At some other point of this publication we emphasize that the aviation mechanic does not only maintain the aircraft entrusted to him but also the equipment around it.

-And that equipment includes APU, APP engines, compressors, cleaning equipment etc.

-Here we have the external starter engine designed and built by Lieutenant Alford J. Williams for his aircraft.

-In a mobile cart with enough electric storage batteries and a mast with four electric starters coupled to a single shaft turning the propeller hub to start the plane's engine.

"Alford's idea"

-When the main engine of the aircraft starts running on its own, the coupler is expelled from the hub and the whole equipment becomes separated.

-Precisely in the Spanish civil war (1936-1939), the Republican air force that had Russian material started the engine by a similar coupling but with the mechanical drive from a van's transmission output, as shown in the illustration below.

“Starting system for the Polikarpov I-15 and I-16”