Curtiss HA

Designed by Capt B L Smith of the US Marine Corps as a two-seat patrol fighter floatplane for use in the Dunkirk- Calais area, the HA - known unofficially as the "Dunkirk Fighter" - was intended to combat the Brandenburg float fighters and was built at the experimental plant of the Curtiss Engineering Corporation. Of conventional wooden construction with fabric skinning, the HA was powered by a 425hp Liberty 12 engine and featured an unusually rotund fuselage. Proposed armament comprised two synchronized 7.62mm Marlin machine guns and two Lewis guns of the same calibre on a Scarff mounting in the rear cockpit. The HA was flown for the first time on 21 March 1918, but was found to be unstable longitudinally and seriously tail heavy. The initial test terminated in a crash. Curtiss was then awarded a contract for two further prototypes, the first of which, the HA-1, utilized salvaged components from the original HA and featured revised vertical tail surfaces, an annular-type radiator and relocated wings. The HA-1 demonstrated appreciably improved handling qualities, but was written off after a fire in the air. The third HA prototype, the HA-2, differed appreciably from the HA-1.