P-6E Development History

The path to the famous P-6E variant is sort of complicated, and involves several modifications and quite a few redesignations along the way.  It can be said to begin with the third P-6A (Ser No 29-262) which was redesignated XP-22 when used to test new radiator and oil cooler installations for the 600 hp V-1570-23 engine. The final modification to the XP-22 produced an entirely new nose, with the oil cooler and radiator located on the belly situated between the undercarriage legs. A three-bladed propeller was used.  Machine guns were lowered to troughs on the fuselage sides under the engine cylinder banks rather than between them as on previous versions.  A new single-leg undercarriage was also installed. Spats were placed around the wheels. These new features were eventually removed from the XP-22 and were installed on the YP-20. They were replaced by the original P-6A equipment and the XP-22 reverted to a standard P-6A. 

In the meantime, the third P-11 (Ser No 29-374) had been completed as a YP-20 with a 650 hp Wright R-1870-9 Cyclone radial engine in place of the failed Chieftain engine. The fin and rudder were changed slightly by raising the division between the rudder balance area and the top of the fin by half a rib space. This radial powerplant installation ultimately turned out to be unsatisfactory. #29-374 was then fitted with the 600 hp V-1570-23 Conqueror engine, mounted with a new horizontal tail, and given the single-strut undercarriage  first tried out on the XP-22. A tailwheel was used in the place of the tail skid. The YP-20 was then  re-designated XP-6E, the prototype of the most famous of the Hawk line of pursuit aircraft. 

Airframe #29-374 was also used to test a turbo-supercharger as well as an enclosed cockpit and re-designated XP-6F. 

One P-6E airframe, #32-254 was refitted with an unsupercharged V-1570F engine and called XP-6G, then P-6G, finally reverted back to P-6E by re-installing the V-1570-23 engine. 

The first production P-6E, #32-233, was modified by placing two .30 cal mechine guns in the top wing and two in the bottom wings just outside the prop arc and re-designated XP-6H.

Experimental Hawks

The Path to the P-6E, The "X-Hawks"