P A R A C H U T I N G ' S N E W S M A G A Z I N E
Ask the Editor
Contents of Batch 26:
Which grippers are right for me?
How tight should my closing pin
be secured?
What's the best way to slow
down my Sabre's openings?
W.W.II Japanese Kamikaze
Skydivers...
Young jumpers trying new
canopy maneuvers.
Is it legal for a jump
plane to shuttle jumpers for money?
Where can I find a lawyer
to sue a DZ?
Is it safe to skydive after
having a stress-related heart attack?
The following questions were submitted by visitors to our
Web site and answered by the editor of Skydiving
magazine. .
To ask a question of your own, click here.
Which grippers are right for me?
Q. I recently graduated from AFF and am about to order a jumpsuit. What diameter of grips is most common?
A. Sequential competitors like big fat grippers on both the inside and outside of the leg as well as longer arm grippers that sometimes extend well up to the shoulders. They put them to good use, as modern sequential is a physical sport with a lot of vigorous tugging and pushing.
Fun jumpers usually select fewer and shorter grippers, often of a smaller diameter.
Larger and longer grippers can affect fall rate because they can significantly increase your surface area. That's something to remember if you have a small frame (i.e., if you're skinny).
The best compromise is fatter grippers of conservative lengths. The manufacturer of your jumpsuit can tell you which gripper styles are most popular.
If you don't get grippers on the inside of your knees, be prepared to hear occasional whining from your fellow jumpers. But don't worry; they'll get over it.
How tight should my closing pin be secured?
Q. I have a Mirage G3 container. When I pack it, how much pull force should be required to extract the pin? Whenever I close other people's kit I've noticed a wide variation in both the amount of effort to get the pin in the loop and consequently the force required to pull the pin out. I'm thinking that my loop may be too long and I'm concerned this may lead to a horseshoe.
A. T.K. Donle of the Relative Workshop - it makes the Vector rig - had a quick and useful answer:
"If you can close the rig by hand," he said, " the pilot chute can open it."
Donle said a modern pilot chute exerts about 80 pounds of force at terminal, and that's enough force to open even the most tightly closed main container.
He said measurements show a Vector that's been packed "hard as a brick" - very tight - requires less than 15 pounds of pull on the bridle to untuck the bridle, open the flap and remove the pin. An average rig, he says, takes about 10 pounds. A rig that was loose but not too loose needed 8 pounds.
To just remove the pin (flap open and bridle clear) from properly packed rigs requires a force of about 2.5 to 5.0 pounds. The tight "brick" requires 7.5 pounds.
Sandy Reid of Rigging Innovations - maker of the Voodoo and Talon rigs - turned in similar numbers: 10 to 15 pounds with the flaps closed and bridle tucked away.
"Anything below 10 pounds does not feel secure," Reid said.
If you think your loop is too loose, then it probably is. Since you can't make it too tight and still close the rig by hand, shorten the loop so the pin is snug. Closing that last flap should take a little effort.
What's the best way to slow down my Sabre's openings?
Q. My [Performance Designs] Sabre sometimes opens very hard. I've heard putting a larger slider on it will help. Will it?
A. We put your question to Rusty Vest, customer service manager at Performance Designs:
There are a number of factors that can cause a faster-than-desired opening. Some of them are known. Some of them are not known. Sometimes it is a combination of factors. The effects of most of these combinations are unknown.
The first factor is that parachutes are made out of fabric. Fabric is not sheet metal and does not have a zero tolerance.
The second factor is that each parachute is handmade. The people that build the parachutes are highly trained, but the fact is that no two people have exactly the same technique. The machines they use are not always going to stay tuned, tensioned, or timed exactly the same.
A parachute manufacturer designs a canopy that has tolerances built into every seam and stitch. There are unknowns that take place within the tolerances of the fabric, machines, and production that no one can predict or test for. Unlike an electronic product that can be plugged in to see if it works, all a parachute manufacturer can do is inspect to see if a canopy has been produced within the tolerances.
So will a larger slider eliminate hard openings? Maybe. Once in a while. Sometimes.
If this were the answer to hard openings there would be none. This is not model-specific either. It is canopy-specific.
My best advice is that if all the suggested information described in our "Solving Deployment Problems" handout, or "How to Prevent Hard Openings" at www.performancedesigns.com has been followed to a tee and a customer is still having problems, the canopy should be sent back to us for evaluation. Both of these articles are the same, just in a different format.
A larger slider can be tried, but our experience has shown that it is only a sometime fix. We are always happy to try this route if it best suits the customer's need and time schedule, and as long as he understands that it might not cure the problem.
W.W.II Japanese Kamikaze Skydivers...
Q. Someone keeps trying to convince me that the Japanese had plans during World War 2 to strap a bomb to a man, have him jump out of an airplane and then freefall into an American ship moving at 20 to 25 knots. The plane would have to be at an altitude high enough to avoid the guns on the ship. I told him that the feat would be impossible. Could you help me with this?
A. We don't know if the Japanese actually considered this idea. Regardless, we doubt it would have worked.
A skydiver would have a tough time "steering" even a small 100-pound bomb that was attached to him or her. (And a 100-pound bomb wouldn't inflict much damage on a warship.) We know from making tandem and bundle jumps that control is significantly more difficult as mass and freefall speeds increase.
Hitting a moving ship would be essentially impossible, unless the pilot released the planeless Kamikaze at the exact correct point. But if the pilot could do that, why not do it with a conventional bomb, instead of a meat bomb?
Finally, controlled freefall wasn't developed until after Word War 2, when French parachutists discovered body positions and techniques that enabled them to freefall without tumbling and spinning.
The first "baton pass" - where one freefalling jumper passed a short stick to another in freefall - didn't take place until 1958. We doubt very much that anyone in Japan in the 1940s knew how to maneuver in freefall, let alone steer a bomb from above 20,000 feet. (We'd love to watch the practice sessions, however - from a bunker.)
Young jumpers trying new canopy maneuvers.
Q. I have five static-line jumps and one more practice ripcord pull before my first freefall. I would like to know more about canopy control. What would happen if I did a spiral turn to the left and released my left toggle and pulled sharply on my right-hand toggle? Would it scare me?
A. Your canopy would make a quick "wingover"-type turn to the right. It's a hook turn. Some jumpers call the maneuver a "control reversal." It's no big deal when done at altitude. Try it.
Would it scare you? Probably, but that's part of the fun.
Some tips:
Do such experimenting up high, above 2,000 feet. If you do it radically enough, and depending on what canopy you're jumping, you might collapse the canopy to some extent. It probably won't, but there are a lot of variables involved.
If the canopy does collapse, either a little or a lot, it will probably inflate if you simply put the toggles all the way up. If it doesn't, you can help things by pumping your toggles slowly and deeply.
But a canopy can lose a lot of altitude during a turn like this.
Another hint: Build up to radical canopy maneuvers. In this case, start with a gentle left-hand turn and a moderate control reversal. Make the next one a little more vigorous and so forth.
And another: Be sure you're well separated from any other jumpers who might be in the air with you. Radical, unexpected maneuvering can sometimes lead to canopy collisions (or fat lips).
It's considered bad manners to fly one's canopy unpredictably in a crowd; it's like changing lanes suddenly on the freeway.
You should explore your canopy's flight envelope and learn what it will do and how it behaves in all flight modes. It will make you a better skydiver, just like learning how to control your car in a skid will make you a better driver.
Just use your noodle. Do the new stuff up high, in clear air. Be ready to deal with collapsed cells and line twists.
Is it legal for a jump plane to shuttle jumpers for money?
Q. My DZ has a Twin Otter. On some weekends it visits other DZs, some more than 100 miles away. Usually a few jumpers go along. Each pays about $50 for the ride, which sometimes includes a jump at each end. Someone said these flights aren't legal. Are they?
A. It's hard to say without knowing the particulars.
Most jump aircraft operate according to Part 91 of the Federal Aviation Regulations. These are the least-restrictive regulations, but they generally prohibit for-hire flights that take off at one airport and land at another, regardless of the distances involved.
To legally transport people from one point to another for money, an aircraft operator must operate according to FAR Part 135, the rules that govern commercial and air-taxi operations. (Part 91 allows a pilot to share out-of-pocket expenses with his passengers, but if he invites passengers along for a fee, an FAA inspector would probably contend he's functioning as a commercial operator.)
Compared to Part 91, Part 135 imposes higher maintenance, equipment and operational requirements. (Airlines operate under Part 121, which is stricter still.)
A few jump aircraft operate under a Part 135 certificate, so they might be able to transport passengers for money. But most don't, so they can't legally charge for even short cross-country flights.
Besides, most jump aircraft have limited navigation, communication and back-up equipment. They aren't really suitable for cross-country flights, especially at night or in poor weather.
Where can I find a lawyer to sue a DZ?
Q. Can you give me the name of an attorney who knows how to sue parachute centers? My son was injured recently because the radio they gave him didn't work.
A. We're sorry to hear about your son and hope he heals quickly.
We don't know any attorneys who in recent years have successfully prosecuted a skydiving-injury lawsuit. They are frequently filed, but it seems many are withdrawn or dismissed early in the process.
One reason for the dismissals is that more and more jurisdictions are upholding the validity of the hold-harmless agreements that are signed these days by participants in high-risk sports.
Most skydiving centers use these "waivers" as part of their risk-management programs. They are particularly important because it's nearly impossible for a skydiving center to buy liability insurance.
If such agreements could be grossly paraphrased, they'd basically say, "I know skydiving is risky, and I could be hurt or killed by doing it. But I want to do it anyway. So I'm freely giving up my right to seek legal redress if I'm hurt, even if the parachute center was at fault."
In many instances, the courts have ruled the agreements are legally binding contracts in which the participant promises not to sue, even if the sports company was clearly at fault.
If your son signed such an agreement - and he probably did - you should obtain a copy of the document and have it reviewed by your attorney. Your son most likely waived some of his legal options.
A better course of action might be to discuss your son's injuries with the owner of the parachute center. If the DZ played a role in your son's accident, it might be willing to help pay his medical expenses - without going to court.
Is it safe to skydive after having a stress-related heart attack?
Q. I'm a Peruvian skydiver who recently had a heart attack. This is strange because I'm 25 years old and I take care of myself - good diet, plenty of exercise, no smoking. My doctors think stress may have caused it. Because skydiving is not a common sport here, my doctors can't give me an opinion on my continuing to skydive. Do you know a doctor that can help?
A. Patrick Weldon, a medical doctor and experienced skydiver, answered this question:
The most important issue is why did you have a heart attack. You said you're healthy, but even fat, out-of-shape people don't have heart attacks at age 25. You need to find a cardiologist, get some blood tests and get more information about your health.
You will never recover completely from your heart attack; the part of your heart that was "attacked" is forever dead. Preventing a second attack is your only hope.
As much as I hate to say it, you should probably avoid skydiving - or any strenuous activity - until you get some answers.
SKYDIVING welcomes questions from its readers. All will get a prompt answer, and some will be published. Mail, fax or email them to sue@skydivingmagazine.com.
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