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Sabre 1 front riser turns bucking

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I have recently started jumping a sabre 1 170. I bought it used and all implications seemed to point to it being relatively new. It was bought being told it had only 40 jumps on it and it very much appears this way.

The issue i am having has nothing to do with openings. I have never had an issue with hard openings with the 4-5 different first gen sabres I have flown. I actually have nice soft openings without any different packing techniques being used. one of the lucky few i suppose.

The issue I am having is being unable to execute front riser turns. Everytime I try the canopy bucks away. It appears that the nose is collapsing and reinflating and no turn is actually happening. This goes for both right or left input.
Is this typical for Sabres? My first few sabres i had never really tried front riser. Or is there something out of trim, something that Can be changed/adjusted relatively easy?

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Have you had a rigger measure the lines?
Is there any play in your brake lines?

The Sabre 1 has a relatively light front riser pressure, or at least the 170 I had did. Closed cells/bucking were never a problem for me.

I'd suggest measuring for line trim, or having someone do it for you.
http://www.performancedesigns.com/docs/linetrims/LS_120-170LT.pdf

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What DSE said, that is not typical...check you steering line length. When you look up while under canopy, if you don't see a visible bow in the lines they are likely too short. Lots of people have a tendency to set their toggles/steering lines shorter than optimum...

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A friend just went through this, the factory brake line length was way too short; using front risers with the toggles in hand would pull down the tail as well and cause bucking.
Rigger lengthened the brake lines a little at a time, my friend ended up with 8" longer to be able to use front risers.

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Yet another answer of "Check your brake line length,"

I have a 170 Sabre2, and it had brake lines that were too short. The brake lines were taut and the back of the canopy was deflected down slightly even with the toggles at the rings.

Front riser turns would go about 90 degrees and start to buck and flutter.

Letting them out a lot, to the point that I have about a foot of backwards "bow" when all the way up made a huge difference.

If you don't know how, ask your local rigger. It's a reasonably simple task that should only take a few minutes.
"There are NO situations which do not call for a French Maid outfit." Lucky McSwervy

"~ya don't GET old by being weak & stupid!" - Airtwardo

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Originally posted 2003:

The length of the steering lines can drastically affect how a canopy flies. High performance canopies are affected much more than lower performance canopies. All canopies should have some slack or a slight bow in the steering lines. If the steering lines are too short and pull down the tail of the canopy during full flight, even slightly, the canopy is flying in brakes. If the canopy is flying in brakes, it will not have as much speed to trade for lift during the landing flare. Over time the steering lines shrink as a result of friction from the slider during opening, as much as 6 inches in extreme cases. New canopies or line sets adjusted to have no slack in the steering lines will begin to fly in brakes as the control lines shrink.

To maximize the performance of your canopy it is necessary to understand the construction of the steering lines. The steering lines on a canopy are made of several parts. The upper control lines, usually four or five lines cascade or split at the top of the central control line and attach to the tail. The central control line attaches the upper control lines to the lower control line. The lower control line attaches from the finger-trapped loop (for setting the brakes) at the bottom of the central control line to the toggle. The lower control line is where your rigger can make adjustments.

If you do not use your front risers, adjusting steering line length is a fairly simple process. To check your control lines, pull one toggle down an inch or two while watching the tail of the canopy in flight. The tail should not move and the canopy should not turn. If it does, your lower steering lines need to be lengthened. Make small adjustments, no more than an inch at a time. This may require several adjustments. It is better to be an inch too long than an inch too short. Once you find the correct length, have your rigger finger-trap and bar-tack the lower steering line to eliminate the knot next to the toggle which can hang up on the guide ring. Periodically check the steering lines to see if they have shrunk and need to be lengthened again. Micro-line can shrink 4 to 6 inches or more over its life span. Vectran tends not to shrink with wear but is not as durable as Micro-line.

If you use your front risers, adjusting steering line length is more complicated. Having enough slack in the lower steering lines on a high performance canopy is more critical to how the canopy will fly. In a front riser turn you are pulling the toggle down a little with the riser and there has to be some slack to prevent pulling down the tail. If the tail of a high performance canopy is pulled down even a little when front risering, the riser pressure will be much higher and the recovery arc (the amount of altitude required to get back under the canopy) will be shortened. To check if the steering line is long enough, clear your airspace, do a full 360 degree front riser turn (keeping the toggles in your hands), and watch the tail of the canopy. As the speed increases, the drag on the control line increases and if there isn’t enough slack, the tail will be pulled down. You need enough slack so that the tail won’t be pulled down while pulling the toggle and the riser down at the maximum speed of the canopy. Another easy method of checking your steering line length is to compare the front riser pressure from the front riser 360 with the toggles in your hands to a front riser 360 without the toggles in your hands. It is important to have plenty of altitude and clear airspace before letting go of the toggles and front risering. Again, make small adjustments no more than an inch at a time and have your rigger finger-trap and bar-tack the lower control line once you have them adjusted correctly.

With the steering lines correctly set, your canopy will dive longer and faster, have lower front riser pressure, and you can get the most out of your canopy.

Derek V

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People are tellong you the brake lines are too short. They should finish the sentence. The brake lines are too short to do front riser turns with the steering toggle still in your hand. They are NOT to short to have full and immediate steering control of the canopy.

Since I don't do front riser turns to landing I want the toggles to react as soon as I start to pull them. That means no slack. In order to do front riser turns with the toggles in your hand they have to be set with slack. This will mean that you will have to pull the toggle down from the keepers several inches before the canopy starts to do a normal turn. And if you set them too long you won't be able to stall your canopy or get full flare out of it.

Neither setting is 'right' or 'wrong' or 'too short' or 'too long'. The setting that is right FOR YOU depends on what you want to do with your canopy. PD factory settings on the canopies I've dealt with are right for my kind of flying but not for what you want to do. It's not that they're wrong, but one setting doesn't do it all.

If you don't understand what I've said above have someone demonstrate with your canopy.
I'm old for my age.
Terry Urban
D-8631
FAA DPRE

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Quote

Over time the steering lines shrink as a result of friction from the slider during opening, as much as 6 inches in extreme cases. New canopies or line sets adjusted to have no slack in the steering lines will begin to fly in brakes as the control lines shrink.



If one is not diligent about untwisting brake lines (removing the candy cane effect) does this cause link shrink to be even more dramatic?

Meaning if you had two canopies, one that regularly had the brake lines untwisted and one that didn't and they did an equal number of jumps, if the properly untwisted canopy lost 6 inches in length due to shrinkage, how much would the improperly maintained brake line shrink?

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