Greg Arnold wrote:

L/D? When the nose pushed down at 160 knots, crabbing into a 50+ knot
headwind and you've got +5 knots of up in wave you won't care...
I can't wait to see what magic Greg Cole pulls off with the Duck Hawk.

Darryl has it right - the limit for high speed wave flights is Vne, not
L/D. But, extrapolating from an ASW 27 B polar gives ~20:1 at 160 knots.
Attempting to extrapolate to 200 knots is pointless, so we'll have to
wait for Windward Performance to publish a curve.

Just to finish the thought - you only need 8 knots of lift to maintain
altitude at 20:1 and 160 kts.

I am skeptical about 20:1 at 160 knots. I think the best Dick Johnson
flight test was the ASH-26 at 9 pounds wing loading, and it was below
20:1 at 120 knots. A more realistic figure might be 10:1 at 160 knots,
which would require 16 knots of lift to maintain altitude.

You can get the ASW 27 B curve from Schleicher's site and draw your own
line. It's guess, because the curve only goes to 210 kph, but the curve
I drew "looks right", using the 55.6 kg/m2 line as the starting point.
I'm sure it's not 10:1, but certainly between than 15:1 and 20:1. The
ASH 26 is not a good choice for comparison because it has the same
aspect ratio as the 27, and only goes to 45 kg/m2 (the 9 pounds you
mentioned).

--
Eric Greenwell - Washington State, USA
* Change "netto" to "net" to email me directly

* Updated! "Transponders in Sailplanes" http://tinyurl.com/y739x4
* New Jan '08 - sections on Mode S, TPAS, ADS-B, Flarm, more

* "A Guide to Self-launching Sailplane Operation" at www.motorglider.org