I have been flying foamies for about a year. I would like to convert one of my gas 3D planes to electric. I built a take-off on the Cobra. It has a 48" wing with a built up fuse. The weight with a YS63 was right at 5lbs.

Could anyone tell me what combination would give me approximately the same performance in an electric set up? What size motor, batteries, ESC, prop etc. I was told it would run me about $700 to make the conversion. Could I do it for less?

Thanks for any help.

Hal

For a similar project, you might want to check out Mark Vigod's conversion of the Hangar 9 Twist 3D.

One thing the big electrics aren't at this time, is inexpensive. $700 for the LiPoly battery, motor, ESC, and support equipment sounds about right, though. You could do it cheaper, but you would be sacrificing performance. NiCd or NiMH batteries are cheaper, but heavier. Brushed motors in this size range are far and few between, so you wouldn't be saving much here.

Hal,

For a 5lb 3D plane, use a power system that can deliver around 150 watts per pound (or 150w/lb).

This means that you need a motor that can handle at least 5 x 150w or 750 watts.

Using and outrunner like an [link=http://www.hobby-lobby.com/brushless-axi4130.htm]AXI 4130/16[/link] motor can provide this power for a good cost value. The outrunner motor is also maintenance free as there is no gearbox to lubricate or pinion gear to worry about slipping.

A 20 cell NiCd or NiMH setup with a 14x7 or 15x7 APC e-prop is a good starting point. The combination AXI 4130/16 motor and Jeti 77-amp Opto ESC ([link=http://www.hobby-lobby.com/brushless-combo-axi.htm#413016]PM413016C[/link]) can be purchased at Hobby Lobby for only $329. This is less than half your $700 budget.

I would start out with two 10-cell battery packs, and, if you like the result, switch to two 3-cell Lithium packs.

Good luck!

You may not like the 3 pounds of battery, though... You can mitigate this some by using lighter cells, Sanyo HR4/5FAUP 1950mAh NiMH cells, to be exact. They're 1.6 ounces per cell vs. 2.1 for the GP3300 3300mAh NiMH, so on 20 cells, you save 10 ounces. Of course, there's no free lunch, so you will lose about 1/3 to 1/2 your flying time over the GP3300s.

The 'FAUP cells are good to bursts of 40 Amps, which is also right where the AXis are happiest.

Two packs of these will cost around $200 (~$4.50 per bare cell), which puts you close to ballpark range for LiPoly. GP3300 NiMHs are up somewhere around $6 per cell, if I'm not mistaken.

Thanks guys for the help.

I have been talking with a guy that owns a hobby shop. He has recommended the following setup:

B40 or B50 size brushless motor - $60
Castle creations speed control - $119
Gearbox - $22
6S2P LiPo 4000 mah with 60amp capability - $320

That is a total of $521.

Since I want to do 3D with the plane he says I will probably need the B50 and the larger batteries.

Any thoughts?

Hal

If you can get a Hacker B50 motor for $60, tell us where. That seems AWFULLY cheap. Even the Himaxx wanna-bes are well over $100.

$22 for a gearbox to handle that much power seems awfully cheap too.

Matt

According to him it is a Hacker clone. He claims they are pretty good motors. He also sells a planitary gearbox for $59.95 that we are considering.

I am wondering what battery combination I will need? I want to do 3D with it so I need the power but I don't want a lot of weight.

Hal

I've gone the HiMaxx 3618/4500 and planetary gear box route and wish I had put the $160 into a big AXI instead. Much better choice for what I wanted. Not saying the HiMax is a bad motor. I burned up a PHX 80 trying to run the motor direct drive with an 11X8, 9S pack! Well over 100 amps with no dammage to the motor. That was before I learned to use the Whatt Meter every time I tried something new!

I'm very happy with the AXI 4130 on 6S, (9S is much better!), with 19X8 EAPC in my 60 size E-U-CAN-DO. Should have gone that way in the first place. I'm running 6S3P till I can afford a 9S3P pack as the amp draw on 9S2P is too much for the batteries.

I suggest the big AXI.....You'll never look back!

look at my at-6 conversion thread with the axi 4130/16 on 6S...lots of torque. I could even fly on 7S , but my 8 Lbs plane does not need it