Forums: Skydiving: Safety and Training:
Reserve Size

 

First page Previous page 1 2 3 Next page Last page  View All

davjohns  (B 36948)

Dec 24, 2007, 2:54 PM
Post #1 of 74 (2956 views)
Shortcut
Reserve Size Can't Post

Newbie question.

Why are reserves so often smaller than mains?

I would think that if things have gone wrong, one would want the assurance of a larger, more docile canopy.

I am thinking that smaller canopies might deploy faster and that might be part of the reason, but am not sure.

Thanks for any responses.

Dave.


dharma1976  (D 28634)

Dec 24, 2007, 3:43 PM
Post #2 of 74 (2915 views)
Shortcut
Re: [davjohns] Reserve Size [In reply to] Can't Post

smart move

follow your gut...

my reserve is a 126, my main is a 103.

cheers

Dave


JustChuteMeNow

Dec 24, 2007, 4:34 PM
Post #3 of 74 (2897 views)
Shortcut
Re: [davjohns] Reserve Size [In reply to] Can't Post

I don't know if I can answer your question but in many cases jumpers get a reserve that is farily close in size to their main. It may be a little smaller or a little bigger than the main canopy but it is similar in size. The prevaling wisdom is that in case of a two out situation that two canopies that are similar in size will play better together than canopies that are not.

Most reserves are seven cell canopies and they are not trimmed to fly aggressively.

And while a smaller reserve canopy will generally open faster than a bigger reserve canopy that is not the reason people go small. They go small because there is a limit to what size reserve pack tray will be compatible with a main pack tray that holds a small canopy. The optima reserve is helping to address this issue because it does pack smaller than conventional reserves.


Zing  (D 6343)

Dec 24, 2007, 5:27 PM
Post #4 of 74 (2880 views)
Shortcut
Re: [JustChuteMeNow] Reserve Size [In reply to] Can't Post

No, no, no ... How can you have the neatest, keenest color-coordinated flashy, greatest, latest best thing you can have gear unless you buy the newest micro-mini high-impactor crater-making spare, so ya'll can be the coolest looking one at the dropzone ... besides, the smaller and lighter your gear is, the more lead you can pack on for free-falling.
Remember boys and girls, it ain't free, and it ain't falling.
I once calculated that an average load of jumpers in a DC-3 was carrying between 300 and 400 pounds of lead shot in weight vests and weight belts.


sundevil777  (D License)

Dec 24, 2007, 5:41 PM
Post #5 of 74 (2871 views)
Shortcut
Re: [davjohns] Reserve Size [In reply to] Can't Post

In general, rigs look better when the reserve is smaller than the main. Of course it is a lousy reason, but it does matter to many.


Premier billvon  (D 16479)
Moderator
Dec 24, 2007, 11:48 PM
Post #6 of 74 (2796 views)
Shortcut
Re: [davjohns] Reserve Size [In reply to] Can't Post

>Why are reserves so often smaller than mains?

Because smaller reserves = smaller containers, and smaller containers are considered cool. Also, some newer jumpers figure they will jump a larger canopy and then have the reserve for when they downsize their main. They might jump a Pilot 188 and have a PD143 using the thinking that "well, I'll probably never need it - and if I do, it will probably be when I've downsized to a Pilot 150, and it won't be a big deal."

Needless to say, that can come back and bite you.

Personally I have a Crossfire2 109 and a PD126, and my next rig will probably have a Optimum 143 and something like a Xaos-21 99. I have never been under a reserve thinking "you know, I wish that reserve were smaller" - but there have been a few times I wished it was larger, like the time I had to land on the road between the powerlines at Perris.

>I am thinking that smaller canopies might deploy faster . . .

Not really a reason.


DougH  (D License)

Dec 25, 2007, 5:51 AM
Post #7 of 74 (2752 views)
Shortcut
Re: [davjohns] Reserve Size [In reply to] Can't Post

Mine isn't... I have a 175 reserve and a 132 main. I will allways try to get the biggest possible reserve when I am buying a container setup.


Brains  (D License)

Dec 25, 2007, 6:54 AM
Post #8 of 74 (2733 views)
Shortcut
Re: [davjohns] Reserve Size [In reply to] Can't Post

You have already gotten several examples of reserves that are larger than mains, and some reasons that it might be the other way around, although not GOOD reasons. I can't think of a good reason to have a smaller main. PD's website has a section on Reserves and i am going to butcher the quote but it goes something like this, "Do you really want to be jumping possibly the smallest canopy you have ever flown in an emergency situation?"

I also jump a 107 main and i have a 126 reserve. One of my older rigs used to have a 113 reserve and i had to use it once, flew great, landed great, etc. but when i landed i decided to get rid of the rig and get something that would hold a larger reserve, looking up at it (the 113) i remember thinking,"Man, i sure wish this was bigger"


pilotdave  (D License)

Dec 25, 2007, 7:25 AM
Post #9 of 74 (2724 views)
Shortcut
Re: [davjohns] Reserve Size [In reply to] Can't Post

I think a lot of people use reserves that are way too small. In a lot of cases, it's because the container manufacturers limit what size reserves can go with what size mains. If you want a tiny main, you need a tiny reserve. Then there's the reserve manufacturers that keep going smaller and smaller to make the jumpers happy. There's just no need for the PD 99 reserve. Nobody needs a reserve that small. Even the 106 and 113 are ridiculous in my opinion. Then there's the optimum 99. WTF? I think they went the wrong way with the optimums. If I could replace my 143 with an optimum 200, why wouldn't I? I dont think theres a need for a 99 reserve that packs smaller.

Watch videos of main/reserve entanglements. It happens often enough that there are plenty of videos of them out there. I always wonder if the reserve was a 143 instead of a 113, would it have flown better while trailing the sub-100 main? I bet it would.

Manufacturers need to step up and start offering safety over looks.

Dave


Reginald  (D 28162)

Dec 25, 2007, 8:04 AM
Post #10 of 74 (2711 views)
Shortcut
Re: [billvon] Reserve Size [In reply to] Can't Post

In reply to:
I have never been under a reserve thinking "you know, I wish that reserve were smaller"

Well said!


Andrewwhyte  (C 1988)

Dec 25, 2007, 8:45 AM
Post #11 of 74 (2701 views)
Shortcut
Re: [billvon] Reserve Size [In reply to] Can't Post

You have to wonder about the argument that you do not want your reserve to be much bigger than your main because they wont play nice together otherwise.
The argument goes that Bill should not have a big ol' 143 with a Xaos 99, he should get a Optimum 99 or 106. Do people really think that a 99ft rectangular, 7-cell, F-111 canopy is going to be compatible with a cross-braced swooping canopy? It wont.


redlegphi  (A License)

Dec 25, 2007, 9:07 AM
Post #12 of 74 (2693 views)
Shortcut
Re: [pilotdave] Reserve Size [In reply to] Can't Post

My understanding was that they found that if the two canopies weren't of similar size, there was more likelihood of a two-out situation ending in a side by side or downplane.


pilotdave  (D License)

Dec 25, 2007, 9:11 AM
Post #13 of 74 (2692 views)
Shortcut
Re: [redlegphi] Reserve Size [In reply to] Can't Post

I'd rather have a side by side or downplane with a 200 reserve and 105 main than an entanglement between a 105 main and 99 reserve. But that's just me.

Dave


dragon2  (D 101989)

Dec 25, 2007, 10:43 AM
Post #14 of 74 (2671 views)
Shortcut
Re: [Brains] Reserve Size [In reply to] Can't Post

In reply to:
I can't think of a good reason to have a smaller main.

Accuracy jumpers sometimes have a much smaller reserve than their main Wink


JustChuteMeNow

Dec 25, 2007, 10:58 AM
Post #15 of 74 (2664 views)
Shortcut
Re: [Andrewwhyte] Reserve Size [In reply to] Can't Post

Quote:
You have to wonder about the argument that you do not want your reserve to be much bigger than your main because they wont play nice together otherwise.

I think most people DON'T wonder about it because of the study that performance design did and the army did testing this scenario. Please read the report listed below and maybe you will change your mind. Of course, maybe you won't.

Dual out study by performance design


Andy9o8  (D License)

Dec 25, 2007, 10:59 AM
Post #16 of 74 (2662 views)
Shortcut
Re: [davjohns] Reserve Size [In reply to] Can't Post

I want a reserve large enough to survive a no-input landing, even if I'm taking a nap.


kallend  (D 23151)

Dec 26, 2007, 8:40 AM
Post #17 of 74 (2530 views)
Shortcut
Re: [JustChuteMeNow] Reserve Size [In reply to] Can't Post

In reply to:
Quote:
You have to wonder about the argument that you do not want your reserve to be much bigger than your main because they wont play nice together otherwise.

I think most people DON'T wonder about it because of the study that performance design did and the army did testing this scenario. Please read the report listed below and maybe you will change your mind. Of course, maybe you won't.

Dual out study by performance design

The only conclusion I could find regardling relative size from that study was this:

2. conclusion: Use great care to choose proper equipment. Choose
canopies that are not drastically different in size. A general rule of thumb is to
choose a reserve that is similar in size to the main canopy.



JustChuteMeNow

Dec 26, 2007, 9:20 AM
Post #18 of 74 (2515 views)
Shortcut
Re: [kallend] Reserve Size [In reply to] Can't Post

Quote:
The only conclusion I could find regardling relative size from that study was this:

2. conclusion: Use great care to choose proper equipment. Choose
canopies that are not drastically different in size. A general rule of thumb is to
choose a reserve that is similar in size to the main canopy.


I thought this was pretty common knowledge but some people want to post statements arguing the opposite. Unfortunately bad information can get people hurt which is why I posted the study. That said, people are free to make their own decisions and I respect their right to do so.


RafaelYP  (D 54)

Dec 26, 2007, 10:55 AM
Post #19 of 74 (2488 views)
Shortcut
Re: [davjohns] Reserve Size [In reply to] Can't Post

Y bought a spedtre 210. The only rig I found in Deland, Z-Hill, was 210 main 193 reserve.


Premier billvon  (D 16479)
Moderator
Dec 26, 2007, 10:59 AM
Post #20 of 74 (2486 views)
Shortcut
Re: [JustChuteMeNow] Reserve Size [In reply to] Can't Post

>I thought this was pretty common knowledge but some people want
>to post statements arguing the opposite.

I will argue the opposite. In many cases, a jumper may be safe under a Xaos-27 95; that does NOT mean a Tekno 99 is a good idea.

Most jumpers will be under their reserves several times during their jumping career; generally some of those will require landing out in new/tight LZ's. Most jumpers will never experience a two-out. Choose gear that will land you safely under the most likely conditions you will see.


JustChuteMeNow

Dec 26, 2007, 11:51 AM
Post #21 of 74 (2470 views)
Shortcut
Re: [billvon] Reserve Size [In reply to] Can't Post

Quote:
I will argue the opposite. In many cases, a jumper may be safe under a Xaos-27 95; that does NOT mean a Tekno 99 is a good idea.

I don't disagree with you; however, the great majority of skydivers will never be in a situation where they will be jumping a canopy of that size. For the select few that are in that group I have already stated that people are free to make their own decisions and I respect their right to do so. Everyone weighs their perception of risk differntly.

While a two out situation should be prevented if at all possible that doesn't mean it won't happen. For that reason IMO it makes sense to jump a reserve similar in size to your main. I will now emphasize your point again. That same reserve should also be capable of landing you safely under the most likely conditions that you will see. And I don't want to stir the pot here but that is generally a reserve very similar in size to the main unless like you stated earlier a person is jumping a mega small main.


gearless_chris  (D 29012)

Dec 26, 2007, 1:30 PM
Post #22 of 74 (2444 views)
Shortcut
Re: [JustChuteMeNow] Reserve Size [In reply to] Can't Post

I've seen a 2 out situation exactly once, Rantoul '06. I've seen reserve by themselves many times, 5 of my own, and many other peoples. I don't see the point in having a Cypress and a reserve if you wouldn't survive landing the reserve un-conscious anyway. Most of the time when you're under a reserve it's at a lower altitude than normal, under an un-familiar canopy, with a better chance of landing out in un-familiar territory, I'd much rather have my Raven 1 than a Micro Raven 120 just because I worked my main size down to a 120. If reserves were meant to be loaded 2:1 I might think differently though.


mark  (D 6108)

Dec 26, 2007, 1:40 PM
Post #23 of 74 (2434 views)
Shortcut
Re: [gearless_chris] Reserve Size [In reply to] Can't Post

In reply to:
I don't see the point in having a Cypress and a reserve if you wouldn't survive landing the reserve unconscious anyway.

Most AAD fires are a result of people forgetting to pull. They're conscious, just busy doing other things. For those folks, having a Cypres makes sense -- except for screwing with Darwin.

Mark


JustChuteMeNow

Dec 26, 2007, 2:06 PM
Post #24 of 74 (2423 views)
Shortcut
Re: [gearless_chris] Reserve Size [In reply to] Can't Post

I don't think I can count on two hands how many two outs I have seen and I have had one of my own. On one skyvan load alone at couchfreaks in 2006, I saw 4 two outs on one load. They do happen and they will continue to happen for a variety of reasons. However, I am NOT advocating that people jump an unusually small reserve JUST to keep within the recommendation of the PD study. Like BillVon implied, jumpers need to do what is best for them based on their circumstances and experience.

I know what works for me based on the canopies that I jump and I assume experienced jumpers will do what they believe works best for them.


DrewEckhardt  (D 28461)

Dec 26, 2007, 5:27 PM
Post #25 of 74 (2380 views)
Shortcut
Re: [JustChuteMeNow] Reserve Size [In reply to] Can't Post

In reply to:
Quote:
I will argue the opposite. In many cases, a jumper may be safe under a Xaos-27 95; that does NOT mean a Tekno 99 is a good idea.

I don't disagree with you; however, the great majority of skydivers will never be in a situation where they will be jumping a canopy of that size. For the select few that are in that group I have already stated that people are free to make their own decisions and I respect their right to do so. Everyone weighs their perception of risk differntly.

The great majority of skydivers are loading their F111 seven cell reserves beyond the pound per square foot that was acceptable when such canopies were jumped as mains, with much less experience on that type of canopy, and with a higher chance of landing out on sub-optimal terrain due to longer jump runs with more groups (up to 24 jumpers from an otter with lots of 2 and 3 way freefly groups versus 14 from a twin beech and bigger groups) with a similar fully-open altitude (you can end in the same place as a 2000' container opening with a 200' main opening when you start at 3000', snivel for 800', and spend a little while dealing with a spinner).

The reserve's lower porosity gives us some added headroom although at some point they just don't land well enough especially on uneven terrain where you can't run or slide.

Somewhere above a pound per square foot nearly everyone agrees that reserves land fine.

Somewhere below two pounds per square foot nearly everyone agrees the stall speed is too high.

Where the cross-over happens is up for discussion.

With a field elevation of 5000' MSL and density altitudes reaching 10,000 feet (standard temperature is barely 40 degrees F) I think tall aerofoil rectangular seven cells don't land well enough much above 1.3 pounds per square foot versus 1.5 pounds/square foot for rectangular 9 cells, 1.7 for older ellipticals, and 1.8 for newer non-cross braced designs. I've only made a few hundred jumps at sea level but suspect an extra .2 is about right.

That puts the point at which a larger reserve becomes prudent below the wing loading of many less experienced jumpers and something that as few as 11% of dropzone.com posters can ignore

http://www.dropzone.com/...ading%20poll;#921140

In reply to:
While a two out situation should be prevented if at all possible that doesn't mean it won't happen. For that reason IMO it makes sense to jump a reserve similar in size to your main. I will now emphasize your point again. That same reserve should also be capable of landing you safely under the most likely conditions that you will see. And I don't want to stir the pot here but that is generally a reserve very similar in size to the main unless like you stated earlier a person is jumping a mega small main.

A two out situation is nearly avoidable by following accepted safety practices : planned container opening high enough to meet the BSR specified 1800' cutaway decision altitude (2000' for a canopy that opens in 200' and then descends slowly, 3000'+ for one that might snivel for 800' and then dump 90 feet per second until you decide you're not going to kick out of the line twists) and enough reminders to open so that actually happens (multiple audible altimeters for disciplines where the ground is less visible like VRW).

A simple cutaway is almost certain when you're spending 6 minutes of a pack job (not the 60 you'd use on a reserve) and jumping high-aspect ratio non-square planforms that tend to spin-up and quickly loose altitude.

Its better to optimize for the more likely later case.

A 135 canopy for a 175 pound guy is arguably neither "a mega small main" nor "reasonable sized reserve." With the possibility of higher density altitudes he'd be better served by a 150 reserve (PD143) regardless of how far he downsizes in the future.

I liked a 150 when I regularly jumped 135s as mains and still think its a fine choice with my Samurai 105.


(This post was edited by DrewEckhardt on Dec 26, 2007, 5:36 PM)


First page Previous page 1 2 3 Next page Last page  View All

Forums : Skydiving : Safety and Training

 


Search for (options)