This engine is one of three built by Jim Hawk of Oklahoma in the late 1980's. It is an Eldon I 2636, designed by Eldon Dwyer as a (large) model hydroplane power-plant. Jim's versions of the design feature water cooled head and exhaust, three linked Perry carbs, and a 120° crankshaft. The engine is a methanol drinking, six-cylinder two-stroke, so this arrangement will have pairs of cylinders firing three times per revolution.
Click on images to view larger picture.The Eldon I 2636 was the brain-child of Eldon Dwyer, New Mexico USA, being purpose-designed to power his model hydroplanes. The first prototype, circa 1982, was machined from bar-stock and was based around K&B piston/liner assemblies.
This was apparently successful and led to a second version being built using extensively cored sand-cast components for the crankcase. Eldon formed a company called Robotronics that sold plans and castings for the engine. The number sold is not known, nor precisely how many were completed. In the early 1990's, the Miniature Engineering Museum (MEM) acquired both the prototype engine and the proof-of-concept version for the cast crankcase, along with the pattern board and core box (pictured above). This second engine features an electric starter as the envisaged hydroplane installation would make it largely inaccessible for conventional starting via a pull-cord 'round the flywheel.
Jim Hawk built three Eldon I 2636 engines. Two were painted black, while the third was left natural aluminium and went into Miguel deRancougne's collection. Following Miguel's passing and the auction of his collection, believed to be the largest the world has yet seen, the engine became disassociated from its provenance information and landed in hands of Malcolm Stride, aka Nemett, the IC editor for Model Engineer since 2005. Photos of it appeared in Model Engineer, issue #4236 of June 2005, asking is anyone know what it was? Malcolm also sent photos to us here at Model Engine News, where the engine featured as Watzit #74, eventually leading to positive identification by Paul Knapp of MEM. Paul provided all the photos and information on this page and notes while one of the black Hawk/Eldon versions is on display in the MEM, the location of the other is unknown.
And in case you think you may have heard the name Jim Hawk before, check out the Morton M42 page.