Five hundred views and no fully right answers, so here are the answers.
1. A Kreider-Reisner K-34 three seat biplane application by the Kreider-Reisner Division of Fairchild considered a Kimball "Beetle K" engine for possible use in the KR-34 at Hagerstown, Maryland after 1929. The tests were not deemed successful and the "Beetle K" engine was not incorporated in production KR-34s. (The KR-34 had formerly been known as the Challenger C-4). The actual K-R test aircraft with the 135 Hp "Beetle K" engine was a sole KR-32 Serial #148 registered to Kimball Aircraft Corp. as -5015 for test and development.
2. The Kimball "Beetle K" was a seven cylinder air-cooled radial-type engine.
3. The odd feature of this radial engine was it's F-head makeup. The intake was a side-valve built into the cylinder head and the exhaust was a valve-in-head operated by a push-rod. The timing sequence of each valve was operated by a cam disc. Both the cylinder head and the cylinder were liberally finned for air cooling.
The "Beetle K" was a large engine displacing 535 cubic inches and at 580 pounds dry less hub and starter was heavy for its horsepower. It was rated 135 horsepower at 1,800 rpm. The engine crated at the Kimball Aircraft Corp. factory in Naugatuck, Connecticut was to sell for $2,900.
Of interest, the unorthodox Caminez four-cylinder radial engine was also tested, but did not power any production Kreider-Reisner Challenger-series biplane. Does anyone know of any other even-cylinder (per row) radial aircraft engines? And please don't suggest a two cylinder engine, as that would be an opposed, as distinct from a radial engine. Nobody said this was easy!
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