Where the Tow Assist came from, and why it's so important to safely towing a paraglider.
Its funny how time flies. As I'm updating this page I'm well aware
that we have been towing now for almost 20 years. We've come a long way since
the early days. As a company we have sold well over 650 hydraulic winch systems
and just over 19,000 tow bridles worldwide since we started supporting the
towing community. I'm grateful for the support and advice of our customers
worldwide without whom this would never have been possible.
In order to fully explain the benefits of our towing bridles we
really need to go back to the origins of paraglider towing. We believe that
towing is one of the easiest ways to get high with a paraglider. At TowMeUp.com
we all tow actively from both land based vehicles and boats over the water.
We’ve been actively towing paragliders since the mid 90’s, and in the early
days getting decent equipment based on real life experience was difficult at
best. We found it frustrating that there was no reliable source of well made,
quality tow bridles available in the US. After testing many different models,
and seeking advice from very active tow pilots in the industry, we developed an
assortment of tow bridles for various applications which worked quite well.
We were smitten with the ease of paraglider towing, and trained
several pilots, going to dozens of incident free towing events. But in the
early days, paraglider towing was in its infancy, and there was no nationwide
source of towing information. For the most part everybody in different areas of
the country had their own ideas of how to tow a paraglider. The techniques we
use worked well for us, yet we continued to hear of places around the country
with serious launch accidents. Pilots were being injured by dramatic surges
following weak link brakes after launch, which led to many operators refusing
to use weak links because they “compromised” flight safety. We found this
baffling, since we rarely saw a weak link break, and when we did, there was
always a good reason for it. Eventually we started hearing complaints that
towing was dangerous because it was putting way to much strain on the gliders,
and stretching the lines to the point where the gliders were out of trim,
giving them a propensity to constant stall. There were even a couple companies
running SIV’s that refused to tow Dyneema lined gliders because they were
concerned that the lines stretched more than Kevlar lined gliders.
Now this got our attention, since all the gliders we used were
Dyneema lined gliders. Was this hype to help steer people to a brand that
coincidentally used Kevlar lines, or a real issue. We had to find out.
to even more towing events and we found some amazing things. We saw people
scooter towing pilots to the point where they were literally right over top of
the tow vehicle, and in one case watching the rear end of the tow vehicle come
off the ground. O/K, we thought so perhaps, maybe this is why lines are getting
stretched. How much force does it take to lift the rear of a vehicle off the
ground in the first place?
Then of course, we knew that the tow force increases
exponentially as the line angle increases. Once you get over 45 degrees of line
angle, there is little to gain by towing at a steeper angle, even if it can be
done. So why we wondered weren’t weak links breaking when the gliders were
being dramatically over towed we wondered. The answer was obvious when we
started checking. They weren’t being used. The schools that were over towing
their students had decided weak links were dangerous and stopped using them
In our area we generally encountered 3 distinctly different tow
A steady breeze of over say 8 MPH. A super simple tow launch for a
pilot with decent ground handling skills. Most pilots could hook up, inflate
their glider and turn to face forward and as line tension increased they are
gently lifted into the air. The upper limit of the wind speed was determined by
the pilots abilities. If they could kite, they could typically launch easily.
If their ground handling skills sucked, they got pounded, but that had nothing
to do with the towing part really anyway.
A gentle breeze of say 3 or 4 MPH. Not enough wind to kite in the
early days. (ya, ya, today I too can do a walking reverse in no wind, but the
gliders were just not that capable early on, remember…) Typically we laid out
for a forward launch and as line tension was gradually increased the pilot
would move forward to inflate the glider. It would rise cleanly overhead as the
pilot accelerated, line tension would be applied, and the pilot would easily
levitate into the air.
No wind launches. Seems to be everyone’s least favorite, for no
real reason. On tow they are stupid simple. For our pilots we had pilots do the
exact same forward launch that they would do if there was a gentle breeze. We
REQUIRED that the pilots had to make the effort to get the glider completely
overhead before we would increase the line tension to safely launch them into
the air. We never had any problems.
What we didn’t know was that around the country, dramatically
different launching techniques were being taught, particularly for no wind. The
rational was simple enough. A lot of the tow knowledge at the time came from
hang glider pilots. Wonderful people that taught us a lot of the techniques we
use today. They had learned the hard way that the easiest way to foot launch a
hang glider in no wind was for the pilot to hold back as long as possible while
launch tension was quickly increased, and the pilot was forced to run,
literally sling shooting them into the air. As long as they didn’t trip, things
Unfortunately, paraglider pilots adopted the same technique and
numerous launch accidents occurred. There are dozens and dozens of YouTube
videos available from the pioneering days showing pilots pounding in right off
launch. We saw, made note of the issues, and suggested better techniques to
pilots and tow techs that was corroborated with our experience.
The typical launch accident occurred in no wind when the pilot was
holding back while line tension was rapidly increased. Their glider would
inflate, and begin to come overhead, but hang back significantly. This was a
key point that was not recognized for being as dangerous as it really was at
the time. The glider was open, but essentially constant stalled; it provided
more drag than lift at this point. The winch operator, seeing the glider
inflated would increase the tension. The pilot wouldn’t climb faster (the
glider is constant stalled after all, so why should it) so they increase the
tension further. Eventually the tow forces get high enough where something
breaks. If it was a weak link, it would break down low, if one wasn’t used
something else would fail higher up.
Imagine for a few seconds how you would react if you were say 40
feet off the ground with your glider waaaaay back behind you, and suddenly the
weak link breaks. If you were a super hot dog acro pilot, you would casually
let the glider surge out in front of you, catch the surge as it shoots forward,
get back off the brakes and use this energy stored in the glider to flare to a smooth
although quick landing. Ya, right. Remember this was the early days. We only
had a handful of acro pilots who could pull this off, and few of them used weak
links… go figure.
More realistically, pilots did nothing except go
aaaaaaahahhhhhhhhieeeeeeeee, THUMP! If they were down low, they would typically
pendulum in backwards and pound in on their butt. A bit higher, and the glider
would surge and they would pendulum in and pound in on their face. Higher still
and the glider would surge forward, deflate, and they would pound in hard.
Occasionally pilots would take the opportunity to jam on full and complete
brakes to try to “flare” with the glider behind them, which predictably
resulted in a stall or a spin, and a visit to the emergency room.
At TowMeup.com, we knew what was causing the launch accidents, and
that the way to prevent them was to ensure that the pilot made the effort to
get the glider completely overhead before line tension was applied to launch
the pilot. What we didn’t have was a cure for the problem.
At the time a unique development was occurring. In early 2000
Firebird came out with a paraglider called the Matrix. We immediately bought
one and started flying it. It towed well enough, but there was something odd
and not quite right that originally we couldn’t put out finger on. We typically
towed up to well over 3000’ before releasing so we were unaware of a peculiar
characteristic of this design. One day we attended a scooter tow event put on
by a local paragliding school we really quite liked. The field was relatively
short, so the tows were only to 400’ or so. One thing that was immediately
apparent was that after releasing from tow, the glider was constant stalled and
dropped straight down before restarting into normal flight. We did several
tests and confirmed this was not a fluke, and even called the manufacturer to
query them on the subject. Interestingly enough, within a couple weeks the DHV
came out with an advisory circular regarding the Matrix and its flight
performance that deviated from the originally issued type certificate. It turns
out it had a propensity to enter a stable stall (DHV GS-01-0746-00). We loved
the flight performance of this glider, and elected to trim it slightly faster
and continued to fly it, but we chose not to tow with it due to the potential
hazards of being constant stalled if we came off tow unexpectedly at low
After a few months The Firebird engineers came out with a novel
solution to address the towing issues. They developed a “Tow Assist Device”
that caused the glider to be accelerated when under tow and eliminated the
propensity of the glider to constant stall. Since we happened to have a Matrix
we received one and went out to test it and found it cured the problem. After
towing with it for a while, we decided to try it on other gliders as well, and
found that almost without exception, they were easier to launch on tow. It
turns out that while solving a trim issue on the Matrix, Firebird had actually
created the single greatest improvement to towing safety I have seen in my
towing history. We started buying the device and using them on all kinds of
gliders, eventually determining that the safety benefits were so enormous that
we required them to be used by all new tow pilots, on all gliders. Of course
then we ran into that age old problem. Since it was essentially an attachment
to a tow bridle, they parts and pieces were continually being lost, and we
could never get a reliable supply of tow assist devices.
We decided to redesign our tow bridles to incorporate the tow
assist as a built in feature of the product, and streamline the production by
bringing the production entirely in house. Many people have asked us why we are
so passionate on the tow assist device as a key component of our bridle and why
it is so important.
It’s important to remember that while towing is really pretty
simple and safe, it can go wrong very quickly. The most serious issues are
caused by the pilot being dramatically over towed right off launch and then
having the weak link break. The Tow Assist, as it is incorporated into our
bridles does almost nothing when everything is going right. The sliding link
removes most of the tension on the speed trim system. If the pilot is being
over towed though say, right off launch and the glider is hanging back a wee
bit, it automatically trims the glider faster to allow it to come overhead.
This allows the glider to climb more efficiently and dramatically reduces the
towline forces. Once the glider is overhead the speed input that has been
introduced is automatically eliminated. A side benefit is that if the glider
starts to turn away from the tow line, the side that is diverging will
automatically have a bit of the speed system engaged to help turn the glider
back towards the tow line. This makes it dramatically easier for a new tow
pilot to stay in line with the tow.
There are a few purists out there who complain that the tow assist
device makes the pilot lazy, by requiring them to use less effort and skill to
fly a perfect tow. Our response is that yes, and power steering in my truck
makes me lazy as well, but I’m not about to give up the benefits to be
considered a purist…
This device dramatically reduces the potential for a pilot to
enter a constant stall right off launch, helps to prevent weak link breaks down
low, and makes it easier to control the glider while towing to altitude. As if
that wasn’t enough, wait there’s more….
If you are the tow tech, you have all seen the lazy assed pilot
who launches, and pays no attention to where the glider is going. As the glider
goes way off to the side, there is really very little you can do about it if
the pilot decides to act like a rock. Your only option is to reduce line
tension. This allows pendular stability to take over. The pilot should fall
underneath their glider and hopefully regain control. If there is room and
time, you can increase tension and continue the tow. If not you have to hope
they flare or hope for the best before impact.
Sometimes a tow launch doesn’t go quite as well as planned. You’ll
get pilots who do a brilliant launch only to sit down immediately as the glider
lifts off. This weights the glider, which surges forward and the pilots butt
skips the ground, the glider shoots forward and frontals, and the pilot pounds
in hard. Or maybe the pilot does a great inflation and starts to run but trips
and is about to pound in. My least favorite is when the pilot get
airborne and heads off toward a certain lockout on one side, but I know well
and good that if I reduce the tension they will pound into the tree, stump,
rock, or obstacle that they have decided to become intimately familiar with.
If the pilot has a tow assist device, however, you have another
great trick in your arsenal. You can quite safely crank on the towline tension
and pluck the pilot into the air. The tow assist dramatically reduces the
potential for the glider to constant stall and fall out of the sky. Once the
pilot is safely airborne you can reduce the tow tension, stabilize the climb
rate and continue the tow. For the pilot that is headed towards lockout,
increasing the tension will actually pull the glider faster back towards the
tow line. Unless the pilot jams on the brake to continue to diverge for the
tow, you can often drag the pilot airborne safely sometimes with the glider
skewed way sideways by a huge amount. Once you get the pilot away from danger,
you can reduce the tension and coach them into getting things back under
control or safely dump them in the lake.
So there you have it. You know why we love the assist device. If
the towing operation you choose to work with uses the slingshot launch
technique, you definitely want to use a tow assist type bridle. I really don’t
care who’s you use, but I highly recommend them. I’m pretty sure that we sell
more tow bridles annually than many other manufacturers combined. I’m also
pretty sure that we’re one of the very few, if not the only one picky enough
that every critical load bearing stitch on our bridles is sewn on a
computerized pattern tacker. This is a highly specialized sewing machine that
is designed to place the exact number of stitches exactly where we need them.
Every tow bridle is sewn out in a special fixture so you can easily replace
components if you lose them. It’s even designed to be machine washable, but we
see them mostly getting washed after pilots end up in the lake at an SIV.
Before using our product, or any product; PLEASE make sure you
understand exactly how your equipment is designed to work. ALWAYS TOW WITH A
WEAK LINK. Have a plan, and fly your plan, but be willing to change the plan if
you need to. Most of all Tow High, and have a great flight!