ANATOMY OF A RACING QUAD

“You have the flight controller in the middle, which is grey. It receives a command from the radio receiver, that purple thing. It tells the flight controller what you want it to do. The flight controller knows which orientation it is in, then it gives a certain command to the eucs, which spin the motors at a certain r/min. And that’s as simple as it gets. Most hardcore racers fly in accro mode, so the only sensor that the flight controller uses is a gyro, which measures rate of rotation, so this thing doesn’t know if it’s upside down or sideways. All it knows is if it’s rotating or not. If the gyro measurements are all zero, it knows it’s in a certain orientation. If I’m not giving it an input, It knows it shouldn’t be moving. If the wind blows it, it corrects against the wind. The only time it moves is when I tell it to rotate. Outside of the one sensor there’s just clever codes.

The radio link is 2.4 GHZ, but it’s not prone to inteference because it does frequency hopping. I’m not sure of the exact technology, but on spectrum it’s DSM2. So your control isn’t an issue. The radio sends a control link to the quad and if the quad loses that, it will wait for a second and then drop out of the sky because it doesn’t have a GPS or anything to return to home. And then the FPV is a completely different system; it just gets power from the board.

There’s this conundrum: if you want to go faster, you get props with a higher pitch angle. But you need stronger motors to drive them and those motors will draw more current, so you need a stronger battery and your whole quad just gets heavier. There is an optimal point. In general, the motors don’t have to get bigger or stronger, they get rated differently. Size determines power consumption, but also KV determines power consumption and KV is basically how fast it spins with one volt and zero load. A higher KV motor will spin faster, but you’ll also have to put a lighter prop on it. You’ll get more thrust, sometimes a lower KV motor will spin slower, but you can put a heavier prop on it because it has more torque, which will also give more thrust. You kind of have to decide whether you want to kill your batteries or not. Generally that’s the defining criteria: can you afford to buy more batteries on a regular basis or not.”