On Nov 7, 8:10*pm, Uncle Fuzzy wrote:

I'd be curious about the result. *Our club Janus C has a 20 meter wing
and 'clunky fixed gear'. *The manual claims 43:1. *I know from
experience it's better than my Speed Astir.

I'm pretty curious as well. I don't hold Dr. Finke's qualifications,
but the calibration I get from comparing manufacturers' claims with
Idaflieg and Johnson results leads me to generally approach the
manufacturers claims with something between "probably not" and "no
nfbsk'n way." That skepticism has stood me in good stead so far.

The things I see in the photos and three-view of the SZD that make it
questionable in my mind are that the undercarriage does appear to hang
down quite a bit from the fairing, and is not the cleanly-faired and
mostly enclosed wheel of the Janus and ASK and even of the G103. Also,
the degree of taper of the wing leads me to suspect that there will be
a non-trivial amount of washout, which could tend to make the wingtip
extensions less effective than you might otherwise expect. I seem to
recall that the Slingsby 15/17m Dart is an example of such. To the
Perkoz's credit, it looks to be a nice clean and well-proportioned
machine, so I woudn't be too surprised to lose ten bucks on the wager.

Johnson's tests on the 18.2m Janus rang up an impressive 40.9:1, so it
seems within reason that the 20m variety could do 43:1. I had thought
that Johnson had done the G104, but it's not on the SSA Web Site. It
might well be in the hardcopy Johnson compendium, I'll try to remember
to check that at work next week.

Thanks, Bob K.
www.hpaircraft.com/hp-24