Pbf
06-25-2003, 12:34 AM
#1
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Ok, I'm going to make an electric PBF. I have a Speed 400 motor, a 7C 720maH NiMh, a Hitec SP-1010 10A ESC, 3 GWS Pico Servos. I plan on using 14" x 14" 4mm Coroplast for the wing and a 1:3 gearbox. I would like to be able to hover and do 3d with this plane, but also fly around a bit too. I just need to know which prop size would be best for this setup. I already have a 9x6 and a 10x4.7 Slo-Flyer props here if those would work. Any help would be appreciated, thanks!
06-25-2003, 02:41 PM
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It might help to get a trial copy of
www.motocalc.com then you can play some games on paper
before you buy props, motors, gearbox's, even the airframe.
CU
www.motocalc.com then you can play some games on paper
before you buy props, motors, gearbox's, even the airframe.
CU
06-25-2003, 03:20 PM
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Pbf
You can't just combine random leftover parts together to make an electric airplane, unfortunately.
I can see some potential problems. First, the SP1010 has only 3 or 4 distinct throttle settings, and causes the motor to vibrate badly at anything but full throttle. Hovering requires accurate throttle control. Second, 720mAh batteries may not be robust enough to handle the currents required of them. Motocalc says that a Speed 400 geared 3:1 on 7 cells will draw 6.0 Amps with a 10x7 APC thin electric prop (not a slow flier), so you're probably okay. That said, third, you may not have enough Watts to hover with your choice of power system. Motocalc also says you'll get a "whopping" 8.3 oz of static thrust, so your plane will have to weigh less than 8.3oz to hover. Unfortunately, the power system will weigh more than 8.3 oz, without the plane.
I can see some potential problems. First, the SP1010 has only 3 or 4 distinct throttle settings, and causes the motor to vibrate badly at anything but full throttle. Hovering requires accurate throttle control. Second, 720mAh batteries may not be robust enough to handle the currents required of them. Motocalc says that a Speed 400 geared 3:1 on 7 cells will draw 6.0 Amps with a 10x7 APC thin electric prop (not a slow flier), so you're probably okay. That said, third, you may not have enough Watts to hover with your choice of power system. Motocalc also says you'll get a "whopping" 8.3 oz of static thrust, so your plane will have to weigh less than 8.3oz to hover. Unfortunately, the power system will weigh more than 8.3 oz, without the plane.
