Mono twirl flying problems

[J 35]

Hi everyone!


I have build an Mono Twirl. I have some problems flying it. It flyes but with more or less control. I can only turn right or it rather moves sideways, hard to explain but it does not behave as expected.
Does anyone have any advise?

Best regards,
Tomas

[alfoot]

Hi Tomas,

I see that this is your first post on RCGroups - welcome :)

Sorry to hear of your problems with the Monotwirl. It would help us to help you if you could provide a few more details.

Useful information would be:-

Is it built exactly as per the plans?

What is its weight?

Motor/propeller/battery used?

Are you an experienced autogyro flyer?

Could you describe the problem in more detail?

If you have a movie of what is happening, that would be very helpful.

Al

[J 35]

Hi Alfoot!

Thanks for the answer. I´m not at home for the moment so I have not the all the details in front of me. I will get back next week.

I´m from Sweden and I´m kind of "intermediate" RC-flyer. This is my first autogyro.

My feeling is that the rotor rpm in not high enough and also that the rotorblades doesn´t flex so much. The model is build exactly from the plan with a bit extra depron to strengthen the nose. The motor is an 80 W and the battery is 11.1 V 360mAh 3s LiPo The CG is exactly under the rotor axle.

[alfoot]

Tomas,

I've been trying to understand why your Monotwirl would only turn right, and I don't have an answer at the moment. My experience was that, if the rotor was too stiff then it would want to roll left (this is with a counter-clockwise rotor as seen from above). Check out the first movie in the Monotwirl thread (now on page 4 or so) and you will see what I mean.

The low rotor speed will not help. Mine turns at 250 to 300 rpm, but it is really important to get the rotor speed up before launch. It might be worth checking for friction at the rotor post.

If you think that the blades are not flapping enough, you could try holding the centre of the rotor hub and flexing the glue joints (you did use a flexible glue like UHU Por for the blade-to hub joint?)

A final thought for now is that, to turn this (and other) autogyro, you will need to coordinate rudder with rotor tilt. As I noted in the building instructions, it turns best with the roll initiated by the rotor tilt, and the turn continued with rudder.

Hope this helps,

Al

[trikesterkyote]

This may be a mechanical problem rather than an aerodynamic one. Check for ANY play in the rotor hub and gently grasp the blades at the rotor hub and lift them up to take out any slack. Then kind of twist them around a bit. If there is any play up or down, or if the blades can get out of the range of the plane of rotation then friction can be transferred to the chassis in such a manner as to impede the ability to turn. Flying sideways is why I get the idea this may be happening. The vertical surfaces are creating enough aerodynamic force to keep the gyro from just spinning around, while at the same time the blde drag may be creating enough input to keep it from turning in the one direction.:confused:

[tashley]

Looking for plans if anyone cares to share.