SAFETY COMES FIRST!
By John Preston
"Radio failure" often occurs when the transmitter, receiver, and all the servos are just fine! Don't take those battery packs for granted! Transporting glow fuel? Read on.
As we sit down to write this column (April), spring has just arrived in the Washington, D.C. area. With the arrival of yet another flying season, we wonder how many fliers will merely blow the dust off their radios, charge the batteries, and expect trouble-free operation throughout the summer? Perhaps some will throw in a quick range check at the field to confirm that everything is operating as it did last fall! Our guess is that there will be a number of mysterious crashes at a lot of flying fields this spring that can be attributed to lack of attention to the vital link between flier and model—the radio.
The subject of radio reliability was recently drawn to our attention upon receipt of a letter from Ed Farabaugh from Fleetwood, PA. Although Ed is strictly a helicopter pilot, the suggestions in his letter apply equally to fliers of both fixed- and rotary-wing models. The following examples of possible reasons for those mysterious crashes all pertain to lack of care or knowledge of the NiCad batteries that power the vast majority of our radios. We believe that battery problems are probably the cause of 90% of cases of radio malfunction, so if you heed Ed's advice your model might survive the summer. Here is his letter.
Letter from Ed Farabaugh
Dear John,
It was with great interest that I read the May issue of MA. Since I am strictly a helicopter flier, I naturally went to Chesney's column first. Then I noticed that George Myers is now involved in choppers, so that was next. I hope you don't mind being in third place, but I read your column next. I really do feel, however, that safety should come first. Let's face it — a 12-pound helicopter with rotor tips moving at 175 mph could really "do a number" on someone if it was out of control.
I have never had a serious accident with a helicopter, but I have witnessed some pretty spectacular crashes. I have a friend who required emergency room treatment to dig a lot of basswood splinters from behind the muscles of his arm, and quite a few stitches to close up the wound! So, I am aware of what a helicopter can do to the human body.
Before I propose that you do an article on helicopter safety (I'll give you some good raw material), I'd like to make an addition to the rather lengthy (but necessary) list of safety rules in your May article.
The only rules involving the radio system itself were on frequency conflict and range testing. At least 50% of the crashes I have witnessed were attributed to "radio failure" rather than to "pilot error," and in many cases the radio failed simply because the "ground crew" didn't know enough about NiCad batteries.
Some examples:
- If you forgot to charge it the night before, don't fly.
- If your servo pots are dirty, and draining your battery, you may manage one and a half outside loops after takeoff!
- If you don't have all your connectors secure with sticky tape (or whatever), your receiver may quit at 300 feet!
- If mechanical linkage is binding, your battery may run out of fuel before your engine does.
- If you are using the wrong charger for the particular battery, you may start the day with a half-full battery and end the day with a completely discharged one.
- You can range-test your system, and not find out that you're already close to "critical voltage" until after the crash.
- Load test your battery before each flight. Expanded-scale voltmeters (with built-in load) are cheaper than a new or rebuilt aircraft. If you don't know how, talk to the local electronics expert (every club has one).
- Use your E.S.V. to establish a normal discharge curve.
- Determine your minimum "safe" takeoff voltage (under load) and add a couple of tenths of a volt for safety, and don't take off below this voltage (no matter how nice the weather is)!
- If you must fly some more, keep a spare (fully charged) battery pack in your flight box.
- If you fly more than one airborne pack, determine the time limit of your transmitter.
- If you don't understand any of the above, see your local electronics whiz. He's a nice guy; and he doesn't want your airplane through his windshield either.
The point I am trying to make is that there are a lot of ways to abuse a radio system, and some of the worst abusers are the most proficient pilots. Maintenance skills are just as important as flying skills. Dazzling the spectators is wonderful, but protecting them is more important.
Clubs should designate someone experienced in electronics to conduct classes on the subject just to point out the hidden dangers.
There have been a couple of articles in the modeling press recently on how to make a simple harness to allow the insertion of a milliammeter into the system to allow a direct reading of current flow with the system operating. Some crashes can only be prevented with this type of setup. It doesn't take very long to do a load test on a battery, and the equipment to do so is a lot cheaper than a crash. Without these relatively simple tools, there is no way to find out that a failure is about to happen.
It's easy enough to blame an uncontrollable aircraft on "radio failure," but with a little bit of effort and understanding of the system, most radio failures can be prevented. It's a lot easier than building a new model, or paying for a new windshield in someone's car—or worse!
It would be difficult to condense the above ideas into a simple, concise "ground rule," but I'll try:
"Become thoroughly familiar with all the hidden dangers inherent in radio systems, particularly with regard to electrical hook-up, mechanical linkage systems, and battery maintenance. Find an expert to get help. If you are an expert, conduct seminars on preventive maintenance."
John, I didn't mean to try to tell you how to do your job as a "safety person," but you did miss an important aspect of RC safety. The radio itself (and particularly the battery) is full of danger. Range-checking a system will only tell you that the system is working at a distance, but it isn't enough to warn you of imminent failure. An "expert" who charges his batteries and goes to the field and flies week after week, without any thorough inspections is not an expert at all. He may fly like one, but after his crash, when someone gets hurt, it isn't enough to say, "The radio failed... I couldn't control it... it wasn't my fault..."
I have been dealing with some of the negative aspects of our hobby. There are those who would label anyone who talks about safety as a "spoil sport" or a fanatic. After all, model aviation is supposed to be a hobby. It's supposed to be fun. Here's a point to ponder: Model aviation is a hobby like golf, horseback riding, skiing, hang gliding, or stock car racing. These pastimes have their dangers, too. Skiers check their equipment. Stock car drivers check their brakes and steering. Horseback riders check their saddles. Riflemen practice all kinds of safety.
Why shouldn't we check our model aviation equipment thoroughly and regularly for safety? After all, six pounds at 80 miles an hour can do a lot of damage!
John, I have a lot of fun with my helicopters. I've been at it for about five years, and I learned a lot the hard way. I've been able to help some beginners by simply trimming their machines to make them easier to handle.
I'm not a "safety fanatic," but I have prevented a lot of crashes, not with flying skill, but with some time on the workbench. I would rather be flying than checking, but I can't afford 10 or 15 crashes a year, so I keep it down to one or two, and these have been relatively inexpensive.
I enjoy your column. Keep up the good work and you'll prevent a lot more accidents than I.
Ed Farabaugh, Jr.
So there you have it. If you feel unsure about how to check out your battery packs, see your local electronics whiz or ship that radio off to the manufacturer or one of his authorized repair facilities and be safe rather than sorry.
Letter from Jack George
Dear John,
Here is an interesting item you might like to include in your "Safety Comes First" column of the AMA magazine:
Just recently a friend and his son were driving to a flying site. Their RC plane with fuel and associated equipment was in the car trunk. About 15 miles from home, as they were driving on a highway, a loud explosion occurred in the trunk. Fortunately, Jerry had a fire extinguisher in the car, and after getting his son to safety he opened the trunk lid and found the compartment enveloped in flames. He managed to put out the fire and save most of his RC gear.
It was found that the gallon, metal container of fuel had exploded for no apparent reason. There was no electrical apparatus near the fuel can. The can was about one fourth full and the fuel was at least one year old. It can only be concluded that the fuel became chemically unstable and generated a highly volatile vapor in the air.
The motion of the car generated an electrical static discharge within the can, either from fuel "sloshing" or can friction against a metal object. Whatever the cause, it is a good idea to discard old fuel which has been stored in partially-full containers for long periods. Also, fuel cans should be transported in a cardboard box, large enough to keep the can from falling over or rubbing against other objects. A rag under the can is further insurance against the spread of any spilled fuel.
Jack George
For what it's worth, our bet is that the hot Florida sun caused the fuel to vaporize and fill the trunk with fumes. Possibly an electrical fault in the car's tail light or turn signal wiring produced a spark that resulted in the explosion. It was fortunate that the car was equipped with a fire extinguisher. Is your car similarly equipped?
Have a safe month.
John Preston 7012 Elvira Court Falls Church, VA 22042
Transcribed from original scans by AI. Minor OCR errors may remain.
