The good news is my plane is quite fast now (I posted a bit about the speed
last week).  205 KTAS is pretty easy, and 207 to 209 is also possible in the
75% power range.  That's the good news.

Bad news, I now seem to have picked up a resonance at these higher speeds.
No noise at 195 KTAS, but above about 198 KTAS I get a high pitched
resonance.  I can't see anything vibrating (flaps, ailerons or H-stab
(larger tail)).  I can't see the gear doors or the rudder, so I don't know
about them.

The sound "sounds" like it is coming from the rear of the plane, but I can't
really tell.  It also "sounds" about the same as when I drop an inch of
flaps at 140 KIAS to get slowed down to gear speed.

Any thoughts?  I'm concerned to the point that the extra 10 knots is kinda
academic - I'm still flying at more like 195 to be safe.

Matt
360, standard gear, large tail...