Bf 109E-3 and Bf 109F, more efficient supercharger air intake -- numbers and sources?

[DavidIsby]

One of the reasons for the superior high altitude performance of the Bf 109F over the Bf 109E-3 was the improved design of its supercharger air intake.

I have seen figures that the Bf 109E-3 had a ram air recovery (percentage of possible air it can cram into its intake) of some 37.5 percent, while the comparable figure for the Spitfire IA was 50 percent.

Does anyone have any numbers or sources as to how much better the Bf 109F was than the Bf 109E-3? What was the Bf 109F's full throttle height (critical altitude)? Do you know where I could find out?

thanks,
David Isby

 

[davebender]

Kurfurst - Your resource on Messerschmitt Bf 109 performance
Kurfürst knows more about Me-109s then anyone I am aware of. His site includes a wealth of historical performance data sheets.

 

[Shortround6]

I have seen figures that the Bf 109E-3 had a ram air recovery (percentage of possible air it can cram into its intake) of some 37.5 percent, while the comparable figure for the Spitfire IA was 50 percent.
David Isby

I am not sure what you mean by this. Some planes had a pressure rise in the intake duct before the engine inlet of several pounds per sq in (or however a country measured it) above the surround air at a given altitude.this did of course vary form plane to plane, it also varied with the planes speed. A plane doing 320mph was going to get more pressure in the inlet duct than one doing 160mph. The difference between full throttle height (critical altitude) when going at full speed and when climbing was sometimes several thousand feet, and when accelerating from a slower cruise speed the critical height will change as the plane speeds up.
A lot of times the critical hight of an engine is given without this ram effect as that is the hight where full throttle/max power is available regardless of what the plane is doing. Any improvement by ram is a bonus.