https://en.wikipedia.org/wiki/McDonnell_XF-85_Goblin
The McDonnell XF-85 Goblin was an American prototype fighter aircraft conceived
during World War II by McDonnell Aircraft. It was intended to be deployed from
the bomb bay of the giant Convair B-36 bomber as a parasite fighter. The XF-85's
intended role was to defend bombers from hostile interceptor aircraft, a need
demonstrated during World War II. Two prototypes were constructed before the
program was terminated.
The XF-85 was a response to a United States Army Air Forces' (USAAF) requirement
for a fighter to be carried within the Northrop XB-35 and B-36, then under
development. This was to address the limited range of existing interceptor
aircraft compared to the greater range of new bomber designs. The XF-85 was a
diminutive jet aircraft featuring a distinctive egg-shaped fuselage and a
forked-tail stabilizer design. The prototypes were built and underwent testing
and evaluation in 1948. Flight tests showed promise in the design, but the
aircraft's performance was inferior to the jet fighters it would have faced in
combat, and there were difficulties in docking. The XF-85 was swiftly canceled,
and the prototypes were thereafter relegated to museum exhibits. The 1947
successor to the USAAF, the United States Air Force (USAF), continued to examine
the concept of parasite aircraft under Project MX-106 "Tip Tow", Project FICON
and Project "Tom-Tom" following the cancellation.
During World War II, American bombers such as the Boeing B-17 Flying Fortress,
Consolidated B-24 Liberator and Boeing B-29 Superfortress were protected by
long-range escort fighters such as the Republic P-47 Thunderbolt and North
American P-51 Mustang. These fighters could not match the range of the Northrop
B-35 or Convair B-36, the next generation of bombers developed by the United
States Army Air Forces (USAAF). The development cost for longer-ranged fighters
was high, while aerial refueling was still considered risky and technologically
difficult. Pilot fatigue had also been a problem during long fighter escort
missions in Europe and the Pacific, giving further impetus to innovative
approaches.
On 9 October 1945, the USAAF signed a letter of intent covering the engineering
development for two prototypes (US serial numbers 46-523/4), although the
contract was not finalized until February 1947. After the successful conclusion
of two reviews of a wooden mock-up in 1946 and 1947 by USAAF engineering staff,
McDonnell constructed two prototypes in late 1947. The Model 27D was
re-designated XP-85, but by June 1948, it was changed to XF-85 and given the
name "Goblin". There were plans to acquire 30 production P-85s, but the USAAF
positive, production orders for more than 100 Goblins would be finalized later.
Role
Parasite fighter
National origin
United States
Manufacturer
McDonnell Aircraft
First flight
23 August 1948
Status
Canceled, 1949
Number built
Two
Program cost
US$3.1 million
During wind tunnel testing at Moffett Field, California, the first prototype
XF-85 was accidentally dropped from a crane at a height of 40 ft (12 m), causing
substantial damage to the forward fuselage, air intake and lower fuselage. The
second prototype had to be substituted for the remainder of the wind tunnel
tests and the initial flight tests.
As a production series B-36 was unavailable, all XF-85 flight tests were carried
out using a converted EB-29B Superfortress mother ship that had a modified,
"cutaway" bomb bay complete with trapeze, front airflow deflector and an array
of camera equipment and instrumentation.
Two main reasons contributed to the cancellation. The XF-85's deficiencies
revealed in flight testing included a lackluster performance in relation to
contemporary jet fighters, and the high demands on pilot skill experienced
during docking revealed a critical shortcoming that was never fully corrected.
The development of practical aerial refueling for conventional fighters used as
bomber escort was also a factor in the cancellation. The two Goblins flew seven
times, with a total flight time of 2 hours and 19 minutes with only three of the
free flights ending in a successful hookup. Schoch was the only pilot who ever
flew the aircraft.
Specifications
General characteristics
Crew: 1
Length: 14 ft 10 in (4.5 m)
Wingspan: 21 ft 1 in (6.4 m)
Height: 8 ft 3 in (2.5 m)
Empty weight: 3,740 lb (1,700 kg)
Loaded weight: 4,550 lb (2,050 kg)
Max. takeoff weight: 5,600 lb (2,500 kg)
Performance
Maximum speed: 650 mph (estimated) (565 knots; 1,069 km/h)
Service ceiling: 48,000 ft (14,600 m)
Rate of climb: 12,500 ft/min (3,800 m/min)
Thrust/weight: 0.66
Armament
4 x .50 cal in (12.7 mm) M3 Browning machine guns
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