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 s , 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 been facing 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 . Design and development . 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 . The USAAF considered a number of different options including the use of remotely piloted vehicles before choosing parasite fighter s as the most viable B - 36 defense . The concept of a parasite fighter had its origins in 1918 , when the Royal Air Force examined the viability of Sopwith Camel parasite fighters operating from " R23 " airships . In the 1930s , the U . S . Navy had a short - lived operational parasite fighter , the Curtiss F9C Sparrowhawk , aboard the airships " Akron " and " Macon " . Starting in 1931 , aircraft designer Vladimir Vakhmistrov conducted experiments in the Soviet Union as part of the Zveno project during which up to five fighters of various types were carried by Polikarpov TB - 2 and Tupolev TB - 3 bombers . In August 1941 , these combinations flew the only combat missions ever undertaken by parasite fighters – TB - 3s carrying Polikarpov I - 16SPB dive bomber s attacked the Cernavodă bridge and Constantsa docks , in Romania . After that attack , the squadron , based in the Crimea , carried out a tactical attack on a bridge over the river Dnieper at Zaporozhye , which had been captured by advancing German troops . Later in World War II , the " Luftwaffe " experimented with the Messerschmitt Me 328 as a parasite fighter , but problems with its pulsejet engines could not be overcome . Other late - war rocket - powered parasite fighter projects such as the Arado E . 381 and Sombold So 344 were unrealized " paper projects " . On 3 December 1942 , the USAAF sent out a Request for Proposals ( RfP ) for a diminutive piston - engined fighter . By January 1944 , the Air Technical Service Command refined the RfP and in January 1945 , the specifications were further revised in MX - 472 to specify a jet - powered aircraft . Although a number of aerospace companies studied the feasibility of such aircraft , McDonnell was the only company to submit a proposal to the original 1942 request and later revised requirements . The company ' s Model 27 proposal was completely reworked to meet the new specifications . The initial concept for the Model 27 was for the fighter to be carried half - exposed under the B - 29 , B - 35 or B - 36 . The USAAF rejected this proposal , citing increased drag , and hence reduced range for the composite bomber - fighter configuration . On 19 March 1945 , McDonnell ' s design team led by Herman D . Barkey , submitted a revised proposal , the extensively redesigned Model 27D . The smaller aircraft had an egg - shaped fuselage , three fork - shaped vertical stabilizers , horizontal stabilizers with a significant dihedral , and 37° swept - back folding wings to allow it to fit in the confines of a bomb bay . The diminutive aircraft measured long ; the folding wings spanned . Only a limited fuel supply of was deemed necessary for the specified 30 - minute combat endurance . A hook was installed along the aircraft ' s center of gravity ; in flight , it retracted to lie flat in the upper part of the nose . The aircraft had an empty weight just short of . To save weight , the fighter had no landing gear . During the testing program , a fixed steel skid under the fuselage and spring - steel " runners " at the underside of the wingtips were installed in case of an emergency landing . Despite the cramped quarters , a pilot was provided with a cordite ejection seat , bail - out oxygen bottle and high - speed ribbon parachute . Four machine guns in the nose made up the aircraft ' s armament . In service , the parasite fighter would be launched and retrieved by a trapeze . With the trapeze fully extended , the engine would be airstarted and the release from the mother ship was accomplished by the pilot pulling the nose back to disengage from the hook . In recovery , the aircraft would approach the mother ship from underneath and link up with the trapeze using the retractable hook in the aircraft ' s nose . The anticipated production shift would see a mixed B - 36 fleet with both " fighter carriers " and bombers employed on missions . There were plans that , from the 24th B - 36 onward , provisions would be made to accommodate one XF - 85 , with a maximum of four per bomber envisioned . Up to 10 percent of the B - 36s on order were to be converted to fighter carriers with three or four F - 85s instead of a bomb load . 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 took the cautious approach – if test results from the two prototypes were positive , production orders for more than 100 Goblins would be finalized later . Operational history . During wind tunnel testing at Moffett Field , California , the first prototype XF - 85 was accidentally dropped from a crane at a height of , 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 . Since the EB - 29B , named " Monstro " , was smaller than the B - 36 , the XF - 85 would be flight tested , half - exposed . In order to carry the XF - 85 , a special " loading pit " was dug into the tarmac at South Base , Muroc Field , where all the flight tests originated . On 23 July 1948 , the XF - 85 flew the first of five captive flights , designed to test whether the EB - 29B and its parasite fighter could fly " mated " . The XF - 85 was carried in a stowed position , but was sometimes tethered and extended into the airstream with the engine off , for the pilot to gain some feel for the aircraft in flight . McDonnell test pilot Edwin Schoch was assigned to the project , riding in the XF - 85 while it was stowed aboard the EB - 29B , before attempting a " free " flight on 23 August 1948 . After Schoch was released from the bomber at a height of 20 , 000 ft ( 6 , 000 m ) , he completed a 10 - minute proving flight at speeds between 180 and 250 mph ( 290 – 400 km / h ) , testing controls and maneuverability . When he attempted a hook - up , it became obvious the Goblin was extremely sensitive to the bomber ' s turbulence , as well as being affected by the air cushion created by the two aircraft operating in close proximity . Constant but gentle adjustments of throttle and trim were necessary to overcome the cushioning effect . After three attempts to hook onto the trapeze , Schoch miscalculated his approach and struck the trapeze so violently that the canopy was smashed and ripped free and his helmet and mask were torn off . He saved the prototype by making a belly landing on the reinforced skid at the dry lake bed at Muroc . All flight testing was suspended for seven weeks while the XF - 85 was repaired and modified . Schoch used the down period to undertake a series of problem - free dummy dockings with a Lockheed P - 80 Shooting Star fighter . After boosting the trim power by 50 percent , adjusting the aerodynamics , and other modifications , two further mated test flights were carried out before Schoch was able to make a successful release and hookup on 14 October 1948 . During the fifth free flight on 22 October 1948 , Schoch again found it difficult to hook the Goblin to the bomber ' s trapeze , aborting four attempts before hitting the trapeze bar and breaking the hook on the XF - 85 ' s nose . Again , a forced landing was successfully carried out at Muroc . With the first prototype ' s repairs completed , it also joined the flight test program , completing captive flights . While in flight , the Goblin was stable , easy to fly , and recoverable from spins , although initial estimates of a 648 mph ( 1 , 043 km / h ) top speed proved optimistic . The first test flights revealed that turbulence during approach to the B - 29 was significant , leading to the addition of upper and lower fins at the extreme rear fuselage , as well as two wingtip fins to compensate for the increased directional instability in docking . All the initial flights had the hook secured in a fixed position , but when the hook was stowed and later raised , the resulting buffeting added to the difficulty in attempting a hookup . To address the problem , small aerodynamic fairings were added to the hook well that reduced the buffeting when the hook was extended and retracted . When testing resumed , on the 18 March 1948 test flight , Schoch continued to have difficulty in hooking up , striking and damaging the trapeze ' s nose - stabilizing section , before resorting to another emergency belly landing . After repairs to the trapeze , Schoch flew the first prototype on 8 April 1949 , completing a 30 - minute free flight test , but after three attempts , abandoned his efforts and resorted to another belly landing at Muroc . Aware of the problems revealed in flight tests , McDonnell reviewed the program and proposed a new development based on a more conventional design promising a 0 . 9 Mach capability , using alternatively a 35° swept wing and delta wing . McDonnell also considered adding a telescoping extension to the docking trapeze that would extend the device below the turbulent air under the mother ship . Before any further work on the trapeze , other modifications to the XF - 85 , or continued design studies on its follow - up could be carried out , the USAF canceled the XF - 85 program on 24 October 1949 . 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 . Further developments . Despite the cancellation of the XF - 85 , the USAF continued to examine the concept of parasite aircraft as defensive fighters through a series of projects including Project MX - 106 " Tip Tow " , Project FICON , and Project " Tom - Tom " which involved fighter aircraft attached to bomber aircraft by their wingtips . Project FICON ( " fighter conveyor " ) emerged as an effective Convair GRB - 36D and Republic RF - 84K Thunderflash combined bomber - reconnaissance - fighter , although the role was changed to that of strategic reconnaissance . Project FICON drew heavily on data from the abortive XF - 85 project and closely followed McDonnell ' s recommendations in designing a more refined trapeze . A total of 10 converted B - 36s and 25 reconnaissance fighters saw limited service with the Strategic Air Command in 1955 – 1956 , before being supplemented by more effective aircraft and satellite systems . Aircraft on display . After the program ' s termination , the two XF - 85 prototypes were stored , before being surplused and relegated to museum display in 1950 .