Dave,
I found this stuff by accident and thought you might be interested. I put it here so every one could read, but it get's deep fast.
http://www.rotaryaviation.com/PSRU Zen Part 1.htm
Read the section under torsional resonance.
http://www.rotaryaviation.com/PSRU Zen Part 2.html
Read the first part.
After reading this, I concluded that the damper should be between the engine and the gearbox. What do you think?
I also found a brief explanation of how to measure torsional resonance. It is not that hard to do. If you are interested I can research it further, or you can, either way:
"A torsion damper of some type-either a spring or elastic coupling, a
quillshaft, or a belt or chain with a little stretch-is an absolute
necessity. There's a simple way of measuring the torsion flexion which
can be quickly used to troubleshoot the problems: on either side of the
coupling, a "tone wheel" or regularly spaced magnetic or optical 'mark'
is placed and a pickup-a LED/sensor or a simple solenoid coil (think
electric guitar or Hammond organ)is placed. The phase relationship
between the two signals is monitored and as the engine/load are cycled,
where the two signals "wobbles" is where the flexion is happening.
It's a simple test to rig up. OMC and Mercury have been doing this for
years. I know because I worked in a music store in Wisconsin and they
would buy a certain type of internally amplified guitar pickup for this
purpose."
This is from a forum discussion that you can access in the rotary airboat thread. It is the last link.
jim
I found this stuff by accident and thought you might be interested. I put it here so every one could read, but it get's deep fast.
http://www.rotaryaviation.com/PSRU Zen Part 1.htm
Read the section under torsional resonance.
http://www.rotaryaviation.com/PSRU Zen Part 2.html
Read the first part.
After reading this, I concluded that the damper should be between the engine and the gearbox. What do you think?
I also found a brief explanation of how to measure torsional resonance. It is not that hard to do. If you are interested I can research it further, or you can, either way:
"A torsion damper of some type-either a spring or elastic coupling, a
quillshaft, or a belt or chain with a little stretch-is an absolute
necessity. There's a simple way of measuring the torsion flexion which
can be quickly used to troubleshoot the problems: on either side of the
coupling, a "tone wheel" or regularly spaced magnetic or optical 'mark'
is placed and a pickup-a LED/sensor or a simple solenoid coil (think
electric guitar or Hammond organ)is placed. The phase relationship
between the two signals is monitored and as the engine/load are cycled,
where the two signals "wobbles" is where the flexion is happening.
It's a simple test to rig up. OMC and Mercury have been doing this for
years. I know because I worked in a music store in Wisconsin and they
would buy a certain type of internally amplified guitar pickup for this
purpose."
This is from a forum discussion that you can access in the rotary airboat thread. It is the last link.
jim
