LSA specs

Peter Dohm wrote:
"J.Kahn" wrote in message
...
ET wrote:
wrote in
ups.com:

John,
I hear what you're saying, but with all that's been said here, and
investigated via spreadsheets, etc., I still don't think the Sonex can
stall near the LSA requirement at max gross wt. and no flaps which
means it is not LSA qualified. And just for grins, I looked up the
figures for the CT Flight Design ( which is a popular seller ) and
guess what. IT doesn't meet the LSA criteria. And I also looked up
the new Vans RV-12 "LSA" and you guessed it....IT doesn't meet the
stall speed criteria ( at least not on paper...I don't think it has
flown yet.) So I'm convinced that something is amiss. I'll keep
researching.

Neal

Well then guess what, the spreadsheet is what's flawed. I guarantee CT
(the best selling LSA by far) and Vans, and the Pete Buck know what they
are doing far better then the developer of your spreadsheet...

3 real world examples of planes that clearly meet the LSA specs but do
not
meet it "on paper".

Do it for the SportStar (http://www.evektoramerica.com/sportstar.html)
and
the StingSport (http://www.sting.aero/) while your at it... I bet you
all
the money in my pocket they won't "compute" either, and the spreadsheet
is
flawed.

Forget about spread sheets. The simple formula in my earlier post...

Sea Level Stall in Kts = Sq root of: [(295 x Gr Wt) Divided by (Clmax x
Wing Area)]

Multiply by 1.15 for mph.

Assume 1.6 for the Clmax. Almost all airfoils are between 1.5 and 1.7,
which gives a 1 mph or so variation up or down relative to 1.6.

...works like a charm. I used it on the Sting sport and sure enough it
comes out to 44kts just as advertised.

Use it on the Sonex and you get 45 kts. Different airfoils will
increase or decrease that by about 1kt.

John

And the old graphs in the Dover Edition of Theory of Wing Sections look like
a CLmax of a little more than 1.6 can be achieved--plus whatever the
fuselage shape might ad.

Don't get me wrong. At 6'1" and 200#, I don't fit in the plane; and I
really don't like it anyway. I just don't have a problem with the specs;
and there have been plenty of designs over the years for which I do have a
problem with the specs.

Peter



Yeah I'm 6' and 200 and the Sonex was a very tight fit. At Osh I
commented on the lack of head room for a long torso type like me and he
said "sit in the middle". Yeah right.