V12DRIVER

My Feedback: (13)

I am not too experienced in electrics and currently converting a Boeing 747 slope glider for electric power. I have already installed 4 GWS EDF-50 fans hooked up to a Wattage IC550 speed control. The battery that I used to test this setup was a 7 cell nickel-metal hydrate 730mah. When I go full throttle, the motors cut off. I would appreciate any info and opinions from any one with knowledge. Thanks in advance!

BTW the speed control is rated for 30 amps , 50 burst

scott88-RCU

My Feedback: (1)

totally possible, but you need to make sure you don't burn out your ESC with too much draw. If these are brushed motors then yea you can do it. If you don't know the amp draw of the EDFs then look it up at www.gws.com.tw and they have many data tables showing amperage on different props. Good luck.

Matt Kirsch

My Feedback: (21)

Simple answer: You're drawing too much current from the battery. Each of those fans draws 2.5 to 3 Amps. Times four, that's 12 Amps total. A 730mAh NiMH pack is only good for about 6-7 Amps.

Every battery has a limit as to how much current draw it can withstand. This is due to the battery's internal resistance. The higher the internal resistance, the less current the battery can withstand. When you exceed a battery's capacity to withstand current draws, its voltage drops drastically. Eventually, the voltage drops below the LVC point on the speed control, and it shuts the motors down.

You need a better battery, like a pack of KAN1050 cells, or perhaps even a pack of CBP650 cells, or KAN650 cells.

V12DRIVER

My Feedback: (13)

Thanks for the info Matt Kirsch. I will try another battery that is more suitable for those conditions.

V12DRIVER

My Feedback: (13)

Got to fly my 747 today and it was a success. I installed 2 speed control ( 1 for each pair of edf50s) and 2 7 cell nickel-metal hydrate 730 mah batteries ....total weight 29 ounces( fixed landing gear with very small, scale-looking wheels included). takeoff rollout was about 150 feet and required alot of elevator to rotate. Once up in the air trimmed out ( lots of up elevator) it flew flawlessly. I had to throttle back to about half throttle to make it look scale but was still a little too fast. After 7 minutes it was time to bring it back home. I cut the throtte on the upwind turn and it glided extremely well. I am going to try adding flaps and leadind edge slats/flaps to see if the plane will slow down more on the approach . I was very impressed the way this palne flew with this power setup ....... it flew better than my A-10. Love this hobby!

john 8750

Glad to hear that!
I sure did enjoy your story.
I'm building a B24. 35.5" 13 ounces. Has 4 IPS motors with 3030 props. The smallest radio gear and a 1200 ma e-teck battery.
I expect it to fly well.