Ok, we do have to consider the angle with which the rope meets the glider,
not the angle of the glider relative to the tow plane.

So if the glider /towplane combination is climbing at say 5 degees, it is
reasonable to see how the rope may be pullling exactly horizontally, or
even a bit downward. (due to sag)

Cookie





The tow plane does At 11:06 15 March 2009, The Real Doctor wrote:
On 15 Mar, 01:15, Bob Cook wrote:
At 13:43 14 March 2009, The Real Doctor wrote:

Bad example, since tow planes pull - give or take a wee bit -
horizontally, regardless of climb angle.

Well, our tow plane certainly does not pull horizontally!

I figure it pulls at about a 10:1 angle or about 5.5 degrees.

The only thing that determines the angle of the pull is the angle of
the tow rope at the glider end. This will be slightly affected by the
caternary sag in the cable, but will by and large depend on the
relative positions of glider and tug.

In high tow, the glider is more or less level with the tug, so the tow
force is more or less horizontal. The tug does NOT pull the glider up:
the glider pulls itself up and the tug supplies the energy. It's just
the same as with a climbing powered aircraft: the prop does not pull
it up to any significant extent - it allows the wings to pull it up.

Ian