BY EDWARD H. HEINEMANN AND EDWARD R. COWLES

PERRY W. PRATT, a leading aircraft engine designer who made key contributions to the development of jet propulsion, died on January 6, 1981, at his home in Jupiter, Florida. He spent his entire career, spanning more than three decades, with Pratt and Whitney Aircraft and its corporate parent, United Technologies. When he retired in 1971, he was the company's Chief Scientist and directed the advanced study and planning group of scientists and engineers who were responsible for searching out and investigat­ing new fields of activity for the corporation, its operating divisions, and its subsidiaries.

Mr. Pratt was born January 10, 1914, in Lompoc, California. He graduated from Oregon State University and did graduate work at Yale and New York University.

Mr. Pratt joined Pratt and Whitney Aircraft (no relation) as a Test Engineer in 1939, and was Project Engineer for the R-2800 Double Wasp engine, which powered a wide array of Allied fighters, bombers, and transports during World War II.

When Pratt and Whitney Aircraft went into the jet engine field, Mr. Pratt was chosen to head the Technical and Research Section of the Gas Turbine Department. In this capacity he had a key part in  the development of Pratt and Whitney Aircraft's family of gas tur­bine engines, which today power a large number of the Nation's front-line military aircraft and three-quarters of the free world's commercial jetliners.

Mr. Pratt was named Assistant Chief Engineer of the Pratt and Whitney Aircraft Division in 1950, Chief Engineer in 1952, Assist­ant Engineering Manager in February 1957, and Engineering Man­ager later that same year. During this period he was granted patents for inventions of induction apparatuses and ignition controls for aircraft engines.

In 1958 United Technologies created the position of Vice­ President and Chief Scientist for the corporation, and Mr. Pratt was elected to that post, which he held until his retirement.

During his career Mr. Pratt was recognized by several technical and engineering organizations for his outstanding contributions. He was elected to the National Academy of Engineering in 1967. The American Society of Mechanical Engineers (ASME) presented him the George Washington ASME Award in 1956 in recognition of his contributions to the engineering profession. He received the Ameri­can Society of Mechanical Engineers' Gas Turbine Division Award for 1967 for his leadership and technical contributions in the devel­opment of aircraft turbojet and turbofan engines.

In 1968 the Institute of Aeronautics and Astronautics selected Mr. Pratt to share the Goddard Award, given to "a person who has made a brilliant discovery or a series of outstanding contributions over a period of time, in the engineering science of propulsion or energy conversion." The citation accompanying the award read: "For their independent and sustained major contributions, each in his own country, to the development of the aircraft gas turbine; and for their imagination, competence and persistence which have made these engines outstanding in human transportation."

In 1972 Mr. Pratt was chosen to receive the Elmer A. Sperry Award of the American Institute of Aeronautics and Astronautics for his role in the development of the JT3 turbojet, the power plant for America's first commercial jetliners, the Boeing 707 and McDonnell Douglas DC-8.

It was the first turbojet engine in the Western world to produce 10,000 pounds of takeoff thrust, and the first to power a production aircraft, the F-100, at supersonic speeds in level flight. More than 21,000 of the engines were produced for such commercial and military aircraft as the Boeing 707, B-52, and KC-135; the McDonnell Douglas DC-8, F-101, and A-3; North American Rockwell F-100; General Dynamics F-102; and the LTV Aerospace F-8.

Perry Pratt and Luke Hobbs (also of United Technologies), who shared the Sperry Award, were recognized "for their leadership, vision and engineering skill in directing the design and development of the JT3 turbojet engine ... which by its performance and reliabil­ity was an essential element in the initiation and rapid growth of the jet age in commercial air transportation.''

During his career Mr. Pratt served in a variety of capacities. He was a member of the Advisory Council of the Department of Aero­nautical Engineering, Princeton University; a member of the Aero­nautics and Space Engineering Board of the National Academy of Engineering; a member of the Industrial and Professional Advisory Council, Department of Aerospace Engineering, Pennsylvania State University; and a member of the Board of Directors of the Coordi­nating Research Council.

Mr. Pratt is survived by his wife, Edith Abraham Pratt of Jupiter, Florida; a son, Spencer Pratt, and a daughter, Mrs. Albert Phillips, both of Glastonbury, Connecticut; his mother, Ruth Pratt of Corval­lis, Oregon; a brother, Edwin Pratt of Bellevue, Washington; and three grandchildren.