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Allison-powered Brewster Buffalo

Skyraider3D

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In some Brewster documents there's mention of an Allison-powered Army fighter based on the Buffalo. Has anyone ever seen drawings of this proposal?
 

hesham

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What is your source Skyraider to can help you ?.
 

Jemiba

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Skyraider3D said:
... Has anyone ever seen drawings of this proposal?

No ! Perhaps an installation similar to the P-40 may have been used ? But the R-1820 radial
was wider, than the Allison, adapting the fuselage to the inline engine probably would have
been no mean task. And the considerable bigger length ahead of the wing quite probably
would have demanded a longer tail.
(spoiled drawings from https://commons.wikimedia.org/wiki/File:Brewster_F2A-1_Buffalo_fighter.svg
and https://commons.wikimedia.org/wiki/File:Curtiss_P-40_3-view.svg)
 

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Stargazer2006

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Neat drawing, Jemiba! Makes me wonder however if that wouldn't have totally upset the center of gravity of the "flying barrel"...
 

eltf177

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Skyblazer said:
Neat drawing, Jemiba! Makes me wonder however if that wouldn't have totally upset the center of gravity of the "flying barrel"...
\

Looking at that drawing I get the exact same impression...
 

Jemiba

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eltf177 said:
Looking at that drawing I get the exact same impression...
Not really sure, as a (very) quick search shows, that the Wright R-1820 engine of the Buffalo had
a weight of 605 kg, the Alison V-1710 of 665 kg. So with regards to engine weight, the difference
wasn't that great, I think.
 

cluttonfred

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[quote author=Jemiba]Not really sure, as a (very) quick search shows, that the Wright R-1820 engine of the Buffalo had
a weight of 605 kg, the Alison V-1710 of 665 kg. So with regards to engine weight, the difference
wasn't that great, I think.[/quote]

It's not just about weight but also location. A radial engine is relatively short, so the center of gravity of the engine itself is quite close to the firewall. An inline or V engine is much longer, so the center of gravity of the engine is much further from the firewall. 665 kg 12 inches from the firewall is very different than 605 kg 6 inches from the firewall.
 

Jemiba

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Probably correct, though I have no idea about the weight distribution
With regards to length of an inline engine. It's probably not homogenous.
But exchanging a radial for an inline engine worked quite well in a number
of cases, e.g. for the Fw 190 A to D, Macchi MC.200 to 202 and, mabe as
the most important example, the Curtiss P-36 to the P-40, as here it was a
change from the Wright R-1820 to the Allison V-1710, too.
 

cluttonfred

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True enough, inline or V to radial swaps were quite common, which is the easier because the radial is usually lighter and always shorter so the right balance can be found by varying the length of the engine mount. Radial to inline or V is harder because either the firewall has to move or the rear fuselage extended to find the right balance.
 

Stargazer2006

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I have numerous plans and profiles of the Buffalo from various sources, but somehow none of them seems to have the CG in it!
My intuition is that if a V-1710 engine had been fitted, the whole tail unit would have needed a major redesign, with rear fuselage slightly extended and maybe the cockpit moved a little behind.
 

Jemiba

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Skyblazer said:
... My intuition is that if a V-1710 engine had been fitted, the whole tail unit would have needed a major redesign, with rear fuselage slightly extended and maybe the cockpit moved a little behind.

Judging several drawings, from the P-36 to the P-40B the tail was more or less unchanged, but the cockpit was
positioned further aft. And the later marks of the P-40 had a considerable longer tail, so we could be on the
right track.
 

klaud3

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Skyblazer said:
I have numerous plans and profiles of the Buffalo from various sources, but somehow none of them seems to have the CG in it!
I remember from Shavrov book on Soviet aircraft that for fighter of that era CG in some 20-25% of Mean Aerodynamic Chord was the typical range. It could move 2-3% fore and aft as the fuel / ammo was loaded and used up, but crossing 30% was generally considered dangerous. I guess Buffalo was not much different.
 
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