|Jan 13, 2015, 02:07 PM|
I had a short opportunity to fly over the weekend and tried a revised version of the same throttle curve I had been using.
I changed the Normal curve to (-100/50/100), so that I'm at 3/4 throttle at mid stick and a little above that in a hover. The top half of the Normal curve matches my Idle 1 curve.
The headspeed sounded better to me and the Swift was a bit more responsive to pitch inputs.
I just did some hovering and some basic circuits along with a few hard pitch pumps to test the response. I've got 530mm Helimax carbon blades on this one.
According to the data from the Castle controller, it's pulling about 13A and 325W in a hover and maximum power in a hard pitch pump is 35A and 825W.
Recorded headspeed was about 1885 in a hover, a maximum of 1950 (at the top of a pitch pump), and minimum of 1821 (at the start of a pitch pump).
So, if these numbers are accurate I think the headspeed is about right for me.
When I get another chance to fly, I will try to test a (0, 100, 100, 100 100) Normal curve also and see how that goes. It would be nice to have a more constant headspeed.
|Jan 18, 2015, 03:25 PM|
Joined Apr 2009
Of note is that I am sure that if you used a rotor tach, you would find the Castle readings will consistently be about 10% high. I think that is because they do not take into account the fact that most motors operate at only a 90% efficiency.
I will try to explain your V curve, as simply as possible relating to voltage and KV. It is a bit more complicated then this, but this should make it adequately understandable.
Think of the ESC as a variable voltage regulator. So at the 100% setting it is feeding the full voltage from the battery. If you have a 22.2 volt 6S pack the 910 KV motor will turn at 910 x 22.2 = 20,200 rpm. At 3/4 stick it would be sending out a command for 75% to the ESC, which in turn would send less voltage to the motor so the motor speed would drop. Ditto for the mid stick position at 50% which would ask the ESC to drop the voltage to the motor even lower, which would drop the rotor speed even more.
If you would run a straight line across the top as RA is suggesting, then your ESC would always give a command to the ESC for a constant voltage. This would result in a constant rotor speed. As the pitch changes resulting in the loads increasing and decreasing, the motor will draw whatever AMPS from the battery it would need to maintain that rotor speed.
|Jan 19, 2015, 01:23 PM|
Joined Jul 2008
Thank you GM, you saved me a lot of typing.
Sorry Lenny970, I was away from any computers over the weekend but GM seems to have covered it all very well.
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