Using Flaps in a Dogfight with the F4U Corsair and others
Video from the channel Greg's Airplanes and Automobiles about Vought F4U Corsair, linked on its Above Ten Thousand entry. Duration: 15:43. Language: English. Video type: Documentary.
What it's about
An explainer on whether deploying flaps improves the turn of a World War II fighter, with the F4U-4 Corsair as the main example. It covers four flap types: plain (P-51 Mustang, Bf 109), split (Spitfire, Hurricane, Fw 190, Mitsubishi Zero, P-40, and most Soviet fighters), slotted (Corsair, Thunderbolt, Hellcat), and Fowler (P-38, Ki-43 Oscar, Ki-84 Frank). It summarizes the findings of a NACA report: flaps only help below the speed at which a flaps-up turn is limited by the stall, and, if some altitude loss is accepted, they allow a tighter turn; Fowler and slotted flaps are the most effective.
Historical context
Most wartime fighters had no dedicated combat flap setting; the Corsair, the P-38, and the Ki-43 did, and there are known cases of Bf 109 pilots, such as Hans-Joachim Marseille, using flaps to tighten a turn. By around 1943, US Navy and Army Air Forces doctrine discouraged close-in dogfighting and favored hit-and-run tactics relying on speed and diving.
Key facts
The F4U-4 is rated for 9 g up to 440 knots, and its 20° combat flap setting can be used below 200 knots. A NACA report criticized its stall warning while praising the Spitfire's. According to the author, 187 Corsairs were shot down in air combat and 922 were lost in accidents, 230 of them while maneuvering in combat. In a simulated duel against a Ki-84, the Corsair sustains 9 g up to 264 knots. With flaps at 20°, its stall speed at 78.9° of bank drops to 173 knots, while the Ki-84 cannot deploy its Fowler flaps until below 146 knots.