R-1830 2-stage supercharging for high altitude fighters?

[Shortround6]

The Bearcat was a simple lightweight single stage R-2800 powered fighter almost a ton lighter than the Hellcat. Elimination of the second stage supercharger and the associated charge cooler was key to this reduction. In my opinion single stage power was more than adequate for the low level war in the Pacific. All the pilots (many of them Pacific war veterans) who flew the Bearcat at the October 1944 Joint Fighter Conference at Patuxent River in Maryland were thrilled with the performance of XF8F-1 prototype.

Other keys to the reduction in weight of the Bearcat was the initial reduction of guns from 6 to 4, the reduction of internal fuel down to 185 US gallons, and the 90sq ft reduction in wing area which resulted in, despite the Bearcats lighter weight, a higher landing speed.
A 1/3 reduction in gun armament, compared to an F6F-5 a 26% reduction in fuel capacity, a 27% reduction in wing area had nothing to with the Bearcats smaller size and weight?
You might want to consider that the F4U and F6F were designed around the earlier A and B series engines and 100 octane fuel, NOT 100/130. The Bearcat's C series engine could run 100rpm faster and it's single stage supercharger might not have been the exact same one used on the older single stage engines. A "B" series engine with a 2 speed supercharge was good for 1600hp at 13500ft compared to the 1600hp at 16,000ft of the "C" series engines in the early Bearcats. The engine in the F6F with the two stage supercharger was good for 1800hp at 15,500ft and 1650 hp at 22,500ft.

If you go with the single stage supercharger in 1941-42 you are betting that the Japanese never develop better superchargers than they had in 1940-41-42. It turns out that they didn't get a lot better but who knew before hand?

I do not have any information on the 1939 fighter trials. I assume at least one of the two stage pursuits you mentioned was a Curtiss Hawk. There were so many iterations of the basic Hawk airframe I can't keep track of them all. The Hawk image you posted in June of last year looks to me like it is turbocharged, but I can't find anything on this model. I also can't find much info on the evolution of the two stage R-1830. Colin1 seems to very knowledgeable about this branch of the R-1830 family. I wonder if he would share his sources with us?

the Hawk picture is of a two stage mechanical drive plane, I am assuming that the duct under the rear of the plane has to do with the intercooler.
The other aircraft was the XP-41

Aircraft: Seversky XP-41

there is as much confusion/mis information about this plane as the Hawk. There were company demonstrators with both turbo and mechanical two stage superchargers. many web sites and books say the XP-41 used a turbo charger and then list a P&W R-1830-19 engine. The R-1830-19 used a two stage mechanical drive supercharger so in every listing of this combination either the turbo fact is wrong or the model number of the R-1830 is wrong. Wiki even says it was a Wright R-1830.

In the Spring of 1939 niether the turbo nor P&W two stage was really ready for squadron use in service.