Time Period: World War II
Country of Origin: United States
Type: Fighter Aircraft, Experimental Aircraft & Prototypes
Manufacturer: McDonnell Aircraft (McDonnell)
McDonnell XF-85 Aircraft Overview
During World War II and the early Cold War, the U.S. Air Force faced a major issue: its strategic bombers could fly thousands of miles into enemy territory, but their fighter escorts couldn’t keep up. The solution? Bring the fighters along inside the bomber.
Enter the XF-85 Goblin, a tiny, egg-shaped fighter designed to be launched from the bomb bay of a B-36 Peacemaker bomber mid-flight. After doing its job—intercepting enemy aircraft—it would then dock back inside the bomber using a retractable trapeze. On paper, it was genius. In practice, it was a handful.
The Goblin was compact by design, just 15 feet long, with no landing gear because it was never meant to touch the ground on its own. It had stubby wings, a bubble canopy, and a single Westinghouse jet engine. Pilots entered it by climbing into the bomb bay, and it was launched and recovered while both planes were in the air—a daring maneuver that turned out to be a little too ambitious.
In test flights during 1948, the Goblin proved flyable, but re-docking was extremely difficult, especially in turbulence. Out of seven free-flight tests, only three successful connections back to the bomber were made. The rest required emergency landings or parachute bailouts.
Why The XF-85 Failed
Though the idea of a “parasite fighter” had some logic behind it, the technology of the time simply wasn’t up to the task. The docking process was too dangerous, and the Goblin itself was underpowered and lightly armed, making it a weak match for more capable enemy fighters.
Meanwhile, the development of aerial refueling and long-range escort fighters made the Goblin’s role obsolete before it even got off the ground (literally and figuratively).
Where Is It Now?
Only two XF-85s were ever built, and both are preserved in museums:
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One is at the National Museum of the U.S. Air Force in Dayton, Ohio.
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The other is in storage at the Mighty Eighth Air Force Museum in Georgia.
They remain fascinating relics of a time when military engineers were thinking way outside the box—and sometimes, inside the bomb bay.
McDonnell XF-85 Specifications
- Crew: One pilot
- Length: Approximately 14 feet 10 inches (4.52 meters)
- Wingspan: 21 feet 1 inch (6.43 meters) with wings fully extended
- Height: Stands 8 feet 3 inches (2.51 meters) tall
- Wing Area: Around 90 square feet (8.4 square meters)
- Empty Weight: Roughly 3,740 pounds (1,696 kilograms)
- Gross Weight: Approximately 4,550 pounds (2,064 kilograms)
- Maximum Takeoff Weight: Up to 5,600 pounds (2,540 kilograms)
- Engine: Powered by one Westinghouse XJ34-WE-22 turbojet, delivering 3,000 pounds of thrust (13 kN)
McDonnell XF-85 Performance
- Top Speed (estimated): Around 650 mph (1,050 km/h or 560 knots)
- Endurance: Can remain airborne for about 1 hour and 20 minutes
- Service Ceiling: Capable of reaching 48,000 feet (15,000 meters)
- Rate of Climb: Approximately 12,500 feet per minute (64 meters/second)
- Wing Loading: Around 51 pounds per square foot (250 kg/m²)
- Thrust-to-Weight Ratio: Estimated at 0.66
McDonnell XF-85 Armament
- Equipped with four 0.50-inch (12.7 mm) M3 Browning machine guns
McDonnell XF-85 Image Gallery
The McDonnell XF-85 Goblin was bold, weird, and a little bit brilliant. It was the aviation equivalent of a secret weapon tucked into a pocket—ready to pop out and fight, then vanish back into the mothership. It didn’t work out, but it’s a perfect example of how wild the early jet age really was. A tiny plane with a big idea… and an even bigger challenge.
