Low towing thought

On Mar 6, 4:38 pm, "Bill Daniels" bildan@comcast-dot-net wrote:
"Tuno" wrote in message

oups.com...

This topic is most interesting. I was never taught the low tow, or
presented with the concept at any of the 3 places I took lessons
(Estrella, Seminole Lakes and Turf, 3 years ago). How is it easier for
the glider driver? Wouldn't it create more work for the tug driver?

Are there any enthusiasts of the low tow who are also enthusiasts of
high wing loading for those good days? I've been in the "low tow"
position unintentionally at max wing loading when the tug driver musta
thought he was pulling a 2-33. Seems like there would be no room for
error if one started out in that position, and the tug then slowed
down!

~ted/2NO

I probably flew hundreds of low tows at the old El Mirage Field. Gus
Brigleib insisted on low tow.

If you are flying a low performance glider, the technique for slack is to
just push the nose lower. The glider will just move down and take the slack
out. If, however, you are flying a Nimbus, it will outrun the tug pasing
under it. Pulling up puts in more slack even as the glider slows down
ending in a jerk.

In the end, I suspect the reason Gus insisted on low tow was the TG-3's he
used as trainers. It was very difficult for the instructor, sitting 8 feet
or so behind the student, to see the tug while in high tow. There was a lot
of rollover structure and greenhouse canopy between the front and rear
cockpits. Low tow gives the instructor a great view of the tug. I really
can't think of another reason for low tow.

BTW, low tow seems easier only because there are fewer references, like the
horizon, to help detect being out of position. If you can't tell you are
out of position, it seems OK. In fact, the opposite may be true. In high
tow, the tugs wingtip vortices tend to push a glider back to center
position. In low tow, they tend to pull it out of position.

Bill Daniels

Gotta jump on this one- sorry Bill!
Suggestion of moving down to take up slack is absolutely wrong. This
will increase relative speed of glider and make the situation worse.
The usual reason for slack is glider quickly descending and thus
slightly overtaking tug. Just like what creates slack in high tow.
Proper technique when you get some slack is simply slide out to the
side until slack comes out. Then return to proper vertical position
and move back to center.
Since you are below the wake , vortices are not really and issue.
One of the nice parts about low tow is that you feel the wake on the
vertical tail as height warning instead of fuselage descending into
wake and causing glider to want to start out of position. 2-33 drivers
will recognize this scenario.
BTW- we've tried top stall the tug by pulling the tail down and not
been able to do it.
Cheers UH

wrote in message
oups.com...
On Mar 6, 4:38 pm, "Bill Daniels" bildan@comcast-dot-net wrote:
"Tuno" wrote in message

oups.com...

This topic is most interesting. I was never taught the low tow, or
presented with the concept at any of the 3 places I took lessons
(Estrella, Seminole Lakes and Turf, 3 years ago). How is it easier for
the glider driver? Wouldn't it create more work for the tug driver?

Are there any enthusiasts of the low tow who are also enthusiasts of
high wing loading for those good days? I've been in the "low tow"
position unintentionally at max wing loading when the tug driver musta
thought he was pulling a 2-33. Seems like there would be no room for
error if one started out in that position, and the tug then slowed
down!

~ted/2NO

I probably flew hundreds of low tows at the old El Mirage Field. Gus
Brigleib insisted on low tow.

If you are flying a low performance glider, the technique for slack is to
just push the nose lower. The glider will just move down and take the
slack
out. If, however, you are flying a Nimbus, it will outrun the tug pasing
under it. Pulling up puts in more slack even as the glider slows down
ending in a jerk.

In the end, I suspect the reason Gus insisted on low tow was the TG-3's
he
used as trainers. It was very difficult for the instructor, sitting 8
feet
or so behind the student, to see the tug while in high tow. There was a
lot
of rollover structure and greenhouse canopy between the front and rear
cockpits. Low tow gives the instructor a great view of the tug. I
really
can't think of another reason for low tow.

BTW, low tow seems easier only because there are fewer references, like
the
horizon, to help detect being out of position. If you can't tell you
are
out of position, it seems OK. In fact, the opposite may be true. In
high
tow, the tugs wingtip vortices tend to push a glider back to center
position. In low tow, they tend to pull it out of position.

Bill Daniels

Gotta jump on this one- sorry Bill!
Suggestion of moving down to take up slack is absolutely wrong. This
will increase relative speed of glider and make the situation worse.
The usual reason for slack is glider quickly descending and thus
slightly overtaking tug. Just like what creates slack in high tow.
Proper technique when you get some slack is simply slide out to the
side until slack comes out. Then return to proper vertical position
and move back to center.
Since you are below the wake , vortices are not really and issue.
One of the nice parts about low tow is that you feel the wake on the
vertical tail as height warning instead of fuselage descending into
wake and causing glider to want to start out of position. 2-33 drivers
will recognize this scenario.
BTW- we've tried top stall the tug by pulling the tail down and not
been able to do it.
Cheers UH


Please note that I did qualify my statement with the phrase "low performance
glider". In the days I was flying low tow, it was rare to find a glider
with more than 30:1. The 2-22's were about 20:1. These glilders won't
accelerate as you nose down. As you point out, higher performance gliders
will over run the rope.

Wing tip vortices have a laminar far field effects that extends at least one
tug wingspan. I did some wing tip vortex turbulence studies in the 1960's
with smoke grenades on the tug wing. That was one of the results. It means
that the glider is always under the influence of the two wingtip vortices
coming from the tug whether the pilot can sense the turbulence or not.

An interesting experiment is to position the glider to one side while in
high tow. Then, keep the gliders wings exactly level with reference to the
tug but otherwise allow the glider to go where it will. The glider will
gently swing back to center as it is pushed by the wing tip vortex. Try
that in low tow and the vortex flow will pull the glider away from center.

Bill Daniels

"Graeme Cant" gcantinter@tnodedotnet wrote in message
...
Vaughn Simon wrote:
"Graeme Cant" gcantinter@tnodedotnet wrote in message
...
In Oz it's a no-no to pop up into high tow as you release (with all due
respect to Oscar's experience and SA's rules) because it's been known to
initiate a kiting situation. I guess our experience is that a 'slow' move
through a turbulent slipstream into high tow isn't all that easy to
accomplish for ab initio and low experience pilots...

That trip up (and/or down) through the wake is part of the drill for the
"boxing the wake" manuver. I would never solo a student who couldn't do
that.

Vaughn

Good.

Your point is?

My point is that the slow "trip through the wake" should not be a problem,
even for ab initio and low experience pilots. It is something that is easily
trained for and practiced.

Vaughn

Thanks, guys. I've learnt a lot from this thread: all I hoped to find
out and a lot of other valuable stuff as well. Mainly that, as a
beginner at that game I'm going far too low. I see more practice in my
future.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

Vaughn Simon wrote:
"Graeme Cant" gcantinter@tnodedotnet wrote in message
...
Vaughn Simon wrote:
"Graeme Cant" gcantinter@tnodedotnet wrote in message
...
In Oz it's a no-no to pop up into high tow as you release (with all due
respect to Oscar's experience and SA's rules) because it's been known to
initiate a kiting situation. I guess our experience is that a 'slow' move
through a turbulent slipstream into high tow isn't all that easy to
accomplish for ab initio and low experience pilots...
That trip up (and/or down) through the wake is part of the drill for the
"boxing the wake" manuver. I would never solo a student who couldn't do
that.

Vaughn
Good.

Your point is?

My point is that the slow "trip through the wake" should not be a problem,
even for ab initio and low experience pilots. It is something that is easily
trained for and practiced.

1. In my instructing experience boxing the wake is a moderately
difficult manoeuvre to carry out in a well-controlled way for ab initio
and low experience pilots. Many experienced pilots botch boxing the
wake on their annual check. That's why instructors set it as an
exercise. I suspect that's why you set it.

2. Boxing the wake doesn't actually involve a trip directly through the
slipstream.

GC

Vaughn

Properly done, boxing the wake begins by a descent
through the wake, a box around the wake, and then an
ascent back up through the wake. This shows the student
the extremes of where one can go safely on tow.

At 13:48 08 March 2007, Graeme Cant wrote:
Vaughn Simon wrote:
'Graeme Cant' wrote in message
...
Vaughn Simon wrote:
'Graeme Cant' wrote in message
...
In Oz it's a no-no to pop up into high tow as you
release (with all due
respect to Oscar's experience and SA's rules) because
it's been known to
initiate a kiting situation. I guess our experience
is that a 'slow' move
through a turbulent slipstream into high tow isn't
all that easy to
accomplish for ab initio and low experience pilots...
That trip up (and/or down) through the wake is
part of the drill for the
'boxing the wake' manuver. I would never solo a student
who couldn't do
that.

Vaughn
Good.

Your point is?

My point is that the slow 'trip through the wake'
should not be a problem,
even for ab initio and low experience pilots. It
is something that is easily
trained for and practiced.

1. In my instructing experience boxing the wake is
a moderately
difficult manoeuvre to carry out in a well-controlled
way for ab initio
and low experience pilots. Many experienced pilots
botch boxing the
wake on their annual check. That's why instructors
set it as an
exercise. I suspect that's why you set it.

2. Boxing the wake doesn't actually involve a trip
directly through the
slipstream.

GC

Vaughn

Nyal Williams wrote:
Properly done, boxing the wake begins by a descent
through the wake, a box around the wake, and then an
ascent back up through the wake. This shows the student
the extremes of where one can go safely on tow.

I agree and this is how I do it and teach it. But in the US, the PTS
doesn't say that you have to do it this way. And, it's referenced source
for the maneuver, The Soaring Flight Manual, also does not mention going
through the wake. If, on a flight review, a rated pilot boxes the wake
without going through it, I keep my mouth shut. But, then later I will
ask for a tow transition through the wake prior to release.

Tony V
http://home.comcast.net/~verhulst/SOARING

On Mar 8, 6:44 am, Graeme Cant gcantinter@tnodedotnet wrote:
1. In my instructing experience boxing the wake is a moderately
difficult manoeuvre to carry out in a well-controlled way for ab initio
and low experience pilots. Many experienced pilots botch boxing the
wake on their annual check. That's why instructors set it as an
exercise. I suspect that's why you set it.

Yes. And I stress *precision* in the exercise. The point is not to
get around the wake as fast as possible, it is to prove to the
instructor that you have the skill to make the various transitions
while maintaining control of the glider.

2. Boxing the wake doesn't actually involve a trip directly through the
slipstream.

Many people begin the exercise by dropping from high to low tow
through the wake. This help establish the reference for where the
bottom part of the box should be.

-Tom

Tony Verhulst wrote:

But in the US, the PTS
doesn't say that you have to do it this way. And, it's referenced source
for the maneuver, The Soaring Flight Manual, also does not mention going
through the wake. If, on a flight review, a rated pilot boxes the wake
without going through it, I keep my mouth shut. But, then later I will
ask for a tow transition through the wake prior to release.


They done went and changed it agin, then:

http://tinyurl.com/2fksg7

faa-h-8083-13, pp101-102 (2003)


"BOXING THE WAKE

"Boxing the wake is a performance maneuver designed
to demonstrate a pilotÂ’s ability to accurately maneuver
the glider around the towplaneÂ’s wake during aerotow.

"Boxing the wake requires flying a rectangular pattern
around the towplaneÂ’s wake. _Before starting the
maneuver, the glider should descend through the wake
to the center low tow position as a signal to the tow
pilot that the maneuver is about to begin_. The pilot
uses coordinated control inputs to move the glider out
to one side of the wake and holds that lower corner of
the rectangle momentarily with rudder pressure. Applying
back pressure to the control stick starts a vertical
ascent, then rudder pressure is used to maintain equal
distance from the wake. The pilot holds the wings level
with the ailerons to parallel the towplaneÂ’s wings. When
the glider has attained high corner position, the pilot
momentarily maintains this position.

"As the maneuver continues, the pilot reduces the rudder
pressure and uses coordinated flight controls to bank
the glider to fly along the top side of the box. The
glider should proceed to the opposite corner using
aileron and rudder pressure, as appropriate. The pilot
maintains this position momentarily with rudder pres-
sure, then begins a vertical descent by applying for-
ward pressure to the control stick. Rudder pressure is
used to maintain glider position at an equal distance
from the wake. The pilot holds the wings level with the
ailerons to parallel the towplaneÂ’s wings. When the
glider has attained low corner position, the pilot
momentarily maintains this position. The pilot releases
the rudder pressure and, using coordinated flight
controls, banks the glider to fly along the bottom side
of the box until reaching the original center low tow
position._From center low tow position, the pilot
maneuvers the glider through the wake to the center
high tow position, completing the maneuver_.

"COMMON ERRORS
-Performing an excessively large rectangle
around the wake.
• -Improper control coordination and procedure
• -Abrupt or rapid changes of position."

---------------------------------------------------


Jack

Adding to Tom's point, there are "locational" variations to boxing the
wake. Where I learned, we would drop down to low tow, climb right back
up to high tow, then box the wake going clockwise around the wake.
Where I fly now, we drop to low tow, box the wake going clockwise
around the wake, then climb back up to high tow. I've heard that at
some sites the wake is boxed going counter-clockwise around the wake
instead of clockwise.

None of these variations really matter much - as 5Z says, the whole
point of the maneuver "is to prove to the instructor that you have the
skill to make the various transitions while maintaining control of the
glider."

-John

On Mar 8, 11:03 am, "5Z" wrote:
Many people begin the exercise by dropping from high to low tow
through the wake. This help establish the reference for where the
bottom part of the box should be.

-Tom