Counter-rotating propellers

Plane’s propellers revolve in opposite directions

The following article is adapted from "Popular Science", November 1931.

Twin propellers, revolving in opposite directions, suc- cessfully drove an airplane in a recent test at Fort Worth, Texas. According to the inventors, M. M. Egan and D. W. Evans, it may make possible hitherto unattained airplane speeds. Vibration is said to be eliminated by the novel com- bination, lessening the likelihood of airsickness. Another ad- vantage is the banishing of “torque,” which causes a plane to tend to lean sideways from the force of its single pro- peller’s whirling. In the new drive, the front screw is mounted in the conventional way upon the main shaft of the engine. Behind it the second propeller whirls in the opposite direction, half again as fast as the first. According to Brig. Gen. B. D. Foulois, Chief of the Army Air Corps, the device is interesting because propellers have changed little and new designs, he believes, are desirable.