GP Electri Cub motor help

[Craigasoarus]

I have wanted to ressurect a model I built 33 years ago and would like to replace the old can motor with a brushless outrunner etc. I recently purchased from Aloft some motors but they look rather small and inadequte so I was wondering if anyone could help an old man who is not a electrician with a motor size and esc size for this application. The weight of my cub with everything flight pack etc. is 32oz. a bit lighter than with the old can motor etc. the wing area is 472 sq. in. and I am interested in solid trainer ROG performance. Thank you folks fore any feedback.

Craigasoarus

 

[Jarron]

Hello Craig!
What motors did you buy from us? I can run Ecalc and see if I can find you a good setup.

-Jarron

 

[Craigasoarus]

Hi Jarron, I bought 3 ea, of the emax 2212/980kv for use with a 9inch prop and 30 amp esc.

 

[Wayne]

Looks like those motors will provide about 28 oz of thrust on a 3S battery and 10x4.7 prop. Do you have enough room to clear a 10" prop?

 

[Craigasoarus]

Maybe on the prop but is 28 oz of thrust pretty good? I was intending to use a 3s battery I have. The original setup I believe was for a 8x4 prop on the 05 size can motor that came with the kit. I bought the 3 motors to have a few more for similar projects like a old world robinhood kit etc. I have tried to study up on electric motor selection but it really is confusing for me. I am mainly a glider flyer.

 

[Jarron]

I ran eCalc, a really great setup calculator and found that if you run that motor on 3s, with a 10x5 prop, you'll put out 34oz of thrust and draw only 15 amps, 28 oz is probably going to be on par with ye olde brushed setup.

 

[Craigasoarus]

So that little motor will work out fine. Great to hear and I can move forward and mount it etc. I just ordered another ESC from you at 20amp and that might be the better to use instead of the 30 amp I had planned, I assume.? Thank you Jarron and Wayne for your quick feedback and also your great service with my orders.

 

[Jarron]

Oh, yes. You'll save a bit of weight too. Don't let these modern electric motors fool you, they are very powerful for their size and weight.

 

[Wayne]

A 10 prop will clear the ground ok when the tail lifts?

 

[Craigasoarus]

I will have to check that today Wayne, I am not sure.

 

[Wayne]

If it is too close, we can go with a little higher KV motor to allow the use of a smaller prop.

 

[Craigasoarus]

I checked my cub leveled and it looks fine with 10 inches, I had originally planned on a 9" but have a 10x4.7 on hand as well so I should be good to go. Thank you Wayne.

 

[Wayne]

You can probably ru a 9x6 with very similar results as the 10x4.7