Safety Comes First
Dave Gee | [email protected]
Motor switches: the pros and cons
I received plenty of feedback from readers about my report on an electric motor propeller-strike accident. Many asked, "Why don't we use arming switches in electric models?"
The answer is that many modelers do use some method of isolating the motors until they are ready for takeoff. Some reasons for skipping such a device are:
- it costs money,
- it eats current,
- it adds weight and complexity, and
- it is hard to find switches that will stand the tremendous electrical abuse of our models.
I can accept the weight issue for extremely small aircraft, but there are commercially available switches that are designed for larger in-flight power systems that hold up just fine.
(Editor's note: There are also easy ways to set up a mix on a computer radio so that a switch inhibits throttle control, similar to the "throttle hold" function on a helicopter radio.)
Maybe I am prejudiced by the reports I read, but saving one's hand from being maimed is worth adding a switch!
While wandering the Los Angeles wholesale toy district, I found a foam Corsair ARF, complete with radio and poorly translated instructions. I let some middle-school kids help me put it together, and it was lucky that we knew how an F4U is supposed to look, because the manual was no help.
The kids belong to a local school model club, and they noticed that the airplane had no master switch. The battery pack plugs in and that's it, except for a mysterious red button on the cowling. They carefully experimented and confirmed that this button armed the motor. Therefore, you could power up and test the controls without having a live propeller. No worries about forgetting to hit the button; it won't go anywhere without that final step. I'm not smart enough to design the circuit, but it is a fine way to arrange things for a park-flyer-size model.
The instruction book did have one useful passage. It read, "Safety precautions: Do not touch the rolling airscrew in order not to be hurt." That's good advice for all of us, courtesy of a computer-translating program.
Rich Paterra is such a clever guy that he came up with a way to have a similar setup on his much fancier model while he tinkers with it. He shared the idea: "I always unplug the ESC and install a standard 4.8 volt Ni-Cd with a spare switch into the port where the ESC plugs into (this is usually the throttle channel). This way the whole ESC and motor are taken out of the equation. You can work on all of the control surfaces and any other accessories that you want to without fear of having the motor starting up on you." That is an elegant solution!
Steve Matthewson described another clever trick to help keep electric systems off when they should be off: "Put a large, thin rubber band wrapped around the handle on the back and down around the bottom of the transmitter and back up the front to the throttle lever. It puts just enough pressure on the stick to hold it down but not bend or hurt any equipment.
"I destroyed an electric helo as well as slicing my arm until I figured out this very inexpensive but effective safety item." This trick has been in use for years. It was apparently discovered by many pilots across the country, but I have decided to give Steve the full inventor's credit because of his wounds and wrecked model.
I'm a helicopter pilot myself, ya know—rubber powered, of course.
Rubber-powered helicopters, free flight, and photographs
On the subject of rubber-powered helicopters, a number of semi-witty e-mails have accused me of using the safety column in a dark plot to push free flight (FF). Some say that it is a nefarious scheme to get modelers to try "radioless" aircraft.
To those who think that I would stoop so low, I reply, "What, you just now noticed?"
This brings us to this month's photographs. Brian Furutani took that beautiful shot of Stan Buddenbohm's indoor discus-launched glider floating inside a blimp hangar. It captures the magic of aeromodeling. There it is, up in the air, no strings attached, flying!
No matter how mature or serious you are, you can feel that same thrill when a big RC aerobatics aircraft taxies out, when a helicopter engine roars to life, or when our new model makes a maiden flight.
Look at the picture of a kid launching his first airplane. He can hardly contain his excitement and wants to give the little model all the help he can as it wings into the sky.
Whether our aircraft costs a dollar or thousands, that feeling is what we are after. Getting hurt is not part of the deal, so we add careful procedures to our flight routine, but fun is still the bottom line.
Another picture shows a rubber-powered Speed model that Don Butman built. I don't know how it will do in competition, but it looks fast sitting there.
This airplane started out as an old-fashioned Guillow's kit. The 15-inch-wingspan aircraft has lightweight iron-on covering. I'll bet that the designers never thought one of their products could end up looking this nice.
Safety image and the sport vs. hobby question
Brian Chan checked in, reminding me of our recent discussion about hobby ads that show small RC models flying in residential neighborhoods. Brian sent me a link to a promotional video posted by the makers of a snappy-looking RC sport aircraft.
It is a stylish, electric-powered foamie, and the video shows some fellows getting it ready to fly in the parking lot of a strip-mall hobby shop. The pilot takes off between parked cars and proceeds to do aerobatics and low passes while a light drizzle blurs the camera lens.
Brian claimed that we would agree about this. It looked bad! Those people were utterly dependent on every part of that model working perfectly while they flew over a business district, with a busy street visible at the end of the driveway. It didn't make me want to buy one of their airplanes; it just made me wonder what other corners their business might cut if a safe image was such a low priority for their company and our hobby.
Our collective image was the subject of a note from Bob Wilson, who has been involved with aeromodeling long enough to know what he is talking about. He said that what we do is a sport—not a hobby.
Most RC pilots now fly ready-made models, and building one's own aircraft is becoming uncommon. When recruiting youngsters, Bob said that parents are sometimes turned off by the thought of their kids "starting another hobby," but that they don't mind a new sport.
Bob also mentioned the serious competitions we have, such as the Nats, in which sportsmen and sportswomen are not exactly collecting stamps.
The dreaded "sport vs. hobby" controversy has gone on for many years, and I'm not going to get caught in the middle! Although Bob makes good points, there is a solid argument on the other side as well. In my column I try to use the terms interchangeably, along with activity, pastime, and pursuit, which are also arguably proper descriptions for what we do.
Do you feel more like a hobbyist or a sportsperson? Some say that "waste of time" is a better term for my activities, but since the magazine pays me I am theoretically a professional. (Editor's note: And entertaining!) My airplanes still look ratty, though.
If you want to weigh in on this or any other subject related to our sport/hobby, please contact me by e-mail or letter at the listed addresses.
LipoLocker — battery safety
Dan Matuschek e-mailed me with information about his new product. I checked out the website and decided to give him a plug, because his invention looks good. He calls it the "LipoLocker."
It's a ceramic cylinder with a complicated-looking baffle system inside. A sand reservoir handles a fire by automatically smothering the battery while the refractory material cools and vents the gases as safely as possible.
Dan uses special ceramic clay that is resistant to thermal shock. It appears that the extinguishing system is good for a single activation. Afterward you'll need to replace the whole thing. If Dan's invention saves your home, I'll bet that you will eagerly send away for a fresh LipoLocker.
The website address is in the "Sources" listing at the end of the column. Dan has some amazing videos posted.
Traveling with batteries
I usually take a model or two when I travel, and it's often a small electric RC one. Sometimes this leads to interesting moments at security, so I appreciated an email from Tim Toutant about transporting batteries on airliners.
Tim has considerable experience in the field and he writes that spare batteries for our aircraft should be carried onboard rather than placed in checked luggage. If they are not in their original packaging, the terminals should be taped and the cells placed in baggies to prevent shorts.
The rules and standards for types of batteries, maximum weight, and capacities are too long to print here, but it would be worthwhile to check with your airline if you plan to take model-airplane battery packs with you.
The people at the security desk might be unfamiliar with the rules or your model equipment. In my experience, if they decide wrong about something they will stick with it, so have your equipment specification sheets and a copy of the applicable airline policy handy.
Sources:
Dave Gee Box 7081 Van Nuys, CA 91409
LipoLocker http://lipolocker.com
Rules for carrying batteries on airliners: http://safetravel.dot.gov
Transcribed from original scans by AI. Minor OCR errors may remain.
