Safety Comes First
Dave Gee | [email protected]
Test-flying new models and the AMA Safety Code
I'M GUILTY! I confess! The AMA Safety Code reads "I will not fly my model aircraft in sanctioned events, air shows, or model demonstrations until it has been proven airworthy." I'm the king of all-night building sessions, and showing up at a contest with a very freshly painted model is nothing unusual for me.
Perhaps this rule could be overlooked in the case of a 9-gram No-Cal rubber model, but I've done it with bigger airplanes too. Granted, I am not known for coldly rational decision-making, but I am not the only one who breaks this rule.
My confession was prompted by a pack of readers, led by LeRoy Cordes, who noticed more than one recent picture caption in this publication claiming that the model shown had performed its maiden flight at a big event or contest. LeRoy said it sends the wrong message, and he is right.
Flying an untested model at an event where people will gather is less than ideal. The urge to show off a new airplane or helicopter can bring great emotional pressure to make a crowd-pleasing flight despite problems that may arise. Judgment calls can lean toward "push your luck" instead of "play it safe." I have seen this tendency and I have been caught up in it.
Again, the seriousness of this situation varies with the kinetic energy of the model involved. An out-of-control free-flight Peanut Scale aircraft is not much of a hazard, but many of our flying machines have the power to cause great harm to humans.
A model's initial flight test is a delicate time in which unforeseen problems may arise. Adjustments may be required. Mishaps are common. Open space could suddenly be handy for an impromptu landing or "arrival."
Do we have the good judgment to postpone the first flight if a new model was not finished in time to be tested before the big meet? Can we make our egos secondary to an important but often broken safety rule? It looks easy from here, but it is much tougher after a late night of last-minute model building.
(Editor's note: The mention in MA of models being flown at a sanctioned event for the first time proved to be misleading. The aircraft in question were test-flown after the official sanctioned event hours, when the field was open to normal model-flying activities and test-flying was permitted.)
RC fail-safe near miss (email from Ash Nityanandan)
I am writing to report a near miss in the hope that it will save someone else’s airplane (or fingers or cat; mine escaped with only a scare). I will be the first to admit that it could have been prevented if I had thought ahead.
I successfully programmed my new Berg MicroStamp 4L receiver for the fail-safe mode with "turn gently left and throttle back." A couple of days later, I powered up my radio on the bench for setup work. Following my usual practice I set the transmitter at half throttle first, then plugged in the receiver and the Pixie-7P ESC to prevent accidental arming of the motor.
I tested the fail-safe by powering down the transmitter. It worked fine: slow left turn and no motor. Then I thoughtlessly turned the transmitter back on.
Since the fail-safe was "low throttle," the Pixie had already interpreted this as an "arming" signal. Since the transmitter was still at half throttle, my airplane took off in the basement. Minor damage and no injuries.
The ironic thing is that two good safety features combined to create a new hazard. The manufacturer said that they would add the info to the manual.
I'm always saying how much fun indoor flying is, but Ash learned that you either need a bigger basement or a smaller airplane.
Those of us who use fail-safes appreciate his hard-earned wisdom. These gizmos can save your model under certain circumstances, at the cost of one more system to learn about and keep an eye on.
Lawn mower interference concerns (letter from John McBride)
We recently had a blip at our flying field. One of our members pulled an old lawn mower out of the shed and began mowing the weeds along our crosswind runway. Meanwhile one of the best pilots in our club lost elevator and crashed into the ground while doing an inverted flyby.
After that another lawn mower began mowing around the main runway. Another member’s helicopter fell from approximately 100 feet altitude, sideways into the ground.
After discussing what had happened, we set up a helicopter on a test bench, turned on the receiver and a transmitter, and instructed the pilot to move rudder only. As he walked around the field with the transmitter, we noticed intermittent control blips, sometimes including severe action of all servos.
We came to the conclusion that the lawn mowers were interrupting the transmitter signals to the airplanes and helicopters. Please let more AMA members know about this. It is a safety concern and a threat to bystanders and pilots.
John’s note came to me with an attachment from the authorities at Muncie, Indiana. After careful consideration, AMA’s technical director and the Safety Committee chairman do not think the lawn mower was responsible for the interference. They said that unless the people at the field did detailed testing with the mower on and off, there is no way to substantiate it.
It is possible that an older mower that perhaps did not have a resistor-type spark-plug cap could produce some interference. However, it is fairly unlikely that this was the cause of the problem.
I get reports of such incidents from time to time, and seldom are the mowers able and equipped to do a proper scientific investigation of all possible sources of interference. Most of us have experienced some type of R/C glitch at some point, and the reality is that often we cannot find the true cause.
Just remember that our systems are not 100% reliable and fly accordingly. Take every reasonable precaution and maybe a couple unreasonable ones. I'll bet John made sure the mowers underwent an ignition-system overhaul just in case!
RTF park flyers and arming switches (from Marty Jasin)
Marty Jasin shares my feelings about those little RTF park flyers; they are great fun for the price! He wrote:
Just want to inform you that a ready-to-fly airplane propeller can bite pretty good. I loaded my airplane into the car before removing the battery when suddenly the throttle went wide open. Seems that another flier was using the same channel as I was on 27 MHz.
Some of the manufacturers of the RTF airplanes are not including an arming switch. In trying to remove the battery from my airplane, my little finger said hello to the propeller and shed a little skin.
This is something that could have been prevented with a switch that could have been turned off with the push of a button, as is standard procedure with wet-fuel airplanes when the airplanes are retrieved.
I fly a bunch of these models, mainly small ones, and I have a hard time remembering to turn on the transmitter first, plug in the battery last, and unplug the battery right after landing, before turning off the transmitter.
Marty kidded me for trying to save the weight of a tiny switch, but I will probably pay in blood for the extra bit of performance! Besides, my fingers have a hard time working some of the teensy switches that do come installed on these models. I told him I would see what the readers have to say about it.
Safety reminders and photos
If you use the e-mail address at the top of the column, be sure to use an informative subject line about MA or airplanes so my antispam program doesn't eat your message. Messages about "EeZee PreskriShuns" or investment offers do not make it through. For those pen-and-ink types, my address is Box 7081, Van Nuys, CA 91409. It's always a delight to get stories, comments, or corrections from them that are smarter than me.
Recent stories in this column about heat guns and soldering irons causing trouble brought many suggestions to simply leave such tools unplugged when they are not in use. That's basic, but apparently I neglected to make the point.
I have a great fear of losing my tools and equipment by fire, so I make quite sure to take that precaution before leaving my workbench. Even a faulty electrical device won't cause trouble if it is unplugged.
I almost forgot about the pictures! Sometimes it takes some convoluted reasoning to get a particular photo into the safety column, and these may push the envelope.
Walker Burr is a sharp young man, and he knows how to get the most out of his rubber-powered free-flight model. Check out the intent look on his face!
This same level of concentration can be a problem at the R/C field since it can blind us to anything beyond our models. Wise fliers use an experienced assistant to keep an eye on the rest of the world for us, and we take turns doing the same for our pals.
That portable frequency board was in use at a casual electric-powered park flyer meet. Even those lightweight models need the safety of a control board. There was no transmitter impound at this event, and nearly everyone knew everyone else, but nobody wanted interference!
Hugh Langhans is posing with one of the excellent Aero Ace RTF models. A lady from the parks department made her first R/C flight that day with a similar airplane, which delighted her and may help the local club the next time a park reservation is needed!
The Aero Aces are made by Air Hogs. They are available at toy stores or via the Internet from www.aeroacemods.com, which also offers a terrific upgraded transmitter.
That beat-up-looking Cub belongs to Don Smith, who has made many careful repairs to various damaged components. He may have been involved in the crashes also. He says that repairing a model is as important as building it since the weight gain and strength of the airframe depend on the quality of the work.
Don also said he wished he didn't have so much skill and experience at repairs. I was deeply sympathetic and know exactly how he feels.
Transcribed from original scans by AI. Minor OCR errors may remain.
