gear tuning in hg

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By Toni Crottet on
Discipline
Hang Gliding
What do we want ?
Flying gliders that have a well defined pitch-up moment.
How do we achieve that ?
- Re-Defining a measurement protocol
- Validate that protocol
- Define a process useable at Cat 1 and maybe Cat 2 events
- Change culture: setting SPROGs too low is dangerous, which you cannot change with pilots level
- Haveing manufactures communicate SPROG settings with the expected pitch-up moment
Issue category :
gliders
2 in favour | 0 against

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By Toni Crottet on Tue, 28 Oct 2025 - 09:33

Thinking more and had contact with manufacturos:

Gold Standard to measure is: Putting the glider in a hall on 3 stands, Attaching a string between the sprogs and measure the distance between the string and the kiel. Comparing it to the manufacturos data. Accuracy around 2mm. Time to meaure: 10min.

Measuring with a level the angle (degrees) seems be less accurate.

I suggest following procedure:

- 1-2 days before and at the training day, pilots can go into the hall and let measure their hangglider
- At the competition, the first three and two others random gets the fast measure at landing
- If needed, take the gliders into the hall for accurate measure
- If the values exceed the value --> direct disqualification from the comp

1. For measurement, giving enough tolerance would make the proposal pass easier. I know that the german certification people do not want to give tolerance, since the measure is accurate. But in order that the pilots are in the boat, we need a good tolerance

2. Immediate disqualification makes that the pilots don't play with the tolerance (which was the case in the past)

3. We need the german certification people to modernize the method. Laser measurement tools are cheap and they provide a no-touch measurement. At the moment, they don't see any use of that, as they are techies. I tried to explain that they will have to make compromises in order that such proposals have a chance to pass. In a way: I rather measure a bit different than not measure at all, cause they way they do it now is not common accepted by the scene.

Different sideeffects can happen:

- Gliders are getting safer
- Pilots do get more aware of proper glider settings
- Pilots get a voice against manufacturers: Make the gliders safer
- Pilots get more confidence

Profile picture for user Robert Kulhanek
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By Robert Kulhanek on Tue, 28 Oct 2025 - 12:27

Hello all.

I don't want to open Pandora' s box but are the glider in competition without definition of pitch characteristics? Or well definition?
When we had Tumble accident in competition last time? (Euro in MKD?) And this happened due improper settings?

add 1) Now S7A-8 define tolerance 1 deg from manufacture settings (not certification). There is difference in what is for certification and rule for participate in competition. Analogy with EN A-D pg classes and CCC class for competition. About the accuracy, I have heard from experienced pilots that guys who know how to measure can do it with repeatability of 0.2 deg. I have similar experience.

add 3) Why only German? There are 3 worldwide standards (GER, USA, GB). All of them are recognized by CIVL and majority of NAC. Every standard has different requirements (numbers and procedures) to fulfill airworthiness criteria.

There is CIVL protocol how to measure
https://www.fai.org/page/sprog-setting-measurement
but nobody do it comps. (since I am in..)
only what i really missing is

....These angles are your sprog settings and can be compared to the data collected over the years at competitions, or your manufacturer’s published values....

the data collected over the years are somewhere missing (not public).

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By Toni Crottet on Tue, 28 Oct 2025 - 20:04

Thanks Robert!!

Yes, I am aware of all this documentations.

We had on the Swiss / German Open in Kandel a lot of measurements done. Those were all in a way free for pilots to use. We regognized different stereotypes of pilots

1. The ones that didn't know anything about. Like I let my glider check three years ago and they were usually completely out of the range. After correctly setting back the sprogs, they were amazed how well the gliders flew again

2. The ones that beleive they can feel the correct setting and have a general very and too low setting. After Alex speach on that it is impossible to feel the correct setting in flight i guess they had to agree and set their sprogs back to correct settings

3. The ones that know whats going on, but playing with tolerances

4. The ones that do really take care, set the sprogs right and are not happy to compete with illegal tuners

After raising the topic, every or almost every pilot present were pushing into the direction that they want correct measurement, that they don't want to compete against illegal tuners and especially they don't want to see any tuck.

I see and agree that tucks are getting rare. But noone want to beleive that gliders got safer without proove and kick that rule out of S7. I was asking on basecamp what they want to do with this rules? There were three options:

1. Kick that rule out and go back to open class
2. Proove that the sprog settings can be lower and change the rules to that
3. Start checking again, since it doesnt make sense to keep the rule without checking

Leaving it as it is, is also a damocles sword for manufacturors: If CIVL decide to measure only a couple of weeks before an event, cause a tuck happend just before there is no time...

The discussion ended up by older pilots beleiveing that we leave it like it is and CIVL trusted them.

- Why the germans?
They are the most active certification bureau (currently working on WW gliders) and are, after looong discussions open for developing just a hands-off method or helping out. Its not meant that they have the only power to certify.

- Pandoras Box?
Different reasons why we should re-open it. With your generation, with all pilots I am speaking (and I like to speak more to the young, coming ones, not that much to the old, going ones) they all want safe, fair and good competitions.
Also, it will give, like it was the case in PG, give the pilots a voice for pushing the manufacturos to develop better, easier and safer wings.
Many reasons more.

- When we had Tumble accident in competition last time? (Euro in MKD?) And this happened due improper settings?
Might be yes. One is too many already. A Wind Dummy in the Euro in Monte Cucco had one as well, but ended up well. Further on on a spring meeting i guess there is been one.
People tell me: why don't you do something. Should we wait again for an accident and only then doing something? Which weights much...

I don't have THE solution. But I promised those pilots to work on it. Thats why pilots like you have the power as well, thanks for taking care.

By JD Kugler on Tue, 28 Oct 2025 - 22:21

In my opinion, this part of S7 is a major issue in terms of fairness between the manufacturers, between those who pay (a lot of) money to get their glider certified and those who don't bother.

For obvious safety reasons we need a rule for sprogs settings, and it should be based on a certification, because the certification is based on clear pitch measurements and not a test pilot's feeling.

For me, we need to start measuring sprogs again during comps, especially CAT1. 5 gliders randomly choosen among the field seems managable. That would also put CIVL officials to good use for once.