10 April 1972: Lieutenant Colonel W. Roy Windover, Royal Canadian Air Force, assigned to the North American Air Defense Command (NORAD), set a Fédération Aéronautique Internationale (FAI) World Record for Altitude when he flew a 1941 Interstate Cadet S-1A, N37239, to an altitude of 9,388 meters (30,801 feet) over Pike’s Peak, near Colorado Springs, Colorado.¹ The FAI awarded him its Médaille Louis Blériot for his achievement.
In 1958, Flight Lieutenant Windover had been the first Royal Canadian Air Force Red Knight, a solo aerobatics demonstration performer, flying a bright red Canadair CT-133 Silver Star.
Windover’s Interstate Cadet S-1A, serial number 82, was built by the Interstate Aircraft and Engineering Company, El Segundo, California, in 1941. The airplane was assigned an Airworthiness Certificate, 18 December 1958, and registered N37239.
The Cadet was a single-engine, high-wing monoplane with a tandem cockpit and fixed landing gear. The fuselage of the Cadet was built of a tubular steel framework with a wooden structure for the wings, covered in doped fabric. The airplane was 23 feet, 5 inches (7.137 meters) long with a wingspan of 35 feet, 6 inches (10.820 meters) and height of 7 feet (2.134 meters). The airplane had a maximum weight of 1,200 pounds (544 kilograms).
The Cadet S-1A was powered by an air-cooled, normally-aspirated 171.002-cubic-inch-displacement (2.802 liter) Continental A65-8 horizontally-opposed four cylinder direct-drive engine, with a compression ratio of 6.3:1. It was rated at 65 horsepower at 2,300 r.p.m. at Sea Level, using 73-octane gasoline.
At the time N37239 set this record, it was powered by an air-cooled, normally-aspirated, 171.002-cubic-inch-displacement (2.802 liter) Continental A75 horizontally-opposed four-cylinder engine with a compression ratio of 6.3:1, rated at 75 horsepower at 2,600–2,650 r.p.m. (depending on variant) at Sea Level. The A75 required 73-octane aviation gasoline.
The Cadet S-1A had a maximum speed of 103 miles per hour (166 kilometers per hour) and maximum diving speed of 139 miles per hour (224 kilometers per hour). The service ceiling was 16,500 feet (5,029 meters) and range was 540 miles (869 kilometers).
Approximately 320 Cadets were built by Interstate during 1941–1942. In 1942 and 1943, another 259 were built as OX-63, L-6 and L-8 Grasshopper light observation airplanes.
N37239 caught fire during a training flight near Amarillo, Texas, 12 January 1995. After an emergency landing, the airplane was destroyed by the fire. The cause was not determined. The airplane was rebuilt and issued an Airworthiness Certificate 8 April 1999. It is currently registered in Farmington, Missouri.
¹ FAI Record File Number 1918
© 2017, Bryan R. Swopesby