Well, SunVisor Flyer-you have caught me in a bit of a conundrum here, as I just didn't think of the Boeing XF8B as a true Fighter aircraft, despite it's nomenclature. It also was a torpedo bomber, a dive bomber as well as an escort fighter by designation/s. And yes, it was heavier than my Quiz question fighter, which flew at a time when nomenclatures were changing from P- for Pursuit to F- for Fighter. The XF8B weighed a hefty 20,508 lbs loaded, with a max takeoff weight of 21,691 lbs. Its engine power was one P&W XR-4360-10 of 3,000 Hp.

I do not know, however, that it EVER played a role developing or testing something new (even though it USED that something new I was referring to). I will get back to that in my next paragraph-so stand by.

I had in mind for this quiz the Curtiss-Wright Corp. XP-62 that they intended to replace the many variations of the iconic but aging Curtiss P-40 Tomahawk; which single engine single seat fighter variations included the Curtiss Warhawk and Kittyhawk variations all derived from the Curtiss P-36 Hawk which first flew in 1935, a couple years after my birth. And, the sole Curtiss XP-62 in mind was also the first used (by several months) to test counter-rotating propellers-two three-blade propellers were on the sole XP62 driven by a Wright R-3350-17 radial engine of 2,300 Hp. The XP62 was designed for several missions as noted above, but never entered production. Only one XP62 was built and flown.

The Curtiss XP-62 had a loaded weight of 14,660 lbs AND a max takeoff weight of 16,651 lbs. Production was initially planned for 100 P-62 fighters from a contract award of May 25, 1942. However, this contract was cancelled BEFORE P-62 construction could begin when Curtiss-Wright was awarded a wartime contract to build (Republic) P-47 Thunderbolts which were of higher, immediate priority. WWII American pilots referred to the P-47 Thunderbolt fighter affectionately as the "Jug", and it was a major force in the war in Europe. The "Jug" could take a lot of punishment and still return to base, destroying 3,752 enemy aircraft in air combat. A total of 15,660 P-47s were produced.

How about considering this quiz to be over-with your noted good input to stand, unless others wish to offer any insights.