Radio Technique
George M. Myers
SINCE THE COLUMNS on propellers were published, I've received a little flak concerning misuse of an electronics column. Sorry, folks. I've been trying all along to treat problems that bother the novice, in a simple and (hopefully) interesting manner. From letters and personal testimony received, I've succeeded most of the time.
I fully realize that the column is in the nature of a public trust, insofar as I am constrained to present complete and accurate data, and to avoid misleading statements as much as possible. To this end I write only about things I know and use, and in addition it is my custom to submit each column to proofreading by novices and disinterested parties (such as co-workers at my job) before turning it in. In this way I can determine whether or not it is possible for normal people to understand my message. As for the subjects I choose, anything related to the technique of radio-controlled flying of model airplanes is suitable for the column, but the editor prefers me to stick closer to the subject of electronic maintenance. This I do, but with the thought in mind that my readers are not electronic engineers or technicians, and therefore have neither the tools nor information to become service-men.
MODEL AVIATION has avoided product reviews so as not to give any impression, even inadvertently, that said product has been singled out for approval as the "official AMA item." Therefore you will not see them here. This does not preclude news reports of significant new trends or techniques in the hobby, however, and my Variant and Cannon micro reports fell in this category. It is also permissible to report on personal experiences with commercial products, and the Digivue tachometer, Astro Flight Analyzer/Charger, Fox tuned pipe, and Robart Super Pumper reports suited this criterion. I intend to discuss some specialized test equipment in the future, which will be available either as kits or built-up. These discussions will emphasize the application of the equipment to solving problems, or will demonstrate useful modifications, rather than being concerned with building time, relative completeness of the kit, clarity of instructions and other aspects that are the purview of a kit review.
This may seem like an over-reaction to criticism, but if it helps clarify the intent of the column and inspires you, my valued reader, to continue reading the column and writing me letters when you have constructive criticism or material you would like to see in the column, it will have served its purpose.
WRAMS Show: This year every manufacturer is thinking small. The Dunham plastic parts of the Cannon micro servo have appeared in the Ace, Litcom and Mathes lines that I know of, and others are considering similar products. Second generation products have already begun to appear, such as the Ace micro servo, which features their 544 chip and a different motor than Cannon. Receivers have been redesigned and repackaged, and the advent of CMOS technology has reduced decoder current requirements to the point where the new GE 100mah batteries are practical for one or two flights of the micro systems between recharges.
Variant is still with us, this year on 72MHz with all the power that's legal (750 mw) but without the two power levels that are used on 27 MHz, to gain parity with all the "good buddies" on CB. Using Variant as the example, we see the other significant trend, a move toward adding optional servo controls to the top-of-the-line transmitters. RS Systems, Variant, Royal and Kraft showed examples, and there may have been others that I missed.
Another trend that is taking hold is offering of very cheap 2- and 3-channel systems, usually with dry batteries (not supplied). While this isn't new, everybody's doing it now. Purchasers of these systems would normally be suspicious of "what's been left out," and that's healthy. Even so, I recently bought a Cox/Sanwa 2-channel system because the whole thing cost less than a flight pack kit, so I thought it might be a reasonable item to risk in 1/2A racing.
At this writing, it still seems like a good idea, since I have quite a few nicad packs to use with it. The novice might be dismayed to find himself buying $7.50 worth of alkaline batteries before he can turn the set on. Regardless of the power source, the transmitter power output is remarkable (more on that later) and the rest of the system works as well as any I own. Friends who own the Hobby Lobby low-priced unit report good results with it, and the same can be said of some World Engines systems seen hereabouts.
These small systems will provide an entry to the hobby for large numbers of teen-agers, and they will inevitably become the subject for articles on upgrading them by conversions to nicads, adding additional channels, adding meters, adding charging jacks and buddy boxes, adding servo direction and span controls, etc. In fact, Ace RC already has a neat case with two-axis stick available for the Cox/Sanwa, and Robart showed a simple mixer that connects the two sticks in a way that mixes the action into the conventional two-axis system. Look for articles in this column on these conversions. If you've already done it, why not show us how?
Since the items that wear most are servo motors and potentiometers, the Aquilla servo by Aerotech Electronics, Box 116, Lincolndale, NY 10540, may be setting a trend. It uses an opto-isolator and a shaded disk in place of the usual potentiometer resistor and wiper. This should be essentially maintenance-free (leaving me one less thing to write about). Now, if someone finds a way to use printed circuit motors with some form of high frequency oscillator, motors will get smaller, lighter and require less maintenance. Next year, perhaps.
Before leaving the subject of the 1977 WRAMS show, it would be fair to mention that there was also on display an endless quantity of new kits, engines and accessories. If you've never attended one of these shows, you should. It gives you a chance to see new things, meet new friends and develop anemia of the wallet.
George M. Myers, 70 Froehlich Farm Rd., Hicksville, NY 11801.
Transcribed from original scans by AI. Minor OCR errors may remain.
