Andy,

A turbulator 2" forward of the rudder hinge line may also help.

HP sailplanes using mylar seals for the large ruddervator gap have had
some success in preventing noise from the vibrating mylars at higher
speed. On my RS-15, I gained another 15 mph or so before the mylar
began to resonate.

Mike


I did an experiment that seems to confirm the noise is caused by a
mylar seal resonance. *I attached an additional mylar seal as an
extension of the width of the existing seal and at the top 6 inches or
so on each side. *The additional width and the curvature keeps the
strips in contact over full rudder deflection whereas before there was
seal separation even with the rudder centered. *I found that the noise
frequency was reduced and the onset airspeed was increased.

Until I find out why the 28 uses thinner skins, and get a factory
appoval to stiffen this area, I'll have to keep flying sideways or
wear earplugs. *So I need the yaw string calibration chart.

Andy
28048