riggerrob

Meh, this is one of those things where it's a matter of personal opinion. Some peoples' brains are hard-wired to digital, others are hard-wired to analog, others can go either way. There's no "good" or "bad" here, just different. ............................................................................... Consider the age of the customer. For example, since I was invented before digital clocks, I struggled to learn how to read analog (round, sweep hand, etc.) clocks. Now analog altimeters are second-nature to me. I don't really focus on my altimeter, just notice glance at it long enough to note whether the needle is near the top (no worries) or near the bottom (6,000 getting close to opening altitude for tandems and FF students). When the needle rotates past horizontal (on the right side of the dial) I desperately want a parachute overhead. OTOH digital altimeters just spit out raw data, that I need to process through my brain before the data means anything. I was always slow at math. Hah! Hah! Meanwhile, customers born after digital clocks were invented naturally absorb digits, but need to pause - and think - about archaic needles.

Some manufacturers deliberately make the stabilizers too short, so that there is less bulk in the corner seam. That make sit easier to sew.

Thanks for doing the detailed research ... er cutting through the B.....S..... I suspect that many of the cases of fabric tearing - at the edge of a sticky ripstop patch - were caused by the salt and grit found in desert soils. The adhesive held the salt in contact with the fabric until it frayed the fabric.

Sarcasm alert! What do you mean by saying that reefing ropes don't work on ram-air canopies????? I have dozens of jumps on a Strato-Cloud equipped with ropes-and-rings reefing. It was a bitch to pack! Holy "pack volume" Batman! My fingers bled after every pack job! Something about stuffing an extra 64 feet of rope into a container originally designed for a slider-equipped Strato-Cloud. 64 feet was not quite long enough for a rope, because it had a bad habit of pulling the end-cells closed multiple times during the canopy ride. The only saving grace was that it opened soft enough to deploy in a full track! If I never have to pack another ropes-and-rings canopy in this lifetime, it will be soon enough! Hah! Hah! Hah!

I am aware of the requirement for the recovery chute for certification. Gary Douris was making the canopy for a number of years. His shop was next to Elsinore. I was jumping one Saturday and he wandered over and we started shooting the shit. I asked him how business was doing and he said great. There had been 4 saves in the last few days. Sparky ................................................................................... Yes! Gary told me about some of the test-flights that he flew in a Cessna 150. Gary described how they deployed the BRS at high altitude, rode it for a few thousand feet, then cut-it-away for a normal landing pattern and wheel landing. "It was quite the E ticket ride!" laughed Gary.

I recently took a ride in a Cirrus with a friend. He told me about the CAPS system -- apparently pilot is required to brief all passengers on how to use it -- and naturally I had questions... The most interesting part to me was that, if the CAPS is deployed, the airframe is ... totalled ... ................................................................................ First, you burn out the rocket motor. Secondly, you tear off the cover strips that protect the risers, where they wrap around the sides of the cabin. Thirdly, the canopy has to go back to the factory for repack. Fourthly, you probably damaged the undercarriage by landing hard, on steep terrain, which might also damage the wingtips, etc.

................................................................................ Apparently TC's standards vary radically between Ontario and B.C. A significant number of B.C. - based jump planes either don't have enough seat-belts to strap in every skydiver ... or the seat-belts are too short ... or seat-belts are anchored to the floor too far forward of skydivers to restrain them during a forced-landing ... or the seat-belts are hidden so deeply that no-one can find them.

.................................................................................... Cuben fabric is a composite of Kevlar,carbon, UHMW polyethelene, etc. Some of those materials (Kevlar) have better heat resistance than nylon, while polyethelene quickly distorts under heat. The proportions vary with the intended use of the final fabric. The challenge is to define exactly which combination of yarns you want in your cuben fabric????????????

" ... Another challenge you have is dealing with fire. It happens a lot around aircraft emergencies. Those chutes and there attachment points would have to withstand high heat while aircraft descended under canopy(s) with passengers breathing fire feeding oxygen? ...." .................................................................................. There are plenty of materials that resist fire better than nylon ... cotton, wool, Kevlar, Nomex, etc. To reduce the risk of spinning propellers cutting bridles/risers, BRS installs Kevlar risers. I have also packed a recovery chute for an ultra-light airplane that had the risers attached to a steel cable ... again to prevent the propeller from cutting the risers. Back when the century-series fighter planes were fashionable, they used to make landing drogue chutes out of Kevlar. The y used Kevlar primarily because the air is so hot behind jet fighter engines.

" " ................................................................................... Sure, use a mortar to deploy a spin recovery chute, wait a few seconds (or until velocity has fallen below 200 knots) then use the spin recovery chute as a pilot chute to deploy the landing chute.

" ... 3) This system strikes me as something that would really just be for saving the airframe as the shock of opening in an passenger jet which is flying out of control would likely kill or cripple most or all of the passengers either from the direct shock of deceleration or from being thrown around during the jerk caused by the opening. ..." ................................................................................. Au contraire ... You still need a reefing system (slider or ropes) to reduce opening shock to keep the parachute structurally intact. You need a reefing system to reduce opening shock below the value that will rip risers off the airframe. Once you add the complexity of a reefing system, it is comparatively easy to increase its effectiveness to soften opening shock to low enough levels that the passengers remain uninjured. IOW you will never be able to built a light-weight system that wil only save the airframe, because a parachute that strong will need to be so much stronger that it will far exceed the weight of a reefed parachute/

Sounds like BRS fired the original inventor. Incidentally, the concept of saving the entire airframe is not new. Many people proposed the concept back during the 1930s, but we had to wait until hang-gliders proved the concept at light weights and very low airspeeds, before we could "speed up" the technology to save entire 3600 pound airplanes. Remember that opening shock increases with the square of the velocity ... at the start of deployment.

"... Transport Canada ... never much cared about seatbelt technicalities. ..."

Dacron's increased bulk helps improve knot efficiency.

A classic example of too much internet research resulting in too shallow a survey, with far more data points than one human can absorb. A good first step would be to narrow your survey to materials. A narrowed materials search will quickly reveal that nylon is by far the most popular fabric for parachute canopies. Nylon is the preferred canopy fabric because it has a great strength to weight ratio and stretches a little to absorb opening shock. We also have 80 years experience sewing parachute nylon together, so the manufacturing technology is "mature." It is usually some sort of symmetrical ripstop weave. Thickness of canopy fabric varies widely, but is primarily determined by speed of opening shock. Opening shock is determined by a dozen other variables, but - by far - the most important variable is the speed of the load (in this case a complete airliner) just before you pull the handle to deploy the parachute. Opening shock increases with the SQUARE of the airspeed.

Oh boy! You certainly have too many questions for a young man. First of all, Ballistic Recovery Systems are widely available for small (less than 3,000 pounds gross weight), slow (less than 20 knots). The leading American manufacturer is Ballistic Recovery Systems in the Northern States. A Russian company makes a similar system for European-built Light Sport Aircraft (less than 1,350 pound seaplanes). No on has tried a BRS with a ram-air parachute because of the difficulty of steering the parachute. To steer a ram-air parachute that large, you need electric servo motors (winches) pulling the steering lines (tied to the rear corners of the parachute). Huge ram-air parachutes have been built for something like 30 years, but they are mainly used by drug smugglers (er ... secretive military customers). They normally incorporate GPS and proprietory software to steer them towards their targets.

Building a completely new harness is usually a factory job. Building a completely new harness is only quicker if you have all the factory patterns, factory tools, factory jigs, etc. If you ask a Master Rigger, he will probably re-use the diagonal back-straps, etc. to save labour, calculations, etc.

Yes Indeed. The combination of long climb to altitude, and the purr and vibration of the piston engines, was good enough to put anyone to sleep. These darned turbines we jump now climb so fast and smooth, that you don't even have time for a good cat nap! ................................................................................ Cat nap? Cat nap? You take your cat skydiving with you? What a kind and considerate human/food bowl filler ....

The white loop is supposed to be sewn to the riser with bar-tacks or plenty of zig-zag. That structural stitching is usually hidden under the confluence wrap. If the structural stitching is not inspected ... it might be missed ... see a couple of Service Bulletins issued by Rigging Innovations. To see the stitch pattern, look at a Service Bulletin on Sigma main risers.

Up-slope (anabatic) winds could help.

.................................................................................. I was not sleeping ... rather I was leading by example ... mentally reviewing the dive plan.

Ah! The good old days of radial engines, when a nap was mandatory on the way up.

Sounds like you are starting with a set of very old risers ... sewn before 3-Ring Inc. published their manual in 1998. The white loop should always have a bit of slack. The slack allows it to act like a pulley, halving the load on the yellow cable. This "halving" effect is an important part of 3-Ring geometry.

Like Sandy Reid says: "If you don't understand something, copy it exactly." IOW sew your magnets in the same way the Javelin factory sews them.

Yes. Lengthening a harness results in ugly old needle punctures. Meanwhile, if you shorten the harness, the old stitch holes are often hidden by leg pads. But - from the factory's perspective - it is simpler to build a new harness. Factories are only interested in "adjusted" harnesses that look almost new, while some Master Riggers are willing to sign off old harnesses that are faded at the same rate as the container.