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magic hand 73" yak set up questions - 6/16/2009 10:43 AM   
pliebo


 

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From: sevierville, TN, USA
Status: offline 		Heres what I have so far.  AXI 5330- 18 .  jeti 77 esc ,  2   5 cell lithium 3850 mah 20 - 30 c ( thunderpower)  I have a few questions if anybody wants to offer assistance.  the motor has 15 - 38 amp max efficiency current, max current 58 amp.  does that mean that it wont put out as much power as a scorpion 5535 which has a max of 85 amp?  Also what effect does the internal resistance have on my set up ?  I want to make sure I will have enough watts for 3-d.  the plane will weigh 11 -12 lbs auw.  thanks for helping, phil

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RE: magic hand 73 - 6/17/2009 6:43 AM   
lejongleur


 

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From: Norwalk, CT, USA
Status: offline 		Your 3850mah packs at 30C can theoretically provide 30*3.85 = 115 amps which is more than enough for anything you are planning.
Using 10S (2x5s) will give you about 34 volts under load - at 58A this equates to 1972 watts.  If you used a motor which could stand 85 amps you might get 85*34 = 2890 watts. 
However, as you have a 77A ESC you are limited to more like 77*34 = 2600 watts. I see the AXI motor is rated for 2600 watts (and 75A according to the specs I read, not 58A), so really, 75*34= 2550 watts is the best you can hope for - in fact you can probably expect to reasonably get more like 2400 watts using the recommended 18x12 or 19x10 propeller.

Sorry for all this rambling, but the answer is that if you prop the motor to get near 2400 watts, you will have the required 200 watts per pound for spirited 3D flying, based on your 12 pounds auw.  Good luck with this monster of yours and I hope this helps...Chris


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RE: magic hand 73 - 6/21/2009 8:16 PM   
pliebo


 

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From: sevierville, TN, USA
Status: offline 		thanks for your help!  I have been doing some more research, and you're right the motor has a max loading of 75A.  and one example I found with the axi 5330 and a 10s lipo with a 19-12 prop is 79 A  and 1941 watts,  with a 20-13 it's 91 Amps and 2088 watts. My next question is Isn't 91 amps too much for a 77 amp speed controller? thanks again, Phil 

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IF YOU ONLY HAVE TO BEND OVER ONCE TO PICK UP YOUR PLANE, IT WAS A GOOD LANDING

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RE: magic hand 73 - 7/1/2009 11:33 AM   
pliebo


 

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From: sevierville, TN, USA
Status: offline 		I ve got the magic hand 73" almost done. I have a couple of questions. With the Yak I had to put the batterries all the way up into the front up against the firewall to get my CG. Would it be sufficcient cooling for the batts to put a couple of scoops on the side of the box? Is there enough air coming into the cowl or should I cut addittional air inlets? I just dont want to cut too many holes in the motor box. The axi 5330 has some monster torque!

The first tests of the power set up is: 92.6A 35.4V, 3278 W APC 20-10
the second test is 89.7A 35V , 3154W APC 20-10

I have ordered a 19-10 and a 20-8 prop to try to get the Amps down.

Your opinions on this set up would be apprecciated. thanks, Phil

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IF YOU ONLY HAVE TO BEND OVER ONCE TO PICK UP YOUR PLANE, IT WAS A GOOD LANDING

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RE: magic hand 73 - 9/2/2009 12:07 PM   
pliebo


 

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From: sevierville, TN, USA
Status: offline 		hi all I've been really enjoying flying this plane. I got a smaller prop on it (a 19 8) and it really pumps! THE POWER IS JUST INSANE, rocketing uplines @ 1/2 throttle! I wish I would have went with a smaller axi cause it's a little heavy for 3-d. It will do some hovering and harriers. You can just feel the heaviness of it in your manouvers. It's great in pattern manouvers, and I'm working on losing some weight.

I would reccommend this plane to anyone. maybe with a little lighter power set up. ( I do have dual 2 cell lipos on the rx ) that is adding some weight. and the plane could fly on a 9 cell if you can make one. Happy flying!

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IF YOU ONLY HAVE TO BEND OVER ONCE TO PICK UP YOUR PLANE, IT WAS A GOOD LANDING

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