I have finaly finished my first gyro. It was converted from a fixed wing trainer. I scratch built the pylon and hub with help from www.autogyro.com, and people and various posts from this web site.
It is powered by a Meco 46, has a rotor span of 72 inches, with DC control, 3 bladed hinged rotor hub limited to 30 degrees up flap and 0 degrees down flap. I haven't flown it yet, been having 30+ mph winds. Used 1/16 bass wood under the trailing edge of the Aerobalsa blades for 2 degrees negative pitch. Thanks for every ones help.

Tye.

Tye,
Your New Gyro looks good.. Should fly fine.

Just guessing but I don't think you will need the 1/16 shim with the Aero Balsa Blades.

Jim

Hi Tye - It will be a new experience! Once airborne don`t let it get too far away as orientation is much more difficult with no wings to look at. Before flying you will be able to check to find if the blades are spinning nicely - just hold the plane (with no motor running) nose high in a reasonable breeze (tending more on the brisk side than gentle) and the rotors should spin after giving them a nudge to get them started. Possibly full throttle will not be needed when the time comes to fly, if you are handlaunching. Or are you intending to take off from the ground?
Autogyro fliers may argue about this. I prefer handlaunching, at least for a start, but others may say this is wrong. I am interested to see if anyone else has something to say on this subject.
Negative incidence - When no delta angle is used I expect you will require this. I suggest you have this negative incidence for the spin tests (hand held as mentioned above) - if the rotor gets spinning well you should feel upwards pull. (ie, - lift) You could then try the same with no packing under the TE and compare upwards `pull`.
Colin Duthie

Hi Tye,

I don't know what the weight of your gyro is but it looks like you have lots of rotor for the size of the gyro. Also, it looks like your pylon is real tall and if it's as tall as it looks you will need a lot of down thrust in your engine, like about 6 to 8 degrees. With a good 46 engine it will ground loop real fast when those blades come up to speed, especially with DC control. When you apply down elevator with DC control, the rotor pitches forward but doesn't lift the tail and force the nose down like a conventional elevator. You probably all ready know that your hang angle should be about 12 degrees negative.

Remember, if you error with too much down thrust and you hand launch, the gyro will just float nicely to the ground, and usually without damage. However, if it pitchs up and you can't get the nose down it will stall, fall back on the tail or roll to the side back to mother earth. Not good!

Best of luck,

Phil

The weight of my gyro is 5 pounds 12 oz. And I had wondered if the negative pitch is too much to provide enough lift.
I thought that with agyro this heavy and with this much rotor span would be too big to hand launch.
The pylon is 11 inches tall, the hang angle is about 10-11 degrees, and the engine down thrust is about 7 degrees.
Thanks for all the input guys, I'll try the spin up without the shims.

Tye

Tintrax,
I decreased the negative pitch on the blades and there is noticeably more lift. It does take a little more to spin up though. But then again the wind isn't blowing as hard today.
Thanks for the advice guys.

Tye