Safety Comes First - 2011/01
Dave Gee | [email protected]
When things look suspicious, let the proper authorities take over
The following is an email that was received by an AMA member who is a recognized helicopter expert.
“I’m a member of AMA and I am interested in acquiring an RC helicopter or build one. I would like to ask a few questions and see if you can help me?
- Is there a supplier of an autopilot with a possibility to insert or program a route with waypoints for specific route?
- If I decide to build a helo on my own using an electric tail rotor motor, do you know of a motor with 6 HP 17000 RPM?
- Where can I find a giant RC helicopter—say over 5 feet in length—for sophisticated flying and night flying? And which helicopter has giant rotor disc diameter?
- What radio shall I use? 2.4 GHz, 5.8 GHz or 72 MHz?
- Can JR 11X be used for autopiloting?”
What would you make of this? The expert wondered if it could be for real or if it was a joke. Or maybe he was in contact with the dumbest terrorist on the planet. The expert sent a careful response asking, “What purpose would you be using this helicopter for?” The reply was “Hobby and maybe imaging.”
Time out! Our models are sanctioned for hobby, scientific, competition, and recreational use. If we want to fly commercially, there is a different set of rules. Taking a photo of your house from an RC glider is great fun. If a real estate agent hires you to photograph property for a client, you are no longer a hobbyist and should comply with local and federal laws regarding unmanned commercial aircraft.
Back to the story in progress, a bit of Internet research was inconclusive. The person was indeed a new AMA member. He had a vague company website, which could have been set up in an hour by any 12-year-old. He was probably legitimate, right? What are the odds? Time was up, and the helicopter expert knew he had to report the email exchange to the proper government authorities and to the AMA. Somehow the word even got to me. What would you have done?
Many AMA members have had concerns about whether our harmless, fun models could be used to deliberately cause harm. The Nazis had an autonomous unmanned aerial vehicle called the V-1 Buzz Bomb that carried a 1,000-pound warhead to a predetermined spot, usually a city away from the combat zone. Our models are tiny in comparison, but they could deliver some small but dangerous payload into a reservoir or crash onto a busy freeway interchange.
The current availability of autonomous flight systems is a worry to the authorities, and the AMA is working to develop policies so that we can have fun using these rigs but remain safe from a national security standpoint. Model aircraft have provided enjoyment and education to millions of people throughout the years. It’s a shame that some might want to misuse our hobby for such low purposes.
There are people in the world who want to plan and execute murderous acts against others. Given the situation, we hobbyists need to be vigilant. We are not expected to judge real modelers from evildoers, but when things look suspicious it is time to let the proper authorities take over.
I am not a proper authority on national security. But I handle the safety column, so if you want to see something here you should email or write to me.
A choice: anonymity or fame
I offer a choice of anonymity or fame. When Chris Hyden generously shared his story, he told me he prefers fame.
Chris wrote:
“I just got started in flying. Last week I went to the field to maiden my glow trainer. No one was there except my dad who doesn’t fly.
“I got everything ready and started the engine fine and put it up to full throttle while it was on a test stand to warm up, when all of the sudden my 10 x 6 prop and spinner flew off the engine and started spinning toward me. I wasn’t able to get out of the way in time.
“The prop just ripped my pants and cut my knee. (I had forgotten to dull the prop.) I found out later that the nut wasn’t on tight enough.”
Later? Chris found out at that moment that the propeller nut wasn’t tight enough! It’s hard to pick just one “most important part” on our complex machines, but the propeller nut is a contender.
Race car crews call it “wrenching” the car: going over every nut and bolt to check tightness. We do (or should do) a preflight inspection as full-scale pilots do, but it is easy to get complacent!
When the aircraft is safely in a test rig, what could go wrong? Plenty! Just ask Chris.
Pilot-station fencing
It’s nice to have some protection from a runaway propeller, and Tom Gatchell wrote to me about the pilot-station fences at his local field. PVC pipe and orange snow-fence–type barricades are often used to protect pilots. He wondered why we don’t see metal posts and chain-link fencing more often.
We discussed the cost factor, the possibility that local permits might be required for such “permanent” structures, and how the plastic type would reliably stop nearly all models. Even chain-link fencing isn’t 100% accident-proof.
I told Tom that I would ask the audience, since there are readers with tremendous wisdom and experience. Have you tried different types of fencing for pilot-pad barriers at your field? Is there some reason why metal is not used more often?
It has been said that touching a transmitter antenna to such a fence can cause range problems, but the new 2.4 GHz radios don’t have long aerials. Please enlighten Tom and me.
Gory reminders and distracted pilots
I generally don’t print gory photos, because some readers might share my delicate nature, but there are some doozies this month!
The stitched-up hand belongs to a man who asked to remain nameless. He took full responsibility for putting his hand into a spinning propeller, noting that “3 blades take 33% more bites,” but he wanted me to discuss a contributing factor in his incident.
A fellow flier at his field is known for bringing small children with him and then letting them run and chase through the pit area. Apparently one of the tykes stepped close to a model’s running engine and distracted the pilot, leading to the injury you see in one of the pictures.
Little kids “playing” in an RC pit area? Bad idea!
I wrote about this topic awhile back and am of the opinion that if small children are taken into an active pit or flight area, they should be held firmly by the hand or carried at all times. The same goes for pets.
Any creature that does not know enough to avoid hazards (and there are plenty at an RC field) should be closely supervised by adults for their own protection and the protection of others. No excuses! You are not doing your kids a favor by endangering them in this way.
There may be a few very young fliers who are an exception to this rule. On the other hand, I have met adults who needed their hands held.
If there is a local club in charge of the site, proper steps should be taken to correct such a dangerous situation. Child endangerment is a criminal matter. Either way, hurt feelings are better than hurt bodies.
Propeller-failure reminder
John Lane wrote to me about a propeller-failure incident that luckily damaged only a model.
“The plane has two 30cc gas motors with 4-bolt hubs. The owner/pilot wanted to use a 3-bladed prop both for appearance and performance reasons. He drilled the hubs to fit and brought it all to the field for a test flight.
“After a careful run-up, everything seemed okay so he took off. On the second circuit we heard a loud noise as the prop shed a blade into the fuselage. He landed with an engine hanging by the fuel line.”
Model airplane propellers take tremendous stress—much more than you might think. Running it on the ground is nothing! Imagine the forces on the blades as they transmit power during aerobatics or throttle changes.
Propellers are designed with careful stress analysis and years of experience. We should think twice before altering one!
- Few modelers have the equipment and know-how to properly test such a modification.
- In this case, the new holes removed stock from the hub and weakened the propeller enough to cause failure.
John did us all a favor with his reminder of this basic engineering principle.
(Editor’s note: Even Laddie Mikulasko, in his cool Turbo DC-3 article on page 18, doesn’t recommend altering these model components, and he shows his model with homemade five-blade propellers! It’s not worth the risk.)
Winch retrieval hazards
The RC glider fliers are seldom mentioned in this column, since their quiet aircraft have small propellers and are statistically safer than most types of models. Michael Morjoseph beat the odds, but not in a good way. He kindly shared a photo of what can happen when a winch retrieval line gets tangled around your leg.
I’ve seen how carefully glider crews handle these systems, but somehow there was a misunderstanding at the field that day. In the instant before the winch was shut down, Michael was badly cut.
Those tow rigs can be very powerful, and it is easy to see why the pilots treat them with such care.
Transcribed from original scans by AI. Minor OCR errors may remain.
