This is my next project, and I need input.

Here is what i'm thinking.

A twin rotor (counter rotating)
12" blades
25" total rotor span
E-flight 370 Brushless motor
GWS gear box 6.6:1
12x6 prop
AUW 13oz or less

If i'm way off base let me know.

How much flight time do you have on autogyros?
Other answers depend on this question....
mickey

I built a twin rotor 40 size in the late 80s, it was my on design based on the article in RCM (Roto-Falcon).
Once I got used to the flight characteristics it was a lot of fun. The biggest problem I had was with high speed it would try to roll over, but just as it started to roll if you would back off the power it would straiten right up. Last week a friend of mine built a fixed head single rotor (two blade) gyro, I was the test pilot and after we got the tilt angle on the head correct it flew just fine, we thought, several laps around the field, and a touch and go, well almost go it never got out of ground effect, I guess I got behind the power curve, No problem we just put in a new battery, and up again, climb out was fine, slow left turn, oops roll over to the left (slam) gravity bitten. We didn't see any reason why it rolled over, checked it out, and put on a new prop and went again. This time it flew fine left and right turns no problems, a little under powered but it flew. We flew it or I should say attempted to fly several times, and at least one out of three times it would roll over. He is using G-10 FG .040!QUOT! thick as a flapping hinge it may be a little thick. Well I guess I got a little off the subject, but thats my experience with Auto-Gyro's thus far.

I do however fly Planes and Heli's quite well, at least in my on mind.

Randy Wishon

p.s. My flying is much better than my spelling and grammar.

Hi,
This looks like a model from a plan called "Al's Gyro". It was quite successful so should go well scaled down as per your plan.The "coning angle" of the blades was quite critical.I will e-mail you the magazine article. A photo is attached.Bill

It's doable but you will have to be quite weight consious. Read the RCM info about Al's gyro for ideas. I am sure Gyronuts can help as well since he has similar experience.

Good luck,
Bob G

My next question is concerning rotor area.
I know that that R squared x pi = area, but what I'm not sure of is if I have two rotors spinning in opposite directions, do I add a certain percentage of the second rotor to total area or not. I know when you figure the area of a fixed wing bi-plane the area of the second wing is not 100% efficient so we normally say total area -25% to get effective area (something like that).

RW

You are into a zone with very little information. There was an RCModeller plan called the Super Libelle which was
a coaxial. The upper rotor was a different size and set to a different pitch.
There's not much info to help with. The suggestion to fly a similar model first (Al's auto I think) and learn
what works is probably the best advice you'll get. I'd expect that you will need a different top rotor from the bottom one, probably with more negative pitch. You'll be definitely doing lots of experiements. Who knows the first guess may be right on the
money and it will fly right off the board.
mickey

Super Libelle
RCM plan #708
1977
http://www.rcmmagazine.com/e/env/000...ml?command=env

http://www.rcmmagazine.com/e/env/000...s-list-11.html

also check out plan #1001, gyro falcon, also a coaxial

Hi,

For what it's worth, I built a coaxial rotor gyro several years ago. Both top and bottom had 3 rotor blades, and both set of rotors had a fixed coning angle to ensure that they didn't get tangled up, and I didn't see any difference in the lift by adding the 2nd rotor. At the time I was using a Clark Y profile blade with a twist at the root end of the blade. However, it looks cool flying.

Phil