On 2/7/2016 3:09 PM, wrote:
I know this is a silly question, but I was reading an article by Dick
Johnson that talked about holding a slight slip while thermally. This
article was written before winglets and I was wondering if the same idea
applied to gliders with winglets. Also, as for slipping to lose altitude
for landing in a glider with winglets, does this place a lot of side load
on the winglets. Should you not slip in landing with winglets?

Sorry for the questions, but would appreciate any help in this.


Not silly questions at all!

UH, Tim T. and Martin G. have each provided insights.

Arguably (reality always rules, of course!), because of the additional
side-surface drag, slipping in the presence of winglets should be more
effective than in their absence...which, of course, is not the same as
suggesting that slipping in a particular glider "will *always* increase the
sink rate." (See below.)

As to whether you should slip or not, if the ship has a POH, that's the best
place to start for specific input, followed by practice aloft before trying it
"near the ground." In any case, your expectation should be that nothing will
break off due to aerodynamic forces of a slip performed at pattern airspeeds.

(Kinda-sorta related, I've flown one non-spoilered,
large-deflection-landing-flap-only equipped, 15-meter glass, glider having
*reduced* sink rate when straight-ahead-slipped with full landing flap in.
That informational bit is simply by way of sharing a perhaps-non-obvious
tidbit regarding "the obvious usefulness of slipping" as a landing aid. The
devil is in the details...)

Bob W.