No. 5479. McDonnell 27D XF-85 Goblin (46-524) US Air Force
Photographed at Strategic Air and Space Museum, Ashland, Nebraska, USA, by Jerry Greer

McDonnell 27D XF-85 Goblin

08/31/2011. Remarks by Johan Visschedijk: "The XF-85 resurrected the concept of a parasite fighter - an aircraft carried by and launched from a bomber for which it was intended to provide defense. This small jet-propelled interceptor fighter was originally developed as the Model 27 under the leadership of Herman D. Barkley, for use by the Consolidated-Vultee B-36 six-engined long-range bomber and was the subject of a Letter of Intent for two prototypes on October 9, 1945.

The small, egg-shaped XF-85 had vertically-folding wings and triple vertical tail surfaces and was to be carried in the forward bomb-bay of the B-36. The XF-85 was to be launched and picked up by a release and hook-on technique using a retractable trapeze, and therefore the it had a retractable hook forward of the cockpit.

No landing-gear was fitted, but for emergency landings it had a retractable steel skid under the fuselage and steel runners under the wingtips. It was intended that while the aircraft was stowed in the bomb-bay of the B-36 it could be re-fuelled and receive radio, radar and mechanical maintenance. Provision was made to jettison the aircraft without pilot in an emergency.

Flight trials were initiated by the second prototype, s/n 46-524, which was powered by a 3,000 lb (1361 kg) s.t Westinghouse J34-WE-37 turbojet. After five captive flights on the trapeze of a specially-equipped EB-29B Superfortress, the XF-85 was first launched at 20,000 ft (6,100 m) over Muroc (presently Edwards AFB), California, on August 23, 1948.

However, the first attempt to hook on at 26,000 ft (7,625 m) was hampered by rough air. The B-29 trapeze fouled the canopy of the XF-86, smashed the Plexiglas and hit the pilot on the head, knocking off his helmet and oxygen mask. The pilot put the oxygen hose in his mouth and made a successful emergency landing on the Muroc desert. The only damage was a broken wing-tip and bent lower fin.

Two months later the same pilot was launched from the B-29, made a 20-minute flight and was successfully retrieved by the B-29 trapeze. Two more flights with successful recoveries followed, but the test program was a dismal failure and the program was terminated on October 17, 1949, after 2 hr 19 min of test flying, including a single flight by the first prototype, s/n 46-523, on April 8, 1949.

46-523 is preserved at the National Museum of the USAF at Wright-Patterson AFB, Dayton, Ohio, while 46-524 is preserved at the Strategic Air and Space Museum.

WINGS. Cantilever low-wing backswept monoplane. Modified laminar flow aerofoil section. Leading-edge sweepback 34. Anhedral 4. Aluminum-alloy flush-riveted structure. In three main sections, consisting of a centre-section and two outer sections, the latter folding upwards for fitting inside the bomb bays of a B-36 bomber. All-metal ailerons with trim and balance tabs in each. Auto-slots ahead of ailerons.
FUSELAGE. Monocoque structure of aluminum-alloy with flush-riveted metal skin. Speed brake beneath rear fuselage. Retractable sky hook ahead of cockpit.
TAIL UNIT. Cruciform (X) type to avoid necessity for folding for stowage aboard a bomber.
LANDING GEAR. No landing gear. During test flights XF-85 was equipped with emergency landing skids. Normally retrieved by hooking on trapeze suspended from parent aircraft.
POWER PLANT. One Westinghouse 24C (J-34) axial-flow turbo-jet engine with a rated take-off thrust of 3,000 lb (1,362 kg). Air intake in nose, exhaust in centre of tail section.
ACCOMMODATION. Pilot's pressurized cockpit had fixed forward portion with bullet-proof panel. Plexiglas bubble canopy slid backwards. Ejector seat. Pilot's equipment included heating, flying suit, bail out oxygen bottle and high-speed ribbon-type parachute.

Created July 15, 2006