On Jul 14, 9:59*pm, Bob Whelan wrote:
On Jul 13, 1:33 am, Derek *wrote:
On Jul 13, 12:31 am, Bob *wrote:

As for 'the silver bullet' in wing-tip-holding-methodology, I've (for
many years now) asked my runners to let the wing rest on their flat
palm, give me the best run they can, and let the tug pull the wing
ahead/away from their open palm...no risk of a(n accidentally held-back)
run; eliminates any winglet issues; never flown (or encountered) a
glider with a downstream protuberance that could hang on anyone's hand
(though I've little doubt one - somewhere - exists!).

If you let the wing rest on the palm of your hand as a wing runner,
how do you prevent the wing lifting off it in a crosswind, if a gust
of wind comes through, or if the tug propwash gets underneath it?

Certainly a theoretical possibility (prematurely losing contact between
palm and wing undersurface, I mean)...this is an example of one of the
Devil's details noted in a previous post.

That said, all I can relate is my experience and an observation, neither
of which unequivocally answers your question.

In my experience (both as a wing runner and glider guider), neither
proposed possibility has ever occurred. Perhaps it's because - when
aerodynamically moving a glider wingtip is under consideration - tip
movement can't happen 'instantaneously'. Personally, I don't put my palm
beneath the wing's undersurface until the glider, glider pilot and I are
all ready to go; prior to that I'm engaging the wingtip by whatever
method I need to in order to achieve whatever it is I'm trying to
accomplish (e.g. lifting the tip off the ground...which I generally do
by grasping the leading edge of the wing; balancing w. partial water,
etc.). It's while doing these preliminaries I get a sense for how much
of an impact (or not) the existing wind/gust field is likely to have. As
noted, gusts have never been an issue for me - as a launcher or launchee.

Nor - by the time I've got the wing in place atop my palm - has any
tug's propwash ever been an issue. The only times I've witnessed
propwash affecting the glider a 1) about the time power is added to
take 'the bulk of' the slack out after the tug has completed positioning
itself (more or less) directly ahead of the glider, and 2) well after
the wingtip has been pulled forward/away-from my palm. In the former
instance, if I'm by a wingtip when it lifts from the ground, I generally
slide my foot beneath it to lessen any graceless 'concrete whap' which
might otherwise occur, while in the latter I've (definitionally) done
all I can do.

YMMV.

In any event, there's definitely more to wing running than would seem to
be the case to an uninformed, casual observer!

Bob W.

Have you ever launched behind a PZL Wilga or similar radial engined
tug with a huge slow running propeller. The prop wash can be
horrendous and can easily force a wingtip onto the ground when the
wingtip runner lets go, or even while he is still holding it! The
resting on the palm technique probably won't work in this case.

Derek C