Hi there, I have a couple Q's on brake settings. I've been hearing mixed opinions on this one. I was always taught that deep brakes=fast openings. Then someone said that shallower settings yielded faster openings??? What's up with this?? How much does brake setting play into opening heading? Does it?? Seems to me like the way you fold the nose is far more important in heading than brake setting. Am I wrong on this one?--Dex
[font size="1" color="#FF0000"]LAST EDITED ON Aug-05-01 AT 11:42 PM (PST)[/font][p]>I was always taught that deep brakes=fast openings. Then someone said that shallower settings yielded faster openings???
I had also always been taught that deep brakes yielded faster openings. However, a while back 460 posted a comment to the contrary, and had an excellent logic to back up his opinion.
I tend to agree with him now (The logic was that a canopy surging forward on opening will inflate faster through the nose openings).
However, logic would seem to dictate that the brake setting can be deeper for the same speed opening with secondary inlets (vtec or PAC valve) on the bottom skin.
I do know that BR recommended to me that I use the shallow brake setting on all Vtec jumps (regardless of slider position). I believe this had something to do with deployment stalls. However, I have been using my normal setup (shallow for slider up, deep for slider down) without mishap.
I wonder if anyone has done any empirical testing on this topic? Until I get a chance to do some actual testing, I'll probably stick with the traditional (shallow for slider up, deep for slider down) set up.
>What's up with this?? How much does brake setting play into opening heading? Does it??
I wish I knew the answer to this. Can anyone help?
>Seems to me like the way you fold the nose is far more important in heading than brake setting.
I would tend to agree, but it's more witchcraft and intuition than solid data.
Does anyone have any solid data on these questions? Perhaps one of the manufacturers can help us here?
--Tom Aiello
tbaiello@ucdavis.edu
P.S. Thanks for starting a technical discussion. So much of what we talk about here is relatively meaningless political drivel. It's good to see someone interested in discussing things that can be useful to all of us.
NO ANSWERS JUST MORE QUESTIONS
MY PERSONAL EXPERIENCE IS LIMITED TO 19 JUMPS AND I WAS WORKING ON THE SHALLOW FOR SLIDER UP, DEEP FOR NO SLIDER / SLIDER DOWN. THEN I GOT TALKING TO A GUY IN NORWAY ( UNSURE OF NAME / EXPERIANCE ) AND HE SEEMED TO THINK ALWAYS USE SHALLOW BECAUSE IF YOU REACT HARD ON REAR RISERS WITH DEEP BREAK SETTING, THEN THE CANOPY IS MUSHY AND DROPS A LOT OF ALTITUDE. HIS IDEA WAS TO ALWAYS USE SHALLOW BECAUSE THIS GAVE BETTER CONTROL TO THE CANOPY EARLY ON. I JUMPED A 240FT CLIFF SLIDER DOWN ON SHALLOW BREAKS AT THE WEEKEND WITH NO APARENT PROBLEMS.
DOES ANY BODY KNOW ANY MORE ABOUT THIS??
Again, no answer but more opinions (mine).
Having a Fox Multi Vtec, I keep (as Tom is doing) jumping shallow setting for slider up and deep setting for slider off, with no apparent problem.
Still there is a point about which I made few months ago and nobody really replied me, satisfactorily. I repost it now.
I think that shallow setting with slider up and deep setting with slider off yield about exactly the same configuration of canopy, I mean the same "breaking". The shallow setting has more length of line running from the setting itself on the riser, but this length of line goes from setting to corner of canopy passing through the slider grommet (making so a "route" made from two lines forming an angle). The deep setting has less length of line compared to the previous case, but now such a shorter length of line goes straight from setting on the riser to corner of canopy.
The (theoretically) longer length of line as per shallow setting "consumes" more length because it must form a route of two lines forming an angle (more distance if compared to a straight line going directly from setting on riser to canopy corner). The deep setting goes straight from setting on riser to canopy corner. I think the settings, shallow and deep, in the end, because each of the two settings have the lines to make a different path, yield the same configuration (or nearly?!?!?) of canopy. Same quantity of break, just to make you understand what I mean. So, same pitch of canopy.
Am I bxllshxtting?
I would to like to hear an opinion of your about this story of "same canopy breaking" with the two settings but two different "routes" of lines.
I think that to measure these real lengths with the 2 different settings in the 2 different configurations is really difficult because you should measure the real straight distance from setting on riser to canopy corner in the 2 cases, very, very difficult at best, because you should measure them on a full flying canopy... ...not even close to reality with a canopy laid on the ground...
Blue Skies
Andrea
Brake settings& Probably the least understood yet one of the most critical parts of equipment setup.
As to brake settings and deployments. They definitely have an impact on what kind of deployment you have, but I'd like to clarify something about brake settings that is often misunderstood. People refer to deep and shallow setting as if they are absolutes. They are simply one, two or more points within a control range that can span several feet. The appropriate brake setting for one person may be totally wrong for the next. Deployment method (slider up or off/down), density altitude, and system weight all play a part in determining what the appropriate brake setting should be. The depth of the setting and the jumper's weight are directly proportional. i.e heavier jumper = deeper brakes. This is why we place a custom deep brake setting on all Mojos, Aces and Blackjacks. It also means that at 145# when you borrow your buddy's 280 the shallow setting would be your only choice or you will open in a stall.
It would be nice if we could just set them as deep and shallow and cover the range, but when you try to deploy a canopy close to it's minimum speed it becomes too sensitive to safely guess. Skydiving canopies have their deployment brakes set at an intermediate point in the control stroke based on a jumper of average weight (for that canopy size) so they have some latitude. They also have no solid objects in the way on deployment.
What this all means with respect to your questions is that unless the deep brake setting was custom placed for you by either the manufacturer, or at your request after experimentation, it may have no relevance to the actual deployment brake setting you need.
So does a deeper setting result in a faster opening? What is a fast opening? Fast to deploy or fast to reach a state that could be considered controllable?
A (relatively) deeper setting will usually create a more positive lower surface inflation, but without the aid of vents or PAC Valves, full pressurization (and thus control) may take longer. At the other end of the spectrum, a brake setting that is too shallow can cause a canopy to over-fly it's leading edge and ultimately result in greater amount of time before the canopy is in control. If your brakes are too deep on a slider-up deployment, a deployment stall is likely.
Does it effect heading? In theory yes, because a canopy that is being restricted from flying forward will seek forward motion in whichever direction it can. It is trimmed with a negative angle and as long as gravity is switched on that means it will try and fly forward. Think of it as a balancing act on deployment.
However, I feel this is only really relevant on slider-up jumps. Far more important to heading performance is what your canopy does between pack opening and line stretch. Most off-heading deployments (no-slider) occur in this stage. There are a number of variables that effect this stage but container closing, container/ parachute compatibility, pilot chute design and size, body position and winds all play a significant role.
For years I've been primping and prepping the nose and lower surface of my canopy; and the longer I observe the results, the more convinced I am that heading performance is much more closely related to closing the container and following the basics during packing (tension & symmetry) than all the voodoo moves .
So where do you want your brakes? As deep as practical without being so deep that a deployment stall can occur. You also want to be able to make immediate riser corrections without inducing a stall. For this reason, a canopy that pressurizes rapidly will allow you to set your brakes deeper. The best way to determine this is via experimentation-preferably from an aircraft.
Tom, I can't tell you why BR suggested using a shallower setting on your vtec but one thing we discovered on our early vented canopies was that the faster pressurization created a canopy that was ready to take off at full speed as soon as the brakes were unstowed. This resulted in occasional surges after the brakes were unstowed. This phenomenon may be the reasoning behind their vtec recommendation. I'd ask them.
We solved this tendency with the BlackJack allowing us to use deep brake settings and have a controlled transition to full flight.
Adam Filippino
Consolidated Rigging, Inc.
http://www.crmojo.com
Adam,
I read very carefully your post. Thanks again for helping us in understanding how things work.
I was wondering if you read my previous post about "my opinion" that <shallow setting+slider up> and <deep setting+slider off> yield (about) the same canopy pitch because of different routes of lines in the two cases... ...provided that shallow and deep setting differ of about 12 cm - 4"¾...
What do you think about this?
Blue Skies
Andrea
I agree Andrea, that because of the extra distance the steering lines must travel when routed through a slider, typically the canopy will deploy in a similar manner. However, as the slider descends, the canopy will begin to generate more forward speed if the deployment brakes are stowed in the shallow setting.
It is this same issue of effective control line length that can cause a DBS appropriate for slider down to result in a deployment stall when used slider up.
Wow, this thread made me realize how many questions I have. The difference between a deployed canopy and a flyable canopy is a subtle point I didn't really consider. Thanks guys.--Dex
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