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#1 flying_pig Jul 11, 2001 03:58 PM

converting a top flite contender
 
I am thinking of converting a top flite contender to electric and would like to use a geared de-walt 14.4 motor and 12 cells. What speed controll would i need? Also has anyone else converted a contender and can offer any advice?

#2 Mr. Wiz Jul 11, 2001 04:13 PM

The TF Contender is a pretty big plane. I think you're looking at a 16 cell system as a minimum and probably 20 cells if you want to preserve its aerobatic personality.

Wiz

#3 jrb Jul 11, 2001 04:24 PM

Check out the FAQs for other rules of thumb; but the 16 to 20 cell count is correct.

A recent RoT suggested 100 watts for each 0.1 cubic inches of displacement, per plans 400 to 610 watts.

Propped for 30 amps, 12 cells (12 volts @ 30 amps) is about 360 watts; good for a lighre .40 ship.

Going brushless with a Maxcim Y wouldn't be a badd choice.

#4 KOMET 44 Jul 11, 2001 04:26 PM

Get the specs on the plane then post that.Can't do anything until you know that.stefanP

#5 flying_pig Jul 11, 2001 04:38 PM

the url for the contender is http://www.top-flite.com/airplanes/topa0210.html and according to the top flight site the specs are

SPECIFICATIONS
Stock Number: TOPA0210
Wingspan: 53.25 in (1350 mm)
Wing Area: 660 sq in (42.6 dm2)
Weight: 6-6.5 lb (2720-2950 g)
Wing Loading: 21-23 oz/sq ft (64-70 g/dm2)
Fuselage Length: 49.6 in (1260 mm)
Requires: 2-stroke .40-.61 cu in (6.5-10 cc) or 4-stroke .52-.70 cu in (8.5-11.5 cc) engine, 4-channel radio w/5 standard servos (5-channel w/6 standard servos if flown with optional flaps)


I would like to use a de-walt motor because i work for work for them. http://www.ezonemag.com/disc/smile.gif

#6 Ed Lyerly Jul 11, 2001 05:49 PM

Flying_Pig,

The Contender is too much airplane for the DeWalt motor and 12 cells. It is sturdily built [heavy] and would require much re-engineering to be successful. Suggest you obtain Dec '99 EFI magazine & or plan MW 2769 for the "Moose". It is a 54" 530 sq in ship that I have seen fly ....and fly well with the DeWalt 18V motor and 14 cells.
Ed

#7 flying_pig Jul 12, 2001 10:54 AM

A friend showed me his old contender and yes i agree the thing is built like a battleship, it reminds me of a big control line model where weight saving has been passed over in favour of strength so i'm looking to build something else now, thanks for all the advice

#8 Ken Lapointe Jul 12, 2001 11:23 AM

The Top Flite Contender makes a great conversion. I used an Astroflight 40G on 20 cells with a 13 x 8 prop. I have pictures and info in the gallery at
http://www.ezonemag.com/articles/200...ry/gallery.htm

I think 18 cells would be the minimum for this plane.


Ken

#9 Megowcoupe Jul 13, 2001 11:31 AM

Re weight on the Contender- Not true! I built two of them glow, and it was a very light glow ship, and unless the new version has been beefed up unmercifully, it probably still is. C/L stunter construction is actualy pretty light.

The airplane has a thick wing though-which means it doesn't really stall, but is kind of slow on the top end. Gearboxes should be a big plus- your worse problem will be ground clearance- I had trouble with a 12" prop on grass.

Sam Brauer
Norwalk, CT

#10 Martin Irvine Jul 14, 2001 08:48 AM

That thick wing will need some horsepower to pull it. The originals were light and had good vertical but not a lot of speed unless a larger engine was used.
You could use the DeWalt in a gearbox but direct drive would probably limit you to 9 or 10" props and 14 cells. That would work if you could keep the weight to 80oz. (5lb) total, but it wouldn't be a great flier. And you wouldn't likely make that weight.
A belt drive will add another 6 oz. to your power system, (and the DeWalt already weighs 16 oz).
Ed suggested the "Moose" plan from EFI. I designed that around the DeWalt motor to make the most out of a direct drive situation. I'll bet it is lighter than the Contender.

Cheers,

Martin

#11 Woody Jul 14, 2001 09:19 AM

The original Contender was much heavier than the new version, but it would still not make a good candidate for conversion. The one I had many years ago was powered by a Super Tigre .51, and it was adequate. You would need lots of cells to get good performance, and the weight would be a killer.


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