Question about ADI

[wmaxt]

Please post it I would like a copy.

The info I have is that 64" of boost was used, though maybe not widely, and 1,725 hp is the correct hp number at that pressure (64"). the easiest source I have to show you is The Planes and Pilots of WWII web page, chack out the graphs in section 3 of the Der Gableschwanz Teufel articals
http://home.att.net/~C.C.Jordan/index.html

According to the Allison web page 90" = 2,300hp with the P-38s V1710-17 series engines, 64" should be enough for the extra 125hp.
http://www.unlimitedexcitement.com/M...0%20Engine.htm

wmaxt

[skychimp]

Originally Posted by wmaxt

Please post it I would like a copy.

The info I have is that 64" of boost was used, though maybe not widely, and 1,725 hp is the correct hp number at that pressure (64"). the easiest source I have to show you is The Planes and Pilots of WWII web page, chack out the graphs in section 3 of the Der Gableschwanz Teufel articals
http://home.att.net/~C.C.Jordan/index.html

According to the Allison web page 90" = 2,300hp with the P-38s V1710-17 series engines, 64" should be enough for the extra 125hp.
http://www.unlimitedexcitement.com/M...0%20Engine.htm

wmaxt

I'm still looking the for the USAAF MAC document, but let me refer you in the meantime to this site's page on 150 grade fuel:

http://www.spitfireperformance.com/1...rade-fuel.html

Particularly, look at these documents:
http://www.spitfireperformance.com/1...25225-doc.html

http://www.spitfireperformance.com/1...-for-150-3.jpg

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About the Allison:

The 1,725 hp figure could only be achieved at 3,200 rpm. The USAAF never authorized 1,725 hp ratings for the P-38, nor did it authorize running the engine at 3,200 rpm (regardless of whether it was obtained at 64" or 70"). If you have the book Vees For Victory: Story of the Allison V-1710 Aircraft Engine 1929-1948 by Daniel Whitney, references to this rating is on several pages, and it's clear it was never approved. That Allison site you posted takes much of it's information, verbatim, from Whitney's book.

[Lunatic]

Okay, 145 not 150 - Jeeze!

The point is running about the same fuel grade the engines could withstand the higher boosts.

[skychimp]

Originally Posted by Lunatic

Okay, 145 not 150 - Jeeze!

The point is running about the same fuel grade the engines could withstand the higher boosts.

There was a significant difference.
115/145 was ultra-high performance fuel.

[Lunatic]

Originally Posted by skychimp

There was a significant difference.
115/145 was ultra-high performance fuel.

So was 150. The number was obtained using the "motor method", which involves taking a standard test engine and running the fuel until detonation occures. Today they have two methods, the motor method and a chemical evaluation, but in those days only the motor method was used.

150 grade fuel would actually allow more boost than 145 fuel. However the 145 fuel has a better (115 vs. 100) lean rating.