I often lament the passing of the era when ordinary people met challenges head on with a sense of adventure and excitement, as opposed to the modern day, when everyone seems afraid to go outside without a helmet and safety glasses. Therefore I don’t usually jump at the opportunity to give unsolicited safety advice. However, it’s a fact that model engines are dangerous, and I haven’t added an article to this website in a long time, so let’s talk just a little bit about engine safety. I’ll try to address the issue in a way that you don’t hear every day.

The first thing I want to point out is the most obvious one. Spinning propellers fly forward. If you’re tuning an engine and it gets too lean it may backfire and reverse its direction of rotation in a fraction of a second, causing the propeller nut to come loose. When this happens the propeller doesn’t reverse. It just keeps spinning, comes off and flies forward. Sometimes it strikes the ground immediately and breaks, and the pieces go generally forward. So what you want to do is move behind the propeller as soon as possible after starting the engine. Don’t tune your engine from the front. Don’t rev the engine while you’re in front. Don’t point the front of your plane at other people while you’re tuning it. It’s a simple rule, and it makes sense, and I see countless youtube uploaders violating it every time they start an engine. That really bugs me. They start the engine and stand right in front of it while talking about how smooth it is or how good it sounds. The first time you see an engine backfire and the propeller fly off, you’ll start moving around to the back without being told.

The other thing I’ll address is habit, and how you may expose yourself to risk even if you have good habits. When you start running model engines you will develop a set of habits to keep yourself safe. Early on, I was kind of freaked out by the whirling propeller, so I started performing an exaggerated reach around the propeller to disconnect the glow plug battery. This is a good habit that I still practice. I will reach around a 10 inch propeller as if it was 20 inches.

My brother in law who was a human factors engineer in the Air Force taught me the term Negative Transfer. It refers to a situation such as driving a car with an automatic transmission after being in the habit of driving a stick shift. Your left foot reaches for a clutch pedal that isn’t there. The other way this tendency manifests is by derailing your chain of habits when the situation changes slightly and you are exposed to a stimulus for which you haven’t developed a response.

I’ll give you my best example. I used to read in the magazines about engines that were installed upside down on the airplane. A lot of column space was devoted to this topic, because a lot of guys had issues with fuel siphoning, difficult starting, and difficult tuning, so I decided to install one inverted on a Telemaster just to find out what all the fuss was about. I gave the example two paragraphs ago of making an exaggerated reach around the propeller to disconnect the glow plug battery. That’s a great habit, and it has contributed to my overall safety. But when I started the inverted engine the first time, my habit went right out the window because my stimulus input had changed. I looked at the engine running, and I looked at the battery hanging down from the glow plug, and I reached right through the propeller to disconnect the battery. I heard a grating sound, and the propeller ground a patch of skin about 1/2″ x 1/4″ off of my right index finger. I didn’t get a solid prop strike. It was just the end of the blade hitting my finger repeatedly. I still have the scar.

I’m sure that as you look for information about model planes you will encounter lots and lots of safety advice. Don’t expose yourself to paint fumes. Don’t power up your propeller, (wet fuel or electric) without securing the plane, don’t use greasy fingers to handle a plane with the engine running. These are all good tips. I just wanted to alert you to something you may not read elsewhere. When you change one little thing, or try something entirely new, watch out because your habits may desert you when you are counting on them. Stay alert for that.