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 20:
Looking for a full-face
helmet for a larger than average size head
What is a hook turn?
Safely skydiving with missing
fingers
Skydiving with Epilepsy -
is it safe?
A cure for chapped lips?
Does exposure to jet fuel cause
Parkinson's disease?
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.
Looking for a full-face helmet for a larger than average size head
Q: I have been unable to find any helmets that fit my head. My head is larger than average, but not abnormally large: circumference 62 centimeters. I know several jumpers who are unable to find full-face helmets large enough for them. What can we do? Will any manufacturers make custom helmets? Will any manufacturers consider making larger shells for people like me?
A: We put these questions to several helmet manufacturers.
Nick Kaminski from Sky Systems in Denver, Colo., said, his company used the results of several military studies to create its range of standard sizes. These studies found that there are not many heads larger than 60 cm., so the XL version of the company's popular Oxygn helmet is sized for 60 cm.
Kaminski had several suggestions, however. One would be to try the company's Nvertigo Freefly helmet. The Nvertigo is not a full-face, but does offer more protection than a soft helmet (or nothing at all).Because of its open-face, fit is less critical, allowing the helmet to accommodate more sizes than the Oxgyn.
Another option is to try Sky Systems standard Factory Diver.This helmet does not offer as many bells and whistles as the Oxygn, but it's made with a larger shell and is available in an XXL.Kaminski believes that the Factory Diver is the largest on the market.
(Most types of skydiving helmets have a shell of a single size. Changing the thickness of the liner creates the various sizes.)
Sky System's last option is to have the company make a custom helmet, but the required time and money - about $1,000 - is substantial.
Jim Hotze of Arrow Dynamics in Eloy, Ariz., makes the Renegade and Apache full-face helmets. He took a simpler approach to create their range of sizes, but the results are the same: Hotze knows that he has a large head, so he just built his mold from his own head and downsized from there. The XL size of the Renegade and Apache will fit a 60-61 cm head.
Hotze says that on occasion, to accommodate customers with larger heads, Arrow Dynamics has modified these helmets by reducing the liner thickness by about 50%.
Arrow Dynamics will also build a custom shell, but again the time and cost ($1,200) is high.
Paolo Giazzi of Parasport Italia in Cavour, Italy, says because the method Parasport uses to create a mold is very expensive, it decided to accommodate the average sizes only.
Parasport's Z1 full-face helmet will fit 52.5 cm to 60 cm heads. As with the other helmets, the size of the Z1 can be adjusted by changing out the liner - but the shell will not allow a larger than 60 cm head.
Giazzi says that because the liner is made up of two pieces, a side and bottom part, Z1 helmets can be made to fit unusually shaped heads by mixing and matching liner pieces.
Parasport does not make custom helmets.
Q: What is a hook turn? What makes it a dangerous maneuver? I'm not a skydiver.
A: A hook turn is a quick canopy turn performed near the ground.
Turning a parachute makes it bank and banking increases its rate of descent. The harder the turn, the greater the bank and the greater the descent rate. The jumper swings out from under the parachute because the parachute is turning and diving while the jumper tends to go in a straight line. The result is a pendulum action: The jumper first swings outside the turning canopy, but gravity pulls him back under it when he stops the canopy's turn.
If the parachute is relatively small (experienced jumpers tend to use smaller canopies because they're more fun, like sports cars), the descent rate and increase in speed can easily be great enough to kill or seriously injure the jumper if he or she hits the ground while still in the turn, or if he's not yet under the canopy.
Some jumpers like to perform hook turns because they're fun, like driving a car at the edge. But if they misjudge their altitude, or if they hit some unexpected rough air or if they clip a tree, they can - and do - get hurt. The ground is very hard, and many orthopedic surgeons are putting their kids through college on the money they've made off of botched hook turns.
But other skydivers perform hook turns somewhat inadvertently. For a variety of reasons (to avoid an obstacle, for instance), they'll initiate a sharp turn near to the ground, where there's not enough altitude for a recovery.
Many jumpers have never received training on how to make the best of a bad landing situation. For instance, it's almost always better to land under control downwind (or crosswind) than to attempt a last-second turn into the wind.
It's also much better to land under control on pavement than out of control on grass.
Hook-turn injuries are almost always preventable, and there's nothing mysterious about them. Many jumpers do them routinely and safely. The moral: Don't maneuver your canopy radically when you're close to the ground unless you know what you're doing.
Safely skydiving with missing fingers
Q: I just made my first AFF jump and loved it! I intend to continue in the sport, but I have a concern: My left hand was hurt in an industrial accident 20 years ago. Four fingers were lost, and the resulting surgeries left it in the form of a mitt or "paw." Is there anything to be aware of in safety or procedure?
A: Some jumpers with missing or less-than-fully-functional limbs have their gear modified to make it work better for them. Handles can be repositioned or reconfigured, for instance. Others opt for a "single-operation" handle. (Rather than having separate main and reserve handles, the rig is configured with a single handle that first jettisons the main risers before pulling the reserve). If your left hand can't grip a steering toggle very well, the toggle can probably be modified to work with what you've got.
If you think modifying stock gear is the way to go, then contact the component's manufacturer first. Chances are it has already made similar modifications before, and it likely has some clever solutions.
If the manufacturer is unwilling or unable to modify its product, then consult with a master rigger.
Since you've made one jump, you're already familiar with what it takes to use today's parachute gear.
Jumpers come in all shapes and sizes. Most are complete specimens, but a few are not. Others are overweight, near-sighted, or one card short of a full deck. Skydiving is a sport where you run with what you brung, so to speak. Go for it.
The following questions are answered by skydiver and physician Patrick Weldon:
Skydiving with Epilepsy - is it safe?
Q: My boyfriend has taken me for four tandem jumps and wants me to take the AFF course at his drop zone. The tandem jumps were great, and I would jump alone in a heartbeat, except that I have epilepsy. Are you aware of any skydivers with seizures? Can skydiving be bad for a person with epilepsy?
A: First, let me thank you for your honesty. Seizure disorders, as you probably know, bring out lots of misunderstanding and plain old fashioned fear in people unfamiliar with the disorder.
You have, however, stumbled upon one of the toughest questions in neurology (my specialty, by the way): When to let an epileptic patient drive, swim, or even skydive.
Legally, when a patient has a seizure, he or she is not allowed to drive a car for six months. And though sports like swimming and skydiving are not regulated, it's probably a good idea to use the same caution.
Some questions I would ask: How well controlled are your seizures? Do you have any aura, or warnings that you are about to have a seizure? And most importantly, do you really understand the risks you would be adding to an activity with its own inherent risks?
Enjoying the occasional tandem may be your only way to experience our great sport, but it is infinitely better than seizing in the plane, in freefall, or under canopy. And never, ever, let anyone (even a well-intending boyfriend) pressure you into anything, especially skydiving.
Q: Winter is coming, which means the end of my skydiving weekends until warmer weather. Last year my lips would stay so chapped that they cracked and bled for days after every jump. Any suggestions?
A: Suggestion number one: Move south. Okay, I live in Louisiana, so I am probably biased, but chapped lips are a common complaint for many jumpers this time of year.
Full-faced helmets certainly offer some protection, and keeping any good chapstick in your jumpsuit is a good idea. On the way to altitude, coat your lips with a generous amount of it, which should limit the amount of windburn on your lips. If this isn't enough, try a sports sunblock that contains zinc (the bright colored ones, like the beach volleyball players wore during the Olympics).
But no matter how much you cover your lips, the actual moisture in them must come from inside you. In other words you must be fully hydrated and drinking plenty of water. Not cokes or beer, but water. Try adding three to four large glasses of water to your daily diet and see if these chapped lips don't get better rapidly.
You may also want to visit the family doctor and have him take a look at your lips. There are several viruses that can aggravate chapped lips, especially the herpes virus, which is related to, but different from the herpes you get below the belt. Modern anti-viral medications can help if your chapped lips are actually virus-induced cold sores.
Does exposure to jet fuel cause Parkinson's disease?
Q: I recently saw a special on the news about jet fuel exposure causing Parkinson's disease. Is this true? As I write this letter I am drinking coffee from my "I love the smell of jet fuel in the morning!" coffee mug.
A: Unfortunately, most television reports of anything that causes cancer, death, or disease are usually grossly exaggerated. In this case, for instance, the actual report was based on a group of men who cleaned large jet fuel canisters for a living. They would spend as much as 40 hours a week breathing jet fuel fumes, and about 10% later developed Parkinson's disease. (The expected prevalence would be around 2 or 3%).
So, while there may be some truth that prolonged, life-long, exposure to breathing jet exhaust may be harmful, we skydivers shouldn't worry at all.
PARACHUTING'S
NEWSMAGAZINE
1725
N. Lexington Ave.
DeLand, FL USA 32724.
Telephone:
(904) 736-4793, 9 am to 5 pm Eastern time.
Fax number: (904) 736-9786.
Click here to return to Skydiving's home page.