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Old 07-05-2002 | 11:30 AM
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gwright
 
Joined: Jan 2002
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From: Champaign Il
Default SPAD Fun-Fly - Electric

there are quite a few spad's flying on e-power,..but a direct drive SP600 with an 8X4 isn't going to cut the mustard. The tiny little direct drive prop isn't going to make enough thrust to do much. It just _might_ fly the plane,.. but it will definately stagger around underpowered. Fear not,.. as you probably don't need another motor (although a very good one would only be $25), just get a gearbox and put a real prop on the front. download motocalc (www.motocalc.com) for the 30-day evaluation. Plug in your motor , cellcount and gearboxes and props till you get some thrust and pitch speed numbers that work. All Sp600 motors are not created equally, either. You really need to know the exact motor you have. There are SP600 motors that are "good" for 180 watts of power,.. and there are SP600 size motors good for 400 watts of power, so you need to know what you have, to determine cellcount and gear ratio needed. One setup that works well on a SPAD, and I have it on my pizza box flyer,..is a Kyosho Endoplasma, geared 4.6 to 1, with a 12X8 APC electric prop, on 10 cells. My PBF is a couple ounces under 3 lbs, and it can be handlaunched vertically at about 60% throttle. This is a 400 watt setup using a $25 motor and $15 gearbox with a $4 pinion. Most generic sp600's shouldn't be "pushed" more than about 225 maybe 250 watts, at most, and they are about 55~60 percent efficient, so you're going to get 100~120 watts to the prop. The endo with the above setup is about 25% more efficient, so for the same flight time (same current draw), you're going to get about 25% more power to the prop. I ventured into e-flight a couple years ago, and have spent a ton of time reading/researching/testing/learning. You _can_ get equal, or better performance than glow,.. just depends on how long you want it to fly per charge. However,.. the direc-drive sp600 arfs and such give e-flight a bad name since they generally struggle around barely flying. Stick a gearbox and appropriate prop on most of them and they are completely transformed.