riggerrob

***I know a small bit about them. Not necessarily specs and engineering but from a user level. I do believe the "adapted" comment was a dig at the Special Operations Vector and Military Javelin which are the most popular "non standard" military freefall rigs in the US military and are beefed up versions of their sport container and/or tandem adaptations. Units that actually have a robust jump mission fell out of favor with the MC4/MC5 in the early 2000s as parachute technology progressed rapidly, and DoD bureaucracy was slow to match that pace. SOVs and MJs were used to fill that gap usually purchased at command or unit level as opposed to service or DoD level. ..." ................................................................................... How many different levels of procurement are there within the U.S. military? I understand that the US Marine Corps have their own procurement process, but how many different levels are there within the US Army? ... or is it a difference between different levels of "robustness" ... er ... specialization: airborne, pathfinders, rangers, Green Berets, Delta, Joint Special Forces and "the guys who are not mentioned in polite conversation?" ... or is it a question of how many dozen ... hundred items are purchased?

Most DZs just strip old student harnesses. Any decent rigger can do that in one day. Otherwise, you could ask any container manufacturer - or Master Rigger - to sew you up some new harnesses. The opening bid would be $400 per harness, before you start counting: sliders, toggles, risers, cutaway handles, ripcord handles, etc.

Experienced jumpers doing stunts with tandems represent less than one percent of tandem jumps. Odds are .... this silly stunt included a clue-less (er un-informed) first-timer.

................................................................................... Butler Parachute Systems built that back-type PEP - for the balloon flight. Butler also built a pair of custom, chest-type PEPs for Rutan's successful round-the-world flight in the Voyager. Butler even got a patent for the chest-type PEP that hung a life-raft under the parachute. He then sold a bunch of similar rigs to the United States Coast Guard.

.................................................................................. That Cessna pilot (in Wisconsin) was wearing a Strong LoPo. He landed (un-injured) in some trees - inside the airport perimeter. Apparently he had already made two tandem jumps. Why they showed him how to flare a modern, square canopy, then hung him under an old-school round canopy is a mystery to me???????

................................................................................... Then there is all the psychological damage to the victim, when they have to re-tell the worst day of their lives umpteen times in front of doctors, shrinks, lawyers, judges, juries, reporters, etc. Often the psychological trauma - of the legal process - is worse than the psychological trauma of the accident.

Is this the one? Sparky ................................................................................... Yes Sparky. Bu tI'll bet that it has twice the parts-count of a Telesis #! Hee! Hee!

The long term goal is to avoid breaking students. The heaviest student - that I ever jumped with - weighed 270 pounds. He was my height ( 6 feet tall), but out-weighed me by more than 70 pounds. He was a retired rugby player, in his thirties. Sure, he had a beer gut, but he also had thighs the size of tree trunks! I did not worry about breaking his leg bones. He understood the additional risk, listened carefully and helped me steer the parachute. After a slide landing, we shook hands and walked off the drop zone. That is always my goal: to walk off the drop-zone beside my student. Sure there are bunch of legal arguments - with lots of numbers and fancy acronyms - but the end goal is always the same - walking off the DZ.

"***... It's considered a "good all around" canopy, which means it does a lot of stuff, without doing any thing in particular very well. ..." .................................................................................... Shhhhhh! Don't tell the canopy formation (CRew) competitors ..... because some of them have won waaaaay more than their share of gold medals while hanging under Triathlons. Shhhhhh!

The Intruder-2 harness/container was designed by Sandy Reid, so it sort of looks like a Telesis 3 student rig with extra hardware to hang ruck-sacks, etc.

Your greatest challenge is finding a school that has big enough tandem parachutes for your weight. Sure many tandem systems are certified for 500 or 600 pounds total suspended weight, but they are only comfortable with 400 pounds of human flesh. That 400 pounds includes your weight, plus the instructor. Military tandems routinely jump with 500 pound bundles, But few civilian parachute schools stock parachutes that large. Another challenge is finding a tandem instructor muscular enough to steer the parachute with all that weight hanging underneath it. Start by talking to skydiving schools that operate larger airplanes, like Twin Otters and Sky Vans. Then re-assure them about your fitness and ask if they have an AFF student rig for BIG students. That answer will give you a hint about whether they are serious about adapting to different-sized students.

Rumour had it that Perris was bidding on some military contracts that included training HALO jumpers.

That seat-belt buckle was probably manufactured under Federal Aviation Administration Technical Standard Order C22 or Canadian MOtor Vehicle Safety Standards, which equal the same quality as TSO C23 (parachutes). Sure, we could get in to a long a rowdy brawl about whether aviation standards are better than automotive standards, but when you consider how few automobile seat-belts are reacalled, and how few people die because of faulty seat-belts, the difference is insignificant. The next challenge is to determine if the seat0-belt buckle is COMPATIBLE with parachute harnesses ... first of all, most seat-belt webbing is 2 inches wide.

The newspaper "le Pioneer) (sp?) recounts the first parachute jump in Quebec, Canada. In September of 1888, Mr. Larsen jumped into the Sherbrooke County Exhibition. Mr. Larsen jumped from a hot-air balloon. He was born in Canada, but lived int eh 'states for many years, then he worked the county fair circuit as a balloonist and show jumper.

I have seen this problem with students many times. It caused by adrenaline rapidly burning through reserves of blood sugar. After students have burned through all their reserves of blood sugar, they faint. Back in the static-line days, we didn't understand it, just knew that one student per thousand was unresponsive under canopy and we had to pick them out of the trees. We only started to understand the problem after doing tandems for a decade or two. The problem is a complex interaction between adrenaline and blood sugar. Adrenaline rapidly burns through blood sugar, then they crash. After all the excitement of a static-line jump, they relaxed under canopy and relaxed so far that they fainted. We only started to understand this problem after we noticed tandem students passing out under canopy. Hypoxia, insomnia, poor nutrition and dehydration all exacerbate the problem.

Velcro works great, primarily because it tolerates large variations in manufacturing. The disadvantage with Velcro is that it wears out after a few hundred jumps. Magnets enjoy - almost as - sloppy manufacturing tolerances, with much longer service life. We have not yet heard of magnets wearing out ... er we are too early in the life-cycle of magnets to understand their limitations/wear patterns/malfunction modes, etc..

Harness/container improvements occur in lurches ... er ... generations. After each new generation is introduced, manufacturers frantically clone/copy/plagarise each other until they perfect that generation, then rest on their laurels for a decade before the next improvement is invented ... then the cycle repeats. Each generation is invented in response to a new competition discipline. For example, reserves on the back were invented by precision landing competitors back during the 1960s. As target discs shrank to a mere ten centimeters, PL competitors needed a better view for heal placement,, so some started swinging their chest-mounted reserves to one side for landing. Back during the 1960s, everyone wore chest-mounted reserves. The next thing we knew, some of them were tossing their (no longer needed) reserves behind their heads, on extra-long risers. The ultimate response came when Security introduced their Crossbow harness/container with both containers on the back. Speed stars were the next competition discipline to drive innovation. With chest-mounted reserves forcing the tenth man as much as ten feet more from the door, there was new incentive to reduce container thickness. When all ten team members switched to piggyback containers, the tenth man could start eight or nine feet closer to the door and reduce completion time by several seconds. Speed Stars also affected the thickness of containers, because the easiest way to pack the same canopies into a thinner container was to make it wider. Wider containers made no difference with the wider suits that became fashionable during the wing-wars of the late 1970s and early 1980s. However, those extra-wide suits created massive burbles that encouraged spring-loaded pilot-chutes to hesitate for an embarrassing extra few seconds. With fashionable pull altitudes near 2,000 feet, this scared skydivers into inventing hand-deploy pilot-chutes that could be deployed BESIDE the massive burble, lopping two or three precious seconds off main deployment times. Sequential relative work (early 1980s) favoured narrower and narrower containers, containers so narrow that they no longer protruded beyond the skin-tight jumpsuits. When canopy formations became fashionable - also during the early 1980s _ skydivers invented several new ways to accidentally open reserve containers. To reduce the incidence of un-planned reserve deployments. tuck-in reserve pin covers were invented. As tandem started to dominate the (first jump) market during the early 1990s, it also drove several container innovations. The first innovation was bottom of container pilot chute pouches. Sure BOCs were standard on tandem containers, and many TIs switched to BOCs on their solo rigs just to reduce transition hassles. Meanwhile, smaller cameras and larger airplanes allowed vidiots to make a living off of tandem students. Many vidiots switched to BOCs because it was easier than routing bridles over and around and under the ever-larger wings they needed to adjust fall rates. Those larger, faster airplanes also allowed skydivers to make hundreds more jumps per year, which wore out Velcro at far faster rates, so manufacturers switched to tuck-tabs, first for main pin covers, then main riser covers and eventually to almost every corner of containers. Sit-flying drove the last nail into the coffin of Velcro. With sit-flyers now exposing their bridles to wind from every angle, they invented bridle covers to better protect their bridles from weird winds. Sit-flying also forced container manufacturers to standardize on BOC pouches, BOB offered the shortest bridle routing from pouch to pin. The least exposed bridle further reduced the risk of pre-mature deployments. Wing-suiting forced a second look at the problem of deploying main pilot-chutes past gigantic burbles. Some wing-suit manufacturers sewed extra pilot-chute pouches onto their suits Wing-suiting also introduced a new ANGLE for deployment: straight towards the jumper's heels. The solution was to invent lower corners - on main containers - that open completely flat. So over the years, we se a succession of new competition disciplines driving innovation. Every innovation reduces a risk in that new discipline and the best ideas cross-pollinate to reduce risk for all casual recreational skydivers.

The website shows the largest one they make is a 253. ................................................................................ First, John LeBlanc loaned me a large Optimum prototype. Secondly, it was larger than PD was selling at the time, so it was a 250 or 280 square foot reserve. Thirdly, that was during the 2009 PIA Symposium, (5 years ago) so may I claim a "senior moment" for my poor memory.

By the end of the summer of 1979, I was tired of carrying students on stretchers off the DZ every weekend. These days we have hardly any solo students and it is experienced jumpers we are calling ambulances for, after they screwed "perfectly good" chutes into the ground.

Hah! I bought a Strato-Star when I had only 50 jumps on rounds.

Optimum reserves weigh about he same as older reserves made by Performance Designs. The only significant difference is the Optimum's smaller pack volume. For example, I once packed an Optimum 28? into a Softie designed for a 210 reserve. The Optimum just "fell" into that container. To the critics, I have packed hundreds of Softies and thousands of sport reserves .....

I prefer the term "African Engineering." Hah! Hah! Seriously, sewing an extra slider stop - onto the outboard A line - is a temporary solution. The long-term solution is to replace the entire line kit when the difference across the A lines exceeds the factory spec (3 inches). My old boss used to grumble about all the time and money I wasted re-lining SET-400s when the (Spectra) lines still looked structurally sound. My fascist rigging standards kept the malfunction rate down to 1/1500. After I quit, my old boss allowed lines to remain in service despite being 5 inches out of trim, then he wondered why certain rigs went un-jumped all summer?????

***... I seem to recall that the Strong Set 400's did not have cross ports. Maybe some one can confirm that? ... It might have been an attempt to control the openings by slowing the inflation of the canopies by reducing the filling through the cross ports. I don't know that's just a guess. ... For example the I've seen the SET roll tips under and it's not really prone to popping out on it's own with out help. ... .................................................................................... Correct! Strong builds their SET 400 and SET 366 tandem mains without cross ports. SETs open fine without cross-ports. They open slowly, sequentially (center cell first and end cells later) and comfortably without cross-ports. Most of the problems with tips folding-under only occur after suspension lines are allowed to shrink beyond factory trim. Those Spectra (polyethelene) suspension lines shrink out of trim in as few as 400 jumps. When the outboard A lines have shrink 3 inches more than the center A lines, the end cells take forever to inflate ... often only opening after the TI has pulled the steering toggles to hip level for 8 seconds. In the worst case scenario - when outboard A lines are allowed to shrink 5 inches more than center A lines - a fist-full of end cell fabric gets trapped in a front slider grommet. The slider tries to drag the end cell down the suspension lines. Sometimes, the slide releases the end cell when it is halfway down the lines, but sometimes the TI has to pump the brakes to release the slider. In a worst-case deployment the slider refuses to release the slider ... Bottom line, you can your rigger now (to replace tired lines) or you can pay him/her later (to repack the reserve with a new free-bag, handles, etc, then reline the canopy with a new drogue, risers, etc.) ....

Follow the logical sequence of concept design. Start by defining the speeds of deployment (fastest airspeed and slowest airspeed). Then define how heavy your load will be (zero-fuel weight and gross weight). Then define how high you need to deploy (maximum cruise altitude and whether you can afford a zero-zero system). Then define how many stages you will need (drogue?). Then define maximum landing speed (save crew? save cargo? save entire airframe?) Then size parachute canopies based on desired landing speed. Will it be cheaper to use medium-sized canopies, but depend upon braking rockets or air bags for the last stage of deceleration? Then start detail design ... Where should you attach your parachutes to the airframe? Where can you stow parachutes inside the airframe? How strong (tensile strength) does the fabric need to be? How strong do the suspension lines need to be? How strong do the risers need to be? Then you start to define which type of material you need for each component. For example nylon may be the best for canopy fabric, but you might need Kevlar or steel risers to resist cutting by hot jet exhaust. Once you have a rough out line of sizes and materials, review parachute volume and compare it with the volume available to stow it inside the airframe. Then do a rough analysis of the system weight. You will find yourself looping back through many of these variables repeatedly. In the end, your professor will probably not care whether your system is commercially viable, as long as you can prove a logical design sequence and accurate estimates of speed, weight, opening shock, volume, etc.

..................................................................................... Anti-inversion netting works great during military, static-line deployment, but is less-effective during straight-line, free-fall deployments. The big problem with static-line deployment (from a C-130 airplane) is the relative wind hitting the skirt CROSS WIND as it deploys. The canopy still tries to partially invert, but the net prevents it from inflating on the other side of the skirt. Another way to reduce the incidence of inversions is to spread the skirt earlier in the deployment process. You can spread the skirt with a spreader gun (widely used on zero-zero ejection seats), by inverting the apex or hanging an extra pilot chute in the middle of the skirt. Inverting the apex and an extra pilot chute serve the same function by increasing spreading force at the skirt much earlier in the deployment sequence. An extra pilot chute was first used on Irvin Canada's AIM canopy back during the 1980s, but the quicker inflation forced them to add the world's largest cat-eye apex, etc. to reduce opening shock. By the end of the 1990s Manley Butler sewed the extra pilot-chute onto a slider to make his patented "Sombrero Slider." See videos of test-drops on Butler's HX series of round canopies installed in pilot emergency parachutes.