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Help please, this doesn't make sense

Old 09-11-2009, 12:32 PM
  #26  
flashburn
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You are not limited to just pusher props so try a standard (tractor) prop and reverse the motors(s) direction.
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Old 09-11-2009, 03:22 PM
  #27  
raflyer
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Originally Posted by flashburn View Post
You are not limited to just pusher props so try a standard (tractor) prop and reverse the motors(s) direction.
I thought about that as well since it is a 30sec job to reverse the rotation.

Also, remember that my watta is for 2 motors so divide my total in two and that number is real close to the output capability of these motors. I had the Foamy 310 twin that thjese motors came from, it was heavy but fast! I know drag may come into play some but i feel it is the props more than anything. I had APC props on it and not these rubber flex like GWS props. I am picking up some APC pushers on the way home from work today so i will let you all know how it goes. I will also try and get some rpm readings.

Just think this is really a good lesson since all the 'numbers' are in line and add up but the predicted performance is not there!
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Old 09-11-2009, 03:28 PM
  #28  
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Originally Posted by ministeve2003 View Post
I found this motor, which looks like it's the same one... most people are running it on 2cells and an 8x4.3 prop, there doesn't seem to be much info on 3cells... although to me 180watts on a 19gram motor seems a bit much.... I don't think it would last long at that... best to Prop down to apc 5x5e if your going to stick to 3cells.... the other prop you might want to try is a 6x3e it might be slow overall, but it will have alot of thrust... which may help....

http://www.hobbycity.com/hobbycity/s..._19g_Outrunner

SK
Don't forget its 173/2= 86.5watts each motor right in-line with manufacture specs. I feel is purely a thrust factor do to the props flexing from the high rpm and low forward speed. We will know tonight.

Thanks for the link!
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Old 09-12-2009, 04:08 PM
  #29  
JRBeaman
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Originally Posted by ministeve2003 View Post
yes, firemanbill's correct, numbers should face the direction of forward motion....
SK
Some props don't have numbers.

I prefer to look at the edges of a prop, as the leading edge is usually thicker
than the trailing edge, just like a wing.

Also, if there is any sweep on the prop tip, it should trail, not lead in the rotation.

Turning props around does not effect the direction of the airflow, you'd have to
reverse the motor for that, or get a reverse pitch (pusher) prop.

Like flashburn said, pushers props are limited in specs, you may want to look
into getting tractor (puller) props (wider selections), and reversing your motor.

Counter rotation may be helpful on twins, but that would require matching
pusher/tractor pair. That may be hard to find in the best specs, so you may
want to forgo the torque elimination as it may not be that significant.

Always a tradeoff...

IMHO
HTH
ENJOY!
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Old 09-12-2009, 04:55 PM
  #30  
darylm44
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I had a wing dragon 4 and upgraded to a brushless motor with lipo. This is a pusher plane. I installed the prop with the numbers pointed towards the nose and made sure the regular prop rotated counter clockwise when looked at from the nose. Worked fine.
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Old 09-13-2009, 07:11 PM
  #31  
iva
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The top speed is the function of the pitch speed and total drag of the airframe. Your total power should be sufficient for a decent performance. I believe that you would benefit from switching to a lower diameter and a higher pitch prop. Something like 5X5 or 5X4 comes to mind.
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Old 09-13-2009, 11:14 PM
  #32  
JRBeaman
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Default Good Answer, Good Answer.

Originally Posted by flashburn View Post
You are not limited to just pusher props so try a standard (tractor) prop and reverse the motors(s) direction.

Exactamundo!

And, you will also have a much wider prop selection.
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Old 09-14-2009, 05:05 AM
  #33  
darylm44
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Originally Posted by ministeve2003 View Post
yes, the formula would look like this

1.2ah x 10c = 12amps

so 12amps constant...
Yes that is the formula. In order for a battery to pull a constant 12 amps it could be

1.2amps x 10c = 12 amps or

1.0amps x 12c = 12 amps or

0.5amps x 24c = 12 amps.

The amps output of a batter is effected by both the size of the battery and the C. You can get the same output with a larger batter & lower C or a smaller battery with a higher C. Flight times will depend on the battery size.
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