All you ever wanted to know about
Aerotowing is a system in which an ultralight aircraft, called a
tug, tows you and the glider aloft. To launch, your glider sits
on a specially designed rolling cart. The cart supports your glider at the
correct attitude for liftoff, and stabilizes it until you reach flying speed.
You will already be prone before you begin rolling, making failure to hook
in almost impossible. The ground crew will connect you and your glider to
the tow line (the tow line any be anywhere from 150-200 feet). Then, after
a signal from the ground crew, the tug accelerates, and as soon as you have
enough airspeed (a few seconds), you rise smoothly from the cart. You then
essentially fly in formation with the tug until its time to release.
Besides the cart, you will also need a V-pull bridle and a release mechanism.
The V-pull bridle is a piece of line such as Spectra or polypropylene
which connects to both of your shoulder straps, and to a point on your
gliders keel. There are two parts to the aerotow bridle system: the
"long part" and the "short part". One end of the "short part" connects to
one harness shoulder loop and the other end to the other harness shoulder
loop. When attached properly it would form a "v" if you pull the center of
the line away from you. The "long part" has a loop in both ends and the "v"
part connecting the shoulders slides through the "long part" so that the
long part is in the middle of the "v." The "long part" then passes through
a ring at the end of the tow line, joining the glider to the tug and the
other end is secured, via a weak link, to a (primary) release mechanism which,
in turn, is attached to a specific point on the keel of the glider. Thus
the tug pulls the pilot and glider evenly, resulting in a more natural-feeling
The "release" actuator looks like a bicycle brake lever and is Velcro-mounted
on the lower control frame. When you squeeze that lever an attached cable
actuates the primary release at the keel attachment point. The "long part"
of the bridle is then free to run through the ring on the tow rope and you
and the glider are left in free flight. A weak link connects the long V-pull
bridle to the release, providing a safe limit on the tow force. If you fail
to maintain the correct tow position (centered, with the wheels of the tug
on the horizon), the weak link will break before you can get into too much
A "secondary release" is a simple "hook & barrel release" attached to
your harness shoulder loop. One side of the short "v" bridle is attached
to the "secondary release," so in the event the "primary release" fails the
pilot merely slides the hook barrel back and the tow line is released.
LAUNCHING OFF THE CART
The ground crew will assist you. After you have done a preflight inspection
of your gear, place your glider on the cart, hook in, and a hang check. Check
that both the cart wheels have enough air a flat tire will cause the
cart to steer in that direction. Your angle of attack should be high relative
to the ground. While in the prone position, ensure that there is nothing
to tangle or get stuck on the wheels or frame of the cart (cords which may
be dangling from the control bar or the harness). Hold onto the cart string
with your thumbs, Or if your club is lucky enough to have a T-Dolly there
is a solid bar to grasp right under your base tube. The string or solid bar
will hold you and the glider securely on the cart when you begin your takeoff
The ground crew will attach the bridle through the aerotow ring and then
to the release mechanism. The tug will move forward to take up the slack
in the tow line. You will feel it pull you forward, but you should resist
and hold your bar position just aft of minimum sink. When you are all set,
the ground crew will give a signal and the tug will accelerate.
While rolling on the cart prior to lift off make any necessary lateral
corrections to steer the cart. FLY THE GLIDER WHILE ITS ON THE CART.
Youll feel the speed pick up and the glider will begin to fly. YOU
WILL LIFT OFF BEFORE THE TUG DOES. If one wing lifts prematurely while you
are still on the cart, quickly make the necessary correction so that you
rise with your wings level. When the feel the cart just start to want to
lift off the ground, specifically, youll feel the weight of the cart
on the string, let go of the string or bar, and let the glider rise up 10-15
feet. This should allow you to have enough speed if the weak link should
break and puts you in a position to land should that happen. If the weak
link breaks when you are still on cart, simply hold on to the string until
you roll to a stop.
As the tug climbs up through your altitude, do whatever it takes (pushout
or pull in, maybe even aggressively) to match the tugs ascent. To reduce
the possibility of pilot induced oscillations make short sliding bumps to
steer left and right. Do not leave your weight shifted left or right for
PILOT UNDER TOW
Watch the tug and control your pitch so that you climb with it.
If you are towing behind a Moyes-Bailey Dragonfly always try to KEEP THE
WHEELS OF THE TUG ON THE HORIZON! When towing behind a Trike always try to
KEEP THE WINGS OF THE TUG ON THE HORIZON! Do not ever take your eyes off
the tug during the tow. Unlike the free flight, while being aerotowed tug
position is everything. Pay no attention to bar position and bar pressure,
focus on only one thing, tug position. Do whatever it takes to keep the
tugs wheels or wings on the horizon throughout the tow. (If the sky
is hazy, approximate the horizon).
Remember: The tug controls airspeed.
Pulling in too much under tow will merely cause the glider to go down, possibly
into the wake of the tug. And cause you to feel a lot of bar pressure.
Pushing out too much will merely cause you to towing too high behind and,
again cause you uncomfortable bar pressure.
If you get above or below the ideal position, it is important to make a pitch
correction right away. There is a lag in time between tug control inputs
and the gliders response to them; learn to anticipate this. If you
hold the correction too long you will overshoot the ideal position and then
have to make the opposition input. You will make it much easier on yourself
if you keep the tugs wheels or wings on the horizon.
MOST COMMON AEROTOW MISTAKES
1. Pilot coming off the cart and rising too quickly above the tug, breaking
the weak link.
2. Pilot not anticipating the tugs quick climb-out after launch, getting
low and then not pushing out far enough to climb up
3. Over-controlling and over-correcting. Make small, relaxed, conservative
movements and corrections.
4. Most students seem to want to undercontrol in pitch
Remember. . .
It is almost impossible to stall under aerotow. The induced thrust vector
makes the glider trim at a higher attitude. It is okay to push way out; you
will climb, not stall. Should you find yourself low behind the tug, you may
need to actually push out on the control bar forcefully, resulting in a
past normal bar position that in non-towing situations would
lead to a stall. However, because of the pull of the tow line,
this action will result in a CLIMB, not a stall. Stay with the tug using
pitch. If you are low, PUSH OUT.
TURNS ON TOW
When the tug begins to turn, relax, and wait for the turn to begin. DO NOT
begin to turn as soon as the tug does, or you will wind up inside the turn.
Just like a water skier who gets inside the boats turn, you will slow
down and sink. Instead, let the tug pull you around. Once you feel the tug
pulling you into the turn, make a short sliding bump to establish your own
turn, roughly matching the tugs bank angle (amount of tilt).
Dont be anxious or impatient on tow: this makes it seem much more difficult
than it really is. Let the tug and glider do the work. The fewer and smaller
your movements, the easier it will be to follow the tug. Early recognition
and compensation are the keys here. By anticipating and correcting early,
you avoid the need for large control inputs.
Remember . . .
1. Wait for the tug to pull you into the turn, then follow
2. Match the tugs rate of turn with smooth sliding bumps
on the bar to the left and right
Helpful Hint. . .
You will find that good towing technique is often more about not doing things
than doing things; a hang glider pilot with a lot of aerotow experience moves
the control bar less on the tow than an inexperienced one. Correct EARLY,
WEAK LINK FAILURES
The pilot is responsible for inspecting the weak link well before the tug
arrives. Any fraying indicates that its time to replace the weak link.
The weak link is designed to act as a fuse, breaking the circuit when overloaded.
In an excessive out-of-position situation, the weak link will snap before
the control authority of the glider would be lost. If you should have a weak
link failure close to the ground it will be important to immediately lower
the nose of the glider, due to the relatively high angle of attack while
under tow and the sudden loss of energy upon release. Regain airspeed and
land normally. Wheel landings are highly recommended.
GLIDER RELEASE FAILURE
If your release fails to operate or the V-bridle hangs up (extremely unlikely)
you have several options:
Use the secondary release
Cut the V-pull/bridle with a knife
If you are high above the ground push out sharply to snap the weak link
Remember. . .
If all else fails, the tug pilot will release the tow rope at the tug end.
Generally the weak link will fail before any situation can develop to a critical
point. However it is better to recognize a less- than-ideal situation and
release intentionally before tow line tension builds to the point of a weak
FLYING WITH THE TOW ROPE
If you are released by the tug pilot and left with the tow rope there are
a couple of thing you can do, and a few reasons why you got the rope in the
Why you'd get the rope - Why would the tug pilot release you:
1. If the tug had an emergency situation, such as a engine out.
2. If on launch you getting high on the tug, this pulls up on the tail of
the tug and puts the tug into a dive the tug pilot will release you immediately
because the tug and the pilot are not in jeopardy
3. If the pilot is in or on his way to a lockout situation
4. If the tug pilot sees the pilot is in distress and cannot release for
5. If the weak link on the tug breaks for the rope breaks
These are the most common reasons the pilot will be left flying with the
Now that you have the rope, what to do with it:
1. If you are low or the ground or any objects, release it immediately. You
do not want it dragging and possibly hooking on anything. Since the rope
will be over the top of your basetube, if it get tangle up in an object,
the consequence could be extreme.
2. If you are high and you the rope and there is nothing to hit, you can
fly back over the landing area, drop it in the field.
3. So people had wadded it up and stuffed down the front of their harness.
Be careful doing because when you go upright to land the rope would possible
come loose and fall down out of the bottom of your harness, causing problems.
Remember. . .
You may not be able to see it, but if you have enough altitude, fly the rope
back over the landing field and drop it. If you are low, release the rope
immediately. Do not land with the tow rope still dangling if you can possibly
avoid it ! If you must land with the rope, do so over an open area.
This is generally pilot induced (called PIO - Pilot Induced Oscillation),
but can be controlled and even eliminated through appropriate control inputs.
Dont be concerned with the exact orientation of the gliders airframe
behind the tug the glider is happy to tow at a skewed angle. To prevent
or stop oscillation, relax and remain still and centered on the bar. Make
gentle correction. Ignore yaw. If you feel like you are losing control, however,
simply hit your aerotow release and fly normally. Dont try to save
a bad situation, if in doubt, just release and we'll figure out how to fix
Hint. . .
Do not correct for yaw. Make bumping corrections. Dont leave your weight
shifted too long.
You already know how to fly, so if you're PIOing it's the aerotowing that's
the problem - release immediately. Trying to hang on generally makes things
While towing, watch the tug pilot. They will give you signals to guide your
flight. If you keep the wheels or wings of the tug on the horizon, staying
in a good position behind the tug, the only signal you will see from the
tug pilot if the "release" signal. If you are out of position the signals
below will be given to the pilot by the tug pilot with their left hand.
TUG PILOT SIGNALS TO HANG GLIDER PILOT TO:
Tug pilots arm held bent at the elbow, pointing up.
Pilot Action: push out and climb
Tug pilots arm held bent at the elbow, pointing down.
Pilot Action: pull in and descend
Tug pilots arm waving in an up and down motion.
Pilot Action: you must release immediately.
Remember. . .
The tug pilot does not need any signal from the hang glider pilot when to
release. The hang glider pilot can release at any time, there is no consequence
to the tug pilot for that action. However, when the tug pilot "waves you
off" (gives you the signal to release) you absolutely must release, right
then, regardless of your altitude or your position - you must release.
When flying behind the tug, you are concentrating on alignment. This may
cause you to lose your ground reference. The tug will never tow you beyond
gliding range of its landing zone. As soon as you release you should locate
the landing field. Look at the tug, the pilot will most likely make a bee
line for the land zone. Otherwise, ENJOY.