Martin P4M Mercator

The US Navy made several attempts to gain the benefit of high over-target performance combined with long range by introducing mixed powerplant. The Martin Model 219 patrol bomber represented one of the results of such a specification, two XP4M-1 prototypes being ordered on 6 July 1944. The first was flown on 20 September 1946 as a cantilever shoulder-wing monoplane with retractable tricycle landing gear. Its powerplant comprised two 2218kW Pratt & Whitney R-4360-4 Wasp Major radial engines, but each nacelle also incorporated a 17,350kg thrust Allison J33-A-17 turbojet. After a protracted development programme 19 P4M-1 production aircraft were built, the first being delivered to US Navy Squadron VP-21 on 28 June 1950, and all served with this unit. Most of them were converted into P4M-1Q Elint aircraft, one being shot down.