Parasite aircraft

The Boeing X-43 being dropped from under the wing of a B-52 Stratofortress.

A parasite aircraft is a component of a composite aircraft which is carried, and air launched by, a mother ship aircraft.

The first use for parasite aircraft was in 1916, when the British used a Bristol Scout, flying from a Felixstowe Porte Baby, a giant flying boat of its time. This eventually developed into modern jet bombers carrying fully capable fighter aircraft. In some cases, these aircraft are able to return to their mother ship. As fighter capabilities increased, this role was seen as less and less necessary.

Military use

Bristol Scout on Porte Baby

Until the middle of the 20th century there was military interest in parasite fighters - fighter aircraft intended to be carried into a combat zone by a larger aircraft, such as a bomber. If the bomber were threatened, the parasite would be released to defend it. Parasite fighters have never been highly successful and have seldom been used in combat. Projects for this type were designed to overcome the great disparity in range between bombers and their escort fighters. Development of aerial refueling has made parasite fighters obsolete.

The first parasite fighters were carried aboard military airships. As early as 1918, the Royal Air Force launched Sopwith Camel fighters from HM Airship 23, and tried again with Gloster Grebes on the R.33 in 1925. The "Imperial Airship" Programme" of 1924 envisaged a commercial airship that could also carry five fighter aircraft as well as troops if put into military use but the military usage was dropped and only civilian use retained. In the following decade, two U.S. Navy airships, the USS Akron and the Macon, were designed with parasite fighter capability. Although operations with F9C Sparrowhawks were quite successful, the loss of both airships in crashes put an end to this programme.

The first bombers to carry parasite fighters did so as part of the Zveno experiments carried out in the Soviet Union by Vladimir Vakhmistrov from 1931. Up to five fighters of various types were carried by Polikarpov TB-2 and Tupolev TB-3 bombers. In August 1941, these combinations would fly the only combat missions ever undertaken by parasite fighters. TB-3s carrying Polikarpov I-16SPB dive bombers attacked the Cernavodă bridge and Constantsa docks, in Romania. After that, this squadron, based in the Crimea, carried out a tactical attack on a bridge over the river Dneiper 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 projects such as the Arado E.381 and Sombold So 344 never left the experimental stage.

During the early years of the Cold War, the United States Air Force experimented with a variety of parasite fighters to protect its Convair B-36 bombers, including the dedicated XF-85 Goblin, and methods of either carrying a Republic F-84 Thunderjet in the bomber's bomb bay (the FICON project), or attached to the bomber's wingtips (Project Tom-Tom). These projects were all soon abandoned, partly because aerial refueling appeared as a much safer solution to extend the range of fighters.

Example of parasitic aircraft combinations

Examples which have flown include

• Porte Baby/Bristol Scout, the first parasite aircraft (1916)
• L 35 (LZ 80)/Albatros D.III, the first parasite fighter flying from an airship (January 26, 1918)
• HMA 23/Sopwith Camel, parasite fighter, flying from an airship (1918)
• Tc-3 and Tc-7 non-rigid airship launched and recovered a Sperry Messenger biplane (1923)
• Royal Air Force Trials of DH 53 Hummingbird light planes launched and recovered by the airship R33 (1924), followed by equipping the airship with two Gloster Grebe fighters (1925).
• US Navy's trials of a glider and a biplane recovered by the USS Los Angeles, followed by the USS Akron and Macon/F9C Sparrowhawk, which formed a very successful U.S. Navy escort fighter program, ended when the airships crashed (1935).
• LZ 129 Hindenburg had trials using parasite aircraft in the days before it crashed at Lakehurst, but the trial proved unsuccessful as the plane hit the trapeze on it's hull.
• Mitsubishi G4M/Ohka Rocket plane.
• Short S.21/Short S.20, Short-Mayo Composite a flying-boat/seaplane combination for transoceanic postal service (1938)
• Tupolev TB-3/Polikarpov SPB, the first parasite aircraft to see combat (1941)
• Dornier Do 217/Messerschmitt Me 328, escort fighter, unsuccessful due to engine problems
• B-36/XF-85 Goblin, an attempt to equip bombers with their own escort fighters (1948)
• B-36/F-84, another, more successful, escort fighter attempt (1952)
• DC-130/Q-2C Firebee, drone launched and controlled from C-130 "mother"
• Lockheed D-21/M-21, for high-speed reconnaissance, based upon the SR-71 Blackbird (1963)

Gallery

• 

  The Akron in flight, November 1931.

• 

  F9C Sparrowhawk inside Akron's hangar.

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  F9C Sparrowhawk successfully hooks on to Akron trapeze, May 1932.

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  Boeing EB-29 with recovery trapeze deployed for FIghter CONveyer (FICON) trials with McDonnell XF-85 Goblin parasite fighter, seen at bottom

• 

  A Republic F-84E on FICON trapeze

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  Project Tom Tom: Boeing B-50 with Republic F-84 Thunderjet

See also

• Airborne aircraft carrier
• Mother ship
• Composite aircraft
• Mistel—German WWII project in which a piloted fighter aimed, then released, a pilotless ("bunker-buster") bomber with an explosive warhead in its nose

Further reading

• Hallstead, William F. (2001). "Parasite aircraft". Aviation History 12 (2): 38–45. ISSN 1076-8858. 

External links

• Pre World War II Russian parasite fighters
• pictures of parasites
• Recent article advocating parasite aircraft
• Video including XF-85 Goblin in flight and FICON aircraft
• Goebel, Greg (August 1, 2011). "The Parasite Fighters". http://www.vectorsite.net/avparsit.html.