Tuesday, February 16, 2010

selection of MOTOR,PROP and ESC

selection of motor entirely depends on the weight of the quadrotor,
here i have given some commonly available motors with respective weight of quadrotor,
one should always take a margin so that he can add extra features later (like real time videography or fpv),
thrust can be multiplied by 4 to give the total thrust so here i am giving thrust of one motor at normal running conditions and recommended propeller.
model voltage current thrust esc prop model wt.
cf2812 11.1v 11 a 460g 18a 8*4.8 1kg
cf2812 7.4v 10a 320g 18a 7*5 800g
cf2822 11.1v 12.3a 720g 18a 8*4.8 1.5kg
cf2822 7.4v 9.3a 430g 18a 7*5 1kg

slow flyer props are preffered in quadrotor.

Saturday, February 13, 2010

HOW MIXERS WORK


I am sure you are familiar with radios and receivers and such, so i will move to the v-tail mixers.
A v-tail mixer(or simply mixer) takes two signals, one through a master input and one through a slave input.
There are two wires that come out. One of them will be the master input + the slave input, and one will be the master input - the slave input.
So if you had a master of (a random number) 6, and you had a slave of 3, one output would be 9 and one would be 3. When you average the two values you get 6, the master input value. This is the case for any set of values that comes through.
So if you hooked the master up to a throttle channel , and the slave to an  aileron channel and place the motors  you are controlling with them on  opposite ends of the model. When you increased the throttle, both motors would speed up. When you slave input, one motor will speed up and the other one will slow down. This will cause your model to tilt, but your average throttle will remain same.

If you wanted to control both aileron and elevator, you have to split up the throttle chanel, one going to the master of each veetail and elevator to the spare slave channel on your new mixer, and you have control of both aileron and elevator.
for a quality control system mixer resolution must be in the range of 200-500 steps per second.