Joined Feb 2013
Some logs of the same hotliner with different direct drive and geared drives
During the last two years I did some comparative experiments to test the performance of different electric drives for a hawk f5b alike hotliner, 1700mm wing span, 1300g weight. Consumed power of all drives is ~2000W on the ground.
I tested three different drives, namely:
1. A direct drive Scorpion HK3026 1000kV on a 6s LiPo on a RFM 10x8 prop
2. A HET 2W23 2950kV on a 6s LiPo on a KPG 1:5.2 gearbox on a RFM 14,5x14 and a 15x16 prop
3. A Kontronik Kira 480 2600kV on 6s Lipo on a KPG 1:5.2 on a RFM 14,5x14 prop.
Here are the corresponding logs for a 5-6 seconds vertical climb. Enjoy!
Scorpion on 10x8 direct drive:
HET 2w23 on KPG 1:5.2 on RFM 14,5x14
HET 2w23 on KPG 1:5.2 on RFM 15x16
Kontronik Kira 480-26 on RFM 14,5x14
The current measurment with the Kira was a bit noisy due to a loose contact in my UniLog sensor, but I was able to fit the data sufficiently by hand.
Interestingly with the same plane and the same LiPo and the same motor run time, the performance of all drives looks pretty similar, namely a peak climb rate of ~50m/s vertical and a half maximum acceleration time of ~2,5 seconds.
It seems to me that the efficiency and the acceleration of the RFM 10x8 prop is only a few percent worse compared with the larger RFM 14,5x14 or 15x16 props.
Next steps will be to measure the motor temperature and 'play' a little bit with the pitch of the props.
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