Basejumper.com - archive

In light of a recent experience:

I'm wondering if anyone,
who has much experience with cold weather jumps (I'm thinking around -18 Celsius = -1 Fahrenheit ),

has noticed more frequent PC hesitations (when stowed) or just occasionally some really scary ones?

this specific jump was 430ft using a 44" PC stowed and about a 1.5 sec delay

but I'm thinking mostly about slider off/down jumps

I have few jumps (not that many that one could draw any conclusions out of them) under those conditions but haven't noticed any hesitations on those ones. Still I'm very interested on this topic, do you have any idea or speculation about the possible reason for more frequent hesitations when jumping in low temperatures ?

I have couple of those cold jumps too and no hesitation or any other problems. Only cold and windy :)

I´m quite interested in this also, if anyone has some ideas which may occur any problem please info us?

FastPete

F111 or ZP?

Could the PC have been, or got, damp when it was packed? Packed in a warm environment then taken outside to the cold with moisture like melted snow or sweat on it?
I've heard of hard pulls due to frozen PC's in skydiving before and that's been at the back of my mind when winter BASE jumping. I'd guess that this would be more of an issue with F111 than ZP.

Mike

Yo Mike, How are you man ? Nice Avatar Pic you have....

i usaly dont jump as its so could,but did you think of that 1,5sec delays whith a 42(i dont know a 44´) should be ok,however i wouldnt stow a bigger pc than a 42´but thats just me..

430ft is loads of altitude for a 42´ no need to go bigger than that..

I saw a MIG-21 jet fighter ejection seat rig recently. To remedy the issue of the fabric sticking together in the huge variety of environments, they put talcon powder between the folds of the canopy. However, this seems too impractical for base jumping.

well it would look cool as the pc or canopy crak open

Hey Sam,
I have lots of jumps in these temperatures, some of them naked, but that's another story. I have never noticed any hesitations that could be attributed to the temperature. Actually they should work better. The same as your canopy will fly better in colder temps., as opposed to hot summer days.
Having 1100 BASE jumps, 90% of those in Canada. That works out to around 400 jumps in the winter. I've jumped in the -40 range with NO noticeable hesitations.

I've made a bunch of jumps below freezing. Not ever below zero Farenheit but definitely below 20 degrees. Airspeed is good. Take all the delay you can and I think that will help shave down the probability of having a hesi. I also try to pack my PC as close to the time of exit as possible.

For one jump in Moab, I left my entire rig halfway up the wall for two nights while we fixed ropes up a route. I opened the packjob at the exit point to make sure there weren't parts of the packjob frozen together. I definitely lofted my PC several times to see it inflate.

Other than that, my primary concern with cold jumps is being careful not to slip on the exit point.

Other that freezing PC's I don't see any reason for a PC hesi due to cold weather. To me, I think the PC would perform better in the cold. The air is more dense in cold weather. The air molocules are closer together. Thats more molocules for the PC to grab. The same thing applys to flying your canopy. The colder it is, the better the performance. I also pull my PC out like Chad. Right before I leave to go to an object I pull out my PC check it and repack it.

Bryan Ody

It's just the common conditions for the winter time here. The local crowd of jumpers is really active especially in stowed slider-down but i've never heard about a hesitation caused by temperature.
I had a pc hesitation once because the PC was slightly wet and freezed.

and by your shaking legs on a exit point theres a real danger there,im happy you see it your self

oh jump before some one fart

Hey Rapid Peter, cheers for the photo. What happened to you for the Spain trip in Feb? Going to the valley this weekend with Ted etc, fancy?

M

I've had only one that comes to mind so it really doesn't mean much. But I did have a noticeable pc hesi on a jump about 30 seconds after my buddy had one on the same jump?!?! 330 ft 42" vented zp/handheld. 2 second delay.
Temp was below freezing.

Hey BK if you didn't pitch at .0001 seconds after you jumped there wouldn't be a hesi.

Bryan Ody

980
stop being such a little baby and grow a pair, you should be hard core like me! I'm so Fen extream!!!

Just my .02 (and I'm certainly not experienced enough to draw from personal experience),

. . . .but if colder air has greater density than warmer air, might that lead to greater snatch force and increased drag?

. . . .Tom A. gave me a brief lecture on the dynamics of pilot chute inflation this weekend; this would have been a good question to inquire about.

Cheers,

J.P.

In theory, colder air ought to be better for PC inflation, for basically those reasons.

If you read through this thread, you will see Lonnie's comment. At this point in time, I'd guess that Lonnie has more sub-zero BASE jumps than anyone else on earth. The theory seems to agree with his experience, but where they might disagree, I'd go with his experience first.

hello !

I JUMP -10 CELCIUS TO -28 CELCIUS 6 MONTH PER YEAR!!
I'VE APROXIMITLY 450 UNDRED BASE JUMP IN WINTER!!
AND IT'S A SERIOUS PROBLEME (PC HESITATION) FOR JUMPING STOWED WITH PC ZP IN WINTER!(1.5 TO 2 SEC. DELAY)

ON APPROXIMATELY 75 JUMP IN WINTER PER YEARS, I'VE 3 OR 5 JUMPS ON THE 75 WHO HAD A PC ESITATION. (serious esitation! sometimes I think I'll dead. )

Also in the 3 others seasons, sometimes I had somes esitation, but not so serious that the esitations in winter, but they are here... with Pc ZP 1,5 to 2 second delay !
I CHANGE THE PC ZP FOR F-111 FOR THE JUMP IN WINTER!

I've a lot of experience, I've jump 875 times on 8 years and I've much experience so belive me.

Thanks for the replies everyone, especially Pascal and Lonnie.

All my PCs are ZP.

I posted to make sure I’m not missing anything about low temp jumps and it’s really interesting that two jumpers with lots of low temp jump experience have opposing views.

Things like not packing a wet (think soaked) PC and leaving it to freeze in the BOC are pretty much common sense ( CUE some smartass here to say: ‘the problem with common sense is that it is not common” ).

I know PCs will hesitate every now and then and I think this was just one of those times.

The PC I used
- 44”
- ZP
- 8 load tape spokes
- 43 jumps
- non-vented
- cordura cap
It’s gotten wet 2 or 3 times, but always allowed to dry before jumping it again. It’s made in Canada and has that attachment system that Tom A really likes (I now have an Asylum PC which I paid an extra $10 for a similar style of attachment, but I have to say that I still far prefer the Paratech attachment, in fact the Asylum one is harder to use and does not seem a fitting part of an Asylum PC, I will get my Asylum PCs with the standard attachment in the future).
This PC uses a large hole mesh with a softer ‘hand’ than the large hole mesh on Asylum PCs (I’m not sure what the other manufacturers use).

That said, I’m not putting any blame on the PC itself, IMHO Paratech PCs are extremely well designed and built and no more likely to hesitate than any other manufacturers similar PC. I jump them regularly and if you want to see one in action I used a 46 Paratech PC for the Tyrolean jump in Hecker’s FRASCA video (the black canopy, there’s 3 Tyrolean jumps in the video).

I’ve had scary hesitations on Asylum PCs too.
I bet if I buy a Morpheus, APEX or any other BASE PC and jump it; it will also hesitate sooner or later.

It’s just the nature of the beast.

IMHO, it's not your pilot chute, it is most likely your pilot chute packing method coupled with your spandex pouch and bridle orientation.

Fair enough.

What are your recommendations regarding the factors you mentioned to minimize (or even avoid?) PC hesitations?

I am mostly interested in the stowed configuration.

Thanks

I dont remember if this is a rumour or what, but I have heard about fatality when a person put his wet rig to the trunk of his car and after couple of hours/days?! he takes it out and jumps from ?! somewhere with his frozen canopy....and dies...
do you guys know something about this...

FastPete

ps. couple of pics from our winter jumps 2006..

That's hardcore. What a hot jumper babe!

he is #6 on "the list."

http://hometown.aol.com/...e/base_fatality_list

which one ?

 
he is #6 on "the list."

http://hometown.aol.com/...e/base_fatality_list
ah...ok. i didnt noticed...thanks

I'm enjoying the rig
Cheers

I HAVE THE BEST METHOD FOR PACKING PC.
FOR YOU AND ORTHERS BASE JUMPER IT IS A QUESTION OF CHANCE! (until now)
COLD WEATHER AND MOISTURE = HESITATION FOR PC ZP
GOOD LOCK, BODY !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
USE F-111 (NO PROBLÈME WITH F-111)
PASCAL COUDÉ (EXITDROP)

Fresh example:

http://ru.youtube.com/watch?v=Uqivh3meJOM

46" ZP PC
330ft cliff
temperature -8C (17F)

Discussion (in Russian) here:
http://krasbaser.ru/viewtopic.php?t=60

Are all of these possible "cold temperature induced" hesitations reported when going stowed? Maybe it is good idea to go HH during winter with ZP PC's?

did somebody ever put a packed PC (F111 and ZP) into the freezer and checked it out what "could" happend....?
maybe it brings some evidence....

i would do it by myself,....but unfortunatly i got no freezer...

"imagination is morer worth than sience, sience it limited..."

in wintertime we jump pretty much in -15-30 C, so its much below freezer, and it works...

I once assisted a master rigger pack a mig-21 ejection seat. i really did more observing than anything else. to deal with the problems of moisture and extreme cold affecting the fabric (to stick together), talcom powder was used between folds of the canopy. i am uncertain how well this would work, but some simple tests with a pilot chute in the freezer might give some insight.

Holy shit.. That was close. Possible cause: Check the kill line which runs up the middle of your PC. Kill lines are 2 individual flat lines. If they are not sewn together, they can 'pinch' fabric from your PC preventing it from fully inflating... Check and if it's not sown together, I recommend you do so, or have a Rigger do it for you... Happened to me, got it sewn, and hasn't happened since!!

Not only does that not look like 330', that doesn't look like a 46" pc. I couldn't find anything about stowing a 46" pc from "330'" in the safety manual. Is that a hand or a riser cover that comes across the screen prior to pc inflation?

Is that a hand or a riser cover that comes
across the screen prior to pc inflation?

It appears to be a hand in finger-less
gloves reaching back and yanking the
container open.

Wow, close call, glad they are okay!

how was the pilot chute stowed?

is there much space near the bridle attachment point for the bridle to migrate between the mesh and the top fabric to cause a center line interference? my first instict watching the video indicates a center line problem. try it. pull it down a few inches and the pilot chute is totally ineffective.

you cant "yank" a container open, unless your pulling on the bridle.

it appears that dude just reached back about the same time his pc inflated.

luckbox.