hand propping a Liberty 12

[Joe Broady]

Yesterday Turner Classic Movies ran "Spirit of St. Louis" with Jimmy Stewart as Lindbergh. There's one scene where, as an air mail pilot, he starts the engine of his plane. He calls it an "old de Havilland," so I guess it's a DH-4. The plane in the movie looks like one. An assistant handles ignition and throttle while Stewart does the honors with the prop. He stands on the right of the nose, gets a running start, grabs a blade (which is at the 9 o'clock position) with his left hand, and gets about a half revolution before the film cuts to the other man and you hear (but do not see) the engine start.

I'm sure the studio insisted that the engine be put in an absolutely dead state when Stewart handled the prop. But back in the day, it must have been a hell of a job to start a Liberty by hand, if indeed they really did that. I doubt that a man with my small frame could do it at all.

Later in the movie you get to see a genuine hand start when Lindbergh sets off on the big flight. A mechanic gets the Wright Whirlwind going on the second try.

There's another nifty scene in the part where Lindbergh buys a Jenny. As he sits in the cockpit talking to the aircraft dealer, you can see the rocker arms jittering.

 

[MIflyer]

In reality the Liberty used an inertia starter, where a handle that stuck out of the engine compartment sideways spun up a flywheel that could then be engaged to start the engine. Supposedly you could start a well tuned Liberty 12 times off of one spin up of the starter. Later they added an electric motor so the starter could be spun up either by battery or by the crank; a friend of mine had one of those starters on his Waco.

A Liberty was 1710 cu inches, same as the WWII V-1710, and would have been a mite hard to hand prop.

 

[kmccutcheon]

A Liberty was 1710 cu inches, same as the WWII V-1710, and would have been a mite hard to hand prop.

Liberty 12: bore = 5.4"; stroke = 6.0"; displacement = 1,648.9 in³. Still hard to hand prop.

 

[MIflyer]

The only time I have easily hand propped my airplane's engine (188 cu in) was when I was just checking to see how dangerous it was to move the prop with the ignition on, Three easy flips of the prop, using no more force than you would to just pull it through, and without priming it first - and it started on the third flip. It has never started that easily when the battery was dead or the starter failed and I really wanted to start it.