Vertical Vibration

[Steve Chenoweth]

Per my prior posting on thrust bearings, I was having problems with a vertical hop. We found that the grease fitting was blocked and the thrust bearings were not getting lubrication. But after about 6 hours of flying, the hop returned, not nearly as bad as before. This time, it turned out to be a loose swash plate, so that is something else to check for when you have a vertical hop. According to long-time Brantly A&P Harold Jenkins, if the swash plate is loose the vibration can come and go and depends on wind direction/speed and other variables.

[9121u]

I Found That Mine Was Same Problem Swash Plate Brass Had Too Mutch Play Also Check Your Outer Blade Dampners And Damper Brackets HAPPY FLYING

[9121u]

Also BRANTLYS Are Very Smooth When They Are Track And Balanced Right If They Get Shake Rattle Bounce I Would NOT Countiue FLYING Land And Investigate The Problem Before Further Flight Friend Of Mine Said He Had A Shake And We Found The Dampner Bracket Bolt Was Loose. HAPPY FLYING

[Ron Spiker]

Steve, what did you do to get the swashplate tightened, and did that take care of the vertical hop?

[Steve Chenoweth]

I am not exactly sure how it was tightened, you can check with Harold Jenkins who did the work (phone number in Resources section). I am happy to report that after over 20 hours, it is still flying smooth and there is no vertical hop.

I take it you are having some vertical hop? The usual suspects are tracking and thrust or clevis bearings, but in my case, the swash plate was also a contributor.

Steve

[Ron Spiker]

Yes, but it's only noticable up above 90mph when by myself or 85 or so with two people. We're going to try a Chadwick in a few weeks, but wanted to see about your loosened swashplate. How much play is in it now?

[Steve Chenoweth]

N888CF is still in the paint shop

As soon as I get it back I'll take a close look at the amount of play in the swash plate and let you know.