Double Release Failure

On Sep 10, 2:37*am, (Alan) wrote:
In article Jim Beckman writes:
At 14:13 08 September 2009, FBCompton wrote:

Important Timing Aspect: *The glider (in low tow) must not touch down
much before the towplane -- this can be a hazardous aspect -- touching
down well before the towplane and stalling it. *The glider wings are
still carrying the weight of the glider while it is flying. *Once the
glider touches the wings stop lifting and the glider creates more
weight drag on the towplane, which if still well above the runway will
be slowed and may stall. *

This seems counterintuitive to me. *When the wings stop lifting, the
induced drag goes away, so the drag on the towplane should decrease. *The
only added drag is friction in the glider's main gear. *What am I missing
here?

Jim Beckman

* It seems backwards to me, too, but I have asked tow pilots about this,
and I was told that they feel the drag decrease when the glider comes off
the ground on the takeoff roll.

* I guess those wheels have a lot of drag.

* * * * Alan

Behind less powerful tow planes, I generally note a 3-5 knot jump in
airspeed immediately following glider lift off.

Frank Whiteley

On Mon, 7 Sep 2009 20:46:08 -0700 (PDT), drbdanieli
wrote:

... text deleted ...
Bottom line, it's not as scary as it sounds but I would suggest proper
training before trying this on your own. Is anyone teaching this
anymore?

Barry

I don't know about today, but AC Williams and his instructors at
Southwest Soaring outside Dallas, TX would frequently do the landing
behind the towplace with his Grob 103's during flight reviews. I did a
few during BFRs in the late 80's and 90's. Mostly a non-event. The
only difficult part I found was coordinating the ground deceleration
so as to avoid overrunning the towrope on the rollout.

Bob

In message
,
Frank Whiteley writes
snip
I flew out to the left and waggled the wings, no
response from the tow plane.
Snip

I had that when learning to give the cannot release signal - it left me
wondering how much use it really is. BTW our tow plane has a retrieve
winch on the rope plus a guillotine for cutting the rope as the release.

--
Surfer!
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