Slowing down to terminal, and line wear

[PLFKING 4]

Hey all....
Two questions for the price of one......1) After a sit or stand or head-down, then going to belly just prior to deployment......how long will it take me to slow down from 170-190 mph to my normal belly speed of around 130 mph ? I've had a few openings that were harder than normal (it seemed), and I'm wondering if maybe I wasn't waiting long enough to "slow down to terminal", and was maybe throwing out at 150-160 mph instead. I generally allow myself 1000 feet to slow down....is that enough ?
2) I really like pulling high....to me, just playing with the canopy (spirals, trying to fly backwards, stalls and recoveries, just hanging out enjoying the scenery, etc...) is the most enjoyable part of the dive. If a normal jumper pulls at 2000 feet, and has a two-minute canopy ride........and I pull at 7-8000 feet, and fly around in half-brakes for a ten-minute ride.........am I wearing out my lines 5 times faster than the normal jumper ? (i.e., loading them for ten minutes vs. two minutes). Or are lines mainly designed to handle the opening shock, and the load thereafter is not as crucial, or to be worried about........
Does anyone understand what I'm asking ? I suspect I may not have explained myself very well......
Don

[PhreeZone 20]

For one.... most sitflying is around 145-155mph. Fastest I've ever been able to get in a stand with only my hands out was 210. Most standing is only about 160.
1000 feet is plenty of time to slow down as long as you are dearching for your flat track afterwards. I've gone as short as 300 feet after rolling out and its just a stiffer opening. I've also deployed right from a sit a few times and a stand once. Granted, I'm jumping somethng that can handle it, but the openings were not bad at all. Got on the next load after all of them. Granted if your belly speed is at 130 you need to dearch to really slow down before you open to makefor softer openings. On my protrack I'm usually at about 105-110 when I deploy in a total dearched track, I never bother on stoping the track.
What wears the lines out the most is the motion of the slider running down them and the motion of the sterring line through the guide ring. because the steering lines get used more then the rest, the lower steering lines should be changed at about 250 jumps and a complete reline at 400-500. And flying backwards is when your canopy is on the stall point. You can get away doing this on squares, but on something elliptical, it probally going to result in a reserve ride.
A side note to all of this, the higher MSL you are when you open the harder opening you will recieve. Opening at 10000msl is going to open alotfaster and there fore harder then at 2500msl.
I'm not sure what to put here right now.....

[FallingMarc 0]

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And flying backwards is when your canopy is on the stall point. You can get away doing this on squares, but on something elliptical, it probally going to result in a reserve ride.

Why would riding the edge of a stall result in a reserve ride on an elliptical?
Marc

[PhreeZone 20]

Because if you would hold it for just a second too long or bump the toggles down just a little bit more and the canopy stalls it will more then likely spin up on you and turn into a spining mal with line twists. Unless you've got a couple of thousand feet under you, the best and safest thing to do is chop and hit the silver.
Also going from the verge of a stall to full flight too rapidly can result in uneven presureazation of the canopy. This can also cause the canopy to spin rapidly.
I'm not sure what to put here right now.....

[weid14 0]

you'll get harder openings at higher altitudes, I really noticed this at Eloy, which is about 1400 feet higher than the DZ's I ususally jump at (the plus side is the swoops are longer). that may be part of teh reason.... isnt' "slowing down to terminal" kind of an oxymoron

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[PLFKING 4]

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.... isnt' "slowing down to terminal" kind of an oxymoron ?

Careful, Weid......."Grammar Nazi" Jessica reamed me about the improper use of this word a couple of weeks ago (but I still can't remember its exact definition !)
Yeah, the additional UV exposure does cross my mind......I'm jumpless for another month (buying myself a Hornet 190 for Xmas), but since I'm still under 100 jumps, I figure I'll be downsizing within the next 200-300 jumps anyway. I'm very careful with my canopies' care in all other respects.
Thanks for the great info, Phree. I will say that playing with my stall point ALWAYS stops before 2000 feet, no matter what altitude I deploy at......no reserve rides yet, and not wanting one either ! And I've been clocked in a hard arch at 130 several times, and three different head-downs between 180-200.....the "170-190" was just a guess. The 145 sit makes sense.....I've done a few hybrids where I could almost stay with a sitflyer trying to slow down. And the majority of my jumps are at a Cessna DZ, so most of the time I don't have to track anyway, since I'm out last......that's why I was wondering about the speed issue. Even if I'm with someone, I generally pull in place (but ALWAYS check the air above, just out of habit), since the guys I jump with usually ride it down to 2000. I throw out no later than 3500, unless I'm at a big DZ with lots of traffic.
Thanks for the insights, guys.
Don

[Aviatrr 0]

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BUT, you are exposing your canopy to significantly more UV, and UV can weaken nylon over time, may want think about that a little

That's the primary reason that CReW canopies don't last anywhere near as long as sport ZP canopies.....they're exposed to the UV for 10-12 minutes each jump rather than 2-3 minutes.....but I'm sure all the grabbing and pulling on the canopies doesn't help much, either.. Mike

[cobaltdan 0]

a few quick notes:
dyters are not the most accurate indicators of speed. we have given our dataloger out for most anyone to jump at different boogies. i have done this for 2 seasons and have never recorded a freeflyer deploying at less than 140.
personally, i fly on avarage around 175. in a stand legs together with arms diagonaly high, i have pushed 257.
to decelerate to 120, 1000' is not enough from an avarage freefly jump.
that (and a broken neck on deployment from a sabre) explain the creation of the cobalt !
as far as flying stalls. up high try it on a cobalt, if you iniatiate it slowly you can fly the canopy backwards without collapsing it. while going backwords you can initiate reverse turns as well. you will deflate the inboard side end cells. transition back to foward flight slow and smooth. its a fun excercise and good practice for base.
as far as the wear and tear on your canopy: fabric: opening shock and uv. even at 15 min at a pop the uv exposure is not that big a deal. paragliders have proven the fabric to last considerably longer...lines: basically the opening and high g turns add a bit as well. during level flight the lines are underloaded. some lines are very sensitive to uv, namely vectran and kevlar type polymers. vectran can loose over 60% its strength within 4 hours of strong sunlight exposure.
sincerely,
dan
atair

[freeflir29 0]

"vectran can loose over 60% its strength within 4 hours of strong sunlight exposure."
Cheese and Rice! I never would have thought UV would be THAT harmful.....Thanks for the info!
"and I'm not easily impressed...Ooohh look...a blue car!" -Homer Simpson

[PLFKING 4]

Thanks for the great info, guys......certainly made me think, and gave me some new stuff to try. New Years can't come quickly enough !
Don

[PhreeZone 20]

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but I'm sure all the grabbing and pulling on the canopies doesn't help much, either

The oils on the body are'nt nice on Nylon either. Climbing all over a canopy with your hands and arms transfers a lot of those oils to both the lines and the canopy.
I'm not sure what to put here right now.....

[lummy 4]

Hmmmm..... But how many jumps is that on average?? You figure that a stong UV day would be in the summer when you'd be jumping the most. Avg time under canopy would be what, 5 minutes to round off? Another 10-15 for packing unless you pack in the hangar (0-2UV)or under shade (4-7 UV)), which would mean 12 (min) to (80max) # of jumps and we could expect to lose 60% strength?

Is the math right?
I guess my question is, when I own my own rig, should I be checking the lines that often?

[lummy 4]

That should be 0-20% of UV and 40-70%UV

[DBTECH 0]

BTW people-we don't slow down TO terminal-we slow down to a 'new-slower' terminal.
Someone said--harder openings at Eloy because of a field elevation of 1500 feet--I don't by it--The Placebo effect comes to mind here.
If you came from a sea-level DZ and opened at 2000 feet AGL/MSL, that would be 3500 feet MSL at Eloy. Plus it's density altitude that counts-and at Eloy it's always lower for a given temperature because of the low desert humidity. (dry air is MORE dense than humid air)
Dave Brownell
Mesa/Eloy AZ

[lummy 4]

(dry air is MORE dense than humid air)
Isn't that the other way around?
Humid air will have more water content and therfore be denser....

[DBTECH 0]

(dry air is MORE dense than humid air)
>Isn't that the other way around?
>Humid air will have more water content and therefore be denser....
DB--As I said-dry air is more dense than humid air--ask any pilot --also check physics books for a good explanation as to why.
Dave Brownell
C-180/182 Jump pilot-(2700 loads

[weid14 0]

nope DB, sorry to disappoint you, everyone on my team said the same thing when I mentioned it.... same packer(s) as all year, same canopies, different depolyment altitudes. I believe that A higher opening altitude will cause a parachute to deploy faster (and therefore a little harder potentially).

[DBTECH 0]

I never said that a higher opening altitude would not cause a harder opening. A higher altitude to me is not 500 to 1000, but 5000+. I am talking density altitude here, which Eloy has little to nil over other DZ's elsewhere in the country. I have been in Illinois when the density altitude was 6000 feet--very hot HUMID day. Eloy, BTW is only 800 feet above SDC. Again, the Placebo effect comes to mind here in regard to Eloy. BTW: I do have 300 jumps at Eloy-900 in Illinois.
Dave Brownell

[riggerrob 643]

"Slowing down to terminal" is legitimate grammar if you exited an airplane flying faster than your normal terminal velocity (ie. when you exit a Boeing 727 jet flying at 190 mph over Quincy).
Also, you you "slow down to terminal" when you transition from a stand to belly-flying because standing terminal is faster than belly-flying terminal.
To clarify Dave Brownell's earlier point, moist air is less dense than dry air because water vapour is less dense than dry air.

[weid14 0]

well, Eloy is 1400 feet higher than Cross keys or deland. of which I jump at most. and I know enough about my canopy opening to know that it is different at Eloy vs these DZ's

[billvon 2,995]

>I never said that a higher opening altitude would not cause a harder opening.
>A higher altitude to me is not 500 to 1000, but 5000+.
I have noticed harder openings in Eloy compared to San Diego, and I have definitely noticed harder openings in Lost Prairie (3000 feet higher than SD.) 1000 feet makes a difference to my canopy, at least, and 3000 makes a big difference.
-bill von

[billvon 2,995]

>1) After a sit or stand or head-down, then going to belly just prior to
> deployment......how long will it take me to slow down from 170-190 mph to
>my normal belly speed of around 130 mph ?
I would recommend choosing a time, not a distance. Five seconds is a good choice - note that this will mean a longer distance at higher initial speeds.
> and I pull at 7-8000 feet, and fly around in half-brakes for a ten-minute
>ride.........am I wearing out my lines 5 times faster than the normal jumper ?
No. Most line wear is caused by the slider rubbing the lines as it descends and then sits and rubs on them near the bumpers. That's why you will notice more wear on your outer lines than your inner lines, and why they will sometimes "shorten" as they get worn (especially on pure spectra lines.) Dirt also causes wear by abrading the lines internally when they are suddenly loaded (as happens during opening.) UV damage comes in a very distant third, although it is a significant factor with canopy fabric.
-bill von