Our standard operating procedure is for the tug to track downwind of the
runway on all launches once through 50 or so feet. Self launchers tend
to do the same.

Why? For the reasons other people have stated - i.e. Because it gives
the glider the maximum number of alternatives.

It increases the time during which you can land ahead, both because of
the extra distance back to the runway, and because of the headwind
component.
It reduces the chance of a situation developing where you are too low to
turn 180 degrees, but can't land ahead safely.
It ensures that you are turning into wind for landing so have less
chance of overshooting the runway.
It ensures that the pilot has the runway in sight during the manoeuvre.
As Eric said, it increases the time you can see the runway because the
downward visibility is better to the side of the nose, so situational
awareness is better.

Naturally it is possible to overdo that and end up too low to reach the
runway. For example if the tuggie forgets that it is a lowly club class
hack on the end of the string, not an uber wingspan supership... So - no
process is perfect when people are making decisions, but this process is
generally safer.

Again, we do this because we don't end up traversing over hangars, trees
etc. Other airfields may differ.


On 2011/03/27 04:22 PM, Eric Greenwell wrote:
On 3/27/2011 6:47 AM, n7ly wrote:

Nobody has seen fit to bring in runway heading versus runway track
while on initial tow in a significant crosswind. In our neck of the
woods this happens. Is a significant factor in least time/space to get
back to a downwind landing.

Let me restate this a bit for those who don't often have 15 knot
crosswind components.

Should the towplane maintain runway heading after liftoff and after
establishing a normal climb, allowing the tow plane to drift while
maintaining runway heading?
Or should the towplane maintain runway track after liftoff and after
establishing a normal climb, keeping the tow plane on what would be
runway centerline?

It makes a significant difference in how many degrees of turn
necessary as you turn into the wind and get lined up for a downwind
landing.

It's easy for me in my motorglider to control my track during the
launch. I typically track about 20-30 degrees downwind of the runway for
these reasons:

* I can easily see the runway, my glide angle to the aim point, and how
much I have left; otherwise, the nose of the glider obscures all that.
* By the time I can no longer land ahead on the runway, I can make an
downwind landing with a ~220 degree turn that begin with an
into-the-wind, towards the runway turn.
* At my airport, the cross runway is can be an even better choice, as I
can make a continuous 270 degree turn and land into the wind.

Why not take off from that runway to begin with? The landing options
beyond it are poor, so I prefer the other runway as long as the cross
wind is 10 knots or less.


--
Bruce Greeff
T59D #1771 & Std Cirrus #57