Rich, as Paul would tell you as well, the hand crank is for the landing gear. The Duck, the F3F, and the F4F Wildcat all had pretty much the same retractable undercarriage design, which ran off of chains, ratchets, and gears up to a hand crank in the cockpit. It's an early, simple design, but is very reliable - though it does take more strength and endurance than later hydraulic and electric systems. ; )