Safety Comes First
Gary A. Shaw
Box 461, Lovell WY 82431; E-mail: [email protected]
SAFE ATTITUDES: Radio Control (RC) flying can be fun, fulfilling, and even scary on occasion, but for the most part we strive for the enjoyment the hobby has to offer, not the stress.
What's unique about this hobby/sport is the variety of answers you'll get from modelers when they are asked why they participate in it.
For many, enjoyment is building something unique then seeing if it works as intended; for others, it's a sense of accomplishment and a feeling of pride when an unproven design finally takes to the air. For many others, modeling is just making friends at the field, hanging out, and having a few laughs.
So why did I state that modeling could be scary, and how does attitude play into the situation? Let's start with beginner fliers and the often observed out-of-control scenario.
Nothing is less fun than having an airplane in the air while trying to keep an eye on a semicontrolled model. Flying an airplane while simultaneously watching a beginner fly a high-speed pass down the runway is even worse.
If you're on the line when the beginner's airplane flies by, you'd probably be lying if you said you didn't step backward a few feet or duck!
What's the fix? Fly with an instructor whenever possible, and consider the use of a buddy box—simple tools to ease the effort of training and a safety net to those who share the field with you.
The following was provided by a modeler who took a hit in the shoulder after a scenario developed that was similar in many respects to what I discussed previously. Let it be a lesson learned.
"As it frequently happens, some of our newer students had come to the field with airplanes ready to go, in search of an instructor. I, on the other hand, just showed up to fly my airplane and have a good time.
"One of our more-accomplished and longtime fliers was helping a student practice figure eights and general flying, but had opted for the transmitter hands-off method of instruction rather than the available buddy-box method.
"Flying three or four mistakes high, the student was doing well, but when he started flying passes over our runway, and only one mistake high, the student lost orientation a couple of times and went behind the flightline.
"Each time the instructor grabbed the transmitter and corrected the airplane's heading, but the dozen or so other fliers (plus some support staff) remained alert to the situation, which normally would not be the case with students flying.
"Each of our four flying stations has an eight-foot-long fence behind it. If I fly when all of our flight stations are filled, I like the option to stand at one end of the safety fence, so I can step back in the event that I spot an errant airplane heading toward the flightline during takeoff or landing.
"On this particular Sunday, because of all the activity in process, I stood in what I felt was a more-prudent-for-the-occasion safe spot. As it turned out, apparently I was mistaken!
"As I practiced lazy eights in the sky, our student was back to doing one-mistake-high passes over the field. He lost it behind the flightline again, and the instructor had to grab the controls, but this time it was a moment late and the airplane headed for the pits!
"The airplane floundered and bobbed as the instructor grabbed the controls and tried to keep the airplane from hitting grounded models and people in the pit area. The airplane headed toward me from behind and the right wing hit me across the shoulders. The airplane then spun to the ground and broke.
"I continued on to do two more lazy-eight laps in the sky as members ran up and asked if I was all right. I then decided that maybe I should land my airplane and fully assess the situation before I 'freaked out' and did something to my own airplane.
"After landing my airplane safely, the instructor apologized, the student appeared markedly disturbed by the occurrence, and I decided to call it a day. Later that evening, I felt the hit I had taken across the shoulders but decided it wasn't so bad, especially considering what the consequences could have been!
"A day or two later, I ran into that instructor at our local hobby shop and we discussed what had happened. This flier felt that while this accident was unfortunate, it was part of the 'risk' we assume while at our flying sites.
"He claimed to not like the buddy-box system of instruction and that he and others had all learned with the transmitter hands-off method and everyone had learned how to fly with no one ever being hurt.
"I also learned on the hands-off method, but after using buddy boxes with students, I can attest to how much more quickly an experienced pilot can regain control of an airplane should the need arise.
"I (and others who later told me) felt that the instructor should have continued having this student practice up-high flight control, especially after his earlier incidents of losing control near the flightline.
"The risks this instructor was taking were not appropriate to the busy field conditions of that day. If this instructor had been alone with only the student, the potential for moving others into harm's way might have been lower.
"Safer equipment was on-site and available. The instructor thought he was flying/instructing safely, but was he? Because no one appeared hurt, did an accident take place? Should others at the field have requested the training to stop after the first incident of losing control? Should I have been standing exactly in front of my flight station? Was everyone present not displaying the proper safety attitude?
"Maybe 'yes' to all."
Vibration Woes: In the past, I've advised modelers to coat the electronic insides of some large servos with epoxy to prevent vibration cracking of components and failure in flight.
The issue at the time stemmed from manufacturers' lack of the use of circuit boards with integrated components, rather long diodes, and other stuff stuck out of boards and highly prone to vibration/solder-cracking damage.
As time went on, most manufacturers corrected the problems they encountered by integrating components with their boards, thereby reducing vibration damage.
A recent letter described a similar problem with the larger servos. The fix is to coat the nonmoving components with epoxy, taking away their ability to vibrate or break.
"I've been an avid modeler for the last 31 years. I have a Giant Stinger that is approximately 3½ years old. I've stored it dry under normal conditions for North Alabama.
"A few weeks ago, after charging and checking the receiver batteries, I turned on the radio and found that the 1/2-scale rudder servo no longer worked. It worked fine the last time I flew it last year.
"The rudder servo is mounted aft in order to minimize linkage length. Two identical aileron servos in the large foam wing still appeared to work fine. I replaced the rudder servo with an unused, virtually identical servo, which I had stored in a plastic bag in my office for the last 3½ years.
"Last week when I flew it, I landed and taxied back. I picked up the airplane and noticed that the rudder servo no longer worked. I've checked the servos and have found cracked circuit-board leads on the power transistors that drive the servo motor.
"I think it's apparent that there is an age-related problem with the solder used to mount these components that apparently leads to cracking of the solder when subjected to vibration after time. Amount of use, as best I can tell, is not a factor since I haven't flown this airplane that much.
"This observation is also substantiated by the fact that the unused, office-stored servo failed after one flight. I doubt that I have more than 30 flights on the Stinger since I built it.
"The 1/2-scale aileron servos apparently haven't been affected yet, given that they are not subjected to the same vibrational loads as is the plywood-coupled rudder servo.
"Two standard-size elevator servos mounted in the same location as the 1/2-scale rudder servo are still working fine, as are the other standard-size servos in the airplane. The airplane exhibits the normal type of vibration associated with a 1/2-scale, two-stroke gasoline engine.
"All servos are mounted using the vendor-supplied rubber grommets. I probably have at least 40 of the standard (smaller) servos and have never had one fail. Some of these smaller servos, which I'm still flying, are at least 15 years old or older.
"I think the obvious difference is that these smaller servos basically consist of a small IC which does not have the vibrational moment found in the power transistors required by the larger motors in the 1/2-scale servos.
"Before I found the failure source, I called the manufacturer and asked them if they knew of any generic problems with these servos. The answer I received was no. After seeing the cracks, I phoned and asked them if they knew of any generic problem. The answer I received was no. After seeing the cracks, I phoned on giving them another telephone call. I've never seen this happen in this hobby, but I think recall would be most appropriate, given the serious nature of the defect.
"Based on those findings, I would strongly recommend that modelers using these particular servos, and other servos using large, unpotted (unsupported by something like epoxy) power components, discontinue their use. Needless to say, a large 30-pound model carrying 20 ounces of gasoline could be dead in midair. I also feel extremely lucky to have found these problems.
"'Nuff said! Check your servos frequently for vibration damage!
Until next month... mg
Transcribed from original scans by AI. Minor OCR errors may remain.
