Apparently one landed out near Ridge Soaring the other day after being caught
in a shower. He was at 6000' msl over Milesburg (less than 10 nm away) and
couldn't make it back to the airport. I wasn't there but heard about it.


Mike Yankee

I have a PIK20B and I have experimented with this aspect of its performance (incidentally, mine is one of those with a different section at the tip - it's FX67K-170 out to the aelerons, then progressively changes to FX67K-150 at the tip). After reading Dick Johnson's articles and noting his assertion that the performance of this sections is strongly dependent on Reynolds number (which is probably why the K21, Nimbus 2, Kestrel, etc. aren't affected so badly - e.g. larger chord). On the basis of his assertion I wandered under a shower cloud (it was virga really) at about 50Kts and around 2Kts sink, the wings got wet and the sink rate went to 8Kts! Following the reasoning about Reynolds number I increased speed to 100Kts, sink rate? Still 8 Kts - it strikes me that you have to accept that there are large changes in the glider's polar and if you don't react to these then you will end up not making it. I think the rule "fly faster when the wings are wet" applies very strongly wi!
th these sections - just remember that they work better at higher Reynolds numbers and there are only two ways to achieve them: put water in it (= flying faster), or fly lots faster when the wings get wet.

Rgds,

Derrick.