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Author Topic: could this be the electric Norvell ?  (Read 590 times)

Offline jim gilmore

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could this be the electric Norvell ?
« on: May 09, 2008, 06:34:24 PM »
http://www.rcgroups.com/forums/showthread.php?t=389111&highlight=%2430+mega+beater
I hope the link works.
looking at this setup I'm wondering if it could be the high powered motor for 1/2 A or 3/4 A

Offline Mike Anderson

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Re: could this be the electric Norvell ?
« Reply #1 on: May 09, 2008, 07:45:17 PM »
This is indeed pretty impressive performance - the amp draw is (almost) a show-stopper on this, though.

23 amps for even a 3 minute flight (beginner stunt  pattern) would need to be a 3s, 1500 mah
battery.  It's about 200 Watts, which is really out of the range of 1/2A anyway and the battery alone
is about twice the weight of what we are currently trying to get by with (2s, 800 or 900 mah).  That doesn't mean it wouldn't work, just that you have to factor that kind of weight (remembering that we are already at 8-10 ounce planes) into the wing area calculations, etc.

My own efforts are to make do with less motor and less battery, and never mind the 6-inch prop
"rule" - that was just for one contest, which I probably won't make it to anyway.  I have a 1/2A
Skyray (with built up wing) flying pretty well on a $15 motor, but flies best with a 7-4 or 8-3 prop.

I did mess around with a 6-6, and I suspect that 6-3 or 6-4 3-blade would be useable also, but the bigger props
are happier at the lower RPMs than the 6 inch ones.

Mike A
Mike@   AMA 10086
Central Iowa

Alan Hahn

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Re: could this be the electric Norvell ?
« Reply #2 on: May 10, 2008, 08:16:54 AM »
Jim,

I agree with Mike.

Half-A is more a state of mind than anything else. It means small.

When I built my contest plane, it was a challenge to meet the rules of a contest (6" diameter prop). I was aiming at the performance of a weak Black Widow (not that Black Widow's are weak, but some individual ones are!), and I think I more or less got there while keeping the weight within bounds. Trying to meet the specs of a Norvel Big Mig which I have used --spinning a 4.75x3" cut down Grish Black Tornado prop at 22+krpm---wasn't my goal. I think the main reason is that spinning a dinky little prop at high rpms is pretty inefficient. You can get away with it in a glow engine because there isn't a lot of weight penalty and that's where you develop the power. But in electric, it is the battery and its capability to supply amps and total watts that begins to kill you in weight terms.

I think electric in larger plane Stunt is so effective because we can use the flexibility of the motor to drive big diameter props at lower and more efficient rpm's than glow. Also with the larger planes, there is also more space to save weight in the structure than in the half-a.

Anyway I would say it would be easy to have a half-a sized plane setup to turn a 7" prop and probably put in better performance than my 6" effort.



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