The biggest study into reserve parachutes was made in 2020 by Dr Matt Wilkes
As a paraglider pilot, it’s the one piece of kit you never want to use in anger. Bastienne Wentzel talks to Stefan Kurrle from Independence about reserves.
Reserves have developed fast in recent years, resulting in many different types to choose from. The three main types are round reserves, squares (which aren’t always square – they can be multi-sided, like a pentagon or octagon), and Rogallo-type steerable reserves.
According to Stefan Kurrle of manufacturer Independence Paragliding, square parachutes are the way to go. “Most squares excel in opening time and pendulum stability,” he explained. “Packing is different than for rounds, but not necessarily more complicated. In my view, there is no reason to buy a round anymore.”
He added: “For the average pilot who doesn’t fly acro, a steerable Rogallo does not really make sense because they do not have the experience or time to activate it.”
There are many different types of squares on the market with varying properties, so how do you know which one to go for?
For a weekend XC pilot the most important properties of a reserve are opening speed and reliability. If it doesn’t open, the other properties don’t matter.
Next, pendulum stability is important because the swing may result in a hard impact. Last on the list is sink rate.
Reserves must undergo a shock test and be certified to EN or LTF standards, both of which test for the above properties.
How to size it
Just like gliders, a reserve takes a maximum all-up weight. It is never wise to choose your reserve too small, as you will come down faster, but what about big?
To pass the EN test the maximum sink rate is 5.5m/s, which is like jumping off a 1.5m wall. Therefore, the best advice is to choose a reserve close to the maximum load. For example, if your all-up weight is 95kg, choose a reserve with a maximum load of 100kg.
You might think “I’ll get a big one to be on the safe side”, but in fact a lower load will decrease your sink rate and increase your pendulum instability. A sink-rate lower than 4.5m/s is not advisable because in rising air you may actually go up.
However, the altitude you fly at should also be taken into account, says Nova Gliders’ Till Gottbrath. “All that refers only to sea level and it doesn’t take the sink rate in higher altitudes into consideration, which increases substantially. Throwing your reserve in the Alps you might easily land at 2,500m. I don’t want to bomb in with 7.46 m/sec. You?”
Till supplied the following table, which illustrates how sink rate is affected by altitude.
Stefan agrees. “If you regularly fly at high altitude – above 1,500m/2,000m – be aware that sink rates increase at altitude. To compensate, a rule of thumb is to reduce the load by 10% for every 1,000m: if you weigh 100kg all-up, choose a parachute with a max load of 110kg.”
Remarkably, the maximum sink rate for LTF is 6.8m/s. At sea level that is like jumping off a 2.5m wall and is like the old-style static-line parachuting or paratroopers jumping out of the back of a plane; you will definitely need to do a parachute landing roll when you meet the ground. The best advice is to make sure your parachute is EN-rated.
The compatibility test
Finally, you must make sure your reserve is compatible with your harness.
Many harness manufacturers today supply their harnesses with an inner reserve container and reserve handle specific to that harness. Stefan advises always using this one instead of the inner container that comes with the reserve. It ensures that the reserve handle and its attachment cord are the right length, so if you pull the handle the outer container opens. “The risk of the reserve getting stuck or being difficult to pull out is much higher when you use an inner container that is not compatible with the harness,” Stefan explained.
The volume of the container in your harness and the reserve package must be approximately the same. Too small and it won’t fit, but too big and it will move around and potentially tangle with the bridle.
When you buy a new harness or reserve do a hang-test before you fly: sit in your harness and pull the reserve package out (you don’t need to deploy the whole parachute in your living room, just pull out the inner container).
Looking after it
Reserves need to be regularly aired, checked and repacked at least once a year, but check what your manufacturer recommends. Proper packing is essential for quick and reliable opening. Your reserve manual should contain clear instructions, but if you are inexperienced or unsure find a reliable packer through your club.
Most manufacturers advise replacing the reserve after ten years because there is no test to determine the safety of an older reserve. It could have suffered from sand or moisture without you knowing it. “By year of use, a reserve is not so expensive,” Stefan argued, “so it is best to replace it on time. We all want to be on the safe side.”