Today In Aviation History: First Flight of the North American YF-93

On January 24, 1950, North Americanโ€™s YF-93 took to the air for the first time, representing a major attempt to evolve the F-86 Sabre into a long-range penetration fighter. Originally developed as the NA-157 and briefly designated F-86C, the aircraft featured increased size, fuel capacity, and power to meet U.S. Air Force bomber-escort requirements. Although two prototypes were built and flight tested, the program was canceled as escort fighters became unnecessary with the arrival of jet bombers like the B-47, leaving the YF-93 to serve only as a test platform with NACA.

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Flight evaluation and comparison of a NACA submerged inlet and a scoop inlet on the North American YF-93A (AF48-317 NACA-139) at NACA Ames Laboratory (NASA photo)
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On this day in aviation history, 76 years ago (January 24, 1950), the North American YF-93 flew for the first time. The YF-93 was a further development by North American of their successful F-86 Sabre fighter. The design originated as the NA-157, the result of a study by North American that sought to create a designated penetration fighter. This specialized fighter was essentially a long-range version of the F-86A. The NA-157 would be larger, and have a greater fuel capacity: 1,961 gallons internally and two 200-gallon drop tanks. This new F-86 variant would also have an increased overall range of over 2,000 nautical miles.

North American YF 93A on lakebed
North American YF-93 48-317 at Rogers Fry Lake, fitted with flush intakes (USAF photo)

The fighter that resulted from the NA-157 study was initially designated as the F-86C. The F-86C was intended to compete with the McDonnell XF-88 Voodoo and Lockheed XF-90 to meet the United States Air Forceโ€™s penetration fighter requirements as a bomber-escort. The larger size and weight of the F-86C required dual-wheel main landing gear, an increased wing-area, and a more powerful engine. The USAF ordered two NA-157 prototypes and ultimately redesignated the aircraft as the YF-93A, considering how vastly different the fighter was from the original F-86 design.

North American F 93 in flight
North American YF-93A 48-317 in flight (USAF photo)

In 1949, the USAF canceled the YF-93Aโ€™s production order. The Air Forceโ€™s priorities had shifted to flight testing the Boeing B-47 Stratojet, a bomber that would not require fighter escort. Nevertheless, North American continued to build the two prototypes and flight test them internally. The YF-93 participated in a fly-off against the XF-88 and XF-90, which the Voodoo ultimately won. The YF-93s were eventually given to the National Advisory Committee for Aeronautics (NACA) for further testing. It was revealed that the fighterโ€™s air ducts were inefficient at high angles of attack, causing a restriction of air flow to the engines.

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North American Aviation engineers with YF-93 48-317 (Wright State University)

The North American YF-93A was powered by a Pratt & Whitney J48-P-6 turbojet engine that produced 6,000 pounds of thrust dry and 8,750 with afterburner engaged. The aircraft could attain a maximum airspeed of 708 mph at sea level and could cruise at 534 mph. The YF-93A had a range of 1,709 nautical miles, a service ceiling of 46,800 feet, and a 11,960 foot-per-minute rate of climb. Had the YF-93 entered service, the fighter would have been armed with six 20 millimeter M24 cannons.

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North American YF-93 48-317 during a test flight (USAF photo)
Austin Hancock

Commercial Pilot, CFI, and Museum Entrepreneur, with a subject focus on WWII Aviation. I am dedicated to building flight experience so I can fly WWII Fighters, such as the P-51 Mustang, for museums and airshows, and in the USAF Heritage Flight. I lead and run the Pennington Flight Memorial, to honor local MIA Tuskegee Airman F/O Leland โ€œStickyโ€ Pennington.

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Commercial Pilot, CFI, and Museum Entrepreneur, with a subject focus on WWII Aviation. I am dedicated to building flight experience so I can fly WWII Fighters, such as the P-51 Mustang, for museums and airshows, and in the USAF Heritage Flight. I lead and run the Pennington Flight Memorial, to honor local MIA Tuskegee Airman F/O Leland โ€œStickyโ€ Pennington.
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