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Old 10-12-2005 | 07:24 AM
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aeajr
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Default RE: Going Electric !!!!!

ORIGINAL: snappinjim

Hi all. I have been flying glow planes for the past three years. I have been thinking very hard about giving up all my glow stuff for electric. I really like the no slime fact and the performance appears to have gotten better in the last few years. I need to know if there are any sites that have great training on getting started. Motor, battery controller information. etc. I do Enjoy building. I have looked at the SR Battries line of kits. Thank you for your help.
Welcome to electric! Sorry to hear you are going to dump glow. Why not fly both?

Flying electric is not much different than flying glow. Just the power system changes so you have to learn about motors, speed controls and batteries. Power is measured in watts rather than horsepower or displacement. Watts - Volts X running amps

So if your motor draws 8 amps at 8.4 V your motor is drinking about 67 watts. That would be a good typical figure for a Speed 370 or speed 400 motor set up in a 16 ounce plane. Flies well, basic aerobatics, good climb rate. But not burning holes in the sky or flying 3D

If you are running this using a brushed motor, like a speed 400, about 40-50% of that power makes it to the prop.
If you are running a brushless motor then typically 70-90% of that power makes it to the prop, so input watts is only half the story. That is why brushless motors are all the rage. They cost a lot more than brushed motors, however prices are getting closer together.
If you get into planes over 2 pounds and you want some performance, brushless is the way to go!

Some old standby guidelines, based on brushed motors, that might be a good starting point.

For casual or easy sport flying, scale like flying, about 35-50 input watts per pound is a good benchmark. Many slow flyers do fine on 30 watts per pound.

For aerobatics, about 75 watts per pound seems to be a good starting point.

For 3D, about 100 watts per pound seems to be the benchmark I have seen used most often.

These are rough rules but they are a starting point.

So if you are building a 2 pound plane and want it to perform some good aerobatics, then a brushless motor that draws about 150 watts would be a good starting point. Assuming 8 cells ( 9.6V) you will need to be feeding that motor at WOT about 15-16 amps.

That helps you pick your motor, your speed controller and your battery pack.

Motor needs to consume 150 watts or more
ESC must handle at least 16 amps ( 20 to be safe)
Battery pack needs to be able to deliver 16 amps ( again figure 20) at 9.6V
Prop will be selected for that motor based on what watts ( voltsXamps) you are looking for and what that motor/battery set-up can deliver.

Even in the glow world, .40s are not all equal so it is in the electric world. The difference is glow is based on 50 year old technology that isn't changing much. Electric is evolving very fast with new motors, speed controls and battery technology hitting the market every year. And it only gets better and cheaper! Good stuff!

Some resources you might find helpful.

New Electric Flyer FAQs
http://www.ezonemag.com/pages/faq/a105.shtml

Electric Motor information
Click on Motor Chart link on this page too
http://parkflyermotors.com/secure/sh...m.asp?recid=11


If you are interested in small electrics in the 8-24 ounce range (parkflyers size) I can highly recommend any of the planes from www.mountainmodels.com and their support is outstanding! They sell the right servos and stuff for the planes too. Ask for their help. They won't steer you wrong.

Also the planes from Multiplex are excellent. Crafted in a resilient foam, called Elapor, they fly great and are very durable. I have flown their Easy Star and the Easy Glider and several people in our club have their Magister.
http://www.multiplexusa.com/models/P...PFmodel_fs.htm


If you like flying wings, Zagi is the big brand name in this slot
www.trickrc.com