How many tumblings can resist the lines in new modern acro gliders...

Can some of profi acro pilots could say smth in this topic ?

Regards,

Jarek

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Marvin Ogger's picture

holahola.

this year i trained a lot and especially the infiniteT.
with a quiet heavy and strong fabric and one new trim on the A and B like xandi said i counted between 1200 and 1500 turns (even with parajumps and all the shity things). this time ill count more exactly because i also think this is pretty interesting and important for the developing of the material etc.

but of course about the last 300 turns i was VERY carefully choosing the position i flew the tumbles and of course with adequate altitude reserves because more or less i was expecting the lines to rip, but it didnt happened.

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PalTakats's picture

Hi!

Great question!

I found Xandi's answer quite realistic. 1000 sounds maybe a lot, but it comes damn quick if you are somewhere where you can train hard. And take in consideration all those no-energy-big-collapse-falling-next-to-the-canopy "parajumps" which actually happens quite oft, and it can sometimes rip your wing.

Anyway it is crazy what the straight turns do to all the acro gliders, both the canopy and the lines. However I believe that hardcore classical tumblings (just 2 turns) have almost the same effect or worse, since during a powerfull entry there is extreme tension.
I think it also really depends on the weight of the pilot, if it is heavier, it stresses the wing more. Luckily, till now I did not have any problems with broken lines (except maybe the brakeline) while flying strong maneuvers. Not like Gabor, who is maybe 15 kg heavier, but he already blew up some wings and harnesses in the air. To this take in consideration that we usually fly with gliders in pretty good conditions and we can change the material regulary, like having 2 wings per year. Still, I think all the comp pilots knows the feeling when they receive a new glider (no matter which brand), it feels great in the beginning, but maybe after 100 turns of infinity you can feel (hardly, but still) a very slight changing in the behaviour of the glider. The lines and the material get streched and sometimes you even hear ripping sounds when some diagonals or whichever part on the canopy during the first radical loads (this happenes when something is stiched a bit too tight together). Of course you have to know your glider well otherwise you might not be able to feel any difference yet, or you can maybe only notice it during some certain moves, for example the way how the glider shoots out from a helicopter.

Unfortunately regarding this there is a problem, while the paragliders are still just a piece of nylon while we put them under extreme G loads, of course they will get old very quick. However, not many of those young pilots who are crazy about learning infinity has the money to finance 2 new acro gliders just to learn one maneuver...The pilot himsef is a huge enough risk for this time, but there is an extra material failure factor which can happen any time (even with new gliders) and it can be even just one single broken lines that puts the glider into a not exitable parachutal or whatever...

So cake care...
Cheers

xandi's picture

Hi !

If you talk about tumbling do you mean straight turns of infinte ?
Well, usually one acro glider makes about 1000 turns.
In this time you have to make some trimm corrections, because even
cevlar lines get stretchend.
The A and B get longer, so you have to make them shorter again.
After 1000 turns also the cannopy is stretched. For normal tumblings the speed will be ok, but maybe not for infinte anymore.

If you fly a lot of tumblings you should change the line set after 500 turns. Then you are
on the safe side.

If you make normal tumblings with one ore two turns you can make even more than 1000.

But all this depends a lot of the material and the way of stitching the cannopy .

Dynema Lines are stretching much more than kevlar lines.

safe landings !

xandi