatViP]

Originally Posted by Viper2000

It doesn't matter whether you're injecting fuel or water, the latent heat reduces the temperature rise through the compressor, which is analogous to an increase in compressor efficiency.

Great ! but don't forget the Mass flow : Lowered Heat + increased Mass Flow = higher efficiency