Frank wrote:


Well, as my Mammy used to say, "Be careful what you wish for, cuz you
just might git it!". I was hoping that my rabble-rousing would generate
some thoughtful discussion, and apparently I'm getting my wish! ;-).

I have a basic problem with the above modeling approach, and that is
that I find it difficult to believe that a 25 year old glider can still
achieve its published polar (assuming it ever did), no matter how well
prepared. I borrow from my power background, where aircraft
performance numbers are routinely inflated by the manufacturers and are
just as routinely missed by the actual aircraft. However, newer
aircraft do come closer than older ones, pretty much regardless of
type. Having said that, I really don't know if Manfred's LS-3 can
still achieve its numbers (maybe it even exceeds them now!).


That's a difficult line of reasoning to head down! If you read
Johnson flight tests over the years, you'll see that even factory fresh
ships sometimes don't live up to expectations. In addition, you'll
definitely find that a lot of 2-4 year old ships right now are
suffering from significant airfoil "issues." My strong belief is that
the variability in performance in a given model (e.g. "best" vs.
"worst" LS4s) far outweighs the margin of error with handicaps. If
someone is really serious about winning in SC, the first thing they
ought to due is to tune the heck out of their ship by sealing and
smoothing. Right off the bat, they'd probably gain 2-3% points
against the competition.

Anyway, a great thread with some very good ideas tossed out along the
way.

P3