The McDonnell XF-85 Goblin, the smallest jet-propelled fighter ever built, was a "parasite" designed to be dropped from a bomber, perform its mission and return to the mother ship. The XF-85 Goblin was egg shaped and its wings, swept back 37 degrees, could fold upward. The XF-85 had no landing gear, but was launched from the bomber and recovered using a hook and a retractable trapeze under the parent airplane. For emergencies, the Goblin had a steel skid under the fuselage and small runners on its wingtips. The tiny fighter was stable, easy to fly and recovered well from spins. However, many pilots found it hard to hook the Goblin in flight to its bomber's trapeze. McDonnell built two XF-85 Goblins, and one joined the collection at the U.S. Air Force Museum at Wright-Patterson Air Force Base, Ohio.