Hi John could you share anymore info on your set up,That video was 3 years ago. At that time I used a knob for control. Now I have 3 buttons and a micro controller. off/reset, Idle, where it takes it from a few RPM to idle speed of 65 RRPM, and fly, taking it from idle to full RRPM. I've seen 215 RRPM peak but it pulls past that. I use between 375-500 milliamp hours for a complete spin up. idle, taxi at idle, and full prerotation, so, between 6 and 10 full prerotations for the batteries I use. I'm working with Denis at Gyrotechnic to fit it to his rotorhead. After I do that I'll work on fitting it to existing Wunderlich heads.
I have just found a few more motor suppliers, some very powerful motors.
Alien power systems.com
I am still trying to get my head around Kv values, I understand that a lower kv will mean higher torque at a lower speed.
But in our situation we are trying to get to a given rrpm, so a lower kv motor will need less reduction to the Bendix than a higher kv motor meaning the torque applied to the Bendix will be the same.
So for our application is the Kv value of any real importance, given that the total reduction will be adjusted to suit target rrpm?
Meaning that the kw value is really the only one of use?
My question was what voltage and current did you test at? How many rotor spinups do you estimate on your battery bank before requiring a recharge? Will you be able to recharge on craft or require external power source?i guess i don't understand your questions. I tested the motor and controllers from 12v up to 40 volts to be sure everything was working good as configured and i have not tested ah draw on the batteries since i haven't tested what it will do with rotors being spun up. if it does that effectively that's all i care about. I will worry about capacity after it spools up my rotors to 200 rrpm or not. As far as conditions go not sure what you mean....weather, temps, calm winds?
I don't have a gyro to test this, but it would seem a simple experiment for someone to add (in small steps?) the equivalent weight to the top of their mast and note the change, if any.Have there been any discussions about the cause and effect of the weight at the top of the mast with this type of system?
John: Do you have a chain around the gear running all the time in flight?Few people would say anything if a person swapped their Dragon Wings for Sky Wheels but that is effectively adding 40 pounds or so to the top of your mast. How come no one is the least bit concerned about that? My entire rotorhead including prerotator motor batteries, everything, weighs 10 1/2 pounds. Most electric prerotators are lighter, not heavier, some dramatically lighter.View attachment 1146627