Stick shake video

[WaspAir]

When wooden blades were more common, they would "take a set" and act unbalanced owing to moisture absorption and the unsupported load from their own weight. To avoid that, it was common to place a stand under each blade to offer support at both root and tip while tied down or hangared. Modern blades are far less susceptible, but you can still use tip stands if you have an issue.

 

[Abid]

When wooden blades were more common, they would "take a set" and act unbalanced owing to moisture absorption and the unsupported load from their own weight. To avoid that, it was common to place a stand under each blade to offer support at both root and tip while tied down or hangared. Modern blades are far less susceptible, but you can still use tip stands if you have an issue.

Its not worth it. In about 15 minute flight with some turns that set is gone

 

[500e]

Have used PB, DynaVibe and Chadwick the PB DV is good and simple and at a price that does not cause hart problems
Balance on the 500 and 300 is not difficult if the blades weigh the same both root and tip not just overall weight
The pigs are where the blade weight is 50/100grams different we have seen blades 300 grams 10.5 Ozs different blade to blade.

On some 4 blade Heads with no blades on 20 to 30 grams out same or more on 5 blade heads.
If you start with a known out of balance you are just hiding the problem

 

[Roundwing]

Is there a chance of someone qualified hosting a seminar at Mentone on the basics of how to reduce the stick shake in our gyros?
It does not to be in great detail just an idea on where to start and the process.

Rick

 

[Mike G]

Is there a chance of someone qualified hosting a seminar at Mentone on the basics of how to reduce the stick shake in our gyros?
It does not to be in great detail just an idea on where to start and the process.

Rick

Rick it looks like you want something like Chris Buchanan organised for 2022 Bensen Days.





Mike G

 

[Mike G]

OR
As
Rick Elliot organised for the Australian ASRA Nationals.

The description of that "workshop" session was :
The “Rotor Track and Balance Workshop” is a simple 1 - 2 hour presentation. It is not a rotor track and balance training session, that would be much longer and more detailed.
The aim is to help owner/pilots to understand what track and balancing is about and how a balancer works. Covering things like, the acceptable vibration limits, what the Polar chart is and how to read it and what the balancer can and, more importantly, cannot do.
The session starts with a very basic, no maths, introduction to vibration frequency analysis and the frequency spectrum to help participants separate out the different gyro vibrations and includes videos of different stick shakes to help diagnostics without complex tools.
The session usually ends up with a lively debate.





Mike G

 

[Mike G]

Thanks Wayne,

I am familiar with the Commander's work. I am more interested in heavier tandem gyros. I have found a few videos online featuring AR-1, TAG, and Auto Gyro machines.

I am hoping I can see what current owners are experiencing.

For example, I found these online. To me it is an unacceptable shake. Am I being unreasonable in my expectations? I am very interested in the opinions of several contributors on this forum.

or

Jim

Jim
You've posted one of my videos but not the one that goes with it. There's a post somewhere on the forum but I can't find it.

These two were taken about 5 minutes apart to demonstrate the effects of control system friction.
Note the stick shake in the first video is all 2/rev.
Mike G

 

[Mayfield]

Jim
You've posted one of my videos but not the one that goes with it. There's a post somewhere on the forum but I can't find it.

These two were taken about 5 minutes apart to demonstrate the effects of control system friction.
Note the stick shake in the first video is all 2/rev.
Mike G

Thank you Mike,

A dramatic difference! I'm considering getting back into gyros, purely as a recreational pursuit, but have a pretty low tolerance for stick shake. It seems some folks have quite a bit higher tolerance than I do.

Jim

 

[ventana7]

I have a request of forum members.

Could some of you please post videos of your stick and airframe in flight? Videos of the stick at both pilot stations would be great.

I would like to know if my expectations vis-a-vis stick shake and airframe shake, are reasonable.

Although I fully understand that a rotating rotor will induce vibrations into the system, it is also my thought that vibration, in the controls, and the airframe, can be minimized.

I have always thought of vibration as potentially destructive and sometimes a warning of wear or other damage.

A description of the aircraft and some rotor specs would help me understand what I am seeing with your videos.

Although I am primarily interested in tandem gyroplanes in the 1200 to 1320-pound range, lighter or heavier gyro videos would be useful.

I am appreciative of any information you are willing to share.

Jim

Jim,

Here are two videos of my two place enclosed Xenon with me flying hands off. It is pretty good but nowhere near as stable for long hands off flying as my RAF/Sparrowhawk was.

Please ignore that one turn where the yarn shows me way out of co-ordinated flight- My instructor Terry Brandt did not teach that and my DPE Jim Mayfield would not have approved.

Rob

 

[AirCommandPilot]

Thank you Bobby. What do you think, subjectively, of the cabin hop and stick shake? The shake did not look bad to me, the cabin hop a little more. Roughly how much does your AC weigh?

Jim

The "cabin hop" was there, but very minimal. The camera always makes it look way worse than it is. My machine weighed around 560 lbs at that time.

 

[Mayfield]

Covering things like, the acceptable vibration limits, what the Polar chart is and how to read it and what the balancer can and, more importantly, cannot do.

The session usually ends up with a lively debate.



Mike

Hi Mike,

Is there a consensus on acceptable vibration limits?

Jim

Note: I fully realize how foolish my question above is, but thought I would ask.

 

[rancherman]

I seen a youtube vid yesterday, where the passenger in a tandem was getting all the typical footage in-flight.
Showing the 2 handed death grip of the pilot... and for some reason, she panned up to the rotor head, and suddenly the video went to slow motion.

I swear, you could SEE the control rods alternating flexing- bowing out- on each 180* makes sense i guess, a compressed tube has to go 'somewhere'.

Maybe y'all seen it already.. It's got to be the worst shake I've seen recorded

 

[okikuma]

I seen a youtube vid yesterday, where the passenger in a tandem was getting all the typical footage in-flight.
Showing the 2 handed death grip of the pilot... and for some reason, she panned up to the rotor head, and suddenly the video went to slow motion.

I swear, you could SEE the control rods alternating flexing- bowing out- on each 180* makes sense i guess, a compressed tube has to go 'somewhere'.

Maybe y'all seen it already.. It's got to be the worst shake I've seen recorded

Paste the YouTube video link from your URL window.

Wayne

 

[ventana7]

I have a request of forum members.

Could some of you please post videos of your stick and airframe in flight? Videos of the stick at both pilot stations would be great.

I would like to know if my expectations vis-a-vis stick shake and airframe shake, are reasonable.

Although I fully understand that a rotating rotor will induce vibrations into the system, it is also my thought that vibration, in the controls, and the airframe, can be minimized.

I have always thought of vibration as potentially destructive and sometimes a warning of wear or other damage.

A description of the aircraft and some rotor specs would help me understand what I am seeing with your videos.

Although I am primarily interested in tandem gyroplanes in the 1200 to 1320-pound range, lighter or heavier gyro videos would be useful.

I am appreciative of any information you are willing to share.

Jim

 

[rancherman]

Paste the YouTube video link from your URL window.

Wayne

after watching it a couple more times, I think I was fooled by the curvature of the fairings around the control rods.. lot's of shiny surfaces reflecting/magnifying movement!

The slow motion part was very interesting though!

 

[ventana7]

Jim -here are a few more videos- in one you see me flying hands off and when I do touch the stick you can see it is a light touch with thumb and forefinger.

The second video is flying around the bases of the 14,000' mountains that provide spectacular scenery where I live.

Rob

 

[okikuma]

More on 2/rev cyclic stick shake.

Wayne

Video

www.facebook.com

 

[Mike G]

Hi Mike,

Is there a consensus on acceptable vibration limits?

Jim

Note: I fully realize how foolish my question above is, but thought I would ask.

Jim, there's nothing foolish about your question, if you didn't know, it would be foolish not to ask.

The usual number used when balancing helicopter rotors and FW props is 0.1 IPS and that is the number used by most guys balancing gyro rotors. Some manufacturers say balance to below 0.2 and I tend to agree with them.

In this photo I’m explaining to the participants that there are 3 numbers to remember.


0.1, 0.5 & 1.0 IPS.

Less than 0.1 IPS is excellent and the goal when balancing.

Between 0.1 and 0.5 is acceptable and probably not worth balancing unless you have access to a balancer and some time to spare. You will probably not feel a big (if any) improvement in your seat and may feel an improvement in the stick if you went from 0.5 to 0.1, but not much (if any) from, say, 0.25 to 0.1.

Between 0.5 and 1.0 it’s strongly recommended that you get the rotor tracked and balanced and you’ll certainly feel the difference.

Above 1.0 there’s no debate get the rotor tracked and balanced.

Some clarifications,
these numbers are :

a) Debatable, I choose them because they’re easy to remember and experience has proved them to be reasonable. Obviously, you need to approach these numbers with a degree of intelligence and not get into the sort of discussion “is 0.51 really worse than 0.49?”.

b) Zero-peak, not pk to pk or RMS.

c) IPS, which is velocity, at a typical gyro Rrpm, 0.1 IPS is about 0.01G if you’re measuring acceleration.

d) Are for vibration filtered to synchronous frequency (1/rev) not total vibration values.

e) Are taken using two orthogonal sensors perpendicular to the axis of rotation and both sensors should read below or within the band of the numbers given.

f) are for vibration measured next to the rotor bearing, values measured elsewhere will tend to be lower unless there is some sort of resonance within the gyro frame/chassis/undercarriage/tail.

I hope this helps.

Mike G

 

[Mayfield]

Thank you Mike. I feel more comfortable having a goal established. A goal of 0.1 IPS with up to 0.5 IPS being acceptable, in most circumstances, makes sense to me.

Jim

 

[okikuma]

That was back when the earth was young and pterodactyls ruled the skies, Wayne. But my memory says I got it down to an acceptable level.. I used a Boyette head and 30 foot Sky Wheels.

Jim,

Revisiting your modified Parsons with the 30' Sky Wheels rotor blades. Did you ever experience the notorious pitch-up problem when entering an updraft / thermal as mentioned by others who have flown on Steve McGowan's Parsons and Steve Graves Marchetti with Sky Wheel rotor blades?

Wayne