Newbie question: staying calmly behind glider tug

[[email protected]]

I'm planning to join the local soaring club and had my first ride last
weekend. I was eager to take the controls while being towed and was
enormously humbled by the experience.

I've had my ppsel for several years, but do not have many hours under
my belt. Never the less, I was looking forward to this and thought:
How difficult could it be? No P factor, just hang in there behind the
tug.

I was embarrassed. I could not keep the glider (a Blanik) anywhere
close to remaining calmly behind the tug. I was all over the sky and
was acutely aware that I must be yanking the tug's tail back and forth
and up and down.

Three times I was rescued by the guy giving me the ride, although by
the last time I was beginning to understand that the tow rope itself
could bring the nose back.

I had not prior instruction before the ride, I really thought it would
not be a problem. BZZZZZT wrong.

Once we cast off, holding headings, holding airspeed and just keeping
the wings level wasn't a problem. I was astonished at how far we
could travel at 60 mph without seeming to loose much altitude. Heck,
I've lost more altitude than that when I was flying cross country and
TRYING to hold my cruise altitude. :-)

One of the more expert glider pilots reassured me that all first
timers have the same problems, and told me that I should concentrate
on holding the wings the same as the tug, and using the rudder to stay
behind it.

I wasn't doing it that way, I was sawing back and forth with the stick
and getting into all kinds of trouble.

I'm eager to try again, but I thought I'd drop in here and ask how
folks stayed behind the tug... If you all can remember back when you
were at my stage. ;-)

Thanks, Corky Scott

[Terry]

Glider instructors have lived this scenario for years:

The Schweizer just would not stop moving around behind the Cub. Left,
then right and always up. Push-then too low, ease off the stick,
then too high. The glider moves first to one side and then with a zoom
across to the other.

"I've got it. Look at how my wings are parallel with the tug.
Your airplane."

In the USA, the primary means of towing a glider is called aero-tow. A
slow speed, relatively high-powered tow plane is attached to the glider
with a 200-foot length of rope that meets regulatory strength
requirements. The glider then flies a formation take-off and climb to
a suitable release point. Even for experienced transitioning pilots,
this maneuver is nearly as difficult as landing. In those first
several attempts, students end up in an ever-increasing departure from
the center.

Like most pilots, one of my initial challenges in learning to fly
gliders was mastering the aero-tow. As a CFI, I see my own
difficulties reflected in current students as they fight the controls
seeking the dead-weight spot where the glider just follows behind the
tow-plane. The dead-weight spot is the point where the glider is
imparting no other force on the tow plane other than the weight of the
glider. Any displacement from this spot makes the tow more difficult
for both the pilot of the glider and the pilot of the tow plane. When
conducting flight tests, I see many problems from applicants during
their demonstration of the Areas of Operation relating to Aero-tow.
Since control of the glider while on tow is a requirement, it carries
some weight on the outcome of the flight test.

Nearly all two place sailplanes are constructed with a tandem
configuration. This adds some difficulty to training, especially with
the topic of transfer of control. A good preflight briefing settling
this is essential.

In conducting the preflight briefing, I follow the order of the flight
beginning with the take-off, through the various maneuvers, and ending
with the release from the tow plane. For the take-off, the dead weight
example holds. We balance the glider on the main wheel until airborne,
adjusting for any cross wind by crabbing so that no additional side
load is imposed on the tow plane during his take-off run. There is a
strong tendency for the glider to climb after lift-off as the tow
imparts the same force on the glider similar to running with a kite.
Were the glider to climb too high, the nose of the tow plane would be
driven into the ground causing at a minimum a longer than normal
take-off roll and a lecture from the tow pilot after your return.

Students will suffer tunnel vision when under stress. This becomes
evident while flying tow as the student becomes so fixated on the tow
plane and maintaining relative position that he will not see even the
horizon beyond. In order to maintain relative position behind the tow
plane, the controls of the glider must be operated not for coordinated
flight, but only to maintain position. Ailerons are used to match the
tow plane's bank. Any divergence from the tow plane bank will cause
lateral displacement, as the horizontal component of lift will rapidly
overpower the stabilizing force of the tug of the rope. Some
instructors will use the phrase in this case of "level your wings,
steer with your feet" to indicate that the wings of the glider are
not parallel to the tug. Too much bank in a turn relative to the tug
will result in the glider falling inside the turn and below the normal
tow position with a resulting slack towline, while too little bank in a
turn will result in the glider accelerating around the tug and climbing
above the normal tow position.

Relative height behind the tow plane is maintained with the elevator.
The typical training glider in the USA is the Schweizer 2-33. When the
2-33 is towed, it is flying at a speed that is nearly 40% above normal
design flying speed. This will cause a need for constant forward
pressure on the stick in order to prevent climbing well above the tow
plane. Lateral position is maintained using the rudder-not the
ailerons. At any one time, the controls in the glider are being
utilized to maintain position, not necessarily coordinated flight. The
goal is to merely be pulled up as dead weight.

Displacement from the normal position will eventually result in a slack
line and if the slack is not carefully removed a broken towrope will
result. It is for this reason that the PTS requires a demonstration of
slack line recovery. It goes without saying that any slack that
develops not be allowed to foul the glider, so move away from any loop
that develops. The action of moving away will tend to remove some of
the slack. At this point the tow plane is relieved of the dead weight
of the glider and will accelerate. Since the glider is not currently
being pulled by the towrope, it will decelerate. If no further action
is taken, and no other force applied that increases slack, such as
turbulence; the slack will just go away. Any attempts to force a
reduction in the slack by using an excess of drag will cause the rope
to snap taught and possibly break. The PTS standard for the performance
for aero-tow is only smooth and effective use of the controls.
Snapping the rope would not be very smooth.

During the typical glider flight, the tow is approximately 5-7 minutes.
This concentrated time can make students confident for the remainder
of the flight or distraught over earlier performance. Consider staying
on tow a little longer on later flights in order to give your students
more time. When I was a student, a long cross-country tow finally
solved my problems with the tow.

[Terry]

Dead-weight is just a figure of speech. I have already been corrected
on that!

Terry

[Stefan]

The answer is (surprize!) practice.

Initially you get thrown around as you described. Then you actually
begin to fly behind the tug. Later you'll find yourself staying in a
reasonable position, ceasing to endager yourself and the tow pilot.
Still later, you'll stay in that position even in turns. First in
shallow turns, later in steeper turns, too. Gradually your yaw string
will stay more and more centered. And someday you'll stay behind the tug
even in moderate turbulence. But it's a long way to go.

Stefan

[Vaughn]

> wrote in message
...
>
> I was embarrassed.

Don't be! I have brought ATPs back down drenched in sweat after a quick
initial lesson. I quickly learned to prepare such students for what usually
happens so they would not feel humiliated if they could not immediately perform.
I have had a few that could stay in position behind the tow plane on the first
try...damn few. IMO Instrument time and helicopter time seems to help because
they teach you not to over control.

I could not keep the glider (a Blanik) anywhere
> close to remaining calmly behind the tug. I was all over the sky and
> was acutely aware that I must be yanking the tug's tail back and forth
> and up and down.

Perfectly normal. Sooner of later you acquire the proper circuitry between
your eyes, your brain, your hand and your feet. Then you will wonder why it was
ever an issue.
>
> Three times I was rescued by the guy giving me the ride

Only three times? That is actually pretty good!

I have never had a student who could not eventually learn to do a safe tow.
I had a hard time myself.

Vaughn



, although by
> the last time I was beginning to understand that the tow rope itself
> could bring the nose back.
>
> I had not prior instruction before the ride, I really thought it would
> not be a problem. BZZZZZT wrong.
>
> Once we cast off, holding headings, holding airspeed and just keeping
> the wings level wasn't a problem. I was astonished at how far we
> could travel at 60 mph without seeming to loose much altitude. Heck,
> I've lost more altitude than that when I was flying cross country and
> TRYING to hold my cruise altitude. :-)
>
> One of the more expert glider pilots reassured me that all first
> timers have the same problems, and told me that I should concentrate
> on holding the wings the same as the tug, and using the rudder to stay
> behind it.
>
> I wasn't doing it that way, I was sawing back and forth with the stick
> and getting into all kinds of trouble.
>
> I'm eager to try again, but I thought I'd drop in here and ask how
> folks stayed behind the tug... If you all can remember back when you
> were at my stage. ;-)
>
> Thanks, Corky Scott

[[email protected]]

wrote:

> I was embarrassed. I could not keep the glider (a Blanik) anywhere
> close to remaining calmly behind the tug. I was all over the sky and
> was acutely aware that I must be yanking the tug's tail back and forth
> and up and down.
>

I was glad to read that--I thought it was just me.
I was glad to read that it is common--I thought it was just us.
I received my ppasel and thought the gliders would be an easy add-on.
I never worked so hard in my life! My first flights were in a Grob
103, and I was all over the sky! Several times I nearly passed the
tow-plane and the instructor was in the back seat yelling
"yeeeeeehaaaaawwwww".


Two flights and I had the cockiness knocked out of me, and settled down
to learn. Went pretty well after that. And I firmly believe that
flying gliders makes a power pilot even better.

Coming in to land, once in the pattern you learn the meaning of
"committment".

[Tony Verhulst]

> I was embarrassed. I could not keep the glider (a Blanik) anywhere
> close to remaining calmly behind the tug.

Welcome to adverse yaw :-).

In 10 years of instructing, I've had exactly 2 power transition
students manage the tow with only verbal assist. It wasn't pretty, but
the job got done.

After a while, you'll realize that with a nose hook on aero tow, the
glider really wants to fly behind the tug and if it ain't doin' that,
it's you :-).

Tony V.

[Bruce Hoult]

In article >,
wrote:

> One of the more expert glider pilots reassured me that all first
> timers have the same problems, and told me that I should concentrate
> on holding the wings the same as the tug, and using the rudder to stay
> behind it.
>
> I wasn't doing it that way, I was sawing back and forth with the stick
> and getting into all kinds of trouble.
>
> I'm eager to try again, but I thought I'd drop in here and ask how
> folks stayed behind the tug... If you all can remember back when you
> were at my stage. ;-)

I can remember it. With zero prior flying experience, my instructor
threw me into the tow on my second flight. That was in a Blanik L13,
almost the same as you flew. I was all over the place at first but
pretty soon was able to follow the tug. But I had no idea where we
were, where the airfield was, or whetehr we were at our planned release
height yet. After a few more flights the concentration required for
following the tug decreased to the point that I had time to look at the
altimeter and notice where we were. And a while after that I had time
to look at clouds, and the vario, and figure out that maybe it was a
good money-saving idea to get off tow early in a thermal. It gets
easier and easier.

About staying behind the tug ... I don't recall ever being taught to use
the rudder for steering while on tow. It was fly coordinated with the
string in the middle at all times.

If you get off to the side, or high or low, the *important* thing is to
stop the divergence and get flying parallel to the towplane again.
Bringing it back into the middle is very much a secondary concern and
doing it gradually is fine, as long as the trend is in the right
direction. But when I bring it back into the middle I was taught to do
it using normal, coordinated turns, aileron and rudder together, but
with only a small angle of bank and you need to start turning back the
other way well before you get halfway back into position. And remember
that you don't just have to get the wings level with the tug. If you do
that then you'll be flying straight, but out towards the other side.
Say you're out to the right already flying parallel to the tug 9you've
fixed things up that much already). During getting back into line you
need to spent about 25% of your time rolling left, then 50% of the time
rolling right (25% getting wings level, then 25% starting a turn to the
right), then the final 25% rolling left to get wings-level again. Like
most of these things, once you "get" it you just do it and don't have to
think about it any more.

--
Bruce | 41.1670S | \ spoken | -+-
Hoult | 174.8263E | /\ here. | ----------O----------

[Bill Daniels]

Let's see, take two wildly different aircraft, tie them together with a 200
foot rope and go fly formation. Sounds like an airshow act.

Bill Daniels


> wrote in message
...
> I'm planning to join the local soaring club and had my first ride last
> weekend. I was eager to take the controls while being towed and was
> enormously humbled by the experience.
>
> I've had my ppsel for several years, but do not have many hours under
> my belt. Never the less, I was looking forward to this and thought:
> How difficult could it be? No P factor, just hang in there behind the
> tug.
>
> I was embarrassed. I could not keep the glider (a Blanik) anywhere
> close to remaining calmly behind the tug. I was all over the sky and
> was acutely aware that I must be yanking the tug's tail back and forth
> and up and down.
>
> Three times I was rescued by the guy giving me the ride, although by
> the last time I was beginning to understand that the tow rope itself
> could bring the nose back.
>
> I had not prior instruction before the ride, I really thought it would
> not be a problem. BZZZZZT wrong.
>
> Once we cast off, holding headings, holding airspeed and just keeping
> the wings level wasn't a problem. I was astonished at how far we
> could travel at 60 mph without seeming to loose much altitude. Heck,
> I've lost more altitude than that when I was flying cross country and
> TRYING to hold my cruise altitude. :-)
>
> One of the more expert glider pilots reassured me that all first
> timers have the same problems, and told me that I should concentrate
> on holding the wings the same as the tug, and using the rudder to stay
> behind it.
>
> I wasn't doing it that way, I was sawing back and forth with the stick
> and getting into all kinds of trouble.
>
> I'm eager to try again, but I thought I'd drop in here and ask how
> folks stayed behind the tug... If you all can remember back when you
> were at my stage. ;-)
>
> Thanks, Corky Scott

[Eric Greenwell]

Stefan wrote:

> The answer is (surprize!) practice.

I would add - "and proper instruction". Practicing poor technique will
mean a long time learning. So, find a good instructor if you can, and
read the towing section in soaring manuals several times.

>
> Initially you get thrown around as you described. Then you actually
> begin to fly behind the tug. Later you'll find yourself staying in a
> reasonable position, ceasing to endager yourself and the tow pilot.
> Still later, you'll stay in that position even in turns. First in
> shallow turns, later in steeper turns, too. Gradually your yaw string
> will stay more and more centered. And someday you'll stay behind the tug
> even in moderate turbulence. But it's a long way to go.

Not so long if the instruction is good! My instructor was not very
experienced, and taught a poor technique. By the time time I was an
instructor, I could teach a student much more quickly than he did when
he taught me.

I realize "long" is undefined here, and Stefan and I might be talking
about the same amount of time. I think he will agree with the importance
of a good instructor in speeding the learning, however.

--
Change "netto" to "net" to email me directly

Eric Greenwell
Washington State
USA

[Jack]

wrote:

> I could not keep the glider (a Blanik) anywhere
> close to remaining calmly behind the tug. I was all over the sky and
> was acutely aware that I must be yanking the tug's tail back and forth
> and up and down.

Don't feel bad. I had lots of USAF close formation time and I was not at
all impressed with my ability to fly a steady tow position, until I
RELAXED and quit trying to force the bird to go where it should.

You'll get a lot better with practice, and somewhat less intensity.

Have Fun.


Jack

[Tom Dukerich]

Corky,

Welcome to ras! I've been an advid reader of you on rah.

I added glider this year and enjoy soaring more than I thought I would.
Initially, I was just adding a rating for the hell of it, but soon found
soaring to be a great flying experience.

I became part owner of a sailplane and have not flown power since. It is
hard to beat hours of flying after a $40 tow.

Keep with it, and keep you feet active.

Tom


On Wed, 07 Sep 2005 14:10:17 -0400, charles.k.scott wrote:

[Roger Worden]

Welcome to soaring! Don't let the difficulty of flying the aerowtow dissuade
you from the fun of learning to fly. See the other thread here called
"Aerotow - learning and teaching". Aerotowing is formation flying - and it
is not easy for the beginner! One school of thought is that the student
should learn basic speed control, turns, and straight-and-level flight
before even attempting to fly the tow. So... talk it over with your
instructor, and maybe get a few more flights in before worrying too much
about the tow.


> wrote in message
...
> I'm planning to join the local soaring club and had my first ride last
> weekend. I was eager to take the controls while being towed and was
> enormously humbled by the experience.
>
> I've had my ppsel for several years, but do not have many hours under
> my belt. Never the less, I was looking forward to this and thought:
> How difficult could it be? No P factor, just hang in there behind the
> tug.
>
> I was embarrassed. I could not keep the glider (a Blanik) anywhere
> close to remaining calmly behind the tug. I was all over the sky and
> was acutely aware that I must be yanking the tug's tail back and forth
> and up and down.
>
> Three times I was rescued by the guy giving me the ride, although by
> the last time I was beginning to understand that the tow rope itself
> could bring the nose back.
>
> I had not prior instruction before the ride, I really thought it would
> not be a problem. BZZZZZT wrong.
>
> Once we cast off, holding headings, holding airspeed and just keeping
> the wings level wasn't a problem. I was astonished at how far we
> could travel at 60 mph without seeming to loose much altitude. Heck,
> I've lost more altitude than that when I was flying cross country and
> TRYING to hold my cruise altitude. :-)
>
> One of the more expert glider pilots reassured me that all first
> timers have the same problems, and told me that I should concentrate
> on holding the wings the same as the tug, and using the rudder to stay
> behind it.
>
> I wasn't doing it that way, I was sawing back and forth with the stick
> and getting into all kinds of trouble.
>
> I'm eager to try again, but I thought I'd drop in here and ask how
> folks stayed behind the tug... If you all can remember back when you
> were at my stage. ;-)
>
> Thanks, Corky Scott
>

[[email protected]]

A couple of earlier posts mentioned "relaxing" and "not over
controlling". That is the key. When I first learned aerotow many years
ago, I too found myself oscillating behind the tow plane and needing my
instructor to rescue me before I broke the tow rope, was cut loose by
the tow plane, etc.

Then the instructor told me, "Next time the tow plane gets a bit high
[or low or right or left] don't do anything for a second or two and
you'll be amazed at how you come back into position." He was right. And
it makes theoretical sense as well. Without getting into control
theory, suffice it to say that while some feedback (correcting for your
position) is needed to maintain stability, too much feedback will
guarantee oscillations. The trick is getting the right amount and
newbies tend to overcontrol. Oh yeah, my instructor also told me to
stop holding the stick with a "death grip." Part of the same syndrome.
Try to relax more.

One other point that might make you feel better (tho I suspect all the
now proficient glider pilots saying "that was me at first too" helps
even more): Learning to fly aerotow is learning to fly formation.
You're lucky that you already have PP-SEL. A totally new glider pilot
is trying to learn to fly, and fly in formation at the same time!

Lastly, welcome to the club. I'm sure that in not much time you'll look
back on this problem (and any others, like getting dizzy in thermals)
and smile at how far you've come so fast.

Martin

[bumper]

I've got a new Husky with tow hook. I've been in contact with Frito-Lay and
they've agreed to provide me with big free decals for the side of my ship
that say, "Fritos®"

I suspect I'll have no problem finding "customers" once I learn how to tow,
but one question keeps nagging me, "How can I stay calmly ahead of the
glider?"

bumper
Minden, NV

[Eric Greenwell]

bumper wrote:

> I've got a new Husky with tow hook. I've been in contact with Frito-Lay and
> they've agreed to provide me with big free decals for the side of my ship
> that say, "Fritos®"
>
> I suspect I'll have no problem finding "customers" once I learn how to tow,
> but one question keeps nagging me, "How can I stay calmly ahead of the
> glider?"

Only half in jest, I think an experienced tow pilot's adrenaline kicks
up several notches as soon as he/she applies full power. You don't want
to be caught in "calm" when the pilot behind you stands the towplane on
it's nose!

--
Change "netto" to "net" to email me directly

Eric Greenwell
Washington State
USA

[[email protected]]

Bumper, I don't know if you a joking, but there is a related story
about "Free-Tows".

When I was a kid, growing up on a gliderport south of Miami, Dad (Fritz
Compton) had a Cub towplane. One particularly wealthy and "loud"
sailplane pilot would alway holler "thanks for the tows - I'll buy 'ya
a tank of gas sometime!" Then walk away laughing. After several dozen
free tows to this guy, Dad turned his anger into art: He painted the
words "El Frito" on the rudder of our Cub, but never got that tank of
gas, probably worth about $5.00 in the 1950's.

My Dad always encouraged me to build my commercial glider operation,
and at age 90 told me this story (again) just last month. I listen
patiently of course, but his business lesson is there, and twenty
gallons of gas for my towplane is now over $100. Later, I shoulda made
that guy pay his debt to our family, but he's dead. But the irony is
that Dad won - he outlived the S.O.B.!

A retired commercial glider operator once told me: "There are two ways
glider operations go out of business: A poor safety culture or they
didn't charge enough for their services."

Burt
Marfa Gliders, west Texas
www.flygliders.com

[Jim Buckridge]

wrote:

> I'm eager to try again, but I thought I'd drop in here and ask how
> folks stayed behind the tug... If you all can remember back when you
> were at my stage. ;-)
>
> Thanks, Corky Scott

It takes practice. It doesn't do much for your thermalling experience,
and it makes you feel like you're losing out on time, but it often pays
to take lessons late in the day when the air is still -- the kind of
air perfect for a hot air balloon ride.

Midday with the sun out is no time to be learning the tow.

[For Example John Smith]

The club I belong to does 3 tows for the price of 2 before 11:30 for the
same reason--to encourage trainees to learn the basics in still air.

"Jim Buckridge" > wrote in message
oups.com...
>
> wrote:
>
> > I'm eager to try again, but I thought I'd drop in here and ask how
> > folks stayed behind the tug... If you all can remember back when you
> > were at my stage. ;-)
> >
> > Thanks, Corky Scott
>
> It takes practice. It doesn't do much for your thermalling experience,
> and it makes you feel like you're losing out on time, but it often pays
> to take lessons late in the day when the air is still -- the kind of
> air perfect for a hot air balloon ride.
>
> Midday with the sun out is no time to be learning the tow.
>

[Tom]

In control system jargon we would say that you have more than unity
gain at 180 degrees of phase shift. What that means in English is that
by the time you recognize you need to make a correction your corrective
action is too much. So you make another corrective action to fix the
problem the first action, using even more control input. This results
in an even larger deviation in the opposite direction. And so it
goes...

Add to this that you have three control surfaces that you are
manipulating (you may feel like they are manipulating you!).

The phase shift part means you are late in recognizing you need to make
an adjustment.

Try making more timely (reduce the phase shift), but smaller
adjustments (reduce the gain). Remember, once you get a large mass in
motion (such as a turn to bring the glider back to center line) it
can't stop immediately, so you have to anticipate stopping it with
control action in the opposite direction.

Start out by towing in the morning before thermal activity starts - it
is much easier to maintain position in calm air.

Don't worry: with practice you will get comfortable with towing.

Good luck!

Tom Seim

[Chris Reed]

One way of putting this into practical effect is, assuming the glider
gets out of position to one side:

1. Level the wings and hold your current position.

2. Start to move the glider back behind the tug in the lateral dimension
only (e.g. if you're out to the left, start to move right, but if you're
also low don't try to climb at the same time).

3. Immediately it starts to move, bring the wings level again.

4. Repeat 2 and 3 until you're behind the tug.

This worked for me when I was learning. Initially the glider moves a
long way each time, but you soon learn to anticipate and stop the
movement quicker. Once you can do this, you can start moving the glider
back into position in just two goes - one large movement and a final
correcting movement - and eventually in one go.

The same technique can work for height displacement.


Tom wrote:
> In control system jargon we would say that you have more than unity
> gain at 180 degrees of phase shift. What that means in English is that
> by the time you recognize you need to make a correction your corrective
> action is too much. So you make another corrective action to fix the
> problem the first action, using even more control input. This results
> in an even larger deviation in the opposite direction. And so it
> goes...
>
> Add to this that you have three control surfaces that you are
> manipulating (you may feel like they are manipulating you!).
>
> The phase shift part means you are late in recognizing you need to make
> an adjustment.
>
> Try making more timely (reduce the phase shift), but smaller
> adjustments (reduce the gain). Remember, once you get a large mass in
> motion (such as a turn to bring the glider back to center line) it
> can't stop immediately, so you have to anticipate stopping it with
> control action in the opposite direction.
>
> Start out by towing in the morning before thermal activity starts - it
> is much easier to maintain position in calm air.
>
> Don't worry: with practice you will get comfortable with towing.
>
> Good luck!
>
> Tom Seim
>

[Tom]

This is a good example of "turning down the gain". When we tune control
systems we generally don't crank the gain up to the max and then reduce
it until the system becomes stable. We do the opposite: start with low
(zero) gain and gradually increase it until the system becomes
unstable.

Part of the confusion is that there are times when large control
movements are required (rolling into a steep bank turn) and times when
they aren't (flying straight and level). The student needs to be
clearly told, and told again and again, when each is appropriate.