Every keen paraglider pilot has heard of others who use a paraglider tow unit, or paraglider towing system as others might call it.
Some team up with a few friends and buy one, to escape the boredom of para-waiting. Or perhaps to escape the lack of suitable nearby hills and mountains.
On the other hand, some learners are actually commencing their training with low, gentle flights attached to a tow unit.
A simple definition. A paraglider tow unit is a system that provides a constant line tension while paying out, pulling in or pulling along a tow-line while launching a paraglider like an over-sized kite.
This page will only discuss tow units, as opposed to towing itself.
The subject of towing, even when restricted specifically to paragliding, is a very broad one! So much has been done, so much has been written. There are a multitude of scenarios.
For example, there is a large variety of vehicles that have been used for towing. On top of that, a variety of mounting methods have been used for the paraglider tow unit itself.
Furthermore, the winch may be stationary, doing all the towing itself.
Even the topic of tow-lines, attachment points, weak links and so on could fill so many pages here that you would be bored rigid as a German-made winch mounting! I'll make an exception for the paragliding tow bridle, a vital bit of gear.
A paraglider tow unit will fall into one of three broad categories.
Firstly, a static tow unit. This is a very simple system. There are no moving parts, except for the towing vehicle. A tension gauge is connected in-line with the tow-line. Forgetting all the details of how the launch progresses, let's just mention that an observer has to keep a close eye on the tension and keep it constant by informing the driver to speed up or slow down.
The tension device can be mechanical, that is, spring loaded. Or it might be what's called a hydraulic tensiometer.
Secondly a stationary winch. This system employs a rotating drum, a tension monitoring system and a motor with a throttle. Internal combustion engines are used exclusively as far as I know. Just as with the static tow system, the winch operator must keep a strict eye on the tension reading during each and every launch. As you would expect, increasing throttle builds up extra tension, reducing throttle decreases tension, during the launch.
The classic stationary winch for paragliding is the scooter tow. This setup has been around forever, in paragliding circles. And still going strong it seems.
Thirdly a payout winch. No, it's not a hi-tech one that cheekily talks back! A payout winch is actually unpowered. It simply lets the tow-line out, under constant tension, while the launch vehicle speeds along. The vehicle must attain a certain minimum speed, to reach the launch tension. The tension is adjustable before the launch. And the most sophisticated paraglider tow unit can alter the tension with high precision during the launch.
A paraglider tow unit like this is safer than other methods because the towing vehicle does not have to compensate for changes in towing conditions.
For example, the paraglider flys through a thermal, which would normally put a lot of extra tension on, perhaps a dangerous amount.
But with a payout winch, the line just runs out quicker and the tension stays fairly constant. Same thing if the driver is inexperienced and has a heavy foot! The tension stays constant despite the extra vehicle speed. Payout winches can be either mechanically or hydraulically braked, usually using a disk brake mounted on the drum. The modern trend is toward the hydraulic variety, as these have proven to give the smoothest and most efficient launches. For a given runway length, a hydraulic winch will always get a paraglider the highest.
I should also mention that payout winches always have a rewind mechanism of some sort. Usually it's a powerful electric motor that can quickly reel in the towline after the paraglider pilot releases it. A bit of power is also handy in case the line falls in trees and has to get dragged through them.
Photo courtesy of Christian Barmala.
It's actually possible to categorize a paraglider tow unit another way entirely.
Firstly, it might be a DIY unit. Do-it-yourself that is. Many groups of pilots or individuals have successfully developed a tow unit of some kind, from scratch. Occasionally, they are kind enough to release a 'how we did it' document for the benefit of others. Sometimes for a cost, sometimes not. Also, detailed information is available in bits and pieces from various sources on the Web, as these people communicate with each other.
For example, published plans, photos, advice in paragliding forums and so on. But that's a pain, hence the page on this site which details some commercially available winches. See if you can find it ;-) Hint: back up a few paragraphs.
Secondly, home grown winch units are available for sale. Perhaps most often where the builders/owners are moving up to a commercially available unit. Locating these is a pain also, since they are so few and far between, compared to say, replacing your defunct washing machine with another unit! Word-of-mouth among the local paragliding instructors is probably your best bet here. Someone might know someone who knows someone.
Thirdly, commercial winch units are increasingly available. Now, paragliding itself has undergone great expansion and development in recent years. Is it surprising then, that mechanical engineers around the world with an interest in paragliding have seen opportunities! The result is a small number of companies which produce extremely well-engineered winches for foot-launched aircraft such as paragliders.
As you would expect, these are 'the ultimate' paraglider tow unit. And boy do you pay for it, in most cases! However, the more launches you do with one of these, the better value they become.
So commercial winch units see plenty of use with paragliding schools that must maintain high numbers of launches to stay viable.