McDonnell XF-85 Goblin

McDonnell proposed a ‘parasite’ (‘symbiote’) fighter had to be small enough to be carried aloft by a bomber and released as required. As early as 1942 McDonnell had proposed such a type as the MX-472 for semi-external carriage by the B-29, and further evolution of the concept resulted during 1945 in four variants of the Model 27 design for internal carriage by the Northrop B-35 and Convair B-36 heavy bombers. Under the spur of early ‘Cold War’ events, McDonnell reworked the Model 27 into the XF-85 Goblin. Designed under the leadership of Herman D Barkley, the XF-85 the subject of a Letter of Intent for two prototypes on 9 October 1945. The XF-85 was to be stowed in the number one or four bomb bay of the B-36 intercontinental bomber. Over target, it would be dropped free to protect the B-36 from enemy interceptors.

The fuselage was virtually filled by the 3000-lb (1361-kg) thrust Westinghouse J34-WE-7 turbojet and its fuel plus the four 0.5-in (12.7-mm) machine-guns and their ammunition, the pilot being seated astride the engine under a bubble canopy immediately aft of the hook that permitted aerial release and recovery of this tiny fighter. The wings were swept at 37 degrees and arranged to unfold from their vertically stowed position, which gave the fighter a ‘hangared’ width of only 5 ft 4.75 in (1.64 m), for an extended span of 21 ft 1.5 in (6.54 m) after being lowered from the parent aircraft. The fighter was intended to be launched from and recovered by a retractable trapeze which was to be extended beneath the parent bomber, no undercarriage being fitted.

In 1947, indoor tests were begun to evaluate the mating arrangement between the Goblin and a mock-up of a B-36 fuselage. On 9 November 1947 the first of two XF-85s was disassembled at the manufacturer's St Louis plant and flown aboard a C-97 transport to Moffett Field, California, for wind-tunnel tests. While being positioned in the tunnel, the aircraft fell 12.2 m, was badly damaged, and had to be returned to St Louis, being replaced at Moffett by the second machine.

On 5 June 1948, this second XF-85 was transported to Muroc AFB, California, and, with no B-36 airframe available for evaluation of the parasite fighter concept, experiments began using an EB-29B Superfortress. Ed Schoch, a former US Navy F6F Hellcat pilot with four air combat kills in the Pacific war, was the only man ever to fly the XF-85.

Flight trials were initiated by the second prototype which was powered by a 3,000 lb st (1361 kgp) Westinghouse J34-WE-37 turbojet. After five captive flights on the trapeze of a specially modified Superfortress (EB-29B), the XF-85 was launched at 20,000 ft (6 095 m) on 23 August 1948, this first free flight terminating in an emergency landing. On his first attempt on 23 August 1948, Schoch was attempting to re-engage the bomber's trapeze when he slammed into it, shattering his canopy, ripping his helmet off, and knocking him unconscious. Schoch recovered in time to make a shaky landing on the XF-85's underside skid in the Muroc desert, damaging the plane.

The second flight on 14 October 1948, resulted in a normal mid-air drop and subsequent hook-up. Three more times, however, struggling to manoeuvre the tricky Goblin, Schoch was forced to make belly landings in the desert rather than regain his link-up with the Superfortress.

On 8 April 1949, the original XF-85 made its first and only flight. In budget-lean 1949, the XF-85 programme was quietly terminated after 2 hr 19 min of test flying, although the Strategic Air Command eventually became interested in the parasite fighter concept when it became possible to carry an RF-84K aboard a B-36. The first XF-85 is on display at the Air Force Museum in Dayton, Ohio, while the second is at the Strategic Air Command Museum in Omaha, Nebraska, displayed in inaccurate markings with a spurious tail number.

Max speed (calculated), 664 mph (1 068 km/h)
Combat endurance, 30 min
Empty weight, 3,740 lb (1 696 kg)
Loaded weight, 4,550 lb (2 064 kg)
Span, 21 ft 1½ in (6,44 m)
Length, 14 ft 10.5 in (4,53 m)
Height, 8 ft 3.25 in (2,56 m)
Wing area, 90 sq ft (8,36 sq.m)

McDonnell XF-85 Goblin