Having done a bit of work in design of composites, I will throw my 2
cents
in. The carbon skins are undoubtedly Bi-directional weave at 45 deg.
The woven cloth has a much lower modulus than the Uni carbon

typically

in spars. The bending loads will be shared on a basis of modulus, and
the wing skins will not be duly overloaded, and will not try to do

more

than it's fair share. If you had low modulus spar material it would

be

a different story. The wing collectively will be very stiff, but the
rather
high wing loading will moderate the "ride'' and peak loads.

This is an ineresting design, and unique - no one is going to mistake
it
for a Piper Cherokee, or even Lancair for that matter. The very

skinny

rear
fuselage is something I would not do - even with all the carbon it is
going to have a relatively low flexural frequency.
Vance J

Thanks for the input.  Some of the apparent "skinniness" is due to the
large cockpit, an illusion if you will.  We're about as big back there
as a Lancair IV.

Incidentally, what do you charge for analysis Vance?  Always
good to refer to someone who does this for a living.

Has anyone read the article in the latest Custom Planes on flutter
starring our first design?

Chris
microcosman.com

Chris - I would be happy to make input into your analysis.  My fee schedule
is best explaned by my statement in my web page (vjaqua.tripod.com)
"if your job is interesting my rates are reasonable, but if it is not
interesting
you cannot afford me" . Fortunately, I do not have to "make a living" at
this. Back when I was commiting engineering for a living, my wife and I
were very frugal, and that combined with fortuitus investments and
decisions have left us with a comfortable existance. I do charge those
that deserve it ( I won't go into that in detail), but most of my work
is accomplished to avoid brain fade.

Since we should probably minimize loading up Paul's newsletter,
you can contact me directly at either vjaqua@yahoo.com or
vjaqua@dslextreme.com

I have written numerous programs for perfomance prediction, stress
analysis, and other design aids, to assist me in these areas. Unfortunately
most of these are in old fashioned BASIC which is getting harder to run
on Windows machines. If you supply me with specifications and dimensions
I can spit back first cut answers rather quickly.

I was aware of the flutter problem with your earlier design (now called
Betty
Boop). I had talked to Ron Carraway about it at variuos times at Copper
State, and this was in my mind when I commented on the apparent
possible low frequency. I could not find the reference in Custom Planes
which issue, etc? - Vance J

I have a few DOS machines lying around Vance that you can have.

Paul Lamar
 
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