Repeated Spirals / G's / Hypoxia?

[jfields 0]

I posted this in the Canopy Control Forum, but rethought it and stuck it here too because it may be more pertinent here. Sorry about the double-posting.

Justin
--------------------------------------------------

One of my recently-developed rituals is to do a clear & pull from altitude on my first jump of the day, if the pilot okays it. I'm first on the plane, last out. I get to practice canopy skills and it is a low-pressure, relaxing jump before I start funnelling the day's formations.

On my clear & pulls, I often do spirals, sometimes pretty hard. They are fun. Yesterday, I did lots of spirals. A bunch of them intermittently from about 14000 feet down to about 10000 feet. Then I did one continuous one, burning through about 3000 more feet, ending at 7000. When I finally let my toggle up from about waist level and straightened out, I had a mad head rush and thought, "Man, I feel like shit!" I was kind of woozy and thought, "I could puke to the ground about now." I didn't, but I might have felt better if I had. My chest was kind of tight and I just didn't feel good. I rested my head against my left riser for a bit, then did really mild manuevers until my landing, which was fine.

Other factors on this particular jump:
The temperature was about 90-92, and humid.
We had a go-around after a 3-way took too long in the door.
Then we had 2 more go-arounds after that for aircraft traffic.
I was last to exit the plane.

I was wondering if the prolonged time at altitude in the plane followed by my opening at 14000 had left me a little hypoxic.

Also, what kind of G's might I have pulled in my 3000-foot spiral? I know it is hard to guess, but I am curious. My canopy is a Sabre 190 loaded at about 1.15:1. I had one toggle all the way up, and the other buried below my waist the whole time. Any ideas on airspeed under canopy during the spiral?

After I landed from that jump, I hit the (non-alcoholic) fluids pretty hard and rested in the shade for awhile. I went up for another jump later and was fine.

Thoughts about which aspect(s) of the jump effected me so much? It was kind of spooky.

[SkydiveMonkey 0]

I think the rules are no more than 6 minutes above 12k, but doesn't hypoxia make you feel good rather than ill?

____________________
Say no to subliminal messages

[jfields 0]

Quote

I think the rules are no more than 6 minutes above 12k, but doesn't hypoxia make you feel good rather than ill?

Well, I definitely exceeded that, if unintentionally.

I thought hypoxia gave you a false sense of euphoria, but maybe it was everything in combination. I'm just not sure.

[rkcheung 0]

I would think that the G-forces from your spirals caused all the blood to be forced towards the lower part of your body resulting in less blood for your head which is why you felt woozy. Or, the continuous spirals could have disorientated your inner ear, which would also result in the woozy, pukey feeling. Kinda like those carnival scrambler rides.

[DISCLAIMER - I only have 10 jumps, so what the heck do I know?
Also, I am a long time lurker, first time poster!

-Ray

[Remster 30]

You spiralled for 7000 feet and you're surprised that you felt like shit? bhawaaahaaaaa

Remster

[jfields 0]

Quote

Also, I am a long time lurker, first time poster!

Ray,

Congrats, and BEER!

That makes sense. It may have just been a factor of degree over other spirals. Or the heat, or the time at altitude. I'm not sure, which is why I'm also looking for the advice of some of the more experienced folks. (At 82 jumps, I'm a newbie also.)

[jfields 0]

Quote

You spiralled for 7000 feet and you're surprised that you felt like shit?

Well, I never said I was smart....

I've cumulatively done that much in a jump before, but perhaps it was just the last one that might have been a touch too long in a single sustained spiral. I don't know.

Way to be unhelpful on the rest of the questions, Remster!

[SkymonkeyONE 4]

Well, you just experienced one of the reasons why fighter pilots wear g-suits. What you got was all the blood pooling in your extremeties due to the g-forces on your body during that long spiral. Could be worse, you could have passed out.

Question: were you hungover from the night before? That really exacerbates the problem. I have jumped hungover before and nearly passed out under canopy; it was NOT the hot ticket under a 75 square foot main or a tandem. Needless to say, I will not jump hungover anymore for any reason. I don't need the money and I will not endanger myself or any student or passenger for a measly $30.

Chuck

[jfields 0]

Chuck,

No hangover. No alcohol whatsoever that day or the prior one. Like you, I would never jump in that type of condition.

You think the g forces alone would do it? What sort of g's can a canopy in a spiral reach? I wasn't sure about that.

Well, at least I know what I did now.

Thanks for the info.

[BikerBabe 0]

The number of g's itself probably wasn't very high. maybe 2-2.5 at the max.

It was the amount of time that your body was subjected to the higher G-loading that affected you, coupled with probable mild hypoxia.

I've done about 60 centrifuge rides, and 5 minutes at 2 G's can be just as bad as 30 seconds at 9 G's.

On another note, euphoria is only one symptom of hypoxia. Actually, hypoxia symptoms vary from person to person, which is why people recommend doing an altitude chamber ride at least once in your life, so you can learn to recognize your own symptoms.

Never meddle in the affairs of dragons, for you are crunchy and taste good with ketchup!

[coconutmonkey 0]

Now ya know what to expect, who needs expesive drugs! High alt spirals and you can catch a great buzz...

Hearts & Minds
2 to the Heart-
1 to the Mind-
Home of the Coconut Lounge, Spa, & Artillery Range

[cobaltdan 0]

we have recorded over 5 g's in a spiral at very high wingoads. on your lightly loaded sabre i would guess around 2 g's.

black out from g force is basically caused by lack of oxygen. blood pressure increases from being forced to one side of the body and you run into issues with oxygen being able to perfuse into your body against the higher pressure. i believe lower oxygen pressue at altitude make this effect worse.

sincerely,

dan<><>

Daniel Preston <><>
atairaerodynamics.com (sport)
atairaerospace.com (military)

[jfields 0]

Dan & Andrea,

Thanks for the informative responses! At least now I have a better idea of how the various issues (G's and the extended time at altitude) combined to make a physiologically unpleasant experience.

Since it didn't get worse than woozy and uncomfortable, no harm done. I don't owe beer for a first self-induced blackout.

[kallend 2,034]

I doubt hypoxia.

I don't like the G forces when I spiral, and I find that pulling my legs up minimizes the discomfort.

I get noticeable disorientation when I do more than 3 spirals - inner ear type dizziness. This on a Stiletto, so maybe it turns faster than your canopy. If I want to spiral a long way I periodically reverse direction now.

I'm over 50, so you're probably in better shape than I am.

[skycat 0]

Hypoxia definately differs from person to person. I personally feel like pukeing on the person sitting next to me and instead of feeling good I feel very stressed out and uptight. Colors tend to be duller, and tunnel vision can occure. The cool thing is when you start sucking on O2 watching it get suddenly bright again and the tunnel opening up.
Kelli
(Thanking god I finally aclimated to CO)

Fly it like you stole it!

[tombuch 0]

Quote

I think the rules are no more than 6 minutes above 12k, but doesn't hypoxia make you feel good rather than ill?

The FAA rule is that pilots must use oxygen for that part of the flight in excess of 30 minutes that is above 12,500, upto and including 14,000 feet.

Pilots must use oxygen for the entire part of the flight above 14,000 feet.

Passengers must be provided with oxygen above 15,000 feet.

The FAA has also issued a recommendation that oxygen be used when flying at night above 8,000 feet. That one is just a recommendation based on the effect of hypoxia on eyesight at night.

Oxygen regulations are covered by part 91.211, probably available at faa.gov.

Hypoxia sometimes makes people feel good, but it can also cause headache, paranoia, and a bunch of other "bad" symptoms.

Tom Buchanan
Commercial Pilot (IAMSEL,G)

Tom Buchanan
Instructor Emeritus
Comm Pilot MSEL,G
Author: JUMP! Skydiving Made Fun and Easy

[pilotdave 0]

Yep, hypoxia usually comes in 2 different forms. Some people get really relaxed and feel euphoric, and other people get nervous or feel sick. Pilots are trained to realize that when they're flying along up high and everything just seems perfect and ya couldn't be happier, get down ASAP. An article in AOPA Pilot or Flying (cant remember which) last year or so was about a new portable blood oximeter (or however it's spelled). It's the thing they clip to your finger in a hospital to measure the oxygen in your blood. They found that the oxygen level dropped way below normal as low as 9000 feet for prolonged periods. A quick breath of pure oxygen raised the level back to normal for a few minutes, then it would start to drop off again.

I wonder if we only like skydiving cause the alititude is like a drug...
Dave

[petur 0]

Quote

I wonder if we only like skydiving cause the alititude is like a drug...

Interesting theory

Here's a short article (in human readable form) on causes, types, symptoms, stages and prevention of hypoxia: http://www.mountainflying.com/hypoxia.htm ... and another one on g-Forces (related to aerobatic gliders) here: http://www.fortunecity.com/olympia/afl/7/AEROBATICS/aerobatics_g-loads.html

---
P.
"It Hurts to Admit When You Make Mistakes -
But When They're Big Enough, the Pain Only Lasts a Second."

[SkydiveMonkey 0]

Must be BPA rules then?

____________________
Say no to subliminal messages

[GrumpySmurf 0]

Know how you feel.
Did a cross country Saturday eve, ended up over the DZ at about 5K - did a few hard spirals to kill off some altitude, felt fine till about a minute after landing, then the headache kicked in and man, I don't think I felt that stomach sick in a long time (sort of a bad hungover feeling, only no beer involved) - had to go lie down, it didn't pass till I woke up the next morning.