Hot Props

Hot Props

Crocodiles and Propellers - Not Much Difference


Sometimes we need to be reminded just how dangerous a propeller can be. 

The first video below shows a fellow pulling a propeller through to check for nicks when the engine started and nearly took off an appendage. He said he could feel the prop brush his arm. Yikes!

In many instances, the ignition might have been left "hot" or a magneto didn't ground properly. Either one could result in the combustion of unburned fuel in a cylinder when a propeller is moved by hand.

This is why we should always treat the propeller as if touching it might cause the engine to start. In the first instance below, this was a three bladed prop on a Piper 6XT which positions your appendage close to the leading edge of a suddenly moving propeller.

The video below is from Flight Safety Australia. Please visit their site for a more complete description of the event.

 

Is Handpropping for You?

 Yes, people still handprop airplanes. It is, however, risky business. In spite of the risks, I believe you should be taught the basics of handpropping. Why? I know from experience that one day you might find yourself in a situation where you’ll be tempted to try this on your own. Doing so without prior training is not very wise. Besides, even if you elect not to handprop your airplane, basic instruction in the correct techniques will enhance your respect for the propeller. 

Find a qualified instructor who’s experienced in handpropping airplanes (he shouldn’t look like the guy in the cartoon picture above). Have that person show you the correct procedures, which include how to grip the propeller, the stance for best leverage and maximum safety, body movement and communication with the person inside the cockpit. 

Perhaps the most important rule for handpropping is to have a competent pilot, who’s familiar with the airplane, at the controls. Why? Once that engine starts, an airplane can move on its own and do a lot of damage. You don’t want this to happen to you. There are several recorded cases of airplanes taking off without a pilot on board after being incorrectly handpropped (try explaining that to the owner of the flight school).  The video below is an old FAA film showing what happens when an airplane isn't secured before handpropping. The fellow that did the handpropping left his non-pilot girlfriend in the airplane as he handpropped the machine. The engine started and..well...you'll see what happened.

 

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