Benjamin Scovill Kelsey (March 9, 1906 – March 3, 1981) was an American aeronautical engineer and test pilot. Serving as America's chief fighter projects officer, he helped bring success in World War II to the United States Army Air Forces by initiating the manufacture of innovative fighter aircraft designs, and by working to quickly increase American fighter production to meet the needs of the coming war.
Kelsey co-authored the technical specifications which led to the development of the P-39 Airacobra and the P-38 Lightning. He worked around Air Corps strictures to initiate the development of drop tanks for American fighters. Kelsey was the driving force behind a program of advanced airfoil research which eventually resulted in the P-51 Mustang.
After the war, Kelsey served in various staff assignments supervising weather operations, personnel and materiel. He was an important committee member of the group that approved and funded the rocket-powered North American X-15.
Early career Benjamin S. Kelsey was born in Waterbury, Connecticut, in 1906, and was raised there. At the age of 15 he completed a flying course with the Curtiss Flying Service at Garden City, New York. He graduated from Massachusetts Institute of Technology (MIT) with a Bachelor of Science degree in mechanical engineering in June 1928, and stayed to teach and conduct research work in the aeronautics department. With fellow aeronautical engineering student Everard M. Lester, Kelsey wrote "A Study in Cams as Applied to the Main Driving Member in Reciprocating Engines".National Air and Space Museum. Research archives. Fairchild Finding Aid, Box 11, Folder 4. Retrieved on March 30, 2009.
Kelsey flew extensively for commercial concerns as well as privately, and obtained a transport pilot license. He joined the United States Army Air Corps and was commissioned a second lieutenant on May 2, 1929. At Mitchel Field, he worked with the Guggenheim Fog Flying Laboratory. As stipulated by Harry Guggenheim, Kelsey flew as Lieutenant Jimmy Doolittle's safety pilot during the first fully 'blind' instrument flight on September 24, 1929, showing observers that he was not in control by keeping his hands visible outside the cockpit. The following year he graduated from Primary and Advanced Flying Schools, and in 1931 he obtained his Master of Science degree in aeronautical engineering at MIT. Assigned with the 20th Pursuit Group at Mather Field and later at Barksdale Field, he served in various tactical unit duties.
Fighter development In 1934, Kelsey was transferred to Materiel Command at Wright Field near Dayton, Ohio, and served as fighter project officer in the Engineering Section. In this role he was the only person responsible for Air Corps fighter development, and was kept busy with inquiries and proposals from aircraft manufacturers.Center for Naval Analyses. William D. O'Neil. Military Transformation as a Competitive Systemic Process: The Case of Japan and the United States Between the World Wars, June 2003. Retrieved on April 10, 2009. Kelsey continued to research blind landing techniques and develop instrument flying practices and hardware. On October 1, 1934, he was promoted to first lieutenant.
Allison V-1710 Kelsey stayed current with efforts by Allison Engine Company to create a liquid-cooled engine suitable for fighters—such engines were seen as offering the possibility of greater speed and higher altitude than air-cooled engines. In late 1936 to early 1937, Kelsey flight-tested the 12-cylinder Allison V-1710-C6 as installed in the experimental Consolidated XA-11A, reaching an altitude of 26,400 ft without turbo-supercharging.The Dispatch, Volume 22, Number 1, Spring, 1997. "The Heart of the Cobra: Development of the Allison V-1710 Engine", Randy Wilson. Allison Press Release on the Certification of its V-1710 Engine by the Air Corps. Retrieved on March 30, 2009. The V-1710 passed difficult Air Corps endurance and reliability tests, and demonstrated a smooth, predictable power curve. Kelsey would subsequently base important fighter specifications on engines of this series.
As Project Officer for Fighters, Kelsey tested a great number of aircraft models, possibly flying more new types of US fighters than any other pilot. He was first to fly the Bell twin-Allison XFM-1 Airacuda prototype on September 1, 1937.
P-39 Airacobra
Kelsey became frustrated by inflexible Air Corps restrictions on pursuit (fighter) aircraft which limited the weight of all guns and ammunition to 500 lbs. He wished for at least of armament so that American fighters could dominate their battles.Bodie, 1991, p. 14. With Lieutenant Gordon P. Saville, Kelsey formulated two new high-altitude fighter specifications in February 1937; one for a single-engine fighter and one for a twin-engine fighter. In Circular Proposal X-608 and X-609, the two men employed the word "interceptor" which had not yet been applied to American military aircraft specifications. In this way, they bypassed the Air Corps limitations. Despite the new term, the proposed aircraft were not fundamentally different in role than traditional pursuit aircraft—just heavier and more powerful. Kelsey specified Allison V-1710 engines with General Electric turbo-superchargers and tricycle landing gear in both proposals, aiming for performance, long range, the ability to climb to in six minutes, and very heavy armament including a cannon.Bodie, 1991, pp. 16–17.
Bell Aircraft won the single-engine X-609 contract with their design of the P-39 Airacobra. After the prototype flew, Kelsey was called to England, and handed oversight of the project off to colleagues who, in keeping with advice from the National Advisory Committee for Aeronautics (NACA), ordered the removal of turbo-superchargers from the aircraft. The P-39 was from that point forward unable to compete in the European Theater against high-altitude German fighters. In Soviet hands, however, the Airacobra excelled in air-to-air combat at low and medium altitudes, racking up the highest individual pilot scores for any American-made fighter type, higher than any other American fighter aircraft ever made.Gebhardt, Major James F., USAF (Retired). "Some Additional P-39 History". March Field Air Museum. Retrieved: 29 October 2009.
P-38 Lightning
Lockheed won the X-608 proposal with their twin-engine Model 22 design, signing a contract with the Air Corps in June 1937. Kelsey flew the first prototype of the P-38 Lightning, the XP-38, on January 27, 1939. After Lockheed performed a series of tests and associated engineering adjustments, Kelsey took the prototype across the country on a record-breaking speed flight in February 1939. Just short of his goal, as he was directed into the landing pattern at Mitchel Field behind three slow trainer aircraft, his prototype's carburetors iced up and the engines would not respond—they continued to idle and would not increase in power. Without the ability to add power, Kelsey fell short of the runway and belly-landed into a sand trap at a golf course, destroying the plane but suffering only minor scratches himself. General Henry "Hap" Arnold was very happy with the speed demonstration and ordered Kelsey to proceed with further development of the design. In May, Kelsey was promoted to the rank of captain.
The P-38 ended up being the "sweetheart of Kelsey's flying career", according to author Jeff Ethell.Confederate Air Force. The Dispatch, Volume 18, Number 1, Spring, 1993. Jeff Ethell, "Lightning From the Ground Up: Lockheed's P-38 Lightning". Retrieved on March 30, 2009. Kelsey stayed in close contact with the twin-engine fighter during every phase of its development and implementation. As part of Operation Bolero, the first-ever delivery of fighter aircraft flying under their own power from the US to the UK, Kelsey piloted a P-38 to the UK in late July 1942. After meeting with British airmen and reviewing the newest developments of air combat, Kelsey returned to the US by ship.Bodie 2001, pp. 101–102.
On April 9, 1943, Kelsey performed a flight test on a modified P-38G to see if Lockheed's newly developed dive flap could be engaged after terminal velocity was reached in a dive. After climbing to 35,000 ft, Kelsey initiated a dive. At maximum speed, he pulled the lever to engage the new flaps but nothing happened. Pulling harder, the handle came off in his hand. Kelsey applied full rudder and aileron at the same time, and suddenly the aircraft lost one wing and the whole tail, and entered an inverted flat spin.The X-Hunters. X-peditions: 1992–2004. Col. Ben Kelsey's Lockheed P-38 Lightning. Test dive From 35,000 feet. Dive Flap Test. Retrieved on March 31, 2009. Kelsey bailed out and suffered a broken ankle upon landing. The P-38 crashed upside down into a hillside near Calabasas, California.Bodie, 1991, pp. 166-167.
P-51 Mustang The existence of the P-51 Mustang has been credited to Kelsey's dogged determination to see the project to completion. He formulated the specifications for the Curtiss XP-46 and placed an order for two prototypes in September 1939, hoping that the advanced aircraft would replace the P-40 Warhawk which had not demonstrated above-average fighting qualities. Production of the new design was canceled by General Henry "Hap" Arnold as it was anticipated that a four-month delay in Curtiss fighter deliveries would be incurred by the radical change. Kelsey's boss, Colonel Oliver P. Echols, shopped the design to the Anglo-French Purchasing Commission who were told to find an aircraft manufacturer that wasn't busy with war production. Echols and Kelsey made it understood that the NACA airflow research data collected on the XP-46 would be made available to the new manufacturer. North American Aviation (NAA) expressed interest and was sold the NACA data for $56,000. They produced a new design, the NA-73, which was approved by the British who christened the fighter "Mustang". Echols and Kelsey arranged to get two prototypes out of the British contract, and, on July 7, 1941, even before the prototypes arrived at Wright Field, Kelsey ordered 150 P-51s from NAA. Nine months later Kelsey ordered 500 nearly identical A-36 Apache models that he was able to purchase with funds intended for attack bombers. In this manner Kelsey kept the assembly line busy, so that the factory would be primed to make Mustang fighters once a new contract could be arranged. After the US declared war in December 1941, thousands of military aircraft were ordered, and NAA ramped up for Mustang production.
Once the Mustang was in combat in the European Theater of Operations (ETO), Kelsey was able to collect pilot's opinions of the aircraft as well as going out on combat missions himself to determine whether improvements could be made to the design. Kelsey clarified and expedited the communication of battlefield requests back to the NAA production team such that the turnaround time of modifications was minimized.National Air and Space Museum. Research transcript, oral history. Interview by Martin Collins of John Leland "Lee" Atwood at North American Aviation , January 19, 1989. Retrieved on March 30, 2009.
France and Britain