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

While towing for Hollister, I noticed their instructor
really liked to practice slack line.

So for my flight review in Avenal yesterday, we did a bunch
of slack line corrections. We did them during one tow,
but broke the rope. 150' of rope ($12), two schweizer rings ($20),
one tost ring ($35), a carabiner (sp?), two half-wiffle balls,
and a short section of "weak link" then back-released from
the 2-33. It plumeted swiftly into a thankfully barren
plowed field below.

A few tows later, we mentioned to the tug pilot we were gonna
try slack line again. He wised up and took off the weak
link assembly ($68) leaving just wiffle and a $10 schweizer
ring.

After a dozen more slack rope practice tries, we broke
that rope. The ring and 10' of rope back released and
plumetted into another (thank god) barren field.

I'm sure some tractor pulling a tiller will grind some metal
at some point and we may get them back.

I thought about slack line. The real problem isn't
too much pulling, it's the "snappiness" with which the
slack line comes out.

It strikes me that on low tow, as slack line pulls out,
it allows a lot softer recovery. When slack comes out,
the tail of the towplane is pulled low, giving some
dampening. Next the towplane slows a little from the
drag, also good. On high tow, neither of these is true.

Sure, sure, I've read very careful use of spoilers and
yawing the sailplane away from the slack are tried and true
methods. However, even using these, there is still some point
there is so much slack you are going to break the
rope no matter what. A friend mentioned during his
first flight to try to get in wave, he with the experienced
instructor broke three ropes before succeeding.

My question is to those who have towed through rotor.
Have any of you tried low tow and high tow and would
care to tell us if you've found a difference in the
number of rope breaks?

How about the idea of towing low and to the left of the
tug? Ignore for the moment that it would annoy the tug
driver to do this on purpose (except maybe if torque
and p-factor now meant he could just leave the rudders
to flop about). Also ignore for the moment it is
drag inefficient. Would this reduce the possibility
of slack line and/or improve recovery chances even more?

How about other dangers? If the rope breaks on low
tow how would you feel about having it
fly over/around top of the wing/elevator/rudder?
Anyone have this happen?

I'm especially interested in the experiences of wave
pilots and those towing through super heavy thermals...
but armchair analysis is also invited :-]

On 4 Dec 2003 14:57:55 -0700, (Mark James Boyd)
wrote:


So for my flight review in Avenal yesterday, we did a bunch
of slack line corrections. We did them during one tow,
but broke the rope.

Sure, sure, I've read very careful use of spoilers and
yawing the sailplane away from the slack are tried and true
methods. However, even using these, there is still some point
there is so much slack you are going to break the
rope no matter what. A friend mentioned during his
first flight to try to get in wave, he with the experienced
instructor broke three ropes before succeeding.

Within 18 years of gliding I have not heard of a single tow rope break
(nor a weak-link break) on my home airfield. We are doing high tows,
we seldom practice slack line corrections, we have pretty turbulent
days either.

Is it possible that you are using the wrong ropes/weak links?

Bye
Andreas

To keep the reply short, I'll only say what I was taught when practising
the "wave tow". First, fly low, well below the propwash. Second: be on
the ball all the time - just "show" the spoilers. Not open them, but just
show an inch of them (unless the the line is slack much which needs
opening them fully to avoid collision with the towplane) and when the
line is about to get straight, close them. Finally, you can always use
some sideslip (yaw?) to keep the line straight. This works, and we were
doing things when my hairs went straight up. [for ones who know how
effective are the Junior's airbrakes, I'll say only that full brakes in a
sideslip with controls fully moved were often not enough to manage all
the situations that the Yak pilot had shown us that day.]

Regards,


--
Janusz Kesik

visit www.leszno.pl - home of the www.css-leszno.it.pl

In article ,
Andreas Maurer wrote:

Is it possible that you are using the wrong ropes/weak links?

Bye
Andreas

The first rope broke at a splice, not at the "weak link."
When it did break, it came as a bit of a surprise (at
least to me), but was caused by the wrong technique
for slack recovery.

The second rope break happened with what may have been a
2000# strength rope. This one happened more or less
expectedly. We did a lot quite a few slack line recoveries,
correctly, and with progressively more slack. In this
case the rope either broke at the last few feet, or
became unwoven from the ring. In either case, this is
what the tow pilot said is the common break point for
a uniform rope. The tow pilot said it felt like we were
intentionally trying to break the rope, which is not so
far from truth.

I would be surprised if the average gliderport has ever
seen a rope break under "normal" conditions.
If so this would likely indicate rope/weak link
problems. Our procedures that day certainly
were not "normal," but certainly convinced me that
yes, the rope can be broken with poor slack technique or
simply too much slack. The gliderports that
use wave (including Minden) are apparently familiar
with the latter...

I've flown through rotor and soared wave (in a Katana),
but never under tow (self-launch). It's hard for
me to imagine towing through rotor WITHOUT getting
a rope break...

We don't spend that kind of money on our weak link... yes.. the rings are
$10-12. the weak link in the rope is cheap..

if you are breaking the actual tow rope because the weak link was removed
(violation of US FAR?) you really don't have a knack for slack line
recoveries..

We use closer to or more than 200ft of rope.. trying to teach on a 150ft
rope gets real "interesting".

When our actual rope breaks (not the weak link) on slack line training.. it
was about due to be replaced anyway. Normally the weak link at the glider
end breaks and the instructor is able to save the ring.

BT

"Mark James Boyd" wrote in message
news:3fcfbbf3$1@darkstar...
While towing for Hollister, I noticed their instructor
really liked to practice slack line.

So for my flight review in Avenal yesterday, we did a bunch
of slack line corrections. We did them during one tow,
but broke the rope. 150' of rope ($12), two schweizer rings ($20),
one tost ring ($35), a carabiner (sp?), two half-wiffle balls,
and a short section of "weak link" then back-released from
the 2-33. It plumeted swiftly into a thankfully barren
plowed field below.

A few tows later, we mentioned to the tug pilot we were gonna
try slack line again. He wised up and took off the weak
link assembly ($68) leaving just wiffle and a $10 schweizer
ring.

After a dozen more slack rope practice tries, we broke
that rope. The ring and 10' of rope back released and
plumetted into another (thank god) barren field.

I'm sure some tractor pulling a tiller will grind some metal
at some point and we may get them back.

I thought about slack line. The real problem isn't
too much pulling, it's the "snappiness" with which the
slack line comes out.

It strikes me that on low tow, as slack line pulls out,
it allows a lot softer recovery. When slack comes out,
the tail of the towplane is pulled low, giving some
dampening. Next the towplane slows a little from the
drag, also good. On high tow, neither of these is true.

Sure, sure, I've read very careful use of spoilers and
yawing the sailplane away from the slack are tried and true
methods. However, even using these, there is still some point
there is so much slack you are going to break the
rope no matter what. A friend mentioned during his
first flight to try to get in wave, he with the experienced
instructor broke three ropes before succeeding.

My question is to those who have towed through rotor.
Have any of you tried low tow and high tow and would
care to tell us if you've found a difference in the
number of rope breaks?

How about the idea of towing low and to the left of the
tug? Ignore for the moment that it would annoy the tug
driver to do this on purpose (except maybe if torque
and p-factor now meant he could just leave the rudders
to flop about). Also ignore for the moment it is
drag inefficient. Would this reduce the possibility
of slack line and/or improve recovery chances even more?

How about other dangers? If the rope breaks on low
tow how would you feel about having it
fly over/around top of the wing/elevator/rudder?
Anyone have this happen?

I'm especially interested in the experiences of wave
pilots and those towing through super heavy thermals...
but armchair analysis is also invited :-]

In article rjQzb.7929$yf.258@fed1read01,
BTIZ wrote:
We don't spend that kind of money on our weak link... yes.. the rings are
$10-12. the weak link in the rope is cheap..
The end of our rope is a schweizer ring. The weak link assembly
is a weaker 3 foot rope with a tost at one end and a schweizer at
the other. A (strong) carbiner connects one end of the weak link
assembly to the end of the rope (schweizer).
We quickly and easily flip the assembly
depending on tost vs. schweizer tow.


if you are breaking the actual tow rope because the weak link was removed
(violation of US FAR?) you really don't have a knack for slack line
recoveries..
Hmm... 91.309(a)(3) seems to say the weak link is only required
if the rest of the rope isn't between 80% and 200% of max cert
glider weight. As far as having a knack...that's why we train, eh?


We use closer to or more than 200ft of rope.. trying to teach on a 150ft
rope gets real "interesting".
We use between 200-300 ft. I guess 240ft is most common. I do
not envy anyone towing on a 150ft rope.


When our actual rope breaks (not the weak link) on slack line training.. it
was about due to be replaced anyway. Normally the weak link at the glider
end breaks and the instructor is able to save the ring.
This was the case for us as well...a weak point broke the first
time. The second time we assume it broke near the glider
end because that is where most wear occurs in the rope (hookup,
wiffle ball rubbing, etc). But the second time was was not
because the rope was weak, just that that point was the weakEST
part of the rope.

We had a great discussion about doing slack line practice over
unpopulated areas in case the rope breaks with enough left
to drag back and back release.

U¿ytkownik BTIZ w wiadomo¶ci do grup
dyskusyjnych napisa³:rjQzb.7929$yf.258@fed1read01...

We use closer to or more than 200ft of rope.. trying to teach on a
150ft
rope gets real "interesting".

I agree: "interesting"... 150ft is a rope used in first flights here
(Poland), the longest. The only situations when we use longer ropes is
the triple tow (30, 50 and 75 metres). I'd rather say, that using the
short rope would make the tow easier. When towing for a typical
thermalling, the 30m (90ft?) rope is just OK, and I often flew with 20m
rope, especially in the mountains - in most cases the tow was easier and
more comfortable to me. 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.
When practising the "wave tow" and in real flights throught the rotors,
the 15-20m long rope is used.

The last advice I could give for Mark is: enter the propwash and stay
here. This should make keeping the rope spanned easier.

Regards,


--
Janusz Kesik

visit www.leszno.pl - home of the www.css-leszno.it.pl

we just swap out the weak link rope... a simple eye splice on the end of the
"rope" and the end of the link with the appropriate ring on the other end.

don't involve a carbineer...

and if the rope breaks.. you don't loose a $30 tost link AND a $12
Schweitzer link if it back releases..

we have had some rope breaks and the glider brings back his end..

or if the weak link breaks with slack line training.. try to save the ring..

BT


"Mark James Boyd" wrote in message
news:3fcfe229$1@darkstar...
In article rjQzb.7929$yf.258@fed1read01,
BTIZ wrote:
We don't spend that kind of money on our weak link... yes.. the rings are
$10-12. the weak link in the rope is cheap..
The end of our rope is a schweizer ring. The weak link assembly
is a weaker 3 foot rope with a tost at one end and a schweizer at
the other. A (strong) carbiner connects one end of the weak link
assembly to the end of the rope (schweizer).
We quickly and easily flip the assembly
depending on tost vs. schweizer tow.


if you are breaking the actual tow rope because the weak link was removed
(violation of US FAR?) you really don't have a knack for slack line
recoveries..
Hmm... 91.309(a)(3) seems to say the weak link is only required
if the rest of the rope isn't between 80% and 200% of max cert
glider weight. As far as having a knack...that's why we train, eh?


We use closer to or more than 200ft of rope.. trying to teach on a 150ft
rope gets real "interesting".
We use between 200-300 ft. I guess 240ft is most common. I do
not envy anyone towing on a 150ft rope.


When our actual rope breaks (not the weak link) on slack line training..
it
was about due to be replaced anyway. Normally the weak link at the glider
end breaks and the instructor is able to save the ring.
This was the case for us as well...a weak point broke the first
time. The second time we assume it broke near the glider
end because that is where most wear occurs in the rope (hookup,
wiffle ball rubbing, etc). But the second time was was not
because the rope was weak, just that that point was the weakEST
part of the rope.

We had a great discussion about doing slack line practice over
unpopulated areas in case the rope breaks with enough left
to drag back and back release.

In article 3fcfbbf3$1@darkstar,
(Mark James Boyd) wrote:

Sure, sure, I've read very careful use of spoilers and
yawing the sailplane away from the slack are tried and true
methods. However, even using these, there is still some point
there is so much slack you are going to break the
rope no matter what.

I've been towed in strong thermals and some pretty serious wave rotor at
e.g. Omarama. I've never had a problem with a big jerk when the slack
comes out of the rope. I don't use spoilers, and I don't yaw. What I
*do* is when the rope is becoming slack I climb (and therefore slow
down). As the rope starts to become tight I descend (and therefore sped
up). Do it right and there is no jerk at all.

Notes:

- make sure you're not still high when the slack comes out. Pulling the
tail of the towplane up is a *bad* thing. In any event, the height
change required is usually not all that much. But if through
misjudgement you are high when the rope comes tight then you should
release.

- if I'd climbed as far as I was comfortable, and was still overtaking
the towplane then I'd use airbrakes. Hasn't happened yet, except on a
deliberate descent.

- I guess it's possible that this might not work as well in something as
draggy as a 2-33. It's great in glass.

Bruce Hoult wrote:
In article 3fcfbbf3$1@darkstar,
(Mark James Boyd) wrote:

Sure, sure, I've read very careful use of spoilers and
yawing the sailplane away from the slack are tried and true
methods. However, even using these, there is still some point
there is so much slack you are going to break the
rope no matter what.

I've been towed in strong thermals and some pretty serious wave rotor at
e.g. Omarama. I've never had a problem with a big jerk when the slack
comes out of the rope. I don't use spoilers, and I don't yaw. What I
*do* is when the rope is becoming slack I climb (and therefore slow
down). As the rope starts to become tight I descend (and therefore sped
up). Do it right and there is no jerk at all.


Same for me. I began gliding in Montpellier where there are serious
rotors due to the mistral, and instructors never taught me to do
anything particular (like using spoilers, etc.) in case the rope is not
tight. They taught me to content following the plane as best as
possible, and apparently this doesn't cause big problems. I have never
seen a broken rope either.



--

Michel TALON