Radio Control Electric Flight
Information and Guidelines
for entering the exciting world of
Electric Powered R/C Flying
The following information is presented to help any R/C Modeller get started in the interesting field of Electric Powered Flying. It is not intended as a scientific or academic treatise but rather a simple compendium of data, knowledge from the authors experience, and helpful jottings from our research of appropriate journals and magazines.
The writer conveys no responsibility nor accepts any liability for the interpretation or use of any of the following information.
This document is broken into 5 parts
Part 1 - Introduction
Part 2 - Understanding power requirements & motors
Part 3 - Understanding batteries
Part 4 - Construction considerations
Part 5 - Conclusions
ABOUT THE WRITER
Phil Langton is a 30 + year radio control flyer who has had an interest in model flight since early pre-teen years. Like many modern modelers he started in control line modeling transferring to radio in the 1970’s when proportional control equipment became relatively affordable. His decades of employment in the Lift Industry and related electrical motor knowledge burnt a deep conviction that “electric” instead of “fossil fuel” powered radio control would one day be a reality. The Australian Lift Industry had a world wide reputation as innovators with one locally owned company developing out-runner motors for lifts in the 1980’s.
It’s no great surprise that with this background the writer has turned his passion for radio control model flying into a quest for “doing it electric”? After all watt alternative is there?!
If you need help, please send me an email via this link
RUMORS & MYTHS
My journey into Electric R/C Flight is littered with lessons learnt the hard way. Much advice although given with sincerity and good intent did not always help in the learning experience. So, although I have found the info herein appropriate for me, the reader must test all things for him/herself and use only what is suitable for their own needs.
The following quips and statements characterize how many modelers view this subject!
1. Electric Flight is only OK for Gliders and slow, small high wing planes.
Response: Bunkum!! Anything You can do I can do as well and maybe better!
2. Electric Flight is expensive.
Response: It can be, but it doesn’t have to be. IC Pylon Racing and Competitive Aerobatic flying can cost “an arm and a leg”too if that’s your bag.
3. Electric Flight isn’t up to Sport aerobatic, competitive aerobatics or helicopters.
Response: Just plain wrong. There is a growing E.F. presence in all areas. In fact it is reported that an electric model won one section of the World Scale Competitions in the USA, in 2002. Since then many electric powered models have been “placed” in World Competitons.
4. I’ve always been afraid of electricity.
Response: Fair enough, high capacity, high discharge battery packs must be treated with much care and respect. Any fuel cell whether fossil or electrically based is a potential safety risk. It’s a good illustration of the saying “Fire is a good servant but a bad master.” However, proper care and safety is vital. It’s important to say right here that charging of any battery of any type inside motor vehicles is dangerous and should not be done.
5. There isn’t much equipment, kits or ARF’s for electric.
Response: Wrong, wrong, wrong! It’s the fastest growing section of the hobby, just take time to notice all the gadgets and gizmos appearing on the local Hobby Shops shelves and walls.
6. There aren’t very many people into ‘electric’. It’s only for the fringe technocrats!
Response: There are more people learning to fly using electric powered trainers today than the traditional IC powered Trainers. Trouble is, they are buying the cheap park flyers and bypassing the proper “Club Scene”.
But at the club level a growing percentage of members are including electric models in their fleet. At some clubs we are seeing large scale permanent charging stations powered from the 240 volt mains supply.
7. All batteries are the same!
Response: No they aren’t, and this is an area we need to learn a lot about. Take the time to study the available material. Join a like interest group and associate with the ‘experts’ in this field.
8. What happens if I try to charge my plane from my car battery? Will it catch fire?
Response: You can, and many people do but there are risks like flattening the car battery and not being able to start the car. Yes fire is possible, but that can happen with methanol fuel too.
9. It all comes down to Common Sense.
It’s true, but it’s a rare commodity these days. There are basic rules of flight that must not be ignored.
The Location of centre of gravity, power requirements, wing loading, battery condition, state of charge and all the usual principals are just as relevant as with any other model flight etc.
RULES OF THUMB & GOOD IDEAS:
The following guidelines will help the reader arrive at a satisfactory beginning in the exciting and challenging new field of Electric Model Flying. We’ve tried to use everyday language where possible, but the units of “Power” “Pressure” and “How much Fuel there is in the tank” end up being expressed as Watts, Volts and Amp Hours or derivations thereof; Sorry!
1. How much Power do I need for a given model?
Response: There are many ingredients in this equation, but here are a couple to get us started.
Power, is expressed as Watts and when related to the weight of the model can give the modeler their first check on whether a certain electric power combination will achieve the flight performance they expect. So, here are some statistics that are somewhat universally accepted.
50 to70 watts per pound for a slow hand launch floater.
70 to 100 watts per pound for fun aerobatics & ROG.
100 to 150 watts per pound to easily ROG off grass.
150 and above for competition, prop hanging etc
200 to 250 watts per pound for electric flan jet models.
|Disclaimer: To the reader... please feel free to download, use and copy this Treatise on the understanding that it is for 'private' use only and must not be used in any way for commercial purposes without the writers permission.
Note also, that the information is a work in process and may be amended at any time should the writer or the Club decide so to do. No responsibility or liability is expressed or implied with respect to the information contained in the Introduction to Electric Flight material.
A copy of this article is also available in pdf format below.