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We often declare gliding as a green sport. What can we do to make it greener and more sustainable.

Some years ago I asked my self; why do we fly with water ballast in competitions? It makes very little sense. What I can gather from history it started by some people just putting more weight in their gliders and realised it went faster. The producers picked up on this and built water tanks/bags as standard in the gliders. A few years later IGC implemented a rule for maximum weight. The weight have been altered a bit since but today we have maximum weights that clearly allows for a lot of extra weight to be added to the glider.

Water ballast is a technical aspect. It’s good in the way that it helps to equalise the performance of the gliders. Modern gliders flying at roughly the same weight have very little performance difference. The pilot have to fly the glider a bit different but it’s the same game as without ballast. Put a good club-class pilot in std-class and he will do well. The same goes the other way. Using water ballast other than equalising the gliders weight has very little impact on the competition results.

A gliding competition (maybe apart from open class) is a measure of the pilots ability to pilot the glider efficient/fast using natural forces as only engine. The goal is not a gadget race where you just buy some new stuff and win it all without effort. With this in mind, a lot of water-ballast makes even less sense.

Std.cirrus in a field
Looks green but is it?

This is also one of the main points to competition gliding being not-so green. Water ballast is dirty. Really. At the last WGC in Poland the club-class gliders weighted between 300-400kg, so an rough average of 350kg. Std and 15m weight an average just below 525kg (some gliders can just fly with 500kg). We can say there is a difference of 160kg, to be on the safe side in the calculations. Towing altitude was around 700m which means there is 160kg extra for every glider that needs to be taken to 700m. So, because of the water ballast we need to tow 160kg x 84 = 13440kg extra to 700m. 13,4 tons of water, 700m every competition day, that does nothing for finding the best pilot. The only difference is the speed numbers in the result. And there is more.

Heavy gliders can’t be towed (mostly) at competitions by modern efficient tow planes. Old, dirty and inefficient tow planes are used. These old tow planes are kept alive largely because of the need to tow heavy gliders. It’s a dilemma for a lot of clubs if to keep alive the old tow plane that can tow heavy gliders or buy an efficient towplane that can only tow lightly ballast gliders. The old planes consume roughly three times as much fuel for the same tow. A cost that we competition pilots, clubs and the environment have to pay.

Competition rules and results have been steering how most gliders are designed. Due to the fact that IGC defined 525kg as max in std/15m most gliders in this class are designed to this weight. Same goes for other classes. This means that everything is oversize and more material is being used to build them. This leads to higher production cost and higher weight of the gliders. Mind, glass/carbon fibre is not really good when it comes to recycling.

On a side note. The rules also forbid chamber changing devices in standard class which means the excellent landing flap/brakes found on the latest Duo Discus can not be used on standard class gliders.

Why don’t we have more electric self launchers? Well, that is also down to weight. The UL gliders are light enough to make it viable. The normal single seater today has a MTOM(Maximum Take Off Mass) of at least 500kg which rules out electric self launch. It’s 500kg or more because we insist on the option to carry a lot of water ballast. Bringing the MTOM back down to around 400kg would make electric self launchers much more viable and available sooner. I’m sure it’s possible to build a 18m glider with electrical self launch that have a MTOM around 400kg, if it was designed for MTOM 400kg. A small removable water ballast tank(like found in the ASW27) can be used to compensate for pilot body weight. It’s then possible for a very light person to compete well against a very heavy person.

I think we are stuck with how the gliders are built but I believe we will see in the future more competition directors limiting the max take off weight. The cost and availability of old tow planes will make it natural and unavoidable. Heavy gliders will only be self launch.

When I went from flying 15m to club-class I didn’t miss the water, on the contrary it was a relief. Not having to fiddle with water ballast is great and the competition is still as exciting. Further more flying a light weight glider that can thermal really narrow and climb well is a joy. It would be very nice to also be able to compete with modern gliders without water ballast.

This summer have also been very hot and dry. In many places there have been a shortage of water or noticed a significant lower ground water level. To play with water during these times is not very good PR for marketing gliding as a green sport. It’s quite irresponsible.

Zlin Z-37 Čmelák
Will the Čmelák still tow me in ten years?

In the early days of gliding they discovered that higher weight equals more speed. In 2018 this is cornering gliding in to a ‘high energy use’ sport that relies on fossil fuels and inefficient technology. By limiting water ballast we will drastically reduce our energy use by allowing the move to much more efficient propulsion. The joy and excitement will still be there. Club class is the most popular class and it’s only non-ballast gliders. Letting go of maybe 10% speed on fast days is all it takes, it's not much.

Let the open class do what it want within 850kg but make sure the big mass classes pursue efficiency, safety and sustainability. By a gestimation I believe limiting water ballast to only equalise glider weight will at least half our use of fossil fuel at competitions.


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