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sammetler@hotmail.com
01-08-2007, 10:24 PM
I have a 1/12th Don Smith b-29. I don't want to power it with gas so I'm going electric. The plane is 75% finished but awaiting final skinning for the installation of the Batt's / Speed Controllers and Motors.

E-Flight 160 Motor 4 Motors
Jeti 90 or Phx 110 SC 4 Speed Controllers
Flight power 3700 37v 10 cell Lipo 4 10 Cell Lipo's

Is this a good set up or what are some recommendations for this bird?

Thanks,
Sam

thunder1
01-08-2007, 10:35 PM
That's a whopper;-) What's the expected airframe weight?

sammetler@hotmail.com
01-08-2007, 10:45 PM
60 TO 70 LBS, Thats figuring 951 grams for the batt's each.

wilscor41
01-09-2007, 05:09 AM
I think you're a bit to big on the power. I don't know which calc your using, but what is the output wattage and with what size props? I could give you a better idea if I knew. I think 750 watts per pound would work well with the B-29
jack

laxlife
01-09-2007, 05:18 AM
Big motors, big voltage but too little tank, ie 3700 mAh? no where near enough. should be 5000 mAh per motor and esc pairing, 10,000 mAh would be more fun

sammetler@hotmail.com
01-09-2007, 03:33 PM
I am predicting using tri 16x10 props. I haven’t done that calc on the watts per pound, I don’t even have a chart to determine what’s in or out regardless. Do you have or know of one?

See this is the difficult part, one person say's too much and another say's too little. I'm not trying to be anything but gracious but this makes it more confusing.

wilscor41
01-09-2007, 03:45 PM
try this calc. it will list wattage out. I've found it to be pretty accurate. It does'nt list every kind of lipo, but you can just add thunder tiger packs till you get the neccesary info.
Regards, Jack http://brantuas.com/ezcalc/dma1.asp

sammetler@hotmail.com
01-09-2007, 03:57 PM
Thanks Jack, I'll try and post the results.

sammetler@hotmail.com
01-09-2007, 09:41 PM
The selection on the motors doesn't include the new big boys as in the 160 from E-Flight. I'm stilll trying to find a sub motor for the calcs but I'd rather put in the exact one I have.

jonnyjetprop
01-09-2007, 11:12 PM
I know of a slightly smaller (119" ws)

http://www.scaleaero.com/maiorana_elec_scale.htm

I believe that they used Maxicim motors geared running at first on nimh batteries and then on 4s first generation lipos. I would think that a power 60 ( or AXI 4130/16) system running on 6s would work. If prop size is a problem, then you could look at a 4130/20 running on a higher cell count. One of my clubmates is flying a Hangar 9 Corsair with the 4130/20 and a 10s pack. He is running a 14" prop instead of the 15-16 inch size.

John

sammetler@hotmail.com
01-10-2007, 11:37 PM
I appreciate all your guys help, doing the math my choices are almost on the money minus going to a 4000 batt and the 110 sc. I’ll upload some pic’s of the bird in it’s early days as well as some flight video once she flies. She’s being built after the 444th Fu-Kemal.