Duncan is a manufacturer of Wankel-type rotary engines, using advanced technology. They started to build them in 1984 and these engines were based on the Mazda RX-7 technique.

-There are about 10 models in the market, from 40 to 350 HP and from 90 to 300 lbs. of weight.

-Starting with the SR-40A single-rotor model that is cooled by forced air through a centrifugal fan. It gives 40 hp at 6,000 rpm.

-The SR-60D, without gear, is cooled by water and has a single rotor too. It gives 60 hp at 4,000 rpm.

-The SR-120R (SR for Simple Rotor), is geared and water cooled. It gives 120 hp at 9,000 rpm.

-The DR-200R (DR for Dual Rotor), gives 200 hp at 8,100 rpm.

"SR-120R"

-The DR-240R gives 240 hp at 9,000 rpm. There is a Dual-Pac version of two DR engines, to give 700 hp, resulting in an engine that is lighter and less bulky than the conventional ones giving only 300 hp.