Allison exhaust unknown

[Brent]

IN my collection of parts for my P-40K project, I have a peculiar exhaust for an Allison. For sure not Merlin as ID'd by the base bolt pattern. Nobody in the P-40 community or the Allison museum curator in Indy can ID it. Any thoughts?

 

[MACHIA]

IN my collection of parts for my P-40K project, I have a peculiar exhaust for an Allison. For sure not Merlin as ID'd by the base bolt pattern. Nobody in the P-40 community or the Allison museum curator in Indy can ID it. Any thoughts?

I read once that in the United States, during WW2, airplane manufacturers sometimes decided what bolt patterns of exhausts where to be used, and even actual exhaust designs. It was not completely an Allison design quite possibly.
I have read extensively on Curtiss aircraft and Allison engines in the past, and if this is of some interest to you, I'll go into my collection of reading material on the subject to try to help you in this matter.
Perhaps you need to turn to people at the Curtiss-Wright Corporation ? They can be found on the web.

 

[MACHIA]

I'll check my documentation on Allison V1710's. I see now that you did reach out to the Curtiss community.

 

[mjfur]

Have you tried asking here?
Ace Allisons, Allison Competition Engines, Inc., Latrobe, PA
Vintage V12s, Inc.

Are there any Part #'s on it?

 

[P-39 Expert]

I read that the Allison engines were delivered without exhaust stubs which were the responsibility of the airframe manufacturer.

 

[Brent]

No visible part numbers. I showed it to Matt Nightingale who had no idea either. It is kinda similar to early P39 photos but does not match the three different P49 engines I have seen. As it came with a stash of Alaskan aircraft parts a Russian bound aircraft is a good bet

 

[MiTasol]

IN my collection of parts for my P-40K project, I have a peculiar exhaust for an Allison. For sure not Merlin as ID'd by the base bolt pattern. Nobody in the P-40 community or the Allison museum curator in Indy can ID it. Any thoughts?

Almost certainly P-39 or P-63. Both used this general type of stack and there were several variations. My guess would be P-63 rather than P-39 as the stacks look too long for the P-39 but that may just be camera angle

 

[Vintageaeroengines]

IN my collection of parts for my P-40K project, I have a peculiar exhaust for an Allison. For sure not Merlin as ID'd by the base bolt pattern. Nobody in the P-40 community or the Allison museum curator in Indy can ID it. Any thoughts?

It is an Allison stack
Left side based on stud holes
not P-38, they were collector types
not P-39 or 63, they had rectangular exits
P-40 had curved exits, one per cylinder
P-51 A had Allison and round exhausts match
many Allison's were shipped with the exhaust flanges and hardware for aircraft co to make exhaust as desired.
Note: could be export P-40. Also the early engines had the two round ports close together and later engines (-80's on) had twin ports about 1/2" greater distance between ports, That allowed more coolant between the exhaust valves.
Mike

 

[MIflyer]

Take a look at these shots. One shows a RAF Airacobra I. Note the "fish tail" type exhausts. I have not see those on a P-39 before, although they are common on P-40's and Allison P-51's. Note the shark mouthed P-400 on Guadalcanal and the P-39D-1 at Port Morsby, which do not have fish tail exhausts.
I wonder why they changed the exhausts?