David D. Onan and Sons of Minneapolis, Minnesota and their successors have built industrial engines.

-Many of them we have seen in the auxiliary power groups on the ground and other devices that are used to support airplanes such as heaters, compressors, etc.

-The company was founded in 1925. Since 1960’s it has passed through various hands, such as Studebacker, Hawker Siddeley, McG. Edison and Cummins.

“Onan on Pellican”

-The two-cylinder 4-stroke engine that gave 18 HP at 3,600 rpm and 22 HP at 3,800 rpm, was seen on the '82 EAA.

-It was also mounted on the Quickie. A turbocharged version to give and maintain 25 to 30 HP for the Super Quickie.

-It is one of the manufacturers of auxiliary power engines and ground groups (APU) of those used by aviation mechanics to support their work and has been well known by all these technical personnel.

-One of the best known was the Model 4040 with opposed cylinders.

-There also were V-engines. Generally they drove electric generators to power the aircraft.

-The mechanic had to know them, start them, adjust them, maintain them, and therefore struggled with this engine like with the one on the aircraft itself.

“The 4040, both sides”

-The author, as an aviation mechanic, had a manual for this auxiliary engine at his workplace.