3 ms·
Most quadcopters aren't gas-powered because they rely on rapidly adjusting the speed of brushless motors attached to fixed-pitch props to control their attitude
by bri3d 11y ago
Most quadcopters aren't gas-powered because they rely on rapidly adjusting the speed of brushless motors attached to fixed-pitch props to control their attitude.
A few hobbyists have built gas quads with variable-pitch rotors, but the amount of mechanical complexity and hassle involved makes a similar nitro-powered single-rotor helicopter more appealing for most hobby applications (stunt flying etc).
As more novel designs that don't rely on precise motor speed control (for example, this one) come into play, I think gas motors will make a minor resurgence as people rediscover the energy density (and therefore flight time) they can achieve.
However, for most hobbyists, electric just makes more sense. It's usually quieter, works indoors, is generally a lot less of a pain in the ass to deal with (no need for starters, glow plugs, choke, adjusting mixture, engine maintenance, etc.), and is usually less heavily regulated.
- jotm 11y agoGas engines could be coupled with one or several CVT transmissions?
- bri3d 11y agoI think you could just use the simplest form of CVT: a variable-diameter pulley under each rotor. You'd still pay a pretty big cost in terms of mechanical complexity, though, which makes the swashplate system more appealing as offers a lot of additional advantages in terms of thrust vectoring.
- SeoxyS 11y agoWhy not hybrid? Have an onboard gas generator to recharge the batteries. As soon as the gas runs out, the drone has X min of battery flight time left to get back to solid ground. No need for mechanical complexity.
- jotm 11y agoHell, you could have a small buffer ultra capacitor or battery providing the motors with electricity while a gas engine at constant RPM recharges it. The whole system would have to have a very high conversion efficiency though...
- bri3d 11y agoThere's an MIT spinoff called Top Flight that was working on a hybrid quadcopter, IIRC. I think the main reason you don't see them in the hobbyist space is size floor (you need a pretty big machine to make the weight overhead of the motor, generator, and charge circuitry work out) and money.