I would definitely try to stay away from glow or any other type of combustion engine. The only type I would even have considered would be Wankel engines, as they probably have less vibration because they don't have a piston. AFAIK it's rotary all the way?
Every glow person I've been in contact with, airplane or heli, who tried to record video or take pictures said that the main problem is vibration. As electric motors are vibration-free it seems to me to be the obvious choice. After being out of the !QUOT!loop!QUOT! for the last 2 last years it seems to be even much more so now.
Now we have access to relatively safe LiPo cells, brushless engines are much more affordable and the price of their speed controllers is also getting more affordable.
I'm considering using brushless instead of Speed480s, but as I already have the 480s I suppose I'll try with them first. I need another couple of speed controllers though..
I believe in big props, but I guess that will also cause it to be more sluggish in its responses?
We want thrust and not speed, which traditionally calls for more diameter and less pitch.
At the moment I'm searching the net for good tutorials on making your own carbon props. There is a lot out there.
I haven't decided yet if I should go for rotor blade single blades type, or for one-piece props.
Any tips/advice on this?
I guess it would be very useful to be able to control the pitch to get them balanced properly?
Does anyone know why rotor blades seems to have the same angle all the way along the blade, while props always twists a lot, so that you get a lot smaller angle at the tip? Why isn't that necessary/desirable on rotors? Wouldn't this mean that a rotor will have much more lift at its tips, and thus also be more likely to have their tips stalled?

And how about using ducted fans? I don't really think that any of the ones available on the market would be useful, because they all seem to have quite small diameter and a lot of pitch, making them useful only for high speed airplanes that need to be launched with a catapult.
According to what I've read about ducted fans a well shaped duct can increase the thrust with up to 30-40 %. That certainly would be a welcome bonus, and very useful for our DF-type flyers The problem is that such big ducts would definitely have to add quite a lot to the weight, especially since to get a good effect it needs to be a pretty precise fit, which means that it have to be stiff (carbon?)
But at the same time they would also protect the environment from the dangerous props, as well as protect the props from damage.


It's a bit surprising that there seems to be no interest in discussing the usefulness of such a device as the Co-Pilot.
It seems to be able to do the job of 2 gyros?