Jack Ridley (pilot)

Colonel Jackie Lynwood Ridley (June 16, 1915 – March 12, 1957) was an aeronautical engineer, USAF test pilot and chief of the U.S. Air Force's Flight Test Engineering Laboratory.

He helped develop and test many Cold War era military aircraft.

He worked on the Bell X-1, the first aircraft to achieve supersonic flight, and was highly respected among fellow test pilots, most notably Chuck Yeager, for his engineering skills.

Jack Ridley was born on June 16, 1915, in Garvin, Oklahoma.

Ridley graduated from a high school in Sulphur, Oklahoma in 1935.

Following high school, he entered the ROTC program at the University of Oklahoma where he received his Bachelor of Science degree in mechanical engineering in 1939.

In July 1941, the young engineer received a commission in the U.S. Army field artillery and began a military career, which would continue for the rest of his life.

The science of flight soon attracted him, however, and it was not long before he transferred to the Army Air Forces.

Lieutenant Ridley was sent to the Flying Training School at Kelly Army Air Base in Texas, where he earned his pilot wings in May 1942.

The Air Corps needed engineering-trained pilots and, instead of being sent into an operational combat unit, Ridley was ordered to the Consolidated Vultee plant in Fort Worth, Texas, where his initial assignment was to conduct acceptance tests on four-engine B-24 Liberator bombers.

Soon thereafter, he was named as engineering liaison officer on both the B-24 and B-32 programs.

Even at that early date, the Air Corps was developing the six-engine B-36 intercontinental bomber, later to become the mainstay of the postwar Strategic Air Command, and Ridley found himself assigned to that program as well.

In 1944, Ridley was sent off to further his education.

After attending the Army Air Forces School of Engineering at Wright Field (later renamed the Air Force Institute of Technology), Ridley was sent to the California Institute of Technology where he received his Master of Science degree in aeronautical engineering in July 1945.

Ridley was sent to Wright Field, Ohio, and assigned to the Air Materiel Command's Flight Test Division.

Ridley went to the Air Materiel Command Flight Performance School from January through May 1946.

In the spring of 1946, he graduated with Class 46A.

Even as Ridley was attending the Flight Performance School, the revolutionary X-1 rocket research airplane was making its initial unpowered check flights and, within a year, the USAAF (soon to achieve independence as the United States Air Force) would assume control of the supersonic research program.

Colonel Albert Boyd, the chief of the Flight Test Division selected the project team that would attempt the world's first supersonic flight.

In the spring of 1947, Boyd appraised his roster of 125 test pilots and finally selected three volunteers who were considered very junior in terms of their flight test experience: Captain Charles E. "Chuck" Yeager, 1st Lieutenant Robert A. "Bob" Hoover, and Ridley.

He named Yeager and Hoover as primary and backup pilot respectively, and Ridley as project engineer.

The choice was a happy one.

As Yeager later explained:

"Well, ... Hoover and I were definitely not flight test engineers! We could fly airplanes and we had an instinct for aerodynamics ... but Jack Ridley ... was a brain! Jack Ridley knew everything there was to know about aerodynamics and he was practical. And, besides, he was a good pilot ... and he fit right in with us. He spoke our language. Bob was a Tennessean and I was a West Virginian and, being an Okie, Jack spoke real good language for us."

"Even before we flew the X-1, I talked to him at great length about ‘what are we getting into? You know, what's it mean? We're going to be fooling around out of my realm…and you may understand this stuff but I don't. What the hell are we getting into?' And Jack would patiently explain. And I had a great deal of confidence in him and, you know, if he said something, that, to me, was from the Bible. You could take it to the bank."

Ridley's task was to analyze all of the technical data that was generated during the X-1 flights as it proceeded toward the unexplored region of supersonic flight.

Studying the phenomena that the research plane encountered as it passed through the transonic region, he translated all of the information into pilot terminology for Yeager so that the flight program could be carried forward expeditiously, yet with safety.

As Yeager later explained:

"I trusted Jack with my life. He was the only person on earth who could have kept me from flying the X-1. As committed as I was to the program, and with all that was riding on these flights, if Jack had said, 'Chuck, if you fly in that thing, you're not gonna make it,' that would have been it for yours truly."

Ridley had to rise to meet unexpected problems and new aerodynamic principles.

He faced the problem of a complete loss of elevator effectiveness which Yeager experienced during his eighth powered flight as his Mach meter indicated a speed of Mach 0.94 (his true airspeed was in the range of 0.96-0.99 Mach, just below the speed of sound).

At that speed, the little research plane stopped responding to all elevator control inputs, leaving the pilot unable to change his pitch angle, or to raise or lower the plane's nose in flight.

When speed decreased slightly, the problem abruptly disappeared.

Analysis suggested that a shockwave was forming along the elevator's hinge line, leaving it ineffective.

Ridley determined in that speed range, the elevator itself could safely be dispensed with and the X-1's entire horizontal stabilizer, which could be adjusted for trim changes, be used for pitch control.

The idea worked, and Ridley's concept eventually came to be incorporated in all supersonic aircraft — the "flying tail."

Ridley also improvised a vital piece of equipment at the last minute.

Two days before taking the X-1 on its first supersonic flight, Yeager broke two ribs in a horseback riding accident.

With the aid of an understanding civilian doctor, he was able to conceal his condition from everyone but Ridley.

Without the full use of his right arm, however, it would be impossible to seal himself into the tiny X-1 cockpit.