Has anyone read the article in the latest Custom Planes on flutter
starring our first design?
Chris
microcosman.com
Vance W Jaqua wrote:
Chris- I finally backed up to the Jan issue and read the report. I was
probably one of the people that he mentioned talking to, and I
suggested
raising the frequancy with a stiffening bulkhead in the tail. His more
direct approach of cutting off some vert mass apparently did the job.
An intersting side to this that others on the site might find
interesting
is the fact that this is another demonstration that composite planes
appear to be one of the few configurations where you can fly home
to tell about your experience after flutter. Actually the Piper that
he mentioned seeing the video, also flew home. The flutter almost
instantly broke the spar in the horizontal, and this shifted the
frequency. The skins were still intact, and provided enough
structure for a gingerly return to field. Vance
Can somebody scan that article for me?
Or Xerox it? Are we talking torsional flutter of the entire tail?
How about a few layers of diagonal carbon uni inside the aft fuse?
Paul Lamar
I'll see If I can borrow it from my dad. The chase plane reported
oscillations with a peak to peak of 8" (his estimate). To be fair, he
was flying
beyond the current Vne. We always knew we had too much tail, so
cutting it down was an easy solution. Ron did a tap test over the entire
empenage and found no structural problems. In fact, he'd been
encountering
the flutter on a regular basis, as he made changes to wheel pants/ prop/
engine/landing gear,
in an attempt to locate/fix the vibration.
Chris
microcosman.com
Wow! He has been flying it like that for at least a couple
of years??? I spoke to him after the Apple Valley race and he mentioned it then.
That speaks volumes about the toughness and durability of gup airplanes.
Paul Lamar
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