Martin Gregorie wrote:

How does the speed for best L/D compare with std class gliders?

I think this is a meaningless comparison without knowing that,
particularly as I'd expect a modern section to have a better high speed
polar. I have only an anecdotal data point to add: one of the
Aerovironment guys, who I met briefly at a FF model contest, has a
Sparrowhawk, which is a glider I've yet to see but am very curious about.
During a chat he said he'd flown with a Standard Libelle, which I fly,
and thought their performance was very similar.


Of course they do not go very far because of the very light weight.


An obvious similarity is that both gliders have wing areas that are
smaller than the norm: the Std Libelle is 9.8 m^2 vs around 10.5 m^2 for
most std class gliders. Presumably in both cases this was done to get an
acceptable cruising speed from a light airframe. Libelles go cross
country pretty well, so why are you implying that the new generation of
light 13m gliders won't?

The SparrowHawk has an 11 meter span, so I'd assume a modern 13 meter
glider should be capable of better performance than a Std Libelle.

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

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