Author: Bob Aberle
Edition: Model Aviation - 2004/12
Page Numbers: 82,84,86
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Frequently Asked Questions-2004/12

Bob Aberle

E-mail: [email protected]

This is the ninth monthly column in which I try to give the best possible answers to questions that you write in or e-mail to me. Each question is given a sequential number for identification purposes. Because space here is limited, part of this column will be published and spillover material will be posted on the AMA Web site at www.modelaircraft.org/mag/faq/index.asp. All questions and answers are posted on the Web site. Let's start!

Q72

"Last month in Q65 you talked about the fact that the popular AstroFlight Whattmeter would not operate below 4.0 volts. You referenced a modification that would permit such use. You also said the following: 'If enough people show an interest, Bob Boucher of AstroFlight might offer a meter specifically for this application in the future.'

Well I have good news: AstroFlight just announced a new version of their meter. Would you please verify that fact?"

A72: That's progress for you! I contacted Bob Boucher and he immediately shipped me one of his new AstroFlight Super Whattmeter IIs (item number 101). It is shown in an accompanying photo.

The meter is shipped with the excellent AstroFlight Zero Loss connectors, but since they are not standard in my shop I replaced them with APP connectors. Consider using adapters that will bridge the gap from one brand of connector to another.

Notice the extra cable exiting the meter case — that is the new addition. When you want to read less than 4.0 volts, you attach a standard four-cell receiver battery pack to this cable. After you do that, the meter will read voltage almost down to zero.

Bob also improved the resolution so that instead of the meter reading current to 100 mA, the new version reads to 10 mA. Now one meter will handle all of your needs, even for parking-lot and indoor micro-flying.

For more details and price information, go to www.astroflight.com. When the home page comes up, click on the photo "Digital Peak Chargers," then select Super Whattmeter.

Q73

"I'm looking for an add-on device that will mix two channels for elevon control, like on a flying-wing aircraft design. I heard that someone is offering a device, such as this, that includes several other functions, like a lost model alarm and an audible battery checker. Could you help me locate this product?"

A73: I found what the reader was asking for purely by accident. I monitor the E-Flight Digest and the SFRC nets every day, and I saw a reference to a company called FirmTronics RC Products. I looked up the Web site (www.firmtronics.com) and found the accessory item the reader wanted, plus several other products that sounded interesting. I have no firsthand experience with their equipment, but it appears worth looking into.

The device the reader inquired about is called the WingMax. Details:

  • Weight: 6 grams
  • Price: $24.95
  • Functions: onboard mixing of two channels (for flying-wing and/or V-tail operation), in-flight low-battery-warning alarm, and a lost-aircraft warning alarm if the transmitter signal is lost or turned off.

FirmTronics also offers:

  • PathFinder LMA: airplane locator and low-battery alarm
  • Servo reverser (for use at your receiver)
  • DigiFailSafe: allows programming of servo positions in the event of a lost signal or interference

I hope to obtain several of these devices to review in the near future.

Q74

“I recently experienced a flying-site separation problem where two local clubs were operating from flying fields in very close proximity to one another. To help resolve this problem I was advised to look up AMA document 548 ‘Procedure for RF Interference Testing Between Model Sites’ (reference this specific AMA Web site: www.modelaircraft.org/templates/ama/PDF-files/548.pdf).

Well, I did and it appears that this test procedure depends on a device referred to as a ‘Glitch Detector.’ The only problem is, there is no reference as to what this device is or where one could buy it. Can you help me out?”

A74: As a longtime member of the AMA RC Frequency Committee, I was aware the document was in preparation, but I hadn't noticed the released version until you mentioned it. I looked up the reference to the Glitch Detector and then investigated further.

Options for obtaining a Glitch Detector:

  • Original design: George Steiner developed the Glitch Detector about 10 years ago and published a construction article in the April 1994 Radio Control Modeler magazine. He offered assembly kits at the time. Although kits are no longer available, George recently indicated he has some PC boards remaining and will give them away for the cost of postage. You will need to purchase parts separately. Contact George at [email protected].
  • Commercial unit: Schulze (Germany) makes a "glitch counter" called the blinki-mc4. Icarus Inc. of Canada (www.icare-rc.com) sells it for about $45 US. Details and photos are at www.schulze-elektronik-gmbh.de.
  • Receiver-based counting: Some newer receivers (e.g., FMA Direct's Flight System receivers FS5 and FS8) have built-in glitch-counting capability. A detailed review appeared in the November 2004 issue.
  • Updated Steiner unit: Dan Williams, AMA District II frequency coordinator, updated the Steiner Glitch Detector with a new microprocessor, making it easier to use and calibration-free. Dan is making several units for each AMA district.

When you have a flying-site separation problem, contact your AMA district Frequency Coordinator (listed at the top of the president's column in the “AMA News” section each month). The coordinator can loan a Glitch Detector and coach you on how to use it to solve your problem.

Q75

“Although I enjoy building and flying RC models, I still like to try my hand at some ‘non-RC’ models, like Free Flight, rubber power, and towline gliders. Most of the magazine advertisements are RC oriented. Can you recommend any literature or catalogs that concentrate more on the ‘non-RC’ areas of our hobby?”

A75: I still fly a free-flight model or hand-launched glider on occasion. I started in the hobby in 1950 flying free-flight models and won many contests as a teenager before getting actively into RC. I understand that most hobby-magazine advertising today concentrates on RC, but quite a few businesses still specialize in non-RC model aircraft.

One good source is Peck-Polymers. Their 50-page catalog includes:

  • Peanut and walnut-scale rubber-powered models
  • Sport rubber-powered models
  • Solid-jet fueled aircraft and motors
  • Hand-launched gliders
  • CO2 motors and accessories
  • Tiny electric motors
  • A variety of hard-to-find hobby supplies

You can obtain a copy by contacting Peck-Polymers:

I realize other companies provide similar catalogs. To be fair, send me a copy of your current catalog and I'll list it in a future column.

Q76

“I recently blew the dust off my old RC model aircraft and RC systems. They were put aside when I went off to college. I now would like to introduce my two little boys to this wonderful hobby. The radios I have date back twenty years or more and operate on AM. Will I be permitted to use these radios at AMA sanctioned clubs or events? Are there any FCC rules or regulations that prohibit the use of AM radios?”

A76: It depends on your transmitters. Until March 1982, seven RC channels were available on 72 and 75 MHz. Around that time the FCC granted 50 new channels between 72 and 73 MHz for model aircraft. By 1987 the older channels were being phased out and by 1991 we used only the 50 new, more closely spaced channels. That change required the development of narrow-band RC equipment.

A few important points:

  • There is no regulatory distinction between AM and FM for model RC; FM is predominant but AM systems still exist.
  • The main issue is transmitter bandwidth. Older AM systems may broadcast a wider signal than current narrow-band standards allow and could interfere with adjacent channels.
  • During the phase-out/phase-in period, older transmitters had to be inspected, adjusted, or retired. Acceptable transmitters for narrow-band operation were given a "gold sticker." If your old transmitter lacks that sticker, it likely needs upgrading.
  • New equipment sold since 1991 has been narrow-band compliant, whether AM or FM.
  • Major manufacturers rarely offer checkout-and-upgrade services now, though independent service centers may still do so.
  • Older equipment may also have age-related issues (corroded wiring, dirty potentiometers, etc.) that can be costly to repair.

Given that many basic new RC systems (with batteries) can be purchased for under $150, my recommendation is to retire very old equipment and buy a new system to introduce your children to the hobby safely and reliably.

Transcribed from original scans by AI. Minor OCR errors may remain.