Remembering R. P. Kroon

Rein Kroon and another Westinghouse engineer testing strain on celluloid model of mount for Hale Telescope. (Hagley)


Reinout Pieter Kroon (4 August 1907 – 4 August 1992) was my professor for turbomachinery during my Mechanical Engineering undergraduate years (1968-1972) at the Towne School of Engineering at the University of Pennsylvania (which is in Philadelphia). He was a kind, intelligent, witty and perceptive man, with great insights into what engineers — as public-minded, socially conscious citizens — could and should be. This web-page is my appreciative memorial for him.

“Reinout P. Kroon (1907 – 1992) was a Dutch mechanical engineer who immigrated to the United States in 1931 after earning his M.S. degree from the Federal Technical Institute in Zurich, Switzerland. Joining Westinghouse Corporation that year, he soon became a development engineer in the Steam Division.

“In late 1935, Westinghouse sent Kroon to Pasadena to work on the details of the mounting of the 200-inch telescope. During his six-month assignment, Kroon solved three major design issues. First, he designed the hydrostatic pressure system with which the telescope turns in right ascension on a thin film of oil. Second, he designed the horseshoe and ball bearings for the north and south ends of the yoke. Finally, he designed the spoked declination bearings that allow the telescope to travel north and south.

“Later, Kroon became head of engineering research at Westinghouse where he managed a team that in 1945 developed the first commercially viable American jet engine. In 1960, he joined the engineering faculty at the University of Pennsylvania where he rose to the position of chairman of the graduate division of mechanical engineering.” (

Reinout Kroon was the Team Leader at Westinghouse in the making of the first American jet engine. The story of that effort during the World War II years is described by Kroon in his lecture-pamphlet “What’s Past Is Prologue” (shown below), and the unsuccessful effort to commercialize the initial technical triumph of making that turbojet, during the years 1950-1960, is given in detail by Paul D. Lagasse in his 1997 Master’s thesis in American History (

Professor Kroon was a tall, elegant and personable man; he was a fabulous instructor and an inspiring example of an engineer’s engineer. From him I learned more about fluid mechanics and thermodynamics, specifically about turbomachinery, and — most elegantly — dimensional analysis; he was very adept mathematically. A field trip to the Westinghouse plant where huge turbines (for steam turbine electric generators) were built, was memorable. The stamping machines for fashioning the turbine blades were awesome, and loud!

Reinout had one brother, Berend Jan Gerhard (Bert) Kroon; and he was married to Dora Kroon (born Kaestli, on 25 May 1910, in Bern, Switzerland) with whom he had children, one son being Berend Walter Kroon. Reinout Kroon lived in Kennett Square, Pennsylvania. Professor Kroon died tragically in 1992, on his 85th birthday, as a result of injuries sustained some days earlier in an automobile accident.

What’s Past Is Prologue

Kroon, Dimensional Analysis

PDF files of the two pamphlets displayed below are available from the web-links above.