Safety Comes First
Dave Gee | [email protected]
Propeller injuries top the hit parade
Also included in this column:
- Club training makes contact
- Does your transmitter have a throttle lock?
- To repeat: fingers in propellers equals bad
What is so appealing about propeller strikes? Sticking a hand into a spinning propeller is very popular, but I don’t understand why. Is it the pain? The embarrassment? The blood-soaked bandages?
Propeller accidents are the most common cause of injury in our hobby, despite the fact that we all know about the danger. I’ve gotten a lot of e-mail messages lately with information and advice about propeller safety. Too many pilots have had bad experiences and want to avoid any future ones.
Other countries take this “pro-strike” situation more seriously than we do. Great Britain simply did away with propellers many years ago and has equipped its flying machines with airscrews instead. Now that’s a commitment to safety!
Jerry Hahnfeld, who lives in the US where we still use propellers, wrote about the steps his local club has taken.
“The Midland R/C Modelers Club has significantly reduced the number of propeller injuries at the field by emphasizing that the only safe area is behind the propeller. We emphasize that the pilot should spend as little time as possible in front of the plane.
“After a gas or glow engine is started, the pilot should move behind the plane before tuning the engine. With an electric plane, it is important to always work from behind the propeller.
“There are three reasons that this emphasis has significantly reduced injuries in our club:
- The pilot has no reason to reach through the propeller to tune the engine or adjust the aircraft. All controls are on the same side of the propeller as the pilot.
- Most prop hazards occur at or in front of the arc of the prop. Broken parts can eject in the arc of the propeller or to the front of the propeller. Perhaps more importantly, the pilot is not in danger of injury from a plane that lurches forward due to inadequate tethering. Working behind the prop protects the pilot from the spinning propeller, broken propeller parts, and an unrestrained plane.
- If the pilot’s hand comes in contact with the prop from behind the prop, the hand will first contact the trailing edge of the prop. This often will act as a warning and result in little or no injury. Contact with the leading edge of the prop almost always results in injury—often serious. A pilot is much less likely to be injured from the trailing edge than the leading edge of the prop.
“Since we have started this emphasis, the number of hand injuries has decreased significantly.”
Jerry’s club is on the ball with its prevention program. Who knows how many injuries will be avoided because of this carefully thought-out education effort? Saving your friends from getting hurt is heroic, even if you do it by giving a talk at your club meeting. If your club has a successful safety program or maybe an unsuccessful one, a close-call story, or if you think I’m all wet about something, please let me know. E-mail or paper letters work fine. I offer anonymity or fame, whichever you prefer.
I receive reminders from readers relating that how we hold a model has much to do with the risk of propeller hits. A “hot,” ready-to-fly electric aircraft should be held from the rear whenever possible. Reaching over the propeller to pick up the model is a bad idea, whether it is a gas-powered airplane that is idling or an electric aircraft that is motionless but "armed."
There are two common situations that I hear about far too often. Some gas-power fliers like to reach through the propeller disc to tune the throttle, and some electric pilots have the motor unexpectedly spring to life when a body part is inconveniently located. Again, it isn't as though we don't all know how bad it is to touch a moving propeller.
Glider pilots are yawning now, but more of them are using electric power to get their airplanes into the air. If you're not used to having a propeller on the nose of your model, you're much more aware of the hazard.
The motors I've seen on those "powered" gliders are extremely strong. The pilots don't want to wait around for their airplanes to get to altitude. That is all the more reason to treat those blades with care.
Alan Buckner wrote in about an unpleasant incident he had, and the clever solution he uses now.
"I was working on an electric plane and managed to reverse the throttle while the motor was hot. I stopped it from hitting me with my left hand, causing some extensive nerve and tendon damage in the process, but it could have been a lot worse.
"Since then, I've been urging people getting into electrics to use a throttle-lock function whenever possible. There are a couple of ways to do this with many of the computerized systems in use now.
"The easiest method is to use the heli program instead of the airplane one, if the transmitter offers it and the airplane itself is fairly simple. You then configure the Throttle Hold function so that it shuts off the motor when engaged and disable the other heli-related functions.
"Sometimes you can achieve the same thing in airplane mode using a switch-activated throttle-to-throttle mix. Red Scholefield talked about this idea in his MA column and included the programming that I sent him."
Alan has the right idea. I like mechanical or electronic solutions that reduce the chance for trouble to occur. Sometimes I do dumb, inattentive things and it would be nice to have my equipment set up to anticipate my foolishness.
Check out Red's columns for information or e-mail him and ask for the throttle-lock attachment.
Do you want some real avoidance? Try sailplanes and ducted fans. This month's photos have a common thread, showing facets of our hobby that have little danger of propeller injuries.
The man shown launching a Rapier-powered FF model is Rob Cobb. Did you ever meet a real sparkplug-type person? That's Rob.
His enthusiasm is sky-high, and he has a great time whether his airplane flies well or not. That little rocket flew too well for the field and he had to fetch it out of a tree. You should have seen the grin on his face!
Rapier motors are the modern equivalent of Jetex, but they are lighter, simpler, and more reliable. They won't slice your finger as a propeller will, but I have explored the possibilities of mishaps. They include minor burns from the hot motor casing, the hot exhaust plume, and the electronic cautery element used for ignition.
I've learned not to touch any of those things, because if I do get burned and let out a yelp, Rob comes over and giggles at me.
Sending fire skyward on an uncontrolled aircraft requires care and good judgment. Here in brushfire-prone California, the fliers know that there are seasons and locations where these motors are not okay.
Another approach to propeller-strike prevention is illustrated by Will Woods, wearing dapper shorts, sending an Indoor Catapult Glider zooming toward the ceiling. Hand-Launched Gliders (HLGs) are great fun but are surprisingly hard on the joints of us older people.
Our bodies weren't designed to make vertical throws, and shoulder injuries are too common among serious HLG pilots. Indoor and Outdoor Catapult launch has exploded in popularity, because it offers the excitement of glider flying without the need for physical therapy afterward.
When he is not showing his skill with small, unpowered aerial vehicles, Will publishes the Black Sheep Squadron's club newsletter—one of the world's finest. He wouldn't want to risk his two typing fingers with a dangerous spinning propeller, so Indoor Catapult Glider is what he flies.
The man launching a rubber-powered Delta Dart is Captain Tom Huff, a distinguished guest speaker at the 2010 AMA Expo and commander of the Naval Test Wing Atlantic. He is also a modeler who got a kick out of flying a classic Indoor Rubber model with a propeller that is anything but hazardous.
Tom is a great person and I was delighted to get to meet him. I printed the Dart covering with his picture on it. After he flew and signed the model, we gave it to the winner of a mass-launch contest in the kids' make-and-take area.
Tom also tried his hand at indoor RC, demonstrating considerable skill with a 3-D electric model. I happened to be standing next to another distinguished man: former astronaut Robert "Hoot" Gibson (space shuttle commander, pilot, Top Gun graduate, etc.). Hoot pointed to Tom's impromptu display of indoor aerobatics and said "Now that's something I can't do."
Later I let Hoot fly an Old-Timer-style RTF, although he had never flown indoor RC. After half a lap he did better with the little foamie than I ever will. It's humbling to hang out with guys such as those.
Brace yourself for a shameless plug, not directly related to safety. That great little RTF I mentioned is a Flyzone Playmate, and I have had tremendous fun with mine indoors and out. It is an excellent trainer that can also do mild aerobatics.
The classic 1930s styling with modern radio equipment inside makes for an appealing airplane, and I highly recommend it.
—MA
Sources
- Dave Gee
Box 7081 Van Nuys, CA 91409
- Red Scholefield
- Black Sheep Squadron newsletter
- Flyzone
(800) 637-7660 www.flyzoneplanes.com
- Rapier motors (Shorty's Basement)
(740) 225-8671 www.shortysbasement.com
Transcribed from original scans by AI. Minor OCR errors may remain.
