Worst to first

[Airframes]

Fuselage, engine cowlings and prop (for later, 4 blade Typhoon prop) and tail planes looked the same (late Typhoons used Tempest tail planes). Tempest fin was extended, and, of course, the main wing was redesigned and a different plan form.
At certain angles, it was / is difficult to identify a Tempest from a Typhoon, unless it was a Tempest Mk.II, with radial engine.

 

[Elvis]

The poor Brewster Buffalo

I think the Finns proved there never was a problem in the first place. It's all the "updates" that came later on that did it in.


Elvis

 

[swampyankee]

Which to me begs the question why wasn't money pushed to Allison to incorporate a supercharger setup similar to the Merlin?

Cheers,
Biff

A very good question, which may indicate that Allison was too busy with other projects, such as turbocharger development, to put enough work on mechanically-driven superchargers. Or Allison had a bad relationship with GE.

From what I've read, the V-1710 was quite robust, with its supercharger having poor aerodynamics in its diffuser being the hindrance to its performance.

 

[parsifal]

Late model Ki-61 to Ki100. Late model Ki61s were grounded for lack of engnes. When the radial was fitted the resulting "lash up" was probably one of the piston engine fighters ever built, certainly superior to its inline forbears. .

 

[Shortround6]

Allison didn't do much turbocharger development. The turbochargers were government furnished equipment, the turbo controllers were government furnished equipment.

And once again, General Electric had near monopoly on supercharger design for aircraft engines until about 1937/38 so there was no pool of supercharger engineers to go to if you wanted something better. Both P & W and Wright had used General Electric designs and even General Electric supplied parts up until then (and even for a few years after on older designs).
Allison during the 30s actually supplied supercharger parts to GE as a subcontractor that were resold to P & W and Wright.

The Allison supercharger was actually pretty good in 1939/40. It would supply enough air for 1040hp at a higher altitude than the DB 601 or any other service V-12 of the time except the Merlin. and the Merlin wasn't that far ahead. This all changed in the summer of 1940 with the introduction of the Merlin XX with the Hooker modified supercharger.

Everybody rags on Allison for not having a better supercharger after 1940 but few people criticize P & W for needing a two stage supercharger on the R-1830 to come close to the performance of the Merlin XX using a single stage supercharger. Where is the criticism of Wright for failing to come up with a decent supercharger, either single stage or two stage to give the R-1820 or R-2600 decent altitude performance?

 

[wuzak]

Allison didn't do much turbocharger development. The turbochargers were government furnished equipment, the turbo controllers were government furnished equipment.

And the GFE turbos went to the airframe manufacturer, not Allison.

It seems that in the US the airframe manufacturers were responsible for the exhaust system beyond the exhaust port flange. They developed their own ejector exhausts, and turbo installations.

It doesn't appear that Allison ever ran a V-1710 with a turbo on the dyno before the XP-37, XP-39 and, possibly, the XP-38 flew.

 

[wuzak]

Everybody rags on Allison for not having a better supercharger after 1940 but few people criticize P & W for needing a two stage supercharger on the R-1830 to come close to the performance of the Merlin XX using a single stage supercharger. Where is the criticism of Wright for failing to come up with a decent supercharger, either single stage or two stage to give the R-1820 or R-2600 decent altitude performance?

Perhaps because the V-1710 was almost identical in capacity to the Merlin which gave a direct comparison.

Certainly the USAAC used the comparison to push Allison for improvements.

 

[Elvis]

A very good question, which may indicate that Allison was too busy with other projects, such as turbocharger development, to put enough work on mechanically-driven superchargers. Or Allison had a bad relationship with GE.

From what I've read, the V-1710 was quite robust, with its supercharger having poor aerodynamics in its diffuser being the hindrance to its performance.

In the 50's, 60's and 70's (even the 80's and 90's!) The big V-12's were used in hydroplane racing.
They were pushed pretty hard so by the mid 70's, guys were pretty much buying swapping with each other, less worn out parts for completely worn out parts.
I made the acquaintance of someone who was on the scene in the 70's and we talked about the old Hydros I remember as a kid (as he crewed on several of those teams) and when I asked about the engines he said that the teams were always able to push the Merlin's harder than the Allison's, and thus, get more power out of them.
I'm also pretty sure that the Merlin is a heavier power plant than the Allison, so it may also be "beefier", thus able to withstand higher stresses while maintaining a reasonable amount of reliability.
I know the Allison was originally designed to power airships, so it needed to run at a steady state for very long periods of time.
I think the Merlin's basic design was originally a race motor, so it needed to handle high amounts of stress over and over again, while maintaining reliability.
I think the P-63 got a version of the Allison that used a two-speed/two-stage supercharger, akin to the Merlin's, and it made pretty decent power, but was still lower than the Merlin's ratings.

 

[Milosh]

There is one Allison powered U still racing.
U-3 Go3 Racing

 

[Elvis]

"Grigg's Ace Hardware", eh?
That's the old "Graham Trucking" boat (maybe its "Graham Trucking" when it races out here?)...and yes, while its a bit of an anomaly, it is a V-12 powered boat.
In fact, it's the only non-turbine boat out on the race course these days.
However, in general, its been quite a while since the old V-12's were in common use.


Elvis