Hi everyone.
I am useless with electrics and I am trying to design a UAV as a final year project. I have so far found that Kokam 1200mah batteries have excellent energy density levels, and have a list of motors to choose from, however I am having difficulty in matching each item, could any body tell me a little about speed controllers!!! I understand some of the workings i.e the pulse voltage regulates the motor speed, but what happens to the current, does this stay at a constant level or does the speed controller adjust this factor with the voltage. I am looking to match a Hacker B20 12L with a combination of kokam 1200 batteries.any suggestions. thankyou for your time[:-]

Are you using the 4:1 gearbox on the hacker? what prop are you thinking about running? This will help determine amp draw and the speed control you need..

... and then the batteries after the amp draw question is answered...

thanks for replying, erm will I need to gear it down. The spec is for a trainer aircraft for a novice pilot to fly, up to now its been direct drive. I need to sort the whole propulsion system before looking into weights and size apparantly, well thats what the teachers tell me, so I have chosen Kokam 1200mA batteries, and the hacker motor. I feel the skill needed is experience when it comes to compatability. After the motor selection for an aircraft, is the propeller or the speed controller the next task to research. again thanks[]

specifically what plane are you trying to put this combo on?

The plane has yet to be designed, wing area, loading, velocity, size etc. hopefully shall follow after the propulsion system is complete. []

I would assume you need to do it the other way round. Design and determine the airframe first, then from that you can come up with a suitable power system using the basic specs of the plane. Weight, type of wing layout, intended flying qualities,(trainer, sport, aerobatic), will have an impact on which power system you will need.

Jesse