Overhead Stick - Drag vs. Control at Higher Speeds?

[Brian Jackson]

Good morning Fellows.

For those whom have flown a gyro with an overhead stick, do you notice any aerodynamic (drag) forces acting on the stick? My curiosity concerns both uncontrolled input and pilot arm fatigue. I imagine the rotor spring could partly compensate for the stick drag at higher speeds, but I'm trying to get a better understanding of how a gust or turbulent drag acting on the stick might influence control and input pressures. Any insights appreciated. Thank you.

 

[gyrojake]

Not really, the only difference is the stick motion is opposite and the length of your stick will dictate comfort and leverage.
Still needs trim spring with a standard gimbal and if the stick is not offset it becomes a visual nuisance.
Some people put a short overhead as a redundant control

 

[Brian Jackson]

Thank you, Jake. I have the geometry worked out but wasn't sure if there would be any unforeseen forces acting on it that I haven't taken into account. Would rather ask the experts than assume. Another item to scratch off the list of things to fret over. That's progress! Love your new heli build by the way.

 

[EI-GYRO]

No noticeable aero drag forces on mine either. Interesting comment from Jake re the offset kink in the stick. I was delighted to get rid of that,
and find no problem with the visuals with a straight stick. Its a bit like looking out a window. You don't really notice the window frame bars, if they are
narrower than the distance between your eyes. You kind of see round them. Not so with the crossbar, however, and it can obscure instruments a bit.
Comfort-wise, I find it quite comfortable, more so than it appears or than I expected. You can set it to suit yourself.
Side-note; I have a piece of stiff fuel tube inserted down through the stick for redundancy in the event of a stick break. It would give adequate residual control and is not so heavy.

 

[Brian Jackson]

No noticeable aero drag forces on mine either. Interesting comment from Jake re the offset kink in the stick. I was delighted to get rid of that,
and find no problem with the visuals with a straight stick. Its a bit like looking out a window. You don't really notice the window frame bars, if they are
narrower than the distance between your eyes. You kind of see round them. Not so with the crossbar, however, and it can obscure instruments a bit.
Comfort-wise, I find it quite comfortable, more so than it appears or than I expected. You can set it to suit yourself.
Side-note; I have a piece of stiff fuel tube inserted down through the stick for redundancy in the event of a stick break. It would give adequate residual control and is not so heavy.

Thanks for the observations. I assume the "kink" being referred to is the radius just forward of the rotorhead on the older Bensens when viewed from the side. The preliminary design of mine is similar, but more of a shallow "Nike" curve that attaches to a more familiar vertical hand grip in lieu of the horizontal cross-bar. There's a reversing mechanism that mimics the stick movement directions of a conventional walking beam that I didn't want being confused for the backward linkage found on most overhead sticks. Cierva used a similar reversing linkage if I'm recalling their patent drawing correctly.

I like your idea of using an insert element for redundancy. Though I cannot cite a specific control stick failure, I've heard it discussed that there have been, and that strengthening the stick is advisable. The tentative plan for mine is to do a thin composite (carbon) external wrap, letting the aluminum tube act as a substrate. This would allow the wrap to form a slightly airfoil cross section if desired, which led me to ask the original question in this thread.

I appreciate the responses greatly. Thank you.

 

[Alan_Cheatham]

Cierva used a similar reversing linkage if I'm recalling their patent drawing correctly.

Cierva did use a reversing link so the movement of the overhead stick's grip mimicked that of a stick controlled airplane, i.e. back for pitch up and right for right roll. Pitcairn did also as you can see in this video.

Many years back I ran across information about a study that was done about a persons adaptability to a reversing vs non-reversing overhead stick. If memory servers non-pilots adapted more quickly to a non-reversing overhead and pilots with fixed wing experience adapted better to the reversing overhead stick although they did find the reversed arc of the overhead confusing at times.

 

[gyrojake]

You gotta quit using the word Experts, you'll get more responses.
I myself have no dignity or pride, but many would feel narcissistic answering a question for Experts !!
It doesn't take an expert to answer most of the questions you ask.

 

[Brian Jackson]

You gotta quit using the word Experts, you'll get more responses.
I myself have no dignity or pride, but many would feel narcissistic answering a question for Experts !!
It doesn't take an expert to answer most of the questions you ask.

Point taken and agreed. Since anyone whom has piloted a gyro is above my knowledge level, I used the word incorrectly to mean them. Perhaps 'experienced' would have been a better choice.

 

[EI-GYRO]

The expert is the guy one page ahead of you in the manual.

Personally, I'm just happy to share whatever I've picked up along the way. It's been fun.

 

[Brian Jackson]

The expert is the guy one page ahead of you in the manual...

I'm so gonna use that! Kind of what I was explaining earlier, but yours has better economy of words.

 

[Jazzenjohn]

I've flown an overhead stick both with it coming down straight in front of me and offset to the side for a more ergonomic movement. The straight stick has the advantage of a built in vertical indicator. The offset stick has a far easier movement for turning right (for right handed people).