Frequently Asked Questions - 2009/08
Bob Aberle | [email protected]
PLEASE WRITE IN with your questions, since that is the only way we can keep this column format going. When referring to published Qs and As (for follow-ups), provide the number as a reference.
References to addresses and Web sites are now placed in a group, separate from the text, at the end of this column under "Sources."
FMA Direct's Cellpro Multi4 can charge all batteries
Q407: "In last month's FAQ column you went into considerable detail on the charging of very small, lightweight and low capacity Li-Poly batteries for use with micro and indoor RC model flying. When I finished reading your answer it looked like I might need three types of chargers to take care of all my electric power needs. What I would like to see is a single, sophisticated charger that could do everything. Is that on the horizon?"
A407: Progress in the micro/indoor flying arena can practically be measured in months rather than years. After only a month I learned about a charger that will work with every battery chemistry. I've already received a sample and I'm testing it. MA's "The Battery Clinic" columnist, Red Scholefield, has also been testing his.
The new charger we are both pleased with is the FMA Direct Multi4 (M4). Key features:
- Charges Li-Poly, Li-Ion, A123, Ni-Cd, NiMH, and lead‑acid batteries.
- Charge current range: 5 mA to 4 A.
- Supports one to four cells.
- Price: $79.95.
- Can charge a single Li-Poly cell at rates as low as 5 mA.
- LCD shows battery voltage and capacity as a percentage of full charge.
- Positive alarm indicates charging complete.
Many small, sub-200 mAh Li-Poly packs (two cells) omit balance connectors to save weight. The M4 can charge these packs as well as single cells. The new circuitry permits charging of low‑capacity two‑cell packs that have no balance connector.
FMA Direct offers a special cable that plugs into the M4 and splits to three ParkZone‑type connectors, letting you charge up to three ParkZone single cells (70 and 110 mAh) at once — provided all attached batteries are at roughly the same charge level. The idea is you run each battery down until the ESC cuts off the motor so they’re approximately equal. A pigtail cable is provided so you can make custom adapters for various connectors. FMA Direct also sells AC‑to‑DC supplies to power the M4 when flying in a gymnasium, field house, or inflatable dome.
You can order the Multi4 charger from the FMA Direct web site, where the instruction manual is also available.
Q408: Pacemaker interference concern
Q408: "I recently had a heart pacemaker device implanted in my chest after experiencing specific cardiac problems. I've been a long-time and active RC flyer and was concerned that the signal emitted by my RC transmitter might cause interference or a malfunction to my pacemaker. What is your suggestion?"
A408: This concern has come up several times. My advice is to contact the manufacturer of your pacemaker and ask for specific recommendations for your device. The manufacturer I contacted replied that modern pacemakers are designed and tested to be resistant to radio‑frequency interference from common consumer devices and that they are not aware of any reported instances where a standard RC transmitter caused a pacemaker malfunction. They recommended the following precautions:
- Do not place the transmitter directly over the chest or the site of the implanted device.
- Keep a reasonable distance between the transmitter (and its antenna) and the pacemaker whenever possible.
- Maintain a minimum distance of about 6 inches between the remote's antenna and the implanted device.
- Avoid standing in front of another antenna if multiple people are flying at the same time.
- If you experience any unusual sensations while operating your transmitter, stop using it and contact your physician and the pacemaker manufacturer.
- If desired, the pacemaker manufacturer can advise you specifically for your model and may be able to perform a test or evaluation.
My recommendation remains: contact your device’s manufacturer, tell them the specific radio equipment and frequencies you use, follow their precautions, and consult your cardiologist if you still have doubts before returning to active flying.
Q409: Carlos Reyes' new book
Q409: “In your FAQ #372 you mention Carlos Reyes and his RC Advisor’s Web site that included a design calculator. I understand that recently (February 2009) Mr. Reyes has released a new book. Can you tell me anything about it and where I might purchase a copy?”
A409: Carlos Reyes' new book, Model Airplane Design Made Easy, is a 206‑page book with photos, diagrams, and a detailed index. Major chapters cover fluid dynamics, airfoils, propellers, structures, wings, airplanes, power systems, design processes, inexpensive design tools, free online resources, and where to buy products. Carlos writes in a clear, often humorous style that makes the material accessible. I give it high marks and keep a copy for reference.
You can purchase Model Airplane Design Made Easy from Amazon.com (discounted price $17.95) or buy directly from Carlos (see Sources).
A410: Laser‑cut switch box from Radical RC
A410: Dave Thacker of Radical RC produced two variations of the original switch box idea. He made a box from laser‑cut plywood parts that assemble easily with CA and mount inside a fuselage so the connectors pass through to the outside for easy access.
- The 3‑pole laser‑cut switch box provides a combo switch function (like an arming switch) plus charging access.
- The 2‑pole variation functions strictly as an arming switch.
- Prices: $5.50 for the three‑pole housing and $4.50 for the two‑pole housing.
These items are inexpensive and suit larger models well (I wouldn’t consider them ideal for parking‑lot flyers).
Q411: Military fonts for decals
Q411: “I’ve seen many of your references to the Bell Inc. transfer decal paper where you can make your own decals on your inkjet printer and apply them to your aircraft. One of my problems has been finding the correct font type and size for my different scale model applications. Is there a Web site you can reference where I can download these fonts?”
A411: A reader (Jack Boone) directed me to a web site that provides military fonts and related resources. See the Sources list for the address.
Follow-up to Q381: Virtual Aircraft Museum
Follow-up to Q381: Reader Frank Pisano directed me to another excellent source for full‑scale aircraft three‑views and aviation photos. The three‑views are very detailed, and there are hundreds of aircraft available. You can print these three‑views on 8.5 x 11‑inch paper and take them to a reproduction facility to enlarge them to the size you need for modeling.
Follow-up to Q383: O‑rings
Follow-up to Q383: Frank Pisano also suggested an alternative source for small rubber O‑rings. He has had success finding various sizes of O‑rings in the plumbing section of The Home Depot and Ace Hardware stores.
Sources
- FMA Direct
(800) 343-2934 www.fmadirect.com
- Model Airplane Design Made Easy
(505) 206-1569 www.rcadvisor.com/book http://tinyurl.com/rcadvisor
- Radical RC
(937) 256-7727 www.radicalrc.com
- Military fonts
www.fonts4free.net/amarillo-usaf-font.html
- Virtual Aircraft Museum
http://richard.ferriere.free.fr
Transcribed from original scans by AI. Minor OCR errors may remain.
