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pnuwin

PD Optimum Reserve - Opens softer. Is it slower?

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I've heard from several sources now (including PD) that the PD Optimum reserve opens softer and flares better than the PD Reserve.

When I hear that it opens softer I think it must have a slower opening. Is this really an advantage for a reserve? Wouldn't a reserve that opens quickly in as little altitude as possible without breaking you or the equipment be a better reserve?

I have a PD reserve at the moment and would consider going to an Optimum for my next set of gear. I realize the difference in opening altitudes would be small and nothing to worry about but why would you want a snivelly reserve if you have limited altitude after an emergency?

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I've heard from several sources now (including PD) that the PD Optimum reserve opens softer and flares better than the PD Reserve.

When I hear that it opens softer I think it must have a slower opening. Is this really an advantage for a reserve? Wouldn't a reserve that opens quickly in as little altitude as possible without breaking you or the equipment be a better reserve?

I have a PD reserve at the moment and would consider going to an Optimum for my next set of gear. I realize the difference in opening altitudes would be small and nothing to worry about but why would you want a snivelly reserve if you have limited altitude after an emergency?



Slower? Not necessarily.

The adage in skydiving is "Slow is smooth - smooth is fast".

TSO is TSO. Off the top of my head, the limits are something like 300' and 3 seconds.

(Please verify. There is some Svedka effect here. But, I mentioned it, so I am probably not really dramatically impaired.)

Openings can be brutal if they open all at once in the last half second.

A smoother opening that starts at time 0 can be as quick as any opening in the past, and yet less brutal on your body.

The Optimum had to meet TSO requirements. (We are told that this is the reason that the bigger Optimum reserves took longer to come to market.)

(Now, to be clear and honest, some of this will depend on your rig. USPA tells us that there have been cases where the suspicion is that rigs were too tight, and reserves did not open in time. That's not the fault of the reserve, is it? We have a SYSTEM that must work properly for the limits to be met.)

But the PD Optimum still had to meet the TSO limits.

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The Optimum was build with a freeflyer in mind, who gets a premature reserve deployment at 200 mph



I believe any canopy opening at freefly speeds is going to be a dangerous event. Even a snivelly Spectre. The slightly slower opening of the Optimum is still going to be very fast compared to a main canopy. It will be brutal to your body and your canopy. Possibly lethal as seen in the past.

Reserve opening speed is important because think about AAD fires at 750ft. You'll have a 10sec reserve ride assuming everything opens as planned. If there is a 0.5sec reserve pilot chute hesitation, then there is a 3sec reserve ride. Any thing else goes wrong and you're dead. Having a softer opening reserve is just depleting your margin of safety.

Maybe I'm over analyzing this but these are things I think about when I choose my gear.

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The Optimum was build with a freeflyer in mind, who gets a premature reserve deployment at 200 mph



I believe any canopy opening at freefly speeds is going to be a dangerous event. Even a snivelly Spectre. The slightly slower opening of the Optimum is still going to be very fast compared to a main canopy. It will be brutal to your body and your canopy. Possibly lethal as seen in the past.

Reserve opening speed is important because think about AAD fires at 750ft. You'll have a 10sec reserve ride assuming everything opens as planned. If there is a 0.5sec reserve pilot chute hesitation, then there is a 3sec reserve ride. Any thing else goes wrong and you're dead. Having a softer opening reserve is just depleting your margin of safety.

Maybe I'm over analyzing this but these are things I think about when I choose my gear.



You are definitely over analyzing things.

getting into AAD firing altitude while in freefall is not a situation that is standard by no stretch. That's why most of us pull somewhere at or above 2K

here, analyst, riddle me this : If two identical reserves are deployed at the same time, will they both open at the same altitude and if so, will the opening feel identical if one had microlines and another had dacron ?

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You are ignoring the fact that the TSO testing still has the same limits for time to open and distance traveled.

Making the opening smoother over more of the available time results in lower overall forces, not a longer time for opening.

No matter how you consider it, meeting the TSO specifications still called for an opening that took no more than a certain amount of time and no more than a certain number of feet.

Once those limits are met, wouldn't you prefer a canopy that did not brutalize your body to one that did?

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Reserve opening speed is important because think about AAD fires at 750ft. You'll have a 10sec reserve ride assuming everything opens as planned. If there is a 0.5sec reserve pilot chute hesitation, then there is a 3sec reserve ride. Any thing else goes wrong and you're dead. Having a softer opening reserve is just depleting your margin of safety.

Maybe I'm over analyzing this but these are things I think about when I choose my gear.




It's like listening to Bill Booth's interview from this link:
http://www.youtube.com/watch?v=tQuJr5wuvSw (from 7:25)


Don't forget about the TSO C23d requirements. Softer doesn't always mean slower.

Blue skies
"My belief is that once the doctor whacks you on the butt, all guarantees are off" Jerry Baumchen

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***In Reply To
Reserve opening speed is important because think about AAD fires at 750ft. You'll have a 10sec reserve ride assuming everything opens as planned. If there is a 0.5sec reserve pilot chute hesitation, then there is a 3sec reserve ride. Any thing else goes wrong and you're dead. Having a softer opening reserve is just depleting your margin of safety.

Maybe I'm over analyzing this but these are things I think about when I choose my gear.




It's like listening to Bill Booth's interview from this link:
http://www.youtube.com/watch?v=tQuJr5wuvSw (from 7:25)



Yes, thanks Mr Booth for that little piece of information.

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you are ignoring the fact that the TSO testing still has the same limits for time to open and distance traveled.

Making the opening smoother over more of the available time results in lower overall forces, not a longer time for opening.

No matter how you consider it, meeting the TSO specifications still called for an opening that took no more than a certain amount of time and no more than a certain number of feet.

Once those limits are met, wouldn't you prefer a canopy that did not brutalize your body to one that did?



So basically what most people are saying here is a TSOd reserve won't take more than 300ft or 3secs to open. An Optimum may be opening smoothly over that 300ft or 3secs to give a soft opening.

These arbitrary numbers required for TSO have been decided as satisfactory (safe) for reserves. Opening faster than this has no advantage. If anything, I'm assuming your faster opening reserve may sacrifice maximum weight and speed performance since the reserve has to disipate more energy in a short spike.

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here, analyst, riddle me this : If two identical reserves are deployed at the same time, will they both open at the same altitude and if so, will the opening feel identical if one had microlines and another had dacron ?



I know where you're going with this, and I know the answer you want. Yes, the dacron lines will make the reserve open softer in the same altitude because of the slight stretch.

But since we're in the over analyzing frame of mind right now, what if the slight stretch from the dacron changed the trim enough to have an affect on opening. The friction from the thicker lines will also slow the descent of the slider :)

No need to respond to this, I'm not that pedantic.

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you are ignoring the fact that the TSO testing still has the same limits for time to open and distance traveled.

Making the opening smoother over more of the available time results in lower overall forces, not a longer time for opening.

No matter how you consider it, meeting the TSO specifications still called for an opening that took no more than a certain amount of time and no more than a certain number of feet.

Once those limits are met, wouldn't you prefer a canopy that did not brutalize your body to one that did?



So basically what most people are saying here is a TSOd reserve won't take more than 300ft or 3secs to open. An Optimum may be opening smoothly over that 300ft or 3secs to give a soft opening.



Not "won't", "shouldn't" is more accurate. USPA and PIA have told us that there are a number of poorly explained cases of reserves that seemed to have the time and altitude to open, but didn't. The possible explanation at this point is that some rigs are so tight that the deployment was not able to meet the TSO'd specs. On another thread I reiterated some other advice that we should be choosing the canopies, and then the rigs, not the other way around.

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These arbitrary numbers required for TSO have been decided as satisfactory (safe) for reserves. Opening faster than this has no advantage. If anything, I'm assuming your faster opening reserve may sacrifice maximum weight and speed performance since the reserve has to disipate more energy in a short spike.



No matter what you do, there is a point where it is just too late. Call them arbitrary if you like. Faster openings might be able to make it even lower than it is now, but, as you say, the gear will need to be that much stronger to remain viable.

Bottom line? I would not worry that the Optimum family of reserve increases the time or altitude required to open, compared to other reserves.

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Yes, thanks Mr Booth for that little piece of information.



Three things that I got from that video. He mentions at 2000 feet you have 14 seconds to impact. Actually you only have about 10 seconds and the last 3 or 4 don’t count.
He refers to soft handles being hard to feel especially with gloves. He was the one that invented the soft handle. Finally he mentions a 1 second PC delay on a AAD deployment. The major cause of reserve deployment is the container with tight corners and up to six flaps for the PC to push through. What does Mr. Booth manufacture?

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But since we're in the over analyzing frame of mind right now, what if the slight stretch from the dacron changed the trim enough to have an affect on opening. The friction from the thicker lines will also slow the descent of the slider :)



During deployment of a ram air canopy all lines load more or less at the same time. What difference there may be is not enough to change line trim since most trim specs. are plus or minus ¼” to ½”.
It is not the size of the lines that slows the slider down it is the surface texture of the line.

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These arbitrary numbers required for TSO have been decided as satisfactory (safe) for reserves. Opening faster than this has no advantage. If anything, I'm assuming your faster opening reserve may sacrifice maximum weight and speed performance since the reserve has to disipate more energy in a short spike.



When did you decide that the test requirements for TSO certification were arbitrary? It has been determined over years of development and testing that these “arbitrary numbers” will ensure that a canopy or H/C system will survive forces developed during its intended use. The test numbers are 120% of Max. operating weight and speed.

Loading a reserve at 1.23:1 with 240 jumps is an issue you should be looking into.

Sparky
My idea of a fair fight is clubbing baby seals

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John LeBlanc explained to me that the Optimum starts to inflate slightly earlier (than an older pattern PD reserve) - in the opening sequence - but it takes longer to inflate. We are talking fractions of a second ... So Optimum opening shock is spread more evenly over the three seconds .. required by TSO ...

Both designs had to demonstrate opening within 3 seconds and 300 feet to satisfy TWO requirements.

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John LeBlanc explained to me that the Optimum starts to inflate slightly earlier (than an older pattern PD reserve) - in the opening sequence - but it takes longer to inflate. We are talking fractions of a second ... So Optimum opening shock is spread more evenly over the three seconds .. required by TSO ...

Both designs had to demonstrate opening within 3 seconds and 300 feet to satisfy TWO requirements.



Rob, it is 3 seconds or 300 feet not both.

Sparky


4.3.6 Functional Test (Normal Pack All Types):

For all 4.3.6 tests the maximum allowable opening time for parachute canopies with a maximum operating weight of 250 lb (113.4 kg) or less, is 3 s from the moment of pack opening. For parachutes with a maximum operating weight of greater than 250 lb (113.4 kg) the maximum allowable opening time shall be increased by 0.01 s for every pound of maximum operating weight in excess of 250 lb (113.4 kg).

Alternatively altitude loss instead of time may be measured and the maximum allowable altitude loss may be calculated as follows.

For all 4.3.6 tests the maximum allowable altitude loss for parachutes with a maximum operating
weight of 250 lb (113.4 kg) or less is 300 ft (91.5 m) from the altitude at pack opening. For parachutes with a maximum operating weight of greater than 250 lb (113.4 kg) the maximum allowable altitude loss shall be increased by 1 ft for every pound of maximum operating weight in excess of 250 lb (113.4 kg).



My idea of a fair fight is clubbing baby seals

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John LeBlanc explained to me that the Optimum starts to inflate slightly earlier (than an older pattern PD reserve) - in the opening sequence - but it takes longer to inflate. We are talking fractions of a second ... So Optimum opening shock is spread more evenly over the three seconds .. required by TSO ...

Both designs had to demonstrate opening within 3 seconds and 300 feet to satisfy TWO requirements.



Rob, it is 3 seconds or 300 feet not both.

Sparky


4.3.6 Functional Test (Normal Pack All Types):

For all 4.3.6 tests the maximum allowable opening time for parachute canopies with a maximum operating weight of 250 lb (113.4 kg) or less, is 3 s from the moment of pack opening. For parachutes with a maximum operating weight of greater than 250 lb (113.4 kg) the maximum allowable opening time shall be increased by 0.01 s for every pound of maximum operating weight in excess of 250 lb (113.4 kg).

Alternatively altitude loss instead of time may be measured and the maximum allowable altitude loss may be calculated as follows.

For all 4.3.6 tests the maximum allowable altitude loss for parachutes with a maximum operating
weight of 250 lb (113.4 kg) or less is 300 ft (91.5 m) from the altitude at pack opening. For parachutes with a maximum operating weight of greater than 250 lb (113.4 kg) the maximum allowable altitude loss shall be increased by 1 ft for every pound of maximum operating weight in excess of 250 lb (113.4 kg).




No matter which, on another thread someone said that it was only the canopy that had to meet these limits, and said that it was from when the canopy was out of the bag.

According to the quoted sections, that's not correct. It is from pack opening.

That means that it includes actions of the container.

When I find that thread again, I'll mention this there.

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That means that it includes actions of the container.



There is nothing that requires that the test be done with a TSO’d harness and container when test just the canopy. You can make the “pack” any way you wish. All it has to do is contain the canopy, bridle and pilot chute in the manner it was designed to and allow it deploy as designed. A very knowledgeable rigger friend of mine, who has received TSO certification in the past, suggested that you could use something like this. See attachment. The trick is understanding how to “read” the regs.

Sparky


http://i397.photobucket.com/albums/pp55/mjosparky/Skydiving/Pack.jpg

My idea of a fair fight is clubbing baby seals

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4.3.6 Functional Test (Normal Pack All Types):

For all 4.3.6 tests the maximum allowable opening time for parachute canopies with a maximum operating weight of 250 lb (113.4 kg) or less, is 3 s from the moment of pack opening. For parachutes with a maximum operating weight of greater than 250 lb (113.4 kg) the maximum allowable opening time shall be increased by 0.01 s for every pound of maximum operating weight in excess of 250 lb (113.4 kg).

Alternatively altitude loss instead of time may be measured and the maximum allowable altitude loss may be calculated as follows.

For all 4.3.6 tests the maximum allowable altitude loss for parachutes with a maximum operating
weight of 250 lb (113.4 kg) or less is 300 ft (91.5 m) from the altitude at pack opening. For parachutes with a maximum operating weight of greater than 250 lb (113.4 kg) the maximum allowable altitude loss shall be increased by 1 ft for every pound of maximum operating weight in excess of 250 lb (113.4 kg).



The larger PD Optimums reserves have max exit weights in excess of 250lbs (260lb to 290lb). If I'm reading this right, it means they can indeed open slower and still be within TSO specs.

e.g. PD Optimum 253 - Max weight 290lb. This gives it an extra 0.4secs or 40 feet.

Does it really matter? probably not. I'm just saying.

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The larger PD Optimums reserves have max exit weights in excess of 250lbs (260lb to 290lb). If I'm reading this right, it means they can indeed open slower and still be within TSO specs.

e.g. PD Optimum 253 - Max weight 290lb. This gives it an extra 0.4secs or 40 feet.

Does it really matter? probably not. I'm just saying.



You gotta just keep poking. If it doesn't matter why bring it up?

Sparky
My idea of a fair fight is clubbing baby seals

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Rob, it is 3 seconds or 300 feet not both.

Sparky



Sparky,

I am interested in the 3 seconds regardless of reserve type. At stable freefall speeds it is approximately 200 feet per second so 3 seconds = 600 feet. I would expect an exponential deceleration as the drag of the inflating reserve increases so achieving anything like 300feet in 3 seconds would seem to be a very tall order. As a result I guess that if a reserve is tested using the 3 second test method it is not likely to be opening in 300feet. Does all that make sense?

Nigel
Experienced jumper - someone who has made mistakes more often than I have and lived.

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That means that it includes actions of the container.



There is nothing that requires that the test be done with a TSO’d harness and container when test just the canopy. You can make the “pack” any way you wish. All it has to do is contain the canopy, bridle and pilot chute in the manner it was designed to and allow it deploy as designed. A very knowledgeable rigger friend of mine, who has received TSO certification in the past, suggested that you could use something like this. See attachment. The trick is understanding how to “read” the regs.

Sparky


http://i397.photobucket.com/albums/pp55/mjosparky/Skydiving/Pack.jpg



Yes, I know Jerry too.

And yes, I now understand that the speeds we are talking about here don't say that a pack is a real container.

Right now I would like to know what it means for our actual containers to be certified.

I don't have the docs, except what parts I can find in other books.

Right now it seems that a lot of people are being misled to believe that there are any actual performance specs for the complete reserve systems as they are actually carried on our backs.

I'll count myself in the group of those so misled.

But I am learning.

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Rob, it is 3 seconds or 300 feet not both.

Sparky



Sparky,

I am interested in the 3 seconds regardless of reserve type. At stable freefall speeds it is approximately 200 feet per second so 3 seconds = 600 feet. I would expect an exponential deceleration as the drag of the inflating reserve increases so achieving anything like 300feet in 3 seconds would seem to be a very tall order. As a result I guess that if a reserve is tested using the 3 second test method it is not likely to be opening in 300feet. Does all that make sense?

Nigel

This test is done static line from an aircraft in level (horizontal) flight, at three different airspeeds, or from a cutaway main. So there is very little VERTICAL velocity at pack opening. That is how the 300 feet test can be passed. When a reserve is opened at terminal velocity, 600 feet is a more realistic number. Add 200 feet for a one second pilot chute hesitation, a common occurrence, and you have 800 feet. Not a good situation is your AAD fired at 750 feet is it? This is why I would like to see AAD's set a little higher.

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" .... So there is very little VERTICAL velocity at pack opening. That is how the 300 feet test can be passed. When a reserve is opened at terminal velocity, 600 feet is a more realistic number. Add 200 feet for a one second pilot chute hesitation, a common occurrence, and you have 800 feet. Not a good situation is your AAD fired at 750 feet is it? This is why I would like to see AAD's set a little higher.

"

...........................................................................

Then we would have to listen to numerous complaints about AADs "mis-firing" below 2,000 feet!
Hah!
Hah!

I am so old that I have seen one FXC 12000 mis-fire at 7,000 feet. All the rest of those FXC "mis-fires" looked like less than 2,000 feet. What is any junior jumper doing in freefall below 2,000 feet?

Then when Cypres was introduced, we heard complaints about Cypres "mis-firing" at 1,000 feet. What is any licensed jumper doing in freefall at 1,000 feet?

So Bill, if you raise AAD firing altitudes, you will just have to listen to a new round of excuses about how their AAD "mis-fired!"
Hah!
Hah!

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What is any junior jumper doing in freefall below 2,000 feet?

What is any licensed jumper doing in freefall at 1,000 feet?



Falling. ;)
"I may be a dirty pirate hooker...but I'm not about to go stand on the corner." iluvtofly
DPH -7, TDS 578, Muff 5153, SCR 14890
I'm an asshole, and I approve this message

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Rob, it is 3 seconds or 300 feet not both.

Sparky



Sparky,

I am interested in the 3 seconds regardless of reserve type. At stable freefall speeds it is approximately 200 feet per second so 3 seconds = 600 feet. I would expect an exponential deceleration as the drag of the inflating reserve increases so achieving anything like 300feet in 3 seconds would seem to be a very tall order. As a result I guess that if a reserve is tested using the 3 second test method it is not likely to be opening in 300feet. Does all that make sense?

Nigel

This test is done static line from an aircraft in level (horizontal) flight, at three different airspeeds, or from a cutaway main. So there is very little VERTICAL velocity at pack opening. That is how the 300 feet test can be passed. When a reserve is opened at terminal velocity, 600 feet is a more realistic number. Add 200 feet for a one second pilot chute hesitation, a common occurrence, and you have 800 feet. Not a good situation is your AAD fired at 750 feet is it? This is why I would like to see AAD's set a little higher.



Thanks that is very interesting.I wondered how they measured the 300 feet when it is used.
Experienced jumper - someone who has made mistakes more often than I have and lived.

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Thanks that is very interesting.I wondered how they measured the 300 feet when it is used.




Well, I suppose you could drop it at 300'... if it hits before its inflated... well. ;)
"I may be a dirty pirate hooker...but I'm not about to go stand on the corner." iluvtofly
DPH -7, TDS 578, Muff 5153, SCR 14890
I'm an asshole, and I approve this message

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