I've bought the Top flight DC-3 and want to fit it with E-flite brushless motors but don't know what size motors to use! It's a 10 lbs aircraft and recomended prop size is 10x6.
Can anyone tell me which E-flite motors to use? And How does the dual motor system work as far as power? Keep in mind that I want to slightly over power this airplane!

I have a suspicion that 10x6 is not actually a good prop size for this plane..at 10lb you need at least 500W total, so 4x125W - or some sort of speed 400 type outrunner - will be good BUT they won't want to turn 10" props..

Maybe a bunch of esskay 400XT's would come close enough,..might be able to drive a 9x7 three blader with those.

Dunno much about eflites but I'd go for something that will do about 12A on a 3s LIPO pack with the lowest KV you can find.

The DC3 is I think a rather heavy plane and needs plenty of pitch speed. This tends to equate to smaller props turning faster..I have a feeling it didn't fly that well on 'recommended' power trains..there is at least one old thread in the scale forum I think.

Originally Posted by vintage1

I have a suspicion that 10x6 is not actually a good prop size for this plane..at 10lb you need at least 500W total, so 4x125W - or some sort of speed 400 type outrunner - will be good BUT they won't want to turn 10" props..

Maybe a bunch of esskay 400XT's would come close enough,..might be able to drive a 9x7 three blader with those.

Dunno much about eflites but I'd go for something that will do about 12A on a 3s LIPO pack with the lowest KV you can find.

The DC3 is I think a rather heavy plane and needs plenty of pitch speed. This tends to equate to smaller props turning faster..I have a feeling it didn't fly that well on 'recommended' power trains..there is at least one old thread in the scale forum I think.

This post doesn't make a lot of sense. For starters, a DC3 is a twin so for 500 watts you'd need 2 motors at 250 watts so I'm not sure what the 4x125 has to do with it. Your recommendation of a motor that'll pull 12a on 3s would only give you ~130 watts per motor and 260 watts is not nearly enough to fly a 10 pound DC-3.

There's a very good thread about converting this kit here:

http://www.rcgroups.com/forums/showt...eferrerid=1676

Originally Posted by Mark Wolf

This post doesn't make a lot of sense. For starters, a DC3 is a twin so for 500 watts you'd need 2 motors at 250 watts so I'm not sure what the 4x125 has to do with it. Your recommendation of a motor that'll pull 12a on 3s would only give you ~130 watts per motor and 260 watts is not nearly enough to fly a 10 pound DC-3.

There's a very good thread about converting this kit here:

http://www.rcgroups.com/forums/showt...eferrerid=1676

Sorry..too much alcohol. I was thinking DC4.. You are right, it makes no sense to use 4 speed 400's

Thanks for pointing out the thread..my suspicion that 10x6's are no good still holds tho.

Need a pair of 250 watt motors..something like AXII 22 or 28 series..

An Axi 2820/10 or 12 would do the trick quite nicely. In my direct experience, I have had the /10, and it had no trouble swinging an 11x7 APC on 3s. That's about 300 watts in the air. The /12 will tolerate higher cell counts. It's basically a .25-.30 to the glow guys. There is also the 2826 series, which has the same size as the 2820, but it has thicker stronger 26mm curved magnets. On high (5s) cell counts this motor is capable of 800 watts. This motor is a drop in replacement for a .40-.45 glow. This is maybe overkill for your plane. Although it is fashionable to underpower twins, I like 60w/lb as a target better than 50. You don't want to discover that you're underpowered when you're running out of altitude, amps and ideas all at the same time.

BTW, there are some cheap chinese units at united hobby that would do it too, but AXI means quality. I think I sold my 2820 for $10 less than I paid for it, a year and a half later- it was literally as good as new.

-tim

To answer your question, an E-Flight Power 15 would probably be your entry point.

Len