Allison V-1710 for P40 B/C propeller/engine gear ratio question

[bruno_]

Dear all,
I'm looking for the propeller/engine speed ratio of engines that powered the P40 B and C versions.
If I'm not wrong the engine should be the Allison V-1710-33. More specifically I'm looking for such number(s?), since I'm interested in specifications of P40 that served in RAF/SAAF in the North African theatre.
Can you kindly help me?
Thanks in advance!

 

[tomo pauk]

According to the table about the V-1710-33, found at the book 'Vee's for victory', pg. 124, the propeller gear ratio was 2.0:1.

 

[bruno_]

Thank you very much tomo paulk! It looks like one of the highest engine to prop ratios for wwii engines.

 

[kmccutcheon]

Dear all,
I'm looking for the propeller/engine speed ratio of engines that powered the P40 B and C versions.

Here is a good general reference for many of these kinds of questions:
(http://www.enginehistory.org/moddesig.shtml)

 

[wuzak]

Thank you very much tomo paulk! It looks like one of the highest engine to prop ratios for wwii engines.

Bruno, if I understand what you mean about the engine to prop ratio I would say you are incorrect.

The British used a different system - prop rpm:engine rpm, which is the inverse of the American system.

Now 2:1 was a common ratio on P&W R-2800s. Others had 16:9 and still others had 2.5:1
http://www.enginehistory.org/ModDesig/I4 9.tif

The Merlin XX had a reduction ratio of 0.42:1 (2.38:1). The 45 had 0.477:1 (2.096:1).

The Vulture had a reduction ratio of 0.35:1 (2.86:1), the Sabre 0.274:1 (3.65:1).

Engines that had higher rpm capability generally had the larger reduction ratios.

 

[bruno_]

Absolutely right, wuzak. My fault.
@kmccutcheon: thank you for the interesting link!