LeBlond Aircraft Engine Corporation

In 1928 Richard K. LeBlond purchased Detroit Aircraft Engineering Corporation, then a subsidiary of Detroit's automaker Rickenbacker owned by World War I pilot and ace Eddie Rickenbacker[3] and the engineer, Glenn D. Angle.[4] and their 5-cylinder Air Cat engine. LeBlond employed the company's designer and previous co-owner, Glenn D. Angle, to improve the design for further production and development.[2] The LeBlond line was continually refined and improved through late 1937.

In December 1937, in order to offset a large tax liability incurred by the LeBlond Tool company, the subsidiary, LeBlond Engines, was sold at a significant loss to Raymond A. Rearwin of Rearwin Airplanes. The purchase was a perfect fit for Rearwin as his company was one of the largest users of LeBlond engines and gave Rearwin a well accepted radial engine to use on his designs.[5] Rearwin renamed the company Ken-Royce Engine Company after his two sons Ken and Royce Rearwin.[6] After Rearwin moved the assets from Norwood to Kansas City, quality-control issues were experienced, which only seemed to improve after several employees who had made a competing offer for LeBlond's assets were fired. Production of the line continued until World War Two.[7]

Production of the LeBlond designs never resumed, as the design was not economical compared to the newer "flat" (horizontally opposed) engines of the post-war era. LeBlond/Ken-Royce engine parts were provided during the 1950s by Air Associates and in the 1960s the remaining parts were sold to the Antique Airplane Association of Blakesburg, Iowa.[2]

Parts were interchangeable between the 5 and 7-cylinder models of the LeBlond and later Ken-Royce engines, including the cylinder assemblies, gear case and oil pump. As the engine was modular in design, the gear case could be removed intact. The oil pump, being a single unit, could be removed for overhaul or replacement.[2]

The Stromberg NAR-3 carburetor contained a built-in "primer" which acted like a choke by leaking gasoline into the intake stream when activated, in order to prime the engine.[2]

The valve springs used on LeBlond's and Ken-Royce engines were of the volute spring type which is wound in a beehive shape out of strip steel, unnlike most engines, which have nested coil springs wound from round wire. This type of spring was inherited from the original Detroit Air-Cat as at the time of the Air-Cat design in the late twenties, round wire springs had resonance and fatigue problems. The volute design eliminated the resonance and lasted longer.[2]