High tow vs. low tow for rough tows (long)

In article ,
"Janusz Kesik" wrote:

U¿ytkownik Janusz Kesik w wiadomo¶ci do
grup dyskusyjnych ...
Also gaining height (in order to shorten the tow)
by a towplane with glider behind is much, really much easier and less
stressing when using a short 20-30m rope.

I meant gaining height in a towplane with a glider behind, by using the
thermal to support the tug's climb rate.

If the combo has found a thermal, why wouldn't the glider just release
and save money?

Therre have been plenty of times that I've intended to tow to 2000 or
2500 ft but then released in a thermal at 1000 - 1500 ft.

-- Bruce

U¿ytkownik Bruce Hoult w wiadomo¶ci do grup
dyskusyjnych ...
In article ,
If the combo has found a thermal, why wouldn't the glider just release
and save money?
When the combo (now I know the word for it starts the first circle at
70m, it's too low I think... ) Few circles can be useful.

JK

On 5 Dec 2003 10:53:17 -0700, (Mark James Boyd)
wrote:

A lot of different techniques - little consensus

Bruce - Hi to slow and get slack out, then match speeds by diving
Brian - Yaw to reduce snappiness when line comes taut
Janusz - Shorter rope so tug and glider are in the same air
Michel - Low tow and avoid slack line

Let me add the standard procedure that I was told and that all pilots
I know of are using:
Extend the airbrakes (carefully - only about one inch) to get the
slack out. Don't let the speed difference between glider and tow plane
get too big.

Not mentioned is the use of spoilers. I've noticed
one ranked pilot who flies a slick glider sometimes with
ballast uses slight spoiler adjustment to regulate slack line.

Ooops... seems like others are using that method too..

There's one important part when trying to get the slack out: Do not
let the glider get too slow (compared to the tow plane) - otherwise
the acceleration when the tow rope tautens might break the weak link.

The method of how to slow the glider down is a question of taste -
I've used sideslips for that part which also work well (but I teach my
students to use tha airbrake).


Bye
Andreas

In article ,
Andreas Maurer wrote:

On 5 Dec 2003 10:53:17 -0700, (Mark James Boyd)
wrote:

A lot of different techniques - little consensus

Bruce - Hi to slow and get slack out, then match speeds by diving
Brian - Yaw to reduce snappiness when line comes taut
Janusz - Shorter rope so tug and glider are in the same air
Michel - Low tow and avoid slack line

Let me add the standard procedure that I was told and that all pilots
I know of are using:
Extend the airbrakes (carefully - only about one inch) to get the
slack out. Don't let the speed difference between glider and tow plane
get too big.

And if it does, what do you do then?

That's why if I'm going faster than the towplane I prefer to store the
energy by climing a little, rather than by simply throwing it away using
the brakes, or a slip, or a yaw.

The slack isn't going to come out until you're going slower than the
towplane, and you need a way to get back to about the same speed again.

-- Bruce

Let me add the standard procedure that I was told and that all pilots
I know of are using:
Extend the airbrakes (carefully - only about one inch) to get the

Try this in a Janus. Extending isn't a problem, but I wish you luck
closing them again during the tow. Chances are that after successfully
closing them, slack is much bigger than before.

Stefan

U¿ytkownik Bruce Hoult w wiadomo¶ci do grup
dyskusyjnych ...
In article ,

That's why if I'm going faster than the towplane I prefer to store the
energy by climing a little, rather than by simply throwing it away
using
the brakes, or a slip, or a yaw.

But there's a risk that the towplane gets "out of the screen" because You
got higher than it, and then You have a problem...

JK

On Sat, 06 Dec 2003 16:59:44 +1300, Bruce Hoult
wrote:


Extend the airbrakes (carefully - only about one inch) to get the
slack out. Don't let the speed difference between glider and tow plane
get too big.

And if it does, what do you do then?

Pray that I don't break the cable.


That's why if I'm going faster than the towplane I prefer to store the
energy by climing a little, rather than by simply throwing it away using
the brakes, or a slip, or a yaw.

The slack isn't going to come out until you're going slower than the
towplane, and you need a way to get back to about the same speed again.

Basically a good idea - but higher than the tow plane, especially in
gusty conditions, is a place where I try not to be.

Bye
Andreas

On Sat, 06 Dec 2003 11:35:46 +0100, Stefan
wrote:


Try this in a Janus. Extending isn't a problem, but I wish you luck
closing them again during the tow. Chances are that after successfully
closing them, slack is much bigger than before.

Why?
I haven't flown the Janus that often, but to me its airbrakes didn't
feel extraordinary to me?

Bye
Andreas

In article ,
Andreas Maurer wrote:
On Sat, 06 Dec 2003 16:59:44 +1300, Bruce Hoult
wrote:


Extend the airbrakes (carefully - only about one inch) to get the
slack out. Don't let the speed difference between glider and tow plane
get too big.

And if it does, what do you do then?

Pray that I don't break the cable.

I think perhaps if there is some room to go down without dramatically
pulling down the towplane tail, a slight dive might work, perhaps
a little off to the side to add some yaw/dampening effect



That's why if I'm going faster than the towplane I prefer to store the
energy by climing a little, rather than by simply throwing it away using
the brakes, or a slip, or a yaw.

The slack isn't going to come out until you're going slower than the
towplane, and you need a way to get back to about the same speed again.

Basically a good idea - but higher than the tow plane, especially in
gusty conditions, is a place where I try not to be.

So if you start at low tow or right in the propwash, pulling up a little
won't get you above the towplane as quickly. But we are agreed that
so high one can't see the towplane is bad (immediate release) but
that same angle lower than the towplane is not as sketchy (although
now we have the new worry of possible slack rope around the wing
or a much more exciting rope break).


Bye
Andreas

So again, in this thread I was mostly talking about rope breaks
in wave instead of thermals. So I suppose it would be nice
to know how standard tows through rotor go. I imagine one
starts under/before the rotor and the first thing the tug hits is
negative shear or a downdraft. If the tug drops, and
glider doesn't drop too, glider is too high and uh oh.
So the glider can either nose down, slip, or use spoilers to
lose altitude and stay with the tug. Nosing down, if done
wrong (too much) means now you've introduced slack, and when
the glider hits the same downdraft/tailwind a few seconds later,
the rope comes taut and snaps.

Now in the rotor, the tug maybe hits an updraft/positive shear.
If the glider pitches up and stays in position, then when
the glider hits the same updraft/headwind a few seconds later,
the glider will be too high and have to use spoilers/slip/nose down
to maintain position.

Spoilers are tricky to use. We tried them during some of
our slack rope practice and the difference between closed and
cracked is dramatic. Diving the nose seems like it might take
a lot of skill to do right. On the other hand, using
a slip to lose altitude is simply, easy to take out, and
has the added inherent "yaw" benefit.

So perhaps flying low tow or right in the wake, and
using slips is the simplist (but not most elegant) technique.
Then watching what the tow plane does and anticipating the same
thing happening to the glider a few seconds later would help.
Eevn on low tow it seems there is some room to dive a
little to get airspeed at the last second if needed.

I plan to go to the Sierras at some point for some wave fun,
and perhaps will try both high and low tows and see how they
compare. Should be fun

Mark

PS. The dramatic difference between closed and cracked also
came up from a 10 foot rope break. With the fence coming up,
slowing down is important. I couldn't forward slip (wings
too long close to the ground), so I cracked spoilers.
The plane bounced fairly gently once, and then I closed the
spoilers and landed (although a little long).
It seems at 60-70 mph at 10
feet on rope break, I was better off pitching up to climb and
slow down, and opening spoilers during the pitch up climb.
Cracking spoilers at high speeds has a dramatic effect
(perhaps not surprisingly now that I think about it in
my armchair). It seemed pretty clear that spoilers are
designed for losing altitude, not for slowing down. If they
were designed for slowing down, there would be a pitch up
change when deployed, right?


"rec.aviation.soaring - BS free since Dec 6, 2003 11:45 PST" ;-p

Andreas Maurer wrote:

Why?
I haven't flown the Janus that often, but to me its airbrakes didn't
feel extraordinary to me?

The last time I flew a Janus, I needed both hands to close the airbrake.
THE girl who flew it the next day even couldn't close them at all, she
needed the help of the copilot.

Stefan