History of Air-to-Air Refueling and Other Examples of Aircraft Linked to Aircraft
From Oddity to Routine
Aircraft linked together in flight is a common occurrence. For decades the idea linking aircraft together has resulted in many successes and some crazy concepts. Some concepts haven’t gotten past the concept stage. Some concepts beg the question of how it got past the concept stage. Air Forces throughout the world link aircraft together for aerial refueling. Many flight records were made with the record breaking aircraft being launched from a mother ship. Flying aircraft carriers isn’t just in Science Fiction movies.
The first air-to-air refueling, performed with a hose, occurred on June 27, 1923.[i] A DH-4 refueled another DH-4 twice. The refueled DH-4 stayed airborne 6 hours and 38 minutes. More tests followed. In October aerial refueling kept an aircraft flying for 37 hours as it flew from Lamas, Washington to Tijuana, Mexico. In a refueling attempt in November a refueling hose got entangled in the right wings of the tow aircraft. U.S. Navy Lieutenant P. T. Wagner died in this mishap. This ended the program.[ii]
In 1928 Belgium kept an aircraft airborne for 60 hours and 7 minutes with aerial refueling. This set an endurance record. On January 1, 1929 a Fokker C-2 named “Question Mark” took off. Two Douglas C-1s refueled the Question Mark in flight. The Question Mark stayed in the air until January 7. During the flight it made 43 contacts with the refueling aircraft and received 5,700 gallons (21,577 liters) of fuel. The Army Air Corps attempted a formal demonstration in the spring of 1929. Icing caused the tanker plane to make an emergency landing. The aircraft got stuck in the mud. The U.S. Army Department ended the program and shelved air refueling for 12 years. Two commercial pilots broke the Question Mark’s record on May 26, 1929 by keeping a Ryan Brougham airborne for 172 hours and 32 minutes.[iii] Other private efforts extended the endurance record.
During World War Ii the major powers put little effort into developing air-to-air refueling in favor of longer range aircraft. With the onset of the Cold War the U.S. Strategic Air Command (SAC) needed its aircraft to fly longer distances. United Kingdom’s Flight Refueling Limited developed a probe and drogue system. United States Air Force (USAF) Colonel David C. Schilling made the first fighter non-stop across the Atlantic on October 22, 1950. He flew an F-84E Thunderjet. Col. Shilling received the Harmon Trophy for this flight. Colonel William Ritchie flew the mission in another Thunderjet. During a refueling over Iceland the refueling plane’s drogue damaged Colonel Richie’s probe. Colonel Ritchie, unable to refuel, had to eject over Labrador.[iv] The first combat air refueling of fighter-type aircraft happened on July 6, 1951. An aerial tanker refueled 3 RF-80s over the Sea of Japan near Wonsan, North Korea. This doubled the range of the RF-80s. on July 4, 1952 60 F-84Gs flew from Turner Air Force Base (AFB), Georgia to Travis AFB, California non-stop. On this mission 24 KB-29Ps refueled the F-84s in flight. More F-84s followed the same route on July 6. From Travis AFB the F-84s, with refueling from KB-29Ps, flew to Hickam AFB, Hawaii. The F-84s island hopped to Yakota Air Base, Japan. The F-84s arrived at Yakota Air Base on July 16.[v] From there they were ready to carry out combat operations over Korea. This demonstrated how the Air Force could quickly deploy to trouble spots. The Air Force soon made longer non-stop flights. In March, 2011 three B-2 Spirit bombers, with aerial refueling, flew a 25-hour, 11,418mile (18,269 km) bombing mission from Whiteman AFB, Missouri to Libya and back.[vi]
In the Vietnam Conflict the U.S. showed aerial refueling was not just to increase an aircraft’s range but to increase its bombload. An aircraft can carry more weight when it’s flying than when it’s taking off. With aerial refueling an aircraft could carry more bombs and minimal fuel when taking off. Then the aircraft can fill up its tanks in the air and complete its mission. The U.S. used this method often during the conflict.
[i] The first air-to-air refueling occurred on November 2, 1921. Wing Walker Wesley May climbed from the wing of one aircraft to the wing of another. He had a 5-gallon can of gasoline with him. Mental Floss, The Amazing History of Air Refueling, (http://mentalfloss.com/article/71199/history-air-refueling), last accessed 4/21/2018.
[ii] Flight of the ‘Question Mark’, by Ellery D. Eallwork, December 24, 2008, http://www.af.mil/News/Features/Display/Article/143226/flight-of-the-question-mark/, last accessed 4/18/18.
[iii] Flight of the ‘Question Mark’, by Ellery D. Eallwork, December 24, 2008, http://www.af.mil/News/Features/Display/Article/143226/flight-of-the-question-mark/, last accessed 4/18/18.
[iv] Worldpress, Air Refueling Archive, https://airrefuelingarchive.wordpress.com/tag/history, last accessed 4/21/2018.
[v] Worldpress, Air Refueling Archive, https://airrefuelingarchive.wordpress.com/tag/history, last accessed 4/21/2018.
[vi] Daily Mail, Touchdown: B-2 stealth jets return after epic, 11,500 mile journey to bomb Libyan aircraft shelters, by Richard Hartley-Parkinson, March 21, 2011. (http://www.dailymail.co.uk/news/article-1368337/Libya-crisis-B2-stealth-bombers-25-hour-flight-Missouri-Tripoli.html), last accessed 4/21/2018.
Aircraft attached together is another common occurrence. During World War II the most used example was glider towing. An aircraft would tow a glider behind it. When the glider neared its landing area the glider pilot would release the tow cable and land the glider. Most of the major airborne operations during World War II involved gliders as well as paratroopers. Gliders were also used in special operations such as the rescue of Italian dictator Benito Mussolini.
In June 1944 the Germans began their V-1 attacks on Great Britain. Among the V-1’s deficiencies were its range, about 150 miles (250 km), and its launch ramps. The launch ramps could be seen and destroyed. Starting from July 1944 He-111s, carrying V-1s, would launch the V-1s while airborne. Air launched V-1s could strike targets outside the range of ground launched V-1s.
Japanese aircraft launched Ohka Kamikaze aircraft from bombers. After the bomber released the Ohka the Ohka pilot would switch on the rocket engine and try to crash into an Allied ship. The air launched V-1 and Ohka aircraft were the predecessors of the modern Air Launched Cruise Missiles.
During World War II the Germans developed a system appropriately called Huckepack (Piggyback). This involved a system where a single seat fighter was mated to a bomber laden with explosives. The bomber component was named Mistel (Mistletoe). The pilot, who was in the fighter, would fly to the target. The pilot would release the Mistel and return to base. The first use of this system was against the Allied fleet during the Battle of Normandy. They were later used in attacks against bridges to slow the Soviet advance. Mistel attacks had little success.
After World War II the U.S. released aircraft from other aircraft to set many flight records. On October 14, 1947, then Captain Charles E. “Chuck” Yeager, stepped into a Bell X-1 inside a B-29. The B-29 launched the Bell X-1. Chuck Yeager then started the rocket engine and became the first human to break the sound barrier.
The X-15 was another aircraft launched from a mother ship. The X-15 was a hypersonic rocket-powered aircraft. The X-15 still holds the record for a human, powered aircraft. The October 1967 record is Mach 6.72 and set by William J. Knight. NASA made 13 astronaut flights in the X-15. Eight X-15 pilots earned their astronaut wings flying the X-15.
The Lockheed D-21 was a drone. It was developed under Project Tagboard. The initial plan was to mount this aircraft on top of an A12 Blackbird. The Blackbird would launch the D-21 at Mach 3. The D-21 would fly over a designated area and take pictures. The D-12 would fly over friendly territory and eject the camera. A C-130 would retrieve the camera in midair and the D-12 would self-destruct. Lockheed modified two A12s, serial numbers 60-6940 and 60-6941, and re-designated them M21s. The first flight was in December 1964. Kelly Johnson, Lockheed Skunk Works Chief Engineer, cancelled the M21 when a D-21 mishap on July 30, 1966 killed Ray Torick, the Launch Control Officer, and destroyed an M21. The pilot, Bill Park survived. D-21s were then mated to B-52s. The D-21 had a few successful test flights. All 4 operational test flights, which flew over the Peoples Republic of China, were unsuccessful. The cameras weren’t recovered. The last operational mission was March 20, 1971.[i]
NASA used a piggyback system for the space shuttle. They mated the Space Transportation System (STS) Enterprise on the back of a Boeing 747. NASA used the Enterprise for unpowered test flights. The Enterprise would separate from the Boeing 747 then the Enterprise crew would make a “dead stick” landing. NASA used this piggyback system to shuttle Columbia and later space shuttles to Florida. During the first few STS flights the landing site was in California so the Boeing 747 would fly the shuttle from California to Florida. The final piggyback flights for the Space Shuttles was to fly them to museums.
[i] Lockheed D-21 Air Launched Drone, (http://www.wvi.com/~sr71webmaster/d21~1.htm), last accessed 4/22/2018.
Flying Aircraft Carriers
The airship USS Akron was the first flying aircraft carrier. On May 3, 1932 the Akron had two parasite aircraft, a Consolidated N2Y trainer and a Curtis XF9C-1 Sparrow, attached to it. Lieutenants Daniel W. Harrigan and Howard L. Young flew these aircraft from the Akron and then reattached them to the Akron. The USS Akron crashed on April 3, 1933. There were only three survivors. The USS Akron’s sister ship, the USS Macon, made its maiden flight three weeks later. The USS Macon also had parasite aircraft. The aircraft’s squadron’s symbol was a man on the flying trapeze. The Macon commanders developed doctrine and techniques for using its airplanes in military operations. The Macon crashed on February 12, 1935. Radioman 1st Class Ernest Edwin Dailey and Mess Attendant 1st Class Florentino Edquiba died in the incident. This ended the U.S. Navy’s rigid airship program and their flying aircraft carriers.
The Soviet Union developed a concept of using 5 parasite fighters attached to a Tupolev TB-3 four-engine bomber. On August 1, 1941 two TB-3s launched two Polikarpov I-16s. The bomb equipped I-16s destroyed an oil depot in Constanta, Romania without loss. There were further missions on August 11, 13, and 25. These missions damaged the King Carol I Bridge in Romania. The Soviet Air Force canceled these parasite operations because they believed it was too dangerous for the TB-3s.[i]
In December 1941 the U.S. Army Air Forces (USAAF)put in an order for B-36 bombers. The B-36 had a range of 10,000 miles (16,000 Km). This gave the USAAF three options; let the plane fly unescorted, develop heavy long-range fighters, use a parasite fighter. The USAAF gave the parasite fighter project to McDonnell on October 9, 1945. The result was the XF-85 Goblin. McDonnell delivered the first XF-85 to Moffett Naval Air Station on January 8, 1948. As it was being hoisted the latch slipped and the Goblin took a 40-foot drop. The second Goblin successfully completed wind tunnel tests. On July 22, 1948 McDonnell test pilot Edwin F. Schoch sat in the cockpit as the EB-29B mother ship lowered the XF-85 into the slip stream. Schoch started the engine. The first flight where the mother ship released the Goblin was on August 23, 1948. On the third attempt to attach to the mother ship the trapeze bar smashed through the canopy and knocked Schoch’s helmet off. Schoch made a belly landing. There were 3 successful airborne recoveries. All other attempts failed. Total flight testing was 2 hours and 19 minutes. The Air Force canceled the project after concluding:
- Airborne recovery required a skilled pilot even under ideal circumstances.
- With 30 minutes endurance its effectiveness as a fighter was limited.
- The cost of refining the design to eliminate the Goblin’s numerous problems made it impractical to proceed.
The Goblin itself was a maneuverable aircraft. The highest speed it reached was 362mph. The estimated maximum speeds were 648mph at sea level and 573mph at 40,000 feet. The service ceiling was believed to be 48,200 feet.[ii]
In the early 1960s Lockheed developed a design for a flying aircraft carrier. The concept, designated CL-1201, was for 22 parasite fighter-bombers. The design was for an aircraft that used JP-5 jet fuel for take-off and a nuclear powerplant for cruising. This 5,265-ton aircraft was to have a 1,120 feet wingspan and be 560 feet long. Its 4 turbofan engines were to provide 50,000 pounds of thrust. It was to have 182 lift jets. This aircraft didn’t get past the drawing board stage.[iii]
On the civilian side there was also a concept for flying airport terminals. This hasn’t gotten past the concept stage.
[i] Revolvy.com, Tupolev TB-3, (https://www.revolvy.com/main/index.php?s=Tupolev%20TB-3&item_type=topic), last accessed 4/22/2018.
[ii] U.S. Fighters: Army – Air Force 1925 to 1980s, by Lloyd S. Jones, Aero Publishers © 1975.
[iii] Tils Through Time: Short Trip On the Long Road of Aviation History, The Lockheed CL-1201 Flying Aircraft Carrier, June 10, 2010, (http://www.tailsthroughtime.com/2010/06/in-aviation-those-who-dare-to-dream-are.html), last accessed 4/22/2018.
© 2018 Robert Sacchi