Vibration when on Approach

[borrisl]

I've been flying the Varieze for a while now. It's been sitting since completion due to some concerns.

No matter what type of material the prop is made of, when landing and throttling back to around 1500 rpm, the craft vibrates from feedback of some sort from the prop windmilling into the air. My normal practice is to keep the rpm to 1800+ on approach. Is this common and is it a problem?

[Kent Ashton]

Never seen that myself but here are a couple of articles

http://www.epi-eng.com/propeller_technology/propeller_vibration_issues.htm

http://grahamshevlin.com/b2evo////index.php/2005/08/11/vibration_issue_is_now_resolved?blog=3

 

This one had a good idea for watching the hub at the problem RPM

http://www.flight-mechanic.com/propeller-vibration/

[borrisl]

Some good ideas. Might have to check indexing. On the IVO prop or Prince behavior was the same, which to me, rules out prop balance. What are the chances that both props are out of balance in the same way.

[VEZ75]

I have this issue as well. Prop is Hertzler 62X68, Cont O-200. I am told from the previous owner that at the sustained under-speed condition through deceleration 200 mph - 120 mph, it is a cowling vibration/resination. I am waiting to fix cameras to try and quantify this. This also happens on another airplane that I fly, the Piaggio Avanti, but at a much different frequency.

[Jon Matcho]

This also happens on another airplane that I fly, the Piaggio Avanti, but at a much different frequency.

 

Now THAT is a hangar I want to see more pictures of!  I love hearing the Piaggio Avanti overhead here in New Jersey, but haven't seen one in quite a while.  I've been wondering whether it's been relocated.