The Ten-Sixty-Six Hawk was the second of three successive 5 cc engine designs offered by the Ten-Sixty-Six Products Company of Worcester, England. The range is relatvely less well-known among today's predominantly aero-minded collectors because its products were primariliy directed towards the tether car and tethered hydroplane racing communities.

The very first Ten-Sixty-Six model engine was the 5 cc Falcon 1 sideport unit of 1946. The intention was to produce a “family” of engines bearing the Falcon name in 5 cc, 10 cc and 15 cc versions, but only the 5 cc model made it into series production. The 5 cc Falcon 1 was available in kit form only, being produced in quite substantial numbers. It is the most commonly-encountered Ten-Sixty-Six 5 cc model today.

The Falcon was replaced in early 1948 by the disc rear rotary valve (RRV) Hawk, which was a factory-produced model as opposed to a kit. This in turn was supplanted in April 1949 by the final Ten-Sixty-Six 5 cc model. the RRV Arrow. However, neither the Hawk nor the Arrow were any match for the emerging 5 cc racing models exemplified by the ETA 29. The company finally ceased operations in mid 1950.

A full description and test of the Hawk will appear in due course on this website. Complete details of the 10 cc Ten-Sixty-Six Conqueror racing engine and the supposed Ten-Sixty-Six 2.75 cc diesel may be accessed through the links provided.