4 ms·
Because quadcopters are naturally unstable, so you need complex electronics(and sensors and electric motors) to control it. You can make helicopters very stabl
by Htsthbjig 12y ago
Because quadcopters are naturally unstable, so you need complex electronics(and sensors and electric motors) to control it.
You can make helicopters very stable just with weights in the rotor, like any RC fan knows.
Until very recently the inertial motion control complex elements were very expensive.
Accelerometers in cars and gyros in smartphones later had made those sensors inexpensive. The iPhone was released in 2007, that was 7 years ago.
Every air device carries gyros inside, but for controlling the plane they had to give you a digital signal, it is not enough with the artificial horizon sphere.
The simple helicopter design has been mass produced for decades(and wars like Vietnam subsidized them more), and it is well tested and reliable. Any new design has to compete in price and will have to iron lots of bugs at first.
The second most important reason is that you need to use electric motors as normal heat engines could not respond as fast as needed.
So in order to make a quadcopter you need to generate electricity onboard, which means a big hybrid engine.
I see quadcopters as the future, but in order to compete in price, they will have to evolve from small UAVs.
- Htsthbjig 12y agoPS: In order to understand how much wars influenced the development of helicopters, my father used to work manufacturing helicopters in Spain. When Vietnam war ended, the market become so saturated and the prices went down so much that the company my father worked in could not compete and closed its doors.
- headShrinker 12y agoYou touch on a number of good points here. It's true you need accelorometers measuring and giving feedback a few hundred times a second. Electric motors are the only motors that can respond to feedback that fast. So the batteries will be a big deal on a scaled up quad. The most important aspect you didn't mention is that they are inherently inefficient. The more blades you have, the more inefficiency is introduced. that's why scaling them up doesn't make much sense.
- mrestko 12y agoWhy couldn't you use a turbine to generate electricity that is then fed to electric motors controlling the blades? Is there actually a requirement for large, efficient batteries?
- YZF 12y agoYou've just added a bunch of weight and lost a whole bunch of energy in the process. (EDIT: vs. just not using electrical motors. vs. batteries it really depends on the specifics but if you could get what you get out of a battery with a turbine of lesser weight then presumably we'd all have little turbines in our iPhones and electric cars)