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Old 02-22-2005 | 07:00 PM
  #13  
vidpokbob
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From: Bear, DE
Default RE: Gas to Electric conversion guide?

Ok, I'm not trying to be a pain here, I just want to make sure I'm heading down the correct path.

Took the meter home and hooked it up to my still-being-built Slinger. The battery that I have for it is an 1100mAh 8.4V NiCad (I'm planning on going to the 1800mAh NiMH once I buy the DuraTrax Intellicharger), the flying weight of the wing is supposed to be 27 oz (let's use that for now), the ESC/receiver combo is a 30A/5ch and I still have the stock Speed 400 motor that comes with the wing; that should take care of the basics.

I fired up the system and watched the meter as the motor ran full-throttle for a few minutes. I did not know how long to run it, but I hoped that this was long enough. The 2 key figures that I got were that the motor drew a max of almost 10A (9.96Ap) and the power looked to be just a touch under 70W. The battery was less than the 1100mAh to start, but I'll stick with 1100 since I did not write that number down.

So, if I am doing my math right, knowing the motor draw (at least its max), the battery (1.1A) should last me just over 6.6 minutes (I know that's full-throttle, so if I fly 1/2 to 2/3 top speed, I might get 10 minutes or so). And, if I divide the weight of the wing into the power, I'm looking at 41.48 W/lb (70W / 1.68 lbs).

First of all, am I calculating these items correctly based on the readings ?

Secondly, if so, then I think I need to look into getting a better motor that can get me up to, say, 120W which would get me over a 70W/lb rating (which might allow me to something other than fly in a circle...boring !)

Thirdly, is the ESC/receiver combo overkill or a moot point ? The next lower (at least in Electrifly) is a 4ch receiver, but not an ESC combo so I'd need to get a separate ESC (say 20A) and wouldn't that add weight ? And, if I decide to go to a better motor, I figure I would need the extra amps on the ESC anyway.

I think the keys to me sound like the battery (for duration and power) and the motor (more power). I think the ESC should be something that comes afterwards after I know the power needs of the other two. And, I know I can work a different prop, but I don'tr believe any prop will really boost the stock setup enough, right ?

Thanks for helping a fledgling earn more of his wings.....