I am told that motor power is more important than overall weight in controlling a quadcopter in wind.
So, my follow up question is: what are generally considered to be the power ranges (in kv) for brushless motors (each) that are used on quadcopters?
Very-Low to Low
Low to Medium
Medium to medium-High
High to Extra-High
I figure once I know these ranges I can decide on a few motors, design my frame, figure out the total weight and then recalculate my power-to-weight ratio to see if I am happy with where I am at.
Wile_E_Wolf:
what are generally considered to be the power ranges (in kv) for brushless motors (each)
Kv (aka motor voltage constant) is absolutely nothing to do with power.
Its simply the ratio of no-load motor speed to supply voltage at full throttle.
If you measure it in radians/sec/volt it has the same value as the current
constant for the motor (in newtons / amp)
You need to know the supply voltage, prop size and pitch and max power before
deciding on the Kv value, There are online calculators for static thrust and power v.
prop-size and rpm.
"low", "medium" etc are utterly meaningless wihout numbers.
You need to know the supply voltage, prop size and pitch and max power before
deciding on the Kv value, There are online calculators for static thrust and power v.
prop-size and rpm.
The response time of a quadcopter to external forces is a function of the motor Kv and prop size. The higher the Kv and smaller the prop the faster it can correct for wind. The lower the Kv and larger the prop the slower it can correct due to prop mass and motor rpm. The trade off is the smaller the prop the smaller the thrust (lift) and as the prop gets smaller and motor Kv gets higher, the the current draw increases lowering the battery life (flight time). If there was a simulator that allowed you to enter Kv, and prop size as well as wind speed, you could try different combinations to find the best match but simulators (that I have seen and used (I have Reflex XTR and it doesn't have quadcopters) do not usually account for flight time because they assume a battery with infinate flight time (or gas engine with unlimited fuel). I don't think RTF (Ready to Fly) weight is as critical as thrust to weight ratio.
I think that logic applies for a dumb ESC that doesn't try to establish rapid
equilibrium to a new rpm rate - ie one that has torque or input power control
feedback loop rather than a speed feedback loop.
An ESC designed for quadcopter use should, I reckon, be controlling rotor speed directly
with a PID loop to get rapid control of static thrust (if necessary actively decelerating
at times). Static thrust is strongly a function of prop speed, whereas torque and power
also depend on acceleration? Well I suspect this is the case.
It would appear you have not built a quadcopter.
The Flight Stabilization system has connectors for the ESCS. The ESCs need to be programmed for soft shutdown so the quadcopter won't drop out of the sky like a dead bird when it reaches cutoff voltage. Additionally ,parameters like FAST START,
and slow start need to be configured as well as brake, which probably should be soft brake.
The PID part you are referring to is in the FLIGHT STABILIZATION system.(which some people just call the "controller").
If you want mess with everyone's mind, you can put a audio circuit on it with a 5W amp that plays sound of gas engine based on throttle signal. I've seen them . Funny as hell.
haha, thats right up my alley. I just learned about a little thing you can put on your exhaust and it sounds a bit like you have a turbo- makes me laugh.
some guy put a 6" piece of rubber tubing (like a tire innertube but straight) on the exhause of his small Fiat compact (little box car)
and the revved it up. Then he cut 1/2" sections off of it and repeated the test. Initially, with the long piece it sounded like someone
farting. As he continued the process, trimming off pieces, the pitch changed and started going up. Eventually, it sounded like a Ferarri. He took a video of it and it was broadcast on network tv on a morning show (spanish channel) and it was hilarious !