Canopy Specifications - Super Raven
From:
ftr@sam.neosoft.com (Walt Appel)
Newsgroups: rec.
skydiving
Subject: BASE Article #6 - Canopy Specs -- The Super Raven (2 of 5)
Date: Fri, 07 Jul 1995 05:04:55 GMT
This is Part 2 of the sixth in a series of articles that I am posting
about BASE jumping. In this five part article, we take a close look at 4 ram-air parachutes that I consider to be suitable for BASE jumping. Part 2 discusses Precision Aerodynamics' Super Raven.
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.
A Look at the Super Raven
Here are the specifications on Precision Aerodynamics' Super Raven. They come directly from
George Galloway. If you've been skydiving for more than a year or two, you've heard of George Galloway. If you've been following rec.skydiving for more than a few weeks, you probably feel like you know him. I had the pleasure of meeting him at the PIA convention in Orlando this year. Even though George has over 2500 skydives, 25 years in the sport, is the president of a major skydiving parachute manufacturing company, and is a multi- engine and instrument-rated pilot, and master rigger, he's warm, friendly, and more than willing to share his considerable knowledge. Here is some of his knowledge about the Super Raven.
Canopy:
Super Raven
Manufactured by:
Precision Aerodynamics, Inc., P.O. Box 386, Dunlap, TN USA 37327
Sizes available:
120 sq. ft., 135, 150, 181, 218, 248, 282
Number of cells:
7
Aspect Ratio:
2.25
Description of reinforcement at bridle attachment point:
A525 lb. (tensile strength) nylon reinforcement tape runs spanwise(*) across the top skin of the center cell through the bridle attachment point. The load is transferred vertically from the bridle attachment point along the center non- loadbearing rib to a spanwise 525 lb. nylon reinforcement tape on the lower skin by a 525 lb. nylon reinforcement tape. The spanwise reinforcement tape on the lower skin transfers the load to two line attachment points.
Description of reinforcement at suspension line attachment points:
525 lb. (tensile strength) nylon reinforcement tapes run chordwise(*) along each loadbearing seam on the lower skin. 2 - 200 lb. nylon reinforcement tapes forming a "V" shape run from each line attachment point to the top skin. The leading edge tapes on both loadbearing and non loadbearing ribs are secured to the upper and lower surfaces with a 28 stitch bartack and the line attachment points are reinforced with 525 lb. nylon tape.
Canopy material (F-111, Soarcoat ZP, etc.):
Canopy fabric is woven from high tenacity bright nylon yarn containing ultraviolet inhibitors, and finished to 0-3 cfm (**)
Suspension line material:
525 lb. Dacron braid or 825 lb. Spectra braid. The lower control
lines are 900 lb. Dacron braid.
Standard features:
Choice of Dacron or Spectra suspension line, stainless steel connector links, and custom color at no extra charge. Bridle attachment is factory installed.
Comments:
All Raven canopies produced since March 10, 1988 are Super Ravens. Two quick ways to tell by looking are that the Super Ravens have "Raven" end cell logo panels (the standard Raven had no end cell identification) and canopies made in the Super Raven Series incorporate diverging load tapes from the line attachment points up the ribs to the upper surface. (The Standard Raven used single load tapes) There are more Super Ravens packed as reserve parachutes than any other canopy.
*"Spanwise" means from one side of the canopy to the other. On a rectangular canopy, a spanwise line is parallel to the leading and trailing edges. "Chordwise" means from the leading edge of the canopy to the tail, in a line parallel to the sides of the canopy.
** The canopy fabric is equivalent to F-111.
Checklist
Let's go down our generic checklist, i.e., "...a
seven cell with the following features:"
A low aspect ratio
Notice that the aspect ratio is 2.5. The consensus among many BASE jumpers is that an aspect ratio of about 2.0 seems to be the ideal and that the dividing line between low and high aspect ratio is somewhere around 2.5. The Super Raven is in the middle of that range, and I get consistently straight openings on mine. The worst off-heading opening I have gotten was 45 degrees off. It only happened once and I was not able to determine the cause. Your mileage may vary.
Made of non-zero-porosity fabric
The canopy is made of a fabric that is equivalent to F-111.
Dacron or nylon (not Spectra) suspension lines
We're given a choice of Dacron or Spectra on the Super Raven. For BASE, the better choice is Dacron.
...Strong reinforcement scheme at bridle and suspension line attachment points
(Have you got your canopy beside you for reference and comparison?)
The bridle attachment point is directly over the canopy's "C" line group and reinforcement tapes transfer the load to the center "C" lines. You can't see the load tapes at the suspension line attachment points because they have canopy fabric sewn over them. They appear as 1 inch wide ribs running chordwise along the attachment points. Looking inside the cells, you see a "V" shaped reinforcement at each attachment point. As pointed out in the comments section, the old Ravens (pre-March 10, 1988) had a single load tape at each attachment point instead of a "V". The Super Raven is a much stronger parachute.
Very durable construction
This point is very subjective and you need to do a meticulous inspection of the canopy to make a judgement on this one. Look at the stitching at the stress points, i.e., the suspension line and bridle attachment points and all junctions of reinforcement tapes. Do these areas have plenty of extra stitching? What about the canopy fabric--how will it stand up to rocks and trees?
The Super Raven's stress points are reinforced with bartacks. The bartack resembles a very tight zigzag stitch. It is an industry standard stitch pattern used to reinforce stress points.
F-111 and like fabrics are not known for being bullet proof, but using heavier canopy materials would give a significant increase in weight and bulk. Until something better comes along, this seems to be the best choice.
Surface area large enough to give soft landings even in deep-brakes approaches
The Super Raven is offered in a variety of sizes, so you should be able to get one that will land you softly.
I have a 282 sq. ft. Super Raven that I BASE jump, but I'm going to defer discussion of my experience with it to a future article. I will be BASE jumping several canopies and will report my experiences with them.
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Originally Posted by nicknitro71
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