Buzzing Strut

[Springloaded]

One of my struts has a buzzing noise,between 60-70IAS.One of the jury struts had a little bet of movment I tightened it up it got a lot better but can still here it.Put my hand on it you can feel the vibration.Anybody else here this? Suggestions?

[Pete D]

At the bottom of the jury strut where it attaches to the SS eye-bolt that goes through the strut is a small, special plastic hat bushing. It snaps inside the eye-bolt hole before the jury strut/spreader bar are put in place and the bolt inserted. Sometimes that plastic bushing will get some wear and allow the bolt to move around. Easy and cheap to change if needed.

Also, having the prop dynamically balanced can make a big difference in how the airplane feels and also can degrease the wear on the entire airplane because of the reduced vibration.

Pete D

[Springloaded]

Thanks Pete
I will need to get a bushing it did show a little wear(part # ?), I rotated it and tightened it, I had recently changed the cartidge in my propfrom a 50 to 46 when I notcied it.I just changed the cartridge again, went to a 48 the same time I tightened up the jury strut and it did get a lot better.How do I go about getting it balanced.
Thanks
Chuck

[Pete D]

The part number for the "bushing" is: VP5150-002

It takes one per jury strut, or 4 per plane.

To get the propeller dynamically balanced I would talk to SWT Aviation, our dealer in FL to see who they would recommend in that part of the country. We do it here at the factory but that would be a long trip for you.

Their contact information is here:

http://www.cubcrafters.com/csc/swtaviation

Pete D.

[Springloaded]

Pete
Thanks
Chuck

[Pokette]

I noticed on my video with the camera on the strut there is a buzzing. It seems to be the aileron cable vibrating in its bushings. Is there any problem with that?

[Springloaded]

I thought that was what mine was but I reached out and grabbed cable and it didnt stop, I could feel it in the rear strut. Last night I did notice it is Rpm related to so Im going to see about balancing. It is barely noticeable now but I can still here it.

[JohnM]

I noticed on my video with the camera on the strut there is a buzzing. It seems to be the aileron cable vibrating in its bushings. Is there any problem with that?

The aileron cable will vibrate if the tension isn't quite right. I have noticed that it can change with airspeed and tension on the cable when the aileron is displaced into the slip stream. The amplitude of the cable movement can be enough to where it will scratch the paint off of the back of the strut.

John Moreland
SWT Aviation

[JohnM]

Pete
Thanks
Chuck

Chuck,

Give Johnny Stinson a call at Aircraft Maintenance Specialists. He is the CubCrafters Service Center for Florida. I know you have his number. :-)

John Moreland
SWT Aviation

[chipallen]

We have seen this issue on a number of airplanes, (both S2's and Carbon Cubs) sometimes related to prop balance, and sometimes not. In almost every case, the culprit has been the aileron cable vibrating, and if it is not tensioned correctly (45 lbs., I believe), it can even hit the rear of the strut and knock the paint off of it.

Usually, a slight change in RPM makes it go away (as little as 50 RPM), but on my last demo airplane, we tightened the cable slightly, and the entire issue just went away. In any case, if it is the cable, you should be able to see it vibrate, and usually only one side or the other; I've never seen both sides vibrate.

One other suggestion, if you think this issue might be at work on your airplane; we have taken some clear 'leading edge tape" (from Aircraft Spruce & Specialty), and applied it to the rear of the strut - just in case a vibrating cable hits the rear of the strut, the paint will be protected.

The side-benefit from taping the rear of the strut is to prevent paint damage from improper ground handling - line guys will sometime wrap their hands around the strut (grabbing the strut and the aileron cable together) to move the airplane, and the aileron cable rubbing against the strut will damage the paint.

Just my $0.02 worth!!