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Old Sep 19, 2001, 11:36 PM
Tantrums Rock!
CheeseWing's Avatar
Joined Jul 2001
268 Posts
What Electric can give a .40-powered sport a run for its money?

The R/C club I joined is all about their .40-.60 Glow-Powered Big-Siks and Sport planes. I want to show them up with an electric.

I want to get an Electric that will get 8-20 minute flight times, match the speed/thrills of a .40-powered Sport plane . . . without the expense of a brushless motor. . .

I also want the capability to ROG, unlike the Wattage Mirage, Zagi, etc. . .

What would be the most economical, yet performance-capable kit and motor set-up to meet my requirements?
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Old Sep 20, 2001, 02:17 AM
Our Daddy and Heli Junkie
Fred Bronk's Avatar
In Heli Wonderland
Joined Aug 1999
22,774 Posts
Well, to get what you want to any degree you are probably looking at a BL setup. But the Jetis are reasonably priced and can give you more power and duration for your hobby $.

The Jeti controllers are limitied to 16 cells for now, and the 14/3 is what I would see as a 40 size replacement.

To get the flight times you want, good throttle managment will be a must, but I think the 20 minute flight times are pushing it.

With a light plane (probably not an ARF) good throttle use and not all vertical, I think 10 minute flight times would be easy.

EP has the power, it is flight time we are working on!

--------------------------------------------------------------------------------------------------

With that, I moving this to Open Discussion. This is not a slow flyer by any means!
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Old Sep 20, 2001, 02:35 AM
Speed Demon
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Antioch,CA,USA
Joined Dec 1999
12,280 Posts
Quote:
Originally posted by CheeseWing
I want to get an Electric that will get 8-20 minute flight times, match the speed/thrills of a .40-powered Sport plane . . . without the expense of a brushless motor. . .
CheeseWing
Cheesewing, I posted the same thing in the sports plane forum. 8-20 min. flights means low amp draw. A pack of 3000 NiMH can run for ~8 minutes at an amp draw of ~22.5 amps. A sport .40 sized geared power system would input ~600-800 watts. Taking the low side of the power curve we use 600 watts/22.5 amps = ~23 volts = 1 volt/cell under load = ~23 cells 23 cell * 2 oz./cell = 46 oz. battery. More cells and less amp draw gets longer runtime or more cells same ampdraw makes more power. A pair of geared motors running in series would work here (twin or two motors, one gearbox), or possibly a geared Speed 700/ Dewalt drill motor would be the cheapest ways to go (at ~16oz.). Throttle down a bit and increase your runtime. Throw this into a Stik and see how it goes.
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Old Sep 20, 2001, 08:23 AM
Visitor from Reality
United States, VA, Arlington
Joined Dec 1996
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First off, never tell what your flight times are. If anyone asks, tell them you land when you start repeating your aerobatics enough to get bored. Slimers don't know how long a flight is anyway, about 99% of them the never time flight duration. Always land with a minimum of fuss, like you intended to do it on your terms and leave enough juice to taxy clear if the runway surface permits. Shouting "Deadstick" is someone else's solution :

Next off, stop thinking fuzzy electric thoughts. See GWRIGHT postings on the E3D to see what you can do if you quit thinking electric and think 'quiet sports performer'. If he can hover and fly 3D on a $30.00 motor and $15.00 'box - how fast can it go in level if you jigger around with the prop and ratio?

Speed? My 300W Embat got a chance recently to fly with a couple of 40-ish slimeburners. Let's say that they were nearly as fast. Take one Embat kit, the above re-jigged Endo', an alloy UC and skinny wheels, apply a little ingenuity to get the geared motor under the hood, 10 of those new CP2400s ($3.00 - $4.00 a cell, build your own packs). Add all the lightness to the kit you can while building it straight, true and clean - and you are in the game.

Runtime? I have flown the Embat - okay, it has a DD Breathless - for ten minutes, but the last five was doing 'half pipes' practising tailslides. The better you get on throttle management, the longer it flies. The better you learn to retain energy in flight, the longer it flies. Match power settings to "speed and need", never get into situations where you leave the motor hammering away with airspeed bleeding fast and no chance of airspeed recovery. Drop big vertical maneuvres in favour of flat rolling ones after five minutes of flight. Don't fly straight and level any longer than you have to, unless making that darling of the oilfield - the fast, low pass

I don't think you'll get 20 mins anytime soon. I once flew a 10 powered glow Lazy Bee around in circles for about 24 minutes - like thermalling but at thirty feet and over the same spot. The aim was to see just how long it could fly for on a tankful - never been so utterly and pointlessly bored before and since!

Don't fancy a model that looks too much like a clip-winged snoarer? There's rumours of a real donkey-kicking low wing model coming along in much the same size this winter

Lastly, why bother about impressing others? Work to impress yourself - you are probably the only one who'll remember by Monday morning.
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