Excerpt was written by David J. Williams, who is a former airline captain and currently involved with aviation safety, on NYCAviation.com.
For many of us, our first understanding on how to start an airplane was when Bugs Bunny started the engines of the “World’s Largest Airplane” in Hare Lift (FF to 2:04). With a simple push of a button, all of the radial engines were up and running. And as ridiculous as that was, in the sixty years since, starting the modern jet engine has become just as simple as that.
In the Beginning
A century ago, when the Wright brothers started up the four-cylinder engine on the Wright Flyer, they did so by hand. This was the method for the farm tractors, motorcycles, and automobiles of the time, as the electric starter was still several years away. Even had the Wright brothers had access to an electric starter, they likely would have rejected it to keep the weight and complexity of the Wright Flyer to a minimum.
Even after the electric starter became available, during the several decades following the Wright’s flight, the majority of the airplanes produced chose to reject the heavy and expensive electric starter and relied on the pilots hand-propping their new airplanes. Though it seems to be highly dangerous, it is a safe with proper training.
When hand-propping an aircraft, the person outside is the one in control, though the pilot will typically direct the sequence. The engine will then be turned over several times with the ignition off to purge the cylinders of stale air and oil, which is especially critical on radial and inverted engines. Gasoline will then be either poured directly into the intake manifold, or injected with a small hand pump in the cockpit. The person propping then checks the security of the brakes by pulling and pushing on the propeller, and then calls “Contact!” instructing the pilot to turn on a magneto. The term contact is often used to better differentiate between the calls of having ignition system on or off; Contact is used to denote Magneto (or Mag) On, and not to be confused with Mags Off.
The propeller would then be pulled through one compression stroke at a time with the magneto on. When the engine started, the pilot would then resume control of the airplane – adjusting the throttle for proper idle, switching on a second magneto, checking oil pressure, and completing the start procedure from memory.