Leon A. "Jake" "The Bullfrog" Swirbul (March 18, 1898 – June 28, 1960), was an aviation pioneer and co-founder of Grumman Aircraft Engineering Corporation.
Swirbul was born in the Yorkville section of Manhattan. His family moved to Long Island when he was a child. He grew up in Sag Harbor and graduated from Pierson High School. He attended Cornell University until 1917 when he left school to enlist in the U.S. Marine Corps.
Jake Swirbul and Leroy Grumman met in 1924 at Loening Aeronautical Engineering Co. in New York City, one of the many small aircraft firms that sprang up after World War I. When the firm's Manhattan factory was closed after its sale to Keystone Aircraft in 1929, Swirbul and Grumman decided to form their own company. Grumman mortgaged his house to contribute $16,875, and Swirbul contributed $8,125. Two other Loening employees, William Schwendler and Edmund Ward Poor, contributed a little and former Wall Street banker E. Clinton Towl made up the fifth employee of Grumman Aircraft Engineering Corporation, formed January 2, 1930.
The Swirbul Library at Adelphi University is named in his honor