The right sized pilot chute?

[fraschc 0]

I just got a new ZP pilot chute (28 inch) for my Sabre2 135 which is in a Javelin TNJ. My previous pilot chute was F111 (don't know the size). It feels as though canopy is just getting ripped out of the container with great speed and force. The openings are quite brisk, and am not sure I'll be able to tolerate those kinds of openings during a training weekend (12 jumps a day for 4 days). Is it possible that the pilot chute is too big? Would it help if the pilot chute were a 26 inch instead?

I have a ZP pilot chute for my Sabre2 120 which is in a Wings container and the openings are great, however I don't know the size of that pilot chute.

Anyone have any suggestions?

Thanks!
Courtney

[ianmdrennan 2]

It's quite possible I suppose, but I currently have a 32" zp (yes that's 32" zp) and besides a high snatch force I find NO difference in the speed of the openings compared to when I was using the 22".

If you're wondering why I switched back to the original, the 22" sucked for hop n pops cause the bridal was a little too short.

Blue ones,
Ian

Performance Designs Factory Team

[mjosparky 3]

You will find a lot of places that say you must have the right size PC for this and that, but I have not been able to find any place that gives what the right size is. If you come up with anything, please pass on.
Sparky

Edit to add: If you are doing 12 a day for 4 days, my hat is off to you.

My idea of a fair fight is clubbing baby seals

[fraschc 0]

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It's quite possible I suppose, but I currently have a 32" zp (yes that's 32" zp) and besides a high snatch force I find NO difference in the speed of the openings compared to when I was using the 22".

If you're wondering why I switched back to the original, the 22" sucked for hop n pops cause the bridal was a little too short.

Blue ones,
Ian

Now that you mention the bridle, I did notice the bridle on my new pilot chute is longer than the old one suggesting the old one was a smaller pilot chute?

How will an opening with an F111 pilot chute feel compared to a ZP of the same size (i.e. snatch force or anything else)? I was thinking that if I had my pilot chute sized smaller (by a rigger of course and if it was recommended), would the length of the bridle be a problem? Can the bridle be shortened accordingly?

I just don't really know anything about this stuff.

Also I should mention that I do most of my jumps in Eloy (elev. 1500 feet) but the recent jumps that I made with the new pilot chute were in Colorado (elev. 5500 feet). Will it feel different at a lower altitude (i.e snatch force higher or lower)?

Courtney

[ianmdrennan 2]

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Also I should mention that I do most of my jumps in Eloy (elev. 1500 feet) but the recent jumps that I made with the new pilot chute were in Colorado (elev. 5500 feet). Will it feel different at a lower altitude (i.e snatch force higher or lower)?

I can't speak for the bridal = short pilot chute (don't think so..I think it's manufacturer specific) but the higher you deploy above sea level, the harder the canopy will open. You may find that has a lot to do with this and a smaller pilot chute *may* make it a little easier on you.

Blue ones,
Ian

Performance Designs Factory Team

[diablopilot 2]

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Also I should mention that I do most of my jumps in Eloy (elev. 1500 feet) but the recent jumps that I made with the new pilot chute were in Colorado (elev. 5500 feet). Will it feel different at a lower altitude (i.e snatch force higher or lower)?

I would say that the above and the fact IMO a new pilotchute often needs a dozen or so jumps to be "broken" in are the contributing factors.

Canopies open harder at higher density altitudes.

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You're not as good as you think you are. Seriously.

[fraschc 0]

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Canopies open harder at higher density altitudes.

That makes sense. It was also quite hot yesterday making the density altitude even higher I would guess. I'll be in Eloy next week for a training camp so I'll see how it goes there (although it's getting quite hot there now too....making the density altitude there higher as well). If the snatch force is still higher than I would like, I guess I'll consider having the pilot chute sized smaller. Seems reasonable I suppose, huh?
Oh yeah, the new pilot chute that I put on my 120 was perfect the first time. I should really find out what size that one is.

Courtney

[kosanke 0]

I would contact Sunpath and PD. there is a controversy. PD recommends a 27-29" F-111 for a Stiletto 150 that I currently fly. Sunpath recommends a 32" F-111. Sunpath indicates that smaller than 150 will of course require a different size. If you are having hard openings, there are a number of possible problems, the pilot chute size being one of them. hope this helps.

[airgord 1]

Packer.

[fraschc 0]

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Packer.

shut up

[mjosparky 3]

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I would contact Sunpath and PD. there is a controversy. PD recommends a 27-29" F-111 for a Stiletto 150 that I currently fly. Sunpath recommends a 32" F-111. Sunpath indicates that smaller than 150 will of course require a different size. If you are having hard openings, there are a number of possible problems, the pilot chute size being one of them. hope this helps.

I could not find this on Sunpath or PD web site. Where did you find it?
Sparky

My idea of a fair fight is clubbing baby seals

[fraschc 0]

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I would contact Sunpath and PD. there is a controversy. PD recommends a 27-29" F-111 for a Stiletto 150 that I currently fly. Sunpath recommends a 32" F-111. Sunpath indicates that smaller than 150 will of course require a different size. If you are having hard openings, there are a number of possible problems, the pilot chute size being one of them. hope this helps.

I could not find this on Sunpath or PD web site. Where did you find it?
Sparky

I was just told by a PD dealer (not from PD themselves), who also happens to be a rigger, that I should have a 24-26 inch pilot chute for my 135. I guess I'll go ahead and have my 28 inch altered.

Courtney

[piisfish 135]

I have a 84cm (I think 33in) ZP pilot chute with my Saphire2 139. I like it. Got that size mainly for wingsuit flying. Gets everything out of my rig quite fast and VERY straight.

scissors beat paper, paper beat rock, rock beat wingsuit - KarlM

[nicknitro71 0]

I never did buy the argument big PC = hard opening.

I like to stay on the bigger side.

This is what I like:

Anything up to 135-150 = 28"

150-190 = 30"

210 + = 32"

Memento Audere Semper

903

[kosanke 0]

It's not published but if you contact Warren at Sunpath I am sure that he would be of help. Container manufacturers set standards, sell d-bags with pilot chutes, and risers. Buy a canopy, that's what you get. Rusty at PD is the person to talk to. Both companies have great pr and have always been there to answer all my questions, even the dumb ones. I would think that if you are having hard openings and your packing has not changed, except for the new canopy and pilot chute, I would start with Rusty. I know how you feel. Throw and wait for the slammer.

[fraschc 0]

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It's not published but if you contact Warren at Sunpath I am sure that he would be of help. Container manufacturers set standards, sell d-bags with pilot chutes, and risers. Buy a canopy, that's what you get. Rusty at PD is the person to talk to. Both companies have great pr and have always been there to answer all my questions, even the dumb ones. I would think that if you are having hard openings and your packing has not changed, except for the new canopy and pilot chute, I would start with Rusty. I know how you feel. Throw and wait for the slammer.

Thanks! I'll do that for sure. Yeah, the ONLY thing that is different is the pilot chute suggesting to me that it is indeed responsible for the problem.

Courtney

[BASE813 0]

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pilot chute suggesting to me that it is indeed responsible for the problem.

if you look at the deployment process then the larger PC may bring out your bag and lines quicker but as soon as your canopy hits into the deployment process the pilot chute is bascially now redundant. What you call "hard opening" may be infact a quicker deployment and normal opening taking you by surprise. I would say if your line stows are not correct (line dump) and packing is slightly different eg. slider not properly set or nose wide open - this would cause hard openings more so than the PC being 2" larger - you will get a quicker extraction with a larger PC due to the increase in drag (minimal between 2 sizes close together eg. 30 v 32) - but whether this is causing Spanking openings I would find it hard to beleive - "quicker" maybe but not measuarbly harder..................

just my 2" differences worth.......... someone may wish to correct me on my thoughts..............

[ph8068 0]

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Canopies open harder at higher density altitudes.

This may be the case, I will take your word for it. But it is unlikely to be due to the pilot chute.

1. At higher altitudes you fall faster due to the reduced air density.

2. A pilot chute will produce less drag at a given speed for a lower air density.

3. But the speed is faster, and in fact the above two factors actually cancel. So the pilot chute will produce the same drag force no matter the altitude.

You would need to look into other related factors here. Are you confusing a different altitude with a different climate? A differing temperature or humidity can certainly lead to differing opening speeds as a differing amount of air will tend to be retained in the canopy during packing.

[diablopilot 2]

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This may be the case, I will take your word for it. But it is unlikely to be due to the pilot chute.

Correct. In my experience, Kill Line P/C's of any size are rarely the cause for hard(er) openings.

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You're not as good as you think you are. Seriously.

[billbooth 10]

Determining if your pilot chute is the right size for the first time is really quite easy. Have someone video one of your deployments from a distance and slightly below. If the time it takes from main pilot chute release, to line stretch (canopy out of bag) is less than 0.4 seconds, then your pilot chute is too big. If it takes longer than 0.8 seconds, your pilot chute is too small, out of trim, improperly constructed, or you're stowing your lines way too tight.

Once you know what a correctly timed deployment should "feel like", your will automatically know on future jumps if your pilot chute is working properly.

[airgord 1]

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shut up

no, you.

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[scottjaco 0]

I fly a Sabre 150.

I got a '24 inch pilot chute (zero-P) w/ kill line at Square 1.

I thought it was little small but it says right on the package that it is for 150sq ft and smaller.

They also sold a 28' inch for 170sq or higher.

I chose the smaller, cause smaller is sexier!

I haven't flown it yet, do you think the manufacturer is giving bad advice?

edited to add... I did a search on the web and found that they recommend the 24' pilot chute for 170sq ft or smaller "Cobalt" canopy.
http://www.extremefly.com/aerodynamics/FAQ.html#three

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What's the recommended pilot chute size?

Recommended pilot for cobalt 150-170 is a 24" zero-p kill line collapsible. Recommended pilot for Cobalts 65-135 is a 22"-24" zero-p kill line collapsible. NOTE: many containers come standard with a 28-32" pilot. This is more than double the recommended surface area required. A 28” pilot will cause brisk openings especially at higher speeds.

[diablopilot 2]

I don't think you'll have any problem.

And as for Atairs advice, well a properly manufactured Kill line P/C will not cause a harder opening just because it's 28 inches vs. 24.

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You're not as good as you think you are. Seriously.

[fraschc 0]

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Determining if your pilot chute is the right size for the first time is really quite easy. Have someone video one of your deployments from a distance and slightly below. If the time it takes from main pilot chute release, to line stretch (canopy out of bag) is less than 0.4 seconds, then your pilot chute is too big. If it takes longer than 0.8 seconds, your pilot chute is too small, out of trim, improperly constructed, or you're stowing your lines way too tight.

Once you know what a correctly timed deployment should "feel like", your will automatically know on future jumps if your pilot chute is working properly.

Well I a couple jumps this weekend and had my opening filmed and we timed it as per the guidelines written above and it was a quick 0.2 seconds. I think I now have the data to support my original hypothesis that my pilot chute is too big (sorry, I'm a scientist )

Thanks everyone! I'm going to buy a 24" pilot chute.

Courtney

Courtney

[kosanke 0]

could you reply back after you have tried it with the results. also do a hop and pop to see how the low speed deployment differs. Thanks