MLee

About 17 years ago I built a Great Planes Trainer 40 (aileron, rudder, elevator) with an O.S. 40 engine. I drug it out recently and am thinking of converting it to electric. Right now the plane stripped weights about 5 pounds. I thought if I drilled out a lot of the unnecessary wood I could reduce it to about 2 1/2 pounds. Question--If I lightened the plane, what would be a good sized brushed electric motor? would a geared motor work better with a brushed motor? if I went brushless, any suggestions? I don't want to be underpowered, but at the same time am not looking from aerobatic capacity. Suggestions??

srpuls

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Hi why would you want to convert over to electric ?? A os .46fx would cost about a 100.00 ........ However if you want to convert over I use this fomula ....75 watts per pound will fly your plane ok 100 watts per pound will fly the plane very well ...... 150 watts per pound will fly it great .......to get watts you use this formula...amps x volts = watts Eflite has a 46 out runner that would power your plane very well with a 50 amp esc then get a couple of 11.1 volt 3000mah lipos and a lipo charger and you will be good but your looking at over 300.00 to do it

MLee

Thanks for the insight. Does not sould like the effort or $ investment would be worth it, but you have given me some good information for the future.

oceansfiftyseven

I would avoid using brushed motors. However, there are alot of options these days for powering your plane with brushless power systems. Albeit they are far more expensive than a 2-stroke engine. I have a .40 sized cessna that I am running a Mega 22/30/2 motor geared 3.5 to1 using a 12x6 apc on 5s Lipo's and I can't really tell the difference in performance from when I was running the plane with a Saito .56 with the same prop. What I can tell you is that The power package with 2 batteries esc, etc was about $800. The saito was less than $200.

carlosponti

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check out this site for cheap prices i will be ordering there soon. http://www.unitedhobbies.com

Charlie P.

I don't especially like electrics, but if you fly four times every other weekend (assuming 10 oz per flight) that's about $120 in glow fuel per year. Payback becomes two or two and a half years. Not bad at all. We look for five to ten years payback in investments at our company. How long do the motor batteries last for electrics?

Now, if you REALLY went gas (gasoline as opposed to glow fuel), your cost in fuel drops to about $25 per year with four flights every two weeks year round. Toss in one of those new 20cc gas engines for real economy.

MLee

I can see that costwise, it is probably not a good idea to convert. Thanks.

carlosponti

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i read an article on another forum where a guy used six pack cells (nicad) a brushless motor and speed controller on a trainer and it did just fine.

http://www.rcgroups.com/forums/showthread.php?t=264085


i wouldnt go as far as to say its not a good idea. it may be a bit more expensive and really expesive if you use lipos. and really expensive if you buy all name brand components. i plan on converting a 40 sized sport plane with components on that site i posted for 150. that is with esc lipos and brushless motors. its all in what your needs are not price. i prefer not to use glow anymore because of the mess i am left with. plus i have more choices with where i fly with electric. it makes sense for me to give it a try. it may not make sense for you.