Q-105: I’m contemplating my first large scale model aircraft. My initial plans indicate the need for at least 10 servos. I’ve been doing a lot of reading on this subject and have determined that I must be very conscious of my current drain from my airborne battery pack. I also gather that my choice of wiring must also be able to support the higher current levels.
Should I just be considering higher capacity batteries and heavier gage wire,
or is there something on the market that can help me with my new aircraft
project?
A-105: I am not an expert at Giant Scale or quarter scale. I do plan
on building a 1/4-scale Piper Cub Special (PA-11) for the 2005 Northeast
Electric Aircraft Technology Fair, but at a planned weight of 13-14 pounds, I
don’t think I’ll be using 10 servos as you indicated you might.
To answer your questions as specifically as possible, I did make certain
inquires. My good friend Nick Ziroli Sr. told me that his giant P-38 twin used
14 servos. He powered his RC system with higher-than-normal-capacity batteries
and employed the heavy-duty extension cables offered by his RC system
manufacturer. Nick practically wrote the book on Giant Scale, and I have to
assume he has learned a great deal throughout the years.
He went on to speculate that the modelers who fly the giant 3-D-type models,
which do hovering-type maneuvers and a lot of vertical performance, use things
such as redundant battery packs, receivers, and extra-heavy-gage wiring.
Then I put out an inquiry to several of my RC manufacturing friends and to my
surprise, approximately a week later a package arrived from FMA Direct which
contained a newly released product called Power Force Voltage Regulator (part
VRL12). Being curious, I quickly read through the enclosed instruction booklet
and realized that this new product might be just what the serious Giant Scale
flier needs.
The Power Force is essentially a high-power voltage regulator that is intended for powering RC receivers and servos in Giant Scale or simply large model aircraft. FMA Direct even claims that the device is ideal for aircraft employing dual radio systems.
Basically the Power Force accepts input voltage from 2S to 4S Li-Poly battery packs as well as from 5 to 12 Ni-Cd or NiMH cell packs. On the output side, you obtain a choice of a regulated 5 or 6 volts (which would be comparable to a four or five-cell Ni-CD or NiMH battery pack). Heavy-duty F/J and Deans Ultra connectors are provided.
This device can supply as many as 10 amps continuous which should be more than enough to handle any complement of servos that you have in mind. Status LEDs provide a quick visual indication of the battery condition.
There is much more detailed information available about the Power Force for those who are interested. Look it up on the FMA Web site at: www.fmadirect.com.