.25 to electric - fun fly conversion
10-21-2003, 04:52 PM
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.25 to electric - fun fly conversion
I have a fun air 3d 20 that I want to make electric. What should I use.
Fuselage Length ....... 790mm/31in
Wing Span ............. 1020mm/40in
Wing Area ............. 30sq dm/465sq in
Flying Weight ......... ~900g/1.98lbs
Engine Required ....... 2c 15~21
price of the goods is a strong deciding factor. Is it better to get li-poly batteries and go with a brushed motor. Also what is good or bad about cobalt motors?
THANKS IN ADVANCE
Fuselage Length ....... 790mm/31in
Wing Span ............. 1020mm/40in
Wing Area ............. 30sq dm/465sq in
Flying Weight ......... ~900g/1.98lbs
Engine Required ....... 2c 15~21
price of the goods is a strong deciding factor. Is it better to get li-poly batteries and go with a brushed motor. Also what is good or bad about cobalt motors?
THANKS IN ADVANCE
10-22-2003, 01:23 AM
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RE: .25 to electric - fun fly conversion
what is the airframe weight before radio gear? the 2 pound number seems a little heavy for a good e- flyer.. 6-7 ounces or so for airframe weight is a number you should be shooting for.
Ususally one of the best combos for this is a hacker b20 series, 15L w/ a 11-7 apc-e slowflyer and 8 or 9 cells is great. You would need to add a cell or two to your existing packs or modify them... 7 cells under any circumstance won't give you enough RPMS for good 3D or pattern stuff.. the hacker is 139 through new creations rc in texas.
a mega 15 series is forty bucks cheaper, but it's performance is not as good as the hacker from what I've seen. Also available at new creations.
Either motor requires a speed controller, around 60 bucks.
lithium polymers are awesome because of the flight times and light weight, but if you have some packs to start with , I would get a better motor set up and move into the lipos later on.. but... if you want them now, thunder power 3S1P 2100 pack will fly this combo for 20+ minutes and available from espritmodels.com.. you will probably need a new charger..
Here is my little 39" 'pretty' w/ the hacker set up
Good luck!
Rob
Ususally one of the best combos for this is a hacker b20 series, 15L w/ a 11-7 apc-e slowflyer and 8 or 9 cells is great. You would need to add a cell or two to your existing packs or modify them... 7 cells under any circumstance won't give you enough RPMS for good 3D or pattern stuff.. the hacker is 139 through new creations rc in texas.
a mega 15 series is forty bucks cheaper, but it's performance is not as good as the hacker from what I've seen. Also available at new creations.
Either motor requires a speed controller, around 60 bucks.
lithium polymers are awesome because of the flight times and light weight, but if you have some packs to start with , I would get a better motor set up and move into the lipos later on.. but... if you want them now, thunder power 3S1P 2100 pack will fly this combo for 20+ minutes and available from espritmodels.com.. you will probably need a new charger..
Here is my little 39" 'pretty' w/ the hacker set up
Good luck!
Rob
10-22-2003, 07:18 AM
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RE: .25 to electric - fun fly conversion
Actually, 2lb isn't that out of line. The plane's a bit larger than my Wattage Crazy 8, which weighs 28oz in its current configuration. Mine's got good vertical on 160 Watts.
Regardless of the battery choice, I agree brushless is the only way to fly in a 3D ship. Cheap can motors are only about 50% efficient, and you need the most power with the least weight. Cobalts are okay, but their prices are comparable to brushless motors with the same kind of power output, at much higher efficiency. A brushless will turn 80-90% of the electricity it draws into thrust, compared to ~65% at best with a cobalt.
Check out Greg Covey's Wipa Firecat at http://www.gregcovey.com. IIRC, that's a 2lb 3D ship with a fairly affordable AXi outrunner motor and LiPoly packs. I can tell you from first-hand experience that this plane can pull off some pretty extreme moves.
Regardless of the battery choice, I agree brushless is the only way to fly in a 3D ship. Cheap can motors are only about 50% efficient, and you need the most power with the least weight. Cobalts are okay, but their prices are comparable to brushless motors with the same kind of power output, at much higher efficiency. A brushless will turn 80-90% of the electricity it draws into thrust, compared to ~65% at best with a cobalt.
Check out Greg Covey's Wipa Firecat at http://www.gregcovey.com. IIRC, that's a 2lb 3D ship with a fairly affordable AXi outrunner motor and LiPoly packs. I can tell you from first-hand experience that this plane can pull off some pretty extreme moves.
