Mike G

Hi Mike, did you notice this entry in the "Technical Books, Papers and Publications" section:

https://www.rotaryforum.com/forum/ro...-and-vibration

I had actually posted it for you ....;-)

Cheers, Juergen

Hi Mike,

c'est fortement domage que tu ne participe plus au forum. Tes contributions exceptionelles etait toujours une genereuse transmission de tes vastes connaissances et ca m'avait lesser esperer que nous pourrions peut'être etablir une commune dedicé a un discussion scientefique dans ce forum. Cette idee maintenant semble invraisemblable. Est ce'que tu fais des contributions allieurs maintenat?

Bonne chance!

Juergen

Hi Mike,

Many times I was looking to contact you to talk about vibrations.
I am doing a project to reduce the 2 rev in my ELA, and to learn how to do it.
This is project medium term, because in fact, I am manufacturing a three blades rotor head but will take too much, it will be a for long term project, I don’t like the two blade rotors.
My idea is to test the 3 key factors and measure the influence of each one in the 2 rev. in a graphic manner. It will be a DOE ( design of experiments) exercise.
-soft mast
-undersling height.
-in plane rotor rigidity.
For the soft mast I cut the ELA mast and made a new one. The new mast is connected by silenblocks to the frame. I have two silenblocks types, on set in rubber and one set in aluminum ( no dampening at all).
For the undersling I have a modified head that allow me change the undersling height in steps of 1 mm
To increase the rotor in plane rigidity I will modified again my head to install some extra bracing.
I hope to test and measure the influence of each factor in the 2 rev vibration value.
Also, I want to test the vibration level in the rotor and in the seat.
Once we have all the data I will share the conclusions in the forum.
So this is the reason that I am looking for a good vibration meter device.

Au revoir,

Juan Manuel Arco

Mike, I didn't want to run out of room on my last message: Sources of 2-p-r shake are:
friction in teeter bearing, axial play in teeter bearing or pitch pivot, looseness or resonance in cyclic control linkage. Teeter bolt should not be tightened like you would another gyro - it has combo bearings (thrust and axial) to eliminate axial play source of 2-p-r shake - that could be damaged if tightened too tight. First thing to do is be sure you are seeing 2-pr or 1-p-r shake - sometimes not apparent, but can be ID'd easy. If I can help, email - Greg

Hi Mike,

I don't respond on the forum any more - too much time and stress. But, I noticed your thread on 2-per-rev shake. I also noticed Chuck's comment about shake of your MAGNI rotor. I didn't see where you were talking about a Magni. Which Magni are you talking about? Magni rotors should ahve no shake - and 2-per rev shake is particularly abscent in Magni rotors. If it helps, see my article:
http://www.magnigyro.com/features/SMOOTH.pdf
Email me at [email protected] if I can help you resolve your problem. 2-per-rev shake has specific sources, and I would want to help resolve any rotor shake issues you might have that should be corrected.

I may have something you can use for the CG of the rotor.
I will send it personal email. Send your email address.
Bob Gregory
[email protected]