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

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.

Regards,

JK

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

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 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

(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 :-]


Our club,Valley Soaring Club in SE NY and the prior 2 commercial
operations have
used low tow exclusively for more than 30 years. It is used in Oz as
primary. Not sure where else.
Our experience is that slack rope situations are almost totally non
existant. Most all of these result from descending from a higher
position.
We teach and fly in a position just below( almost touching the wake).
In this position, the rope is in line with the natural trailing
position behind the tug. As a result, if the rope is released from the
tug, it falls below the glider and will back release in most cases.
Even if way too low the rope would normally just trail over the top of
the glider. Yes the ring could hit the canopy or other part of the
glider.
Advantages we see:
New students fly the tow without help within 2 or 3 tows. Position is
easy to view, evaluate and adjust.
Glider is on thrust line of tug- efficient, less trim drag, no trim
change.
Nobody ever dove a tug pilot into the ground in low tow.
Slack is virtually not a factor. Easily and gently corrected. No
broken ropes. I have not had a broken rope in 10,000 low tows at
glider end and about 4000 at tug end.

Myth: you can get too low and pull tug tail down stalling him- We
tried and found we could actually go slower in control towing with
Super Cub with glider hanging way low than we could with glider off.

Myth: Rope wil tie itself around wing and disble controls if released
at front. Show me a rope that can go upwind in a 60 mph headind.

Conclusion: It is worth learning to do right. Tug pilot needs to be
aware you will be doing something different(he may need mirror
adjusted differently).

OK now all the experts can shoot holes in my comments- go for it.
UH

At 15:06 05 December 2003, Hank Nixon wrote:
Myth: you can get too low and pull tug tail down stalling
him- We
tried and found we could actually go slower in control
towing with
Super Cub with glider hanging way low than we could
with glider off.

Myth: Rope wil tie itself around wing and disble controls
if released
at front. Show me a rope that can go upwind in a 60
mph headind.

Neither of these are myths, it actually happened two
years ago at the Cambridge Gliding Club though not
as a result of using low tow. The tug was flying too
slow and the Puchacz on the back got gradually lower,
ending up pulling the tugs tail down as he applied
more and more power, eventually the tuggie released
and the rope wrapped itself around the puch wing (fortunately
not fouling any controls in this case). Both aircraft
subsequently landed safely with no damage.

Although I was present on the airfield I didn't witness
the incident, I did speak to the P1 shortly afterwards,
I'm sure someone from the Cambridge club could give
you more detail.

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

Although Bruce's approach is most elegant, I think it
also requires the most skill and best timing. Matching
airspeeds is challenging.

Brian's approach is pretty standard, but also requires a
little bit of timing. I'd also be surprised if he
isn't subtly using a little bit of dive at the end
to help match airspeeds.

Janusz and his 20 meter rope leaves me speechless.
I'd have to try it to have any real opinion.

Michel's low tow seems like a low-skill winner.
As long as you don't get too low and scare the towpilot
into releasing it seems you'll do ok.

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.

Any rotor towpilots have any further opinions?

U¿ytkownik Mark James Boyd w wiadomo¶ci do grup
dyskusyjnych napisa³:3fd0d41d$1@darkstar...
A lot of different techniques - little consensus

Although Bruce's approach is most elegant, I think it
also requires the most skill and best timing. Matching
airspeeds is challenging.

For me it looks for a great way to break the rope, but I migth be wrong
of course.

Janusz and his 20 meter rope leaves me speechless.
I'd have to try it to have any real opinion.

30m rope is a standard, but when switching for a 20m, it seems a bit
scary for the first time when You can see if the ring at the end of the
rope is properly connected to the Wilga's (towplane) towhook. I'm
joking of course, but for the first time it can look strange. Usually one
gets used to it very quickly.

Michel's low tow seems like a low-skill winner.
As long as you don't get too low and scare the towpilot
into releasing it seems you'll do ok.

You can always fly just_in_the_propwash (wake?) as it also helps to keep
controls crisp at low speeds.

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.

It can be used, but very carefully. Don't do this in Pirat, especially if
You're a tiny person. I had some problems with closing the Pirat's brakes
on tow, know at least one girl who wasn't able to close the brakes,
landing at the beginning of the afld. There was at least one accident of
another girl in Pirat caused by large force at the airbrake handle when
towed. But also... wise use of airbrakes in gliders like the Junior or
Puchacz (from my experience) can in most cases solve the problem.

Regards,


--
Janusz Kesik

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