Discussions

Gentlemen

                Ive been really following this post with a big interest, ive been tempted to reply many times to other postings, but due to work pressures, a small mobile phone, and on the go, i waited until the next day, that never gave me the chance.

Its been a really fascinating topic, and a topic i have gleaned a lot of academic knowledge from.

Two things that have really made me think, a while back, someone posted the "Brute force and common sense approach" to this sort of engineering problem. ie take an engine that is maybe 25% bigger then the 2 motors used to fly a device like this, make it as best as you can, then sort out the short falls later, this is the brute force approach, and as a 'seasoned' engineer, used to playing with things bigger then this, this was my 'gut' feelings from the start.

The second was the 50 watts per pound to lift a UAV. Thats not an impossible reality, ive seen adverts and data sheets for small alternators that fit inside the nose cone of an RC prop, will generate from 150 watts to over 5Kw, the tiny one will cost you $2500

Somewhere along the line here, i might be mistaken in thinking, we might have missed some of the basics. I think more of the brute force approach, and less of the maths might get a more reasonable result.

Again, from my dim and distant days, when i wasted my time in Uni, and then worked in the Electrical generating field, a good rule of thumb was...expect about 80% efficiency, 85 if you wanted a bonus on your salary! Scaling things down makes the job easier, as you can factor in other quantities as well.

Please dont abandon this topic, im learning as well!