The Portable Variable Height Training Hill
Many hang gliding schools in the US have found it very difficult
to secure training sites which are usable in all of the various
wind directions which are common where they teach. While hang
waiting is a skill which all pilots need to become accomplished
hang glider pilots, there are few schools which have had much
financial success in teaching it.
A number of schools have therefore searched for ways around the
problem. Giant fans and in-door flying sites, while a possibility
in Japan, where the largest indoor skiing schools are, have been
ruled out here because everytime anyone builds a giant domed building
for flying, someone starts hosting football games in it.
Here in Texas, we had the Trinity River Levees to teach on, but
they were a little too low and a little too steep. Further, we
had to depend on the City of Dallas to keep it mowed. When, in
1993, I saw a motorscooter converted into a stationary winch,
I adopted the idea and began using a stationary winch for training.
By the fall of 1995, 90% of my training was done via the stationary
winch. I found that my training was greatly improved. Students
learned faster, had fewer injuries, and I could teach in any wind
direction 1 mile from my house. Further, I found that I could
move students from scooter tow training to either slope foot launch
or platform tow launch with little difficulty.
I train with scooter tow, using a variation of the traditional
foot launch training methods. Instead of using older design gliders
for training, I use modern gliders, although this is probably
not necessary. I have a field about 1500 ft. long, and I either
place a parked car or an earth anchor at the upwind end of the
field. To this, I attach a pulley. I place the scooter winch at
the downwind end of the field, approximately next to the student.
I then run the tow line from the scooter winch, through the pulley
and back to the student. I usually, but not always teach with
a radio receiver on the student. I try not to use the radio in
a way that makes the student dependent on it, but instead use
it to fine tune the student's skills and to offer the student
instant praise and correction.
The student starts out in the traditional way, running on flat
ground with the glider but without a harness. As soon as he or
she gets familiar with running with a glider, the student dons
a harness and then runs hooked in to the glider. At this point,
the tow line is attached to the student via a single point tow
bridle. The tow bridle and the tow rope are above the base tube
of the control bar. Running with the tow rope attached gets the
student used to following the tow line at launch and to releasing
from the tow line at the end of the tow. When the student starts
the run, only enough throttle is applied to keep the towline taut.
As the student progresses, keeping the glider level and the angle
of attack correct, following the tow line and releasing as he
or she stops, I gradually start helping with the throttle. What
happens is a smooth transition from running to launching. After
a number of tows, the student is flying along the ground at an
altitude of from one to five feet. The goal is to let the student
fly the glider level along the ground neither popping up the nose
at launch nor pulling in the control bar so that the speed of
the tow necessary to keep the student from touching the ground
does not becomes excessive. Further, the student should maintain
directional control of the glider. If the student is not able
to do all of these things, then the operator cuts the throttle
and lets the student back to the ground. Generally, at first,
the student cannot do all of these things together, but after
a very few tows, the student co-ordinates all of the things at
once. Gradually the distance of the tow is lengthened until the
student may fly along the ground for a thousand feet no more than
a few feet high.
After I am confident of the student's ability to fly the glider
under tow a few feet from the ground, I gradually fly them a little
higher, and let him/her release and fly down to land. At this
point, the student has been landing by running the glider to a
stop or rolling to a stop on the training wheels so I start teaching
him/her a flair landing. As the student gets higher on each successive
tow, I have him/her land straight ahead and work on a successful
landing techinque. The landing techinque gives the student practice
in feeling trim speed and pitch control.
As the student gains ability and confidence, I keep towing him/her
higher. Once the student is high enough to do small turns, I have
him/her do "S" turns and come down into the wind. When
the student has reached this point, the demands of flying straight
under tow have pretty much taught the student proper turn technique
so I usually expect the student to have no trouble with making
small turns. If the student cross controlled or habitually flew
the glider too slow, these problems should have by now been corrected.
If they have not, the turns generally pinpoint the problem and
I can correct it here in the training process.
Once the student has shown solid ability to do gradually widening
turns, I start towing him/her as high as possible. At this point,
I encourage the student to push out during the tow to maximize
altitude, warning that if the glider starts to be hard to hold
in a straight line then he/she needs to speed up. Next, I have
the student fly circuits. A circuit is a flight which has the
student do a 180 degree turn downwind and then another into the
wind, hopefully landing at the approximate place where he/she
took off. I always have the student do the first circuit with
a clear understanding of the minimum altitude at which the second
turn should be performed. I make it clear that landing downwind
on wheels is preferable to turning too low. I teach in large
open fields with few obstructions and I usually do the circuit
training under radio supervision. After this point, students start
making very rapid progress.
About here in the training, I take the students to a training
hill to have them demonstrate a slope launch. I have found that
providing the student has been properly taught to launch using
scooter tow, with a low throttle setting and running the glider
off the ground, he/she has no problem performing a proper foot
launch from a training hill. After the students demonstrate mastery
of proper foot launch technique, I take them to a bigger hill
where they have to do a more complicated flight plan and let them
demonstrate to me that they can fly next to a mountain.
I also transition them to platform launch. One of the virtues
of scooter tow, is that scooter tow students almost invaribly
tow excellently from a platform. Whether or not the student may
be already flying holding the base tube in free flight, the student's
first tows from the platform are performed holding the downtubes
and flying semi-upright as he/she learned to do scooter towing.
There is always an instructor on the platform for the student's
first flights and the instructor launches the student from the
platform. The one difference is that the tow line and release
are below the basetube, and the student needs to be reminded that
less pushout is required to climb with the towline below the basetube
than above it. Generally students adjust to this quickly, as they
have been taught not to pushout aggressively while climbing under
tow. At this point, the student is usually towed to about from
800 to 1000 ft. altitude. The students have flown dozens of circuits
by this point, and this will be the normal flight plan once again.
Once the student has made a few launchs from the platform, I have
them switch to the base tube for climbing under tow. This is different
from scooter tow, where I tell the students to remain upright
and holding the downtubes throughout the whole tow. I caution
them to switch back upright if they have trouble controlling the
glider. After they climb to the top of tow on the base tube several
times, I have them launch while holding the base tube and in prone
position. As soon after this as they are comfortable releasing
themselves, I have them doing this also. At this point, a qualified
tow observer with a hook knife may ride the platform instead of
Generally, some where along this point, the students will have
completed their novice tests and acquired a novice rating with
both tow and foot launch signoffs.
Particular points to emphasize during the training process are:
1. Train the student to run the glider off of the ground by making
the student launch at a reduced throttle setting. If the student
habitually runs until the glider flies off of the ground instead
of just pushing out and going prone, the habits learned will promote
a solid foot launch at the mountain. The scooter operator should
reinforce this by cutting off the throttle if the pilot pops the
nose up and goes prone without running. (At least until the student
is very solid on foot launch. A full throttle launch only requires
a few steps.)
2. Train the student to release when he/she is in difficulty.
The operator can compensate for a failure to release in most situations,
but the risk to the pilot is reduced if the tow line is dropped.
3. Train the student to never overfly the turn-around pulley under
tow(or the scooter if no turn-around pulley is being used).
4. Use reliable releases. I have used both a 3 string release
and a mechanical release (designed for use with aerotow) operated
by a downtube mounted lever. Both work well, but I prefer the
lever operated release as it allows the student to release without
taking a hand from the control bar. Always double check the correct
operation of the release before each flight.
5. The winch operator should have a hook knife at hand. The student
should be attached to the tow line with a properly sized weak
link. I use a single loop of 205 leachline with a weakening knot
in it between the mechanical release and the tow ring. If using
a three string release, I use a weaklink of the same strength
but build into the release mechanism.
I attach the release to tow loops at the waist of the harness.
I don't generally use bridles that go around the pilot to the
carabiner because for foot launch, they tend to pull the pilot
up to the biner before launch and let the release move too far
from the pilot thus requiring too long a release line. With the
mechanical release, I have a simple piece of line going from one
tow loop to the other. The mechanical release is attached to the
line with a snap hook. This is so the pilot can unhook from the
glider since the mechanical release must remain attached to the
glider when the pilot unhooks.
I have tried using a Skyting bridle with scooter tow, but have
found no necessity for it. I find that launches are easier and
much more like a mountain launch with the assistance of a single
point above-the-control-bar bridle. On the other hand, gliders
that have a comfort bar or a speed bar tend not to climb well
with a single point bridle. I recomend using a European over and
under style tow system if you plan to tow a glider using a speed
bar or if you plan to do recreational towing. This is where you
have two releases one attached to the tow rope above the base
tube for launch, and and the second attached to an extension to
the tow line which passes loosely under the bar and which you
tow from after the top release is released.
I use a round parachute on the end of the towline to mark the
end of the towline and to keep the rope from falling into a pile
at the pulley. I put a 25 ft. extension past the top of the towline
canopy to keep it from interfering with the pilot at release.
For training in particular, I use a retreval winch. This is a
small winch powered by a car battery used to bring the tow line
back to the start location. I attach the string on the retreval
winch to the bottom of the tow line canopy and am very careful
not to let it tangle with the student at launch. Design of the
winch is the subject of a whole article by itself so I won't give
any detail here, but it's real advantage is to reduce the turnaround
time between tows to about 2 minutes.