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Archive for October, 2012
Posted by RicksterRC | Oct 03, 2012 @ 02:28 PM | 1,505 Views
I did some motor testing.
I did static testing. I weighed the helie's All Up Weight.
I then held them down to the scale with a wrench jammed through the skids and zeroed (tare-d) the scale.
I then recorded the "negative weight" at various times. Initial, 1,2,3 and 4 minutes and the time when the motor was no longer generating enough lift that it would be able to carry the heli. I compared stock V911 motor, stock Y911 (yellow) and V911 with SP720 replacement.
Unfortunately, I don't currently have any working Bravo SX motors to test.

I used a 130mAH fully charged battery for all the tests.
I ran full throttle the entire test.
(would be interesting to do a test where the throttle was set to the weight of the heli and time it - but that would require a lot of effort).
All three helis have Extreme Delrin main gears. The SP70 is by far the quietest.
It spins by hand silently and many more turns than either of the others.
Note these tests were performed on a kitchen counter, so the heicopters were in ground effect.

I did try to record the Blue/White with SP270 motor's lift out of ground effect by tying a 3 foot string between the wrench and the heli. This proved extremely difficult as the string's pull made the heli terribly negatively stable. I had to hold the heli gently above the scale.
For the record, it created about 5g of lift or about 20% of the helis mass. Shows why a gram gained or lost makes a big difference in real life performance!

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