wrote in
oups.com:

No part confused me. I just have a hard time believing that a
fuselage can accomplish 50 percent of the lifting force of the total
body. Yes I know that some lift comes off of the fuselage on planes,
especially the tailwind as you suggest and the hyperbipe type of
designs, but I didn't think the Sonex fuselage shape was that much
different than most other 2 seat SBS types, including the RV-6. I'll
take this into consideration, though I'm still not convinced that the
fuselage lift is what puts the Sonex into the LSA category.

Neal

ET wrote:
wrote in
ups.com:

Actually, the CAFE numbers come out a little better than what Van
states as the performance figures for the RV-6. And the stall
speeds that Van posts are pretty much what J. Roncz predicts in his
spreadsheets, even though Van's are a bit better. But then again
Van's planes may be operating at a slightly higher CL than what
Roncz uses. Which leads me to believe that the spreadsheets are
quite accurate.

This is why I'm having a hard time believing that the Sonex
aircraft meet the LSA rules as written. Even at the lightest
version of their aircraft ( Jabiru 2200 power and flown solo and no
fuel ) the plane would have a hard time meeting the stall
requirements of LSA which require max gross wt. figures with a 51
mph stall speed.

And my intention is to fully understand the LSA rules, not "down"
the Sonex aircraft or the people behind it. I believe the Sonex
and its people to be top notch, as do many others, evidenced by how
many are flying and continue to be built. They are reasonally
priced, economical to operate and good "all around" performers for
their power. And from what I have seen, several of the other
"popular" LSA's would have a hard time meeting the LSA specs. as I
see them written.

Neal



Which part of my post that indicated the fuselage of the Sonex is a
lifting body confused you??? Steve Wittman is said to have won a bet
or two with the same issue on the Tailwind. I have not done it, but
plug the same numbers in for the Tailwind and see what pops out.

--
-- ET :-)

"A common mistake people make when trying to design something
completely foolproof is to underestimate the ingenuity of complete
fools."---- Douglas Adams

Hrm,

Well, where can I get a copy of this spreadsheet?... either you've got
the wrong dimensions, or the spreadsheet is flawed.

The Sonex stalls clean at 46mph, and those are real verified numbers (no
I cant point you to a cafe study or anything but all builders on the
list who have actually flown one have verified their numbers..)

Is the airfoil type taken into account??


--
-- ET :-)

"A common mistake people make when trying to design something
completely foolproof is to underestimate the ingenuity of complete
fools."---- Douglas Adams