Radio Technique
George M. Myers
This column will address methods of performing routine and/or preventative maintenance of RC systems, including functional and specific test and inspection procedures. It is my intention to review and report on test equipment useful to the modeler who is neither an electronics technician nor a test engineer, and who presumably is interested only in preserving the reliability built into his RC system by the manufacturer. I will also comment on professional building techniques which permit more flying performance per hour and dollar invested.
As an initial offering, let's look at some fundamental tools that can make your inspection/maintenance task easier. Start with a table and chair of comfortable height, and a strong light. You can't fix anything you can't see, and you are certain to miss a lot if you try to do it all in your lap. You will also drop a lot of small parts, and therefore waste a lot of time looking for them. Cover your working surface with a piece of soft cloth, such as a worn sheet. This will capture a lot of things that might otherwise go bouncing away. Make your work table large enough so that you won't be knocking everything over when you reach for a tool (48 in. wide by 30 in. deep is a good size). If possible, have drawers to keep your tools and supplies in, to avoid the scratches you get when you set one thing on another. Train yourself to keep the tools in the drawer, rather than on the work surface. If you are like me, this will be harder than paying your income taxes, but persist anyway.
The next tool is a magnifying glass. The electronic supply houses offer binocular lenses mounted on a frame which you wear like a hat. I find these very useful if they have a 3X magnifying power. You are able to see around the sides of the magnifier, and below it, without touching it. This makes it possible to do practically everything in a normal way, yet get a magnified image whenever you need it, merely by looking up.
Next on the list will be an assortment of small screwdrivers, both cross-slot and conventional. Keep them clean and sharp. Nothing degrades the appearance of a piece of equipment faster than a bunch of screws with damaged heads. Practically all damaged screw-heads happen because someone tried to drive it with the wrong size blade. You may not realize it, but screwdrivers have specific sizes, just like wrenches. Very few people will try to turn a 9/16" nut with a 5/8" wrench, but practically everyone tries to turn a No. 1 cross-slot screw with a No. 2 screwdriver. A common simple test is to place the screwdriver in the slot; the screwdriver should fill the whole slot. Forcing it doesn't work; it will overstress the tips, and the blade will break at the same time the screw-head will feel the same overstress, and the slot will fail. Think next time you are tempted to use the wrong size screwdriver. Buy a set of so-called jeweler's screwdrivers or a general-purpose assortment from a hardware store or chain store like Sears. Fill in special types as you find you need. Look carefully; a magnifying glass will help you see what a properly sharp tool looks like, facilitating the removal of burrs. You may find the manufacturer has let us down.
Buy an Arkansas Hard Oil-stone, and an India stone or two. The Arkansas stone is a white piece of marble that is useful for putting a fine edge on tools. It is available in a piece that measures 1/4 x 1 x 3, and is kept wet with oil whenever it is in use, to keep it free of metal particles, and sharp. The India stone is a red rock, usually available in a 1/4 x 1/4 x 4 and a 1/4 diameter x 4 size. India is a little coarser than Arkansas stone, and you should use it for heavier cutting. Get both sizes. Use them to keep your screwdrivers sharp. If you think I'm overdoing this screwdriver thing, think of all the screws you've seen spoiled in your lifetime. Dull tools, or the wrong size tool, got each and every one of them.
OK, now you are all set to take a No. 2 screwdriver (the most common size). A simple test is to place the screwdriver in the slot and look at it. The screwdriver should fill the whole slot, without forcing. If it doesn't, you will overstress the tips of the blade and they will break. At the same time, the screw-head will feel the same overstress, and the slot will fail. You may not realize it, but you are so strong, and the bearing surface of an improperly fitted tool is so tiny, that the stress you create on that surface is greater than the stress that the Empire State Building puts on Manhattan Island. Think of that the next time that you are tempted to use the wrong size screwdriver. Buy a set of the so-called "jeweler's" screwdrivers, and a general-purpose assortment from a hardware store, or a chain store like Sears. Fill in with special types as you find the need for them. Look at them carefully with your magnifying glass, while they are still new, to see what a properly sharp tool looks like, and to facilitate the removal of any burrs if you find that the manufacturer has let us both down.
Radio Technique
OK, now you are all set to take something apart. Is that going to void a guarantee? Do you care if it does? We all know that a large percentage of guarantees aren't worth the paper they are printed on, but not in the RC business. Practically every RC item is backed by a guy who started out doing his thing for himself, and he cares about his customers. In addition, you are prohibited by Federal law from modifying a transmitter in any way. The reason for this is that the RC bands are very "narrow" in terms of electronic characteristics, which calls for careful tuning with precise equipment, to remain legal. Therefore, about the only legitimate reason that you will have for opening a transmitter case is to change the battery, if you have a dry-battery type. Leave the rest of the inside of the transmitter alone. This leaves you with the equipment that you don't normally hold in your hands, and that's plenty. Most of your troubles will come from one of three factors: crash damage, vibration damage, and wear. If you know what to look for, you can find it before it causes an in-flight failure.
Don't make it worse. This motto is followed by every good technician. You should follow it also. Every time that you open up your equipment you run the risk of putting it back together in a wrong way. Since I am assuming that my readers are not technicians, I also assume that you won't have the help of all the nice manuals that technicians have, with their parts lists, exploded views, test procedures and operating characteristics. Therefore, a sharpened pencil with a pad of paper is one of your most useful tools. Make sketches of the way things are, before you take them apart. Then make sketches of the way that they come apart. Identify mating parts with tape, paint or other marks. Put all of the pieces into a secure container, such as the plastic containers that foods and drugs come in. Obviously, you should make sure that they are washed clean before you use them. Label the container with the name of the contents. There's nothing so frustrating as reassembling four servos, only to find a screw on the bench that belongs to one of them. This paragraph must seem juvenile as you read it, but if you ever get into a professional shop, you'll see that they do everything I'm telling you.
I'm going to end this segment of what I visualize as a series of monologues by referring to a product that has collected a lot of attention in the modeling press lately, the MISSION Industries, Inc. ELITE LIFE Automatic Battery Analyzer. This device places a resistive load on either an airborne battery pack or a transmitter battery pack. It monitors the voltage of the pack, and disconnects the load when the theoretical end point of the discharge is reached. By referring to a chart supplied with the unit, the user can evaluate the performance of his batteries relative to an average set of new batteries.
Ever since this device hit the market, there have been reviews of its performance followed by questions from confused owners. These questions point up one fact about test equipment: it presents more questions than answers. You have to interpret the data the equipment gives you. In order to do that, you have to learn more about the equipment, and about the equipment being tested. That's a constant fact in the test business.
Now, without going into a full analysis of the kinds of test data that people are acquiring, let me say this. The most important thing you can learn from this piece of test equipment is whether or not anything has changed. If you perform a test on your equipment when it is working correctly, and then log the data carefully, you provide yourself with an operating characteristic that you know is normal (remember those operating characteristics in the manual you don't have?). Later, when you find that the equipment is operating differently, you have a clue as to what the trouble might be.
The most important test tool you have is your brain. If you interpret your test data correctly, you'll be able to maintain your equipment correctly. See you next month with some tips on simple performance checks that you can make and record on your properly operating new equipment.
Transcribed from original scans by AI. Minor OCR errors may remain.
