This is not advice, but a posting for historical reasons:

BASE Aritcle 5a - More on Deep Brake Settings

From: ftr@sam.neosoft.com (Walt Appel)
Newsgroups: rec.skydiving
Subject: BASE Article #5A, More on Deep Brake Settings
Date: Fri, 12 May 1995 20:10:15 UNDEFINED

This is an addendum to the fifth in a series of articles that I am posting about BASE jumping. The fifth article gave general tips on how to set up a parachute for BASE jumps. This addendum contains Adam Filipino's response to the section of that article that discussed deep brake settings.

Feel free to e-mail me, but don't ask me to recommend specific sites. I will not recommend specific sites, nor do I recommend BASE jumping. BASE, even though it has evolved a great deal over the past few years, is still somewhat experimental and I consider it to be an extremely dangerous activity. I am posting these articles because the lessons that have been learned about BASE have cost us dearly. I do not want to see anyone hurt or killed because they were unknowingly re-inventing the sport.

In case, you're wondering about my background in BASE, I have made 55 BASE jumps, mostly freefalls from under 500 ft, from a variety of sites. I make and sell BASE accessories, e.g., pilot chutes, bridles, mesh sliders, etc., and I have been on the Bridge Day staff for the past few years.

Disclaimer: I am not now, nor will I ever be, the final word on BASE jumping. Nobody is the ultimate authority.

BASE is an extremely dangerous activity. In my opinion, the best way to reduce your chances of injury or death is to talk with as many experienced BASE jumpers as you can, learn as much as possible, *think* about it, and jump in a way that makes sense to you. This article is written from one person's point of view (mine) and you'd be nuts to consider it the best or only point of view. There is a lot more to BASE than any series of articles can present. Use the information only as a starting point.

Author's note: The above disclaimer is not a collection of empty words. In this article, I am presenting a differing point of view. I urge you to seek as much information from as many experienced people as possible before you BASE jump. In that spirit...

Meet Adam Filipino
Adam Filipino is the man behind Consolidated Rigging, maker of the Mojo BASE canopy, which will be discussed in the next article. He is also the Vice President of the Cliff Jumpers Association of America. I first met Adam on the weekend of Bridge Day '88. He and his group were kind enough to take me under their wing and show me how to stay safe when BASE jumping, even though they had never met me before. For that, I will always be grateful and will strive to follow their example.

I contacted Adam to get the specs on the Mojo. As usual, he was more than willing to help and graciously offered to contribute his expertise to this series of articles.

What follows is the text of a note that Adam sent me regarding deep brake settings.

The Importance of Deep Brake Settings
While I am writing I may as well include my thoughts on one of your earlier articles that I mentioned I had some comments on. In speaking about deep brakes you mentioned that they were not really nessacary on tower or bridge jumps due to the lack of an immenent object strike. I disagree with this for several reasons. The most important of which is that deep brake settings (by deep I mean greater than 80% of the effective control range) do far more than simply inhibit opening surge. By pulling in your brakes on deployment you are in effect lowering the canopy's aspect ratio. More importantly you are shortening the control lines. Why are shorter control lines better? It is no coincidence that the lines most likely to end up over the canopy are also the longest. If you shorten these lines they have a harder time getting themselves in front of the deploying canopy. All this said, the fact remains that slider down canopies deploy far more cleanly when packed in "deep brakes".

During slider down deployment, the lower surface experiences complete and instantaneous inflation before the airfoil even begins to pressurize. Any canopy will deploy in a more stable fashion, experience less oscillation due to suspended weight shifts, and have a reduced tendency to surge forward (which usually only helps close off the leading edge due to the fact that it hasn't aquired sufficient internal pressure to stay open against external pressure) if its lower surface has a more positive angle of trim and a more concave profile.

In short, deep brakes make slider down parachutes open cleaner and more reliably. The convienient side effect is increased time to respond to an off heading opening.

However, deep brakes are a very critical thing. As you mentioned, it is easy to induce a stall on opening if the brakes are too deep. This is not a good thing and a smooth recovery is difficult at best. The ideal brake setting for slider down jumping is, in fact, so close to the stall point that common sense dictates we err to the shallow side in order to leave a big enough margin to account for things like body position, altitude (MSL) and delay (which can also play into the equation).

If you are looking for consistently cleaner and safer openings on slider down deployments, you need to do your homework and determine where your stall point is during test jumps from an airplane and move ahead from there. I have this down to something of an (inexact) science and would be glad to help anyone wanting information on this.

Adam Filipino