Elmer Sperry developed the Stallemometer as a follow-on component to the first successful aircraft autopilot, demonstrated by Sperry in 1914. The Stallemometer detected a stall flutter and then function as a switch to drop the nose by twenty degrees through the autopilot until a stall recovery occurred. A light provided a further warning that the stall had occurred and a recovery was underway. Like the autopilot itself, the Stallemometer was not seen by aviators as a desirable innovation due to cost, weight, complexity and its subsuming of pilot control over the flight. Such systems did enjoy a resurgance fifty years later as increasing levels of autopilot autonomy became standard on larger transport aircraft.
This object is not on display at the National Air and Space Museum. It is either on loan or in storage.