Engines designed by Dale Herbrandson and built by DH Enterprises in Lawndale, CA.

-These engines were designed for use in RPV for contracts with the US Gov.

-They were initially based on the German Sthil, chainsaw motors.

-The single-cylinders were the DH-160 with 11 hp, the DH-174 with 13 hp and the DH-220 with 18 hp.

-The Dyad-280 had two horizontally-opposed cylinders and gave 20 hp at 6,000 rpm (years 1975-80), They were two-stroke engines with ignition by magneto or battery with capacitative device discharge.

-There are also the 370, 433 and 580, which are in current production. Below we see the Dyad 160 model in more detail and in several views.

“Dyad 160”

-They also made small twin-cylinders as we can see when we compare them with their common shielded-type spark plugs to Continental or Lycoming engines.

“Dyad 160 frontal view”

“Dyad 160, left-side view”

From Appendix 10: Photograph of an engine used in a pilotless plane in the pusher position. Located in an American museum.

-It is the Dyad 280D model that gives 24 hp at 6,000 rpm.

"Rear view with the propeller nearly touching the air outlets"

-The proximity of the propeller to the air outlets provided an air extraction when the vehicle had no speed.

"The Dyad 280D seen from above"

-It had two carburetors and simultaneous Capacitive-Discharge type (DCI) ignition, with a magnetic pick-up next to the propeller plate. Just like in Citroën Visa II cars.