Prop Vibration

[Blackhawk]

95 Super Decathlon with the three bladed MTV propeller. I thought I saw a posting about vibration with this propeller, but now I can't find it.
What I am experiencing- every once in a while there is a vibration that can be felt in the stick. It starts small, increases, then goes away. It seems to happen randomly (different flight conditions). It is of short duration.

 

[Kiwicub]

Hi Blackhawk,
I could be putting you wrong, but I had a bit to do with a Zlin 50 a few years ago. I think it had an MT prop, but anyway it was a wooden blade constant speed prop, similar to what you have? This characteristic is not unknown............. the reason for it is something like this............... because of the low mass of the blades being made of wood pitch changes may not be as quick as with aluminium blades, and may not occur evenly across the three blades. Hence at any given time not all blades may have the same pitch all the time. Given time they all go to the new setting. This is why the vibration comes and goes and there is little consistency. The owner of this aircraft reported this type of problem also; I seem to remember this is how I explained it away. All a bit hazy now, but might give you something to go on. There are a few acro sites, try them.

Cheers,
Andrew.