The D-C Tornado simultaneous-firing opposed twin glow-plug motor of 4.87 cc (0.297 cuin.) was perhaps the most outstanding product ever to emerge from the workshops of Davies-Charlton Ltd. Introduced in December 1958, this very well-made model broke new ground in the context of the British model engine manufacturing industry. It used a one-piece two-throw crankshaft with split con-rod big ends as well as an ingenious induction system using two rotary valves which were supplied by a single carburettor. The engine started and ran very well indeed, developing some 0.370 BHP @ 14,000 rpm according to Peter Chinn's test which appeared in the July 1960 issue of "Model Aircraft" magazine. Chinn estimated that an output of 0.400 BHP seemed to be well within reach using a higher nitromethane content, a figure which was confirmed by the "Aeromodeller" test of the engine which appeared in their September 1960 issue.
Sadly, the Tornado Twin's technical excellence did not result in large sales, the result being that the engine was withdrawn from the market in early 1961 after the production of perhaps only a few hundred examples. Full details of the D-C Tornado Twin may be found in my earlier article on Ron Chernich's "Model Engine News" (MEN) web-site.