REFLECTOR: Flying front vibration

[Rene Dugas]

Dear folks,

XLRG if flying faster than 170 kts a slight vibration is felt in my feet
near the canard bulkhead.  It gets worse up to 200 kts. but only
slightly.  No vibration in the stick and none visible in canard or
elevators.  Gear doors are up and tight.  I tightened them and checked
on jacks yesterday.  No slack in elevators or hinges detectable.  Canard
bolts are tight and no motion detectable with lifting plane's nose by
canard.  Rear gear doors are closed and flush and snug.  Doors are not
vibrating.  No vibration in rudder pedals or visible in winglets or
wings.

At above 160 knots indicated my trailing edge of the elevator is about
1/8th inch up for level flight.  Have others encountered this.  I feel
it is canard turbulence as the air goes over the canard and hits the
upward deflected elevator there is a resonance or harmonic that is
disconcerting but not particularly unpleasant.  Others do not notice.
The plane with prop balanced is amazingly smooth in operation except at
cruise over 170 kts. I am considering a slight change in canard
incidence.  My angle of attack indicator states at cruise I am at 3
degrees up.  The vibration is sort of like when both windows are down on
a pickup  at 60 mph.  a slight pop or "whop" can be felt.  I closed the
vent to no avail.  This is a vibration not a sound.

Ideas?

250 hrs

Rene'

-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://www.tvbf.org/mailman/private/reflector/attachments/20040927/e9e1d691/attachment.html