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Nov 20, 2021, 08:29 PM
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help to understand Motor Specs and efficiency


Hello:
Maybe somebody can help me to undestand if i do my calculations in a wrong way...

I recently purchase four flywoo 1303.5 51150kv motors with 3"-4" props , thinking in upgrade my rcinpower 1306 3100kv with 5" props, because there are lighter, searching for more flight times and less size/weight.

But the results are weird. I am using 2s lion Sony Vtc6,

My quad,(only with receptor) fly in hover (at home) 18 minutes and spend 2.17A, with a AUW of 200g.
with hq3*2.5*3 props, so:

.....................................Voltage throttle currency.......... thrust Effciency
Manufacturer: ..........7.4.........50% ... 1.1A ... ............. 76g........ 9.34g/w
My results: .................. 7.4........50%.... 1.81A... ............. 50g........ 3.73g/w

testing with 3s battery (250g) it use 2.64A and hover 20 minutes, and the results are similar, very bad:
Manufacturer:..........11.1v .......... 50%............ 1.9A ........... 117g .......... 5.55g/w
My results: .............11.1v ........... 40%........... 1.98A.......... 62gr .......... 2.8g/w

The Rcinpower motors were:
... manufacturer..................... 7.4v........... 50%....... 1.3A ......... 89g........ 9.25g/w
....my results with fpv:...........7.4 ......... 60%........ 1.5A......... 68g.......... 6.13
and i hover 28 minutes with all fpv OpenHd /gps systems and 270gr AUW (spending 2.8A), difference, but good because is included the currency of gps, buzzer, cam, raspberry...wifi...

I am doing something wrong? Maybe only marketing/error specs? Somebody has tested this motors or similar?

Thanks
Oscar
Last edited by oscator; Nov 20, 2021 at 08:40 PM. Reason: add specs
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Nov 20, 2021, 09:48 PM
If it flies, I can crash it.
rocketsled666's Avatar
  1. If you're not using the exact same prop as the manufacturer used, you're likely to get different results. It's not just blade length, pitch and count. If your prop is less efficient than the one they used, that could explain your results.
  2. Do you know your current sensor is properly calibrated? Every current sensor I've ever used has been a big challenge to accurately calibrate. If you're actually drawing less current than you think, that could explain your results.
  3. Your ESC isn't set correctly, the wrong timing or PWM, so your motors aren't running as efficiently as they should.
  4. Manufacturers don't always tell the truth about their products.
Nov 21, 2021, 05:06 AM
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thanks,
1- i use same hq prop that test, i think "minimal" difference, but you are right about it: in 5x30 props i changed gemfan prop for graupner and i got a better flight time (much better...). I have purchase other props that are in the specs, to test the results, but I think it will be similar.
2- About currente sensor, yes, maybe it is not well calibrated, (new AIO FC from Flywoo), so used my Original Skyrc Charger to read the mAh used;
3- ok. Didnīt think about it. Maybe esc are tunnig different.
4- Maybe. I am searching for people testing from this manufacturer,.... the different is big...difficult to explain with minor changes o configurations ( and i know my "test" is not a "technical-perfect" test, sure).

thanks


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