mark

Yup. Such as 15000' jumps after a 10-minute Blackhawk ride! Mark

Rhys: What exactly was Precision's manufacturing fault? Mark

Moving the Cypres cutter location is intended to reduce the chance of a container lock after a Cypres fire -- a kind of total malfunction. In this incident, the original poster writes that the container was open, so the change of cutter location wouldn't matter unless you'd like to speculate the pilot chute snagged on the cutter, something nobody has suggested and which I'd think is extremely unlikely. Mark

rhys: What exactly was out of spec for Precision-built Crossfires? Mark

Your neighbors already know where to take the freebag stuff. Writing contact info on the bridle just gives the unfriendly ones' lawyers a head start. Mark

A-lines through the front grommets, brake lines through the rear grommets. Just forward of the rear grommets are an additional pair, for the C-lines. The grommets are the same size as the ones you have for your micro-line canopy, so they get crowded when they're used with the stouter tandem lines and double brake lines (two brake lines per side, both pretty stout, too). The hope was that the six-grommet slider would reduce the malfunction rate by reducing the occurrences of tension knots. Mark

This one's been floating(!) around for years. The alleged number of required skydivers changes in each retelling, but the general trend has been upward as freefall speeds have increased. I'm sure such a thing is possible, so your instructor friend should practice for his hero slot (docking last) on this Guiness event by docking on someone under a round parachute. Be sure to get video. Mark

I don't think you could count on that. That is, I don't think you could predict a less than 40-pound pull just because the pin is straight. From a packing point of view, the tough part is not breaking the closing loop. I'd be interested in knowing how the test was conducted. What was the direction of pull? Pulling up or at a right angle to the harness can significantly increase the required pull force. Mark

One selling point of the Safety Flyer was that the brakes-set descent rate was about the same as commonly used round reserves. Unconscious: all bets are off. Disabled, though, you may still be able to steer a square reserve sufficiently to land going straight, in a clear area, maybe even into the wind. Who was it that said, "If you have an emergency and have to use your round reserve, you still have an emergency."? Mark

I haven't seen any freebag-deployed rounds, but I've seen several hilarious unintentionally free-sleeved rounds (oops! forgot to tie on the sleeve retainer line!). They opened just fine. Mark

Orienting the links as you describe is the most common way I've seen. It allows more room for the riser (making it easier for the link to orient on the riser during packing and opening), and makes one less bump to ding slider grommets (or allows your silicon slider bumpers to last a bit longer). I've noticed that tandem lines get crowded on #6 links, so I've been thinking about installing those links "upside down," which gives the lines more room, but the riser less. At least one poster here (one whom I respect a lot) installs the links with the short leg toward the riser, on the theory that repeated opening shock deceleration would otherwise cause the barrel to unscrew. I don't worry much about barrels loosening. Lok-tite, a witness mark, and frequent checking is pretty good insurance. Mostly link orientation is about looking good; the standard practice is one that engenders a feeling of confidence. It's symmetrical; it looks normal. From a functional standpoint, it doesn't matter much. Please don't tell my customers that I threaded all their Slinks counterclockwise, the ones on the right as well as the ones on the left -- I think. Mark

As long as we're speculating here, the bent pilot chute spring may be a result of it shifiting in a loose pack job; the loose pack job would also cause a poor launch from insufficient spring compression. Compared to a RWS reserve pilot chute, Mirage's pilot chute does not have as much drag if it launches sideways to the relative wind. Mark

Hello Russ! From your last set of photos: I recognize the club building as the one where I took my FJC, taught by Mike Weber (who took most of your freefall photos, IIRC). This was before the move to the pair of 2-story barracks buildings farther south, which was before the move to the old hospital building. In the 3-way waiting for you to dock, I recognize Paul Bliss's smiling face, and I think I that's Paul Reynolds sideways to the shot (based on the blue and yellow jumpsuit, and the Frankenstein boots). I have no idea whose feet are to the camera. In the three-stack, I'm guessing the late Doug Harris at the top; Ed Lally in the center, and you on the bottom. In the demo team photo, I'm not sure of anyone. Perhaps Jon Pejka facing the camera? (I'll never forget the time he climbed on top of the Huey, then slid down over the front to exit!) Mark

I still see Paul Bliss's name from time to time, usually in connection with the Florida CRW scene. Tom Balboni is still jumping, in Florida. Mike Weber was in Phoenix doing ATC last time I heard -- several years ago I read an attaboy in the EAA magazine about his work with the Copperstate Fly-in. Is there another Max Kohnke? I've seen a pilot by that name in the letters section of "AOPA Pilot." Mark

Wow! That's like major information overload. Is there a way to simplify and still get the reaction you want? Mark

12 = 2 x 6, but 112 2 x 106. The A-lines on a Sabre2 150 are 124" plus a little. With mil-spec Dacron they could stretch to 139," with Spectra to between 131" and 132." That's IF they're loaded to 75% of rated strength, which might happen in a really hard rogue (Bill Von spells "rouge" which is French for "red" which is weirdly appropriate) opening, but consider you've got 20 lines to spread the load to the links. After the canopy is open and you are in straight, unaccelerated flight, the load on each line is something less than 20 pounds, a fraction of the rated strength of Dacron or Spectra. Elongation (or lack) is a deployment issue, but otherwise not a performance issue for either material. For Spectra, the problem is shrinking from grommet friction during opening. If it weren't for the bulk and drag, I think we'd all prefer Dacron because of its dimensional stability -- hence the continuing search for alternatives that's taken us past Kevlar to Vectran, HMA, and beyond. Mark

You can't subtract the weight of your reserve when you're figuring if you're under the TSO weight limit for your equipment. I know when we talk about "suspended weight" the picture in our minds is the weight below the risers. However, the TSO categories refer to "fully equipped" weight, which corresponds to what we call "exit weight." Mark

One way would be to project a shadow against a large piece of paper. Cut out the shadowed area and weigh it; compare the weight with the weight of a 1 ft^2 piece of the same paper. Mark

True for the harness/container and reserve. However, anybody can make a main parachute or components from main risers up. I don't think the FAA has ever ruled on how much work the manufacturer has to do (as they have with the 51% rule for experimental amateur-built aircraft), so if you wanted to test the limits, you could build a Rocket89 from a Xaos89, a few stitches here and there and a new label. Mark.

Hutch and Chip Falls are both open weekends. Chip Falls has a slightly more elastic definition of jumpable weather. PM me for details. Mark

I can't speak to the drop-test mods, but the production square-compatible Wonderhogs had a bungee hesitator loop that held the reserve container closed until bridle extension. IIRC, they also used very short closing loops mounted on the bottom reserve flap instead of the continuous loop (like ParaPhernalia still uses on Softies) used for round-equipped Wonderhogs. You're right about manufacturers going to friction-fit instead of hesitator loops, and I think that's when the bridle stopped being effective as a bag-launcher. The only manufacturer I know still using a hesitator loop is SSK, and then only if you can sweet talk Karen into building just one more one-off. Mark

The wide bridle and freebag were originally touted as anti-horseshoe devices. (We used rubber O-rings instead of rubber bands on the bag, too, before there were "safety stows." We've come a ways!) The bridle by itself (in a horseshoe configuration) does not have enough drag to launch the bag; Bill Booth has some interesting video to prove it. A deployment device of some kind (frap wrap, raeper, diaper, Reuter(sp?) wrap, POD, bag, etc.) that allows line stretch before canopy inflation results in more orderly openings, fewer malfunctions and more comfort. Not all square reserves require freebags. The Pioneer X-210R was optionally diaper-deployed, for example. A freebag reduces to nearly zero the chance of a pilotchute-over-the-nose type malfunction. Mark

If you start with a correctly assembled canopy, it is mathematically -- topologically -- impossible to create a step-through that results in one pair of risers (and its lines) straight and the other pair tangled. To create a "one-sided step-through" you have to disconnect risers or lines. Mark

The composite fabric parachute shown by Atair/CobaltDan at the PIA Symposium was made of remarkable stuff. One reason why it isn't being more widely used is its cost. Right now, the longest piece being made is about 10 meters, about 30 feet. Additionally, if you want to take advantage of the strength from strand orientation, strand layout for rib pieces must be customized for each rib when the fabric is being manufactured -- the strands need to radiate from the planned line attach points, the way reinforcing tape is currently sewn on ripstop (F-111 and ZP) ribs. Also, it doesn't dye well. You'd run foul of the fashion police. Mark

I just ordered batteries today by e-mailing [email protected]. I know they got the order, because I've already gotten the UPS automated e-mail with the promised delivery date. Great customer service! Mark