Pilot Chutes.

[Strynx 0]

I'm really new to this and i'd like to know what are the pros and cons of having a collapsable.
Thanx.

[gus 1]

Hi Strynx,
The advantage of a collapsable pilot chute is that it doesn't drag your canopy as much when you're flying along under it. Under a huge great canopy the difference might not be noticeable but if you're kicking along at 60+ mph under your Cobalt 65 with a fully inflated pilot chute you'll be deforming the shape of the wing and altering its flight characteristics.
I think the only con is that you might forget to 'cock' it before a jump, preventing it from inflating and pulling the closing pin and bag out. You can avoid this with a bungee pilot chute but I've just got rid of mine as they're more subject to material failure as they wear out (IMHO Gus

[freeflir29 0]

Get a Kill line PC. It will make a huge difference in the way any canopy flys. Especially if it's a breazy day. I have seen it deform even the largest student canopies on breezy days.
"I got some beers....Let's Drink em!!!"
Clay

[Strynx 0]

Thanx! So It's really more for flight performance than deployment?

[DBTECH 0]

>Get a Kill line PC. It will make a huge difference in the way any canopy flys.
>Especially if it's a breazy day. I have seen it deform even the largest student
>canopies on breezy days.
What do you mean!? The forward 'airspeed' is the same--breezy day or not!
Dave Brownell

[freeflir29 0]

"So It's really more for flight performance than deployment?"
Exactly!!!
"I got some beers....Let's Drink em!!!"
Clay

[freeflir29 0]

"What do you mean!? The forward 'airspeed' is the same--breezy day or not!"
Let's not over do this one Dave....Yes the canopy will still find the same relative airspeed. However....if it's trying to tow a boat anchor it will not fly as smoothly.
"I got some beers....Let's Drink em!!!"
Clay

[riggerrob 643]

If you look at the Icarus website, you will find that they don't much care which type of pilotchute you use below a wing-loading of 1.25.
When wing loadings are between 1.25 and 1.65, Icarus recommends either a bungee-collapsible or kill-line pilotchute.
When wing loadings exceed 1.65, Icarus recommends using a kill-line pilotchute to avoid the hassle of your pilotchute re-inflating as you come screaming around the corner on you way to the gates at a blade running competition.

[SkymonkeyONE 4]

In my opinion there are no cons to jumping a Kill line PC. Forgetting to cock it is not a good argument for someone with a good packing ethic.
Chuck
My webpage HERE

[mwthomsen 0]

If you are absent minded enough not to cock the thing that will cause your chute to deploy hopefully the individual you ask to check your pins will notice. We are all still asking for a pin check before exit, right?
Mike

[VectorBoy 0]

Less drag = less wing distortion and better flight. Some argue the benefits below a wing loading of 1.2 but I noticed a dramatic improvement on my spectre's ability to flare, loaded only at 1.1. Added bonus the bridle just sits there now, it use to twist too and frow on top of my ZP fabric. There is no argument against forgetting to cock it. Don't forget.

[RemiAndKaren 0]

Quote

"What do you mean!? The forward 'airspeed' is the same--breezy day or not!"
Let's not over do this one Dave....Yes the canopy will still find the same relative airspeed. However....if it's trying to tow a boat anchor it will not fly as smoothly.

I had a revelation in the shower this AM (no I didnt loose any sleep, just had this pop-up thought).
I think the reason Clay in convinced that it makes a big diff in strong winds, is the relative importance of the slow down caused by the PC vs. ground speed.
i.e. (number are just to explain my thoughts)
In a no wind day, airspeed = groundspeed = 25kph (for exemple)
Speed loss due to PC drag = 2.5 kph, or 10% of groundspeed
in a high wind day, say 20 kph winds
airspeed = 25 kph ( that doesnt change)
groundspeed = 5 kph
PC drag = 2.5 kph, or 50% of ground speed.
Remi
Muff 914

[freeflir29 0]

Remi.....you are all over it......your ground speed can change dramatically. I noticed a huge difference when I changed mine. The relative airspeed will stay the same but your SINK RATE will increase causing a much steeper glide angle. Flatter glide=better swoops and just better landings in general.......I have also seen standard P/C's rock the canopy backwards on windy days...doesn't help a students landing if they are oscillating.....
"I got some beers....Let's Drink em!!!"
Clay

[billvon 3,110]

>Remi.....you are all over it......your ground speed can change dramatically. I
>noticed a huge difference when I changed mine.
Agreed - you need the extra forward speed most on windy days.
>The relative airspeed will stay the same but your SINK RATE will increase
> causing a much steeper glide angle.
No, your sink rate will stay the same - the canopy just knows its airspeed, not the groundspeed. But since you're still sinking at 10fps but your groundspeed has gone from 30fps to 20fps (due to a 10fps wind) the approach as seen by an observer on the ground gets much steeper. If the wind reaches 30fps, of course, you'll be coming straight down.
>Flatter glide=better swoops and just better landings in general.......
Faster landings, not better landings. I know of several jumpers who won't jump in zero wind conditions because they can't run out the landing (injured knees etc.) The flare's the same, of course, but the canopy can be stopped more easily when there's a 10kt headwind slowing it down.
-bill von

[freeflir29 0]

"Faster landings, not better landings"
Depends on the canopy I guess. I'm still jumping a relative boat so I like no wind days.....
"I got some beers....Let's Drink em!!!"
Clay

[flyhi 24]

Quote

When wing loadings are between 1.25 and 1.65, Icarus recommends either a bungee-collapsible or kill-line pilotchute.

Which brings up the second question: Why go bungee-collapsible? Other than never having to cock it, what benefit does it have? Due to Wx, we recently were stuck doing Hop n Pops from about 2200 feet. Guys with B-C PC's had to fall a little further before they got pin extraction. Seems like a drawback to me.
Is it hot in here, or am I crazy? - Charles Manson
flyhi

[freeflir29 0]

I try to stay away from junk like bungee P/C's. I've heard a lot about them but they still seem like a "Shade Tree" mechanic way to go about things. I'll take my well engineered Kill Line PC....$60 is not too much to pay for a relibale piece of equipment....
"I got some beers....Let's Drink em!!!"
Clay

[PhreeZone 20]

Bad thing about a Kill-line is if the kill line snaps in the middle (you can't inspect every inch of the line easly) when the Pilotchute is tossed once you are now presented with a Pilotchute in tow situation. A bungee on the other hand can be inspected on every jump to look for wear.
I want to touch the sky, I want to fly so high ~ Sonique

[skycat 0]

Quote

Bad thing about a Kill-line is if the kill line snaps in the middle (you can't inspect every inch of the line easly) when the Pilotchute is tossed once you are now presented with a Pilotchute in tow situation

Errrrr....if the centerline brakes you will not have a PC in tow, you will just have a PC that won't collapse...
Kelli

[PhreeZone 20]

No... it will be in an inverted state.The Pilot chute skin (F111 or ZP) would catch air through the mesh and pull on the kill line, since the kill line is no no longer under tension, the line would pull instead of being held to the canopy. The Bridle would not be pulled down the kill line since the entire system is no longer under tension. Since the Kill line is now freefly pulled, the pilotchute can not inflate, but what it would do, is the skin would continue to pull the kill line untill the PC is now a streamer with the skin on top and the mesh on the bottom.
You can test this by working about 6-8 inches of kill line into the area between the skin and mesh and watch what happens when you twirl the PC around slowly, see how it streamers? With tension on the kill ine the PC inflates, with more tension, the bridle slips up the kill line and relieves the tension caused by the air catching the PC.
I want to touch the sky, I want to fly so high ~ Sonique

[freeflir29 0]

"A bungee on the other hand can be inspected on every jump to look for wear."
Let me see you test it for proper inflation before each jump.....Do you have a gauge to know when your bungee gets stretched? I know K/L P/C's wear out but I have seen ones that have 1,000 jumps and still going strong.
"I got some beers....Let's Drink em!!!"
Clay

[PhreeZone 20]

You don't have to test anything for proper inflation, just look at the bungee to see if its showing signs of wear like rubber strings showing, outer cover spliting, knots/ bartacks coming loose. If the bungee is in good shape, it'll work.
A kill-line is completly covered so its much harder to see abrasion spots on it.
I want to touch the sky, I want to fly so high ~ Sonique

[skycat 0]

Quote

since the kill line is no no longer under tension

The kill line should never be under tension. The tension is on the ribbons inside the pilot chute. If you don't have those ribbons in your pilot chute you should have a rigger look at it.
Per a rigger on checking your pc for proper kill line length.
------------------------------------
The Spectra kill line shrinks from the heat generated from sliding through the bridle as the pilot chute collapses and the bridle stretches over time, affecting the original calibration. Because the change is so gradual it often goes unnoticed until you begin to experience hesitations on deployment. To check for correct kill line length, cock the pilot chute and watch the kill line. Does it become taunt before the two white ribbons that run from the apex (the top of the pilot chute) to the bridle? If it does, then the kill line is too short, not allowing the pilot chute to completely inflate. When cocked, the two white ribbons should be taunt and there should be some slack on the kill line. Also, if the handle of the pilot chute being pulled through the small opening at the base of the pilot chute on deployment, the kill line is too short. Your rigger should be able to replace the kill line, or if the kill line was manufactured with enough excess line, your rigger can simply extend the kill line.
------------------------
btw.......my pilot chute doesn't streamer when I pull out the kill line, it inflates properly.
Kelli

[billvon 3,110]

>No... it will be in an inverted state.The Pilot chute skin (F111 or ZP) would catch
> air through the mesh and pull on the kill line, since the kill line is no no longer
> under tension, the line would pull instead of being held to the canopy.
Where did you get a kill-line PC like that? Every one I've ever seen is constructed exactly like a normal PC (including the pulled-down-apex tapes) with a kill line added. If the kill line breaks, the tapes perform their original function, and makes sure that the PC functions like a normal one.
Perhaps if your PC doesn't have such tapes, you should ask a rigger to add them. It might avoid some unpleasantness if your kill line ever does break.
>Since the Kill line is now freefly pulled, the pilotchute can not inflate, but what it
> would do, is the skin would continue to pull the kill line untill the PC is now a
> streamer with the skin on top and the mesh on the bottom.
I'm not sure that would happen, since round canopies without pulled down apexes (i.e. connections at the edge only, like your PC) still open. Perhaps I'll try it one of these days.
-bill von

[PhreeZone 20]

Well.... all this talk about PC and kill lines made me open mine back up for a closer inspection to make sure I am arguing the right thing. It appears that I was wrong and looking closely at my PC I see why, One of the center ribbons stitching was starting to become unstitched at the bottom and thats what let it streamer on me when i tested it a week ago. This unstitching let the bottom attachment point for the ribbon slide up about an inch and that inch led to a lot of loss of drag. Once I hand sewed the seam back the PC functioned the same way you are describing. I guess I learned a few lessons tonight I want to touch the sky, I want to fly so high ~ Sonique