C23d average peak force values?

[pchapman 261]

Has anyone made a list of Average Peak Forces for some different reserves, a value required by TSO-C23d certification?

For example, neither PD nor Aerodyne list it in their manuals. Jumpshack has the stats in their manual.

The differences would be interesting to see even if one can't conclude too much from the numbers. Does a lower number mean a slower opening reserve, or just a better managed deployment sequence less likely to have hard openings?

I was just thinking about this as I noticed most Angelfire reserves are listed as 3465 lbs max, while I just packed an Optimum 160 and I thought I saw a number like 2400 lbs. I might have remembered it wrong but that's quite a difference. (... that would fit with the 'softer opening reserve' image of the Optimum.)

I also notice that not every canopy gets its own number -- for example, all the small/medium Angelfire reserves with one max certificated weight have one Average Peak Force value, while the larger sizes with another certification weight have a second Average Peak Force. Or perhaps all have the same value -- the manual shows all the same values, while a Word document once seen on this site has the two different values. I don't know which is correct.

[JerryBaumchen 1,048]

Hi Peter,

Quote

a list of Average Peak Forces

This would be great info for people. You need to get working in it right now.

It has been many years since I had a sitdown with one of the major players at PD on this subject. He said, that all other factors being equal, the peak force loads are a result of fill time. In other words, the smaller the canopy ( less air volume to fill it ) would result in higher forces.

It is my understanding ( from the above sitdown discussion ) that the PDR 99 has a measured peak force of over 5,000 lbs. To the best of my knowledge, this is the only TSO C23d/f component that has a measured peak force of over 5,000 lbs.

Most of the harnesses that I have seen, that are certificated under TSO C23d, have about 1800 - 2500 lbs marked on the data panel.

Back about 1980, I received a letter ( which was a reply to a letter that I wrote to them ) from Jim Ruetter, V-P of Pioneer Parachute Company. He said that it was not possible to obtain a 5,000 lb load using a 28 ft canopy & the weight/speed table in TSO C23b/NAS 804. I found that to be a very interesting comment.

A fair number of people think that a harness certificated under the standard category of C23b has a rated load of 5,000 lbs, and that is simply not true.

Let us know when you get the data info ready to publish.



JerryBaumchen

[JohnSherman 1]

Quote

It is my understanding ( from the above sitdown discussion ) that the PDR 99 has a measured peak force of over 5,000 lbs. To the best of my knowledge, this is the only TSO C23d/f component that has a measured peak force of over 5,000 lbs.

If someone has generated 5000 pounds opening shock at 180KTS and 264 pounds with a diapered square and it worked properly, can you imagine what the shock produced by that canopy at 100KTS and 200 pounds (normal terminal skydiver opening)would be?

Quote

Back about 1980, I received a letter ( which was a reply to a letter that I wrote to them ) from Jim Ruetter, V-P of Pioneer Parachute Company. He said that it was not possible to obtain a 5,000 lb load using a 28 ft canopy & the weight/speed table in TSO C23b/NAS 804. I found that to be a very interesting comment.

Jim was correct. He knew, as do I, the origin and foundation of the table. The author (Heinrich Helmut) acknowledged the total inaccuracy of the table 4 days before his passing at the AIAA conference in Houston. Dan Poynter can verify this. Additionally, this is why that chart should not be used for determination of weight and speed for TSO C23b components.

Quote

A fair number of people think that a harness certificated under the standard category of C23b has a rated load of 5,000 lbs, and that is simply not true.

I would disagree as the Racer harness Certificated under TSO C23b does have a rated load of 5000 pounds and we consider it unlimited in weight and speed. It was tested and certified to a measured load of 5000 pounds. This was done at 200 MPH with a 350 pound load with a navy conical undiapered. They were the most horrific openings I have ever seen. It sounded like a 155 howitzer.

[JerryBaumchen 1,048]

Hi John,

Quote

I would disagree as the Racer harness Certificated under TSO C23b does have a rated load of 5000 pounds and we consider it unlimited in weight and speed.

Who rated it?

The FAA does not issue any load rating to any component certificated under C23(b).

I am not saying what your harness was tested to. I am not saying what any measured peak force(s), that you might have measured during any testing, were.

I stand by my comments regarding FAA load ratings.

JerryBaumchen

[JohnSherman 1]

I think we are talking semantics here. Under TSO C23b "Standard Category" is Proof loaded to 5000 pounds. The Approval by the FAA, under the Standard (5000 lbs) or Low Speed Category (3000 LBS), is the load rating.

Maybe what you mean by load rating is the Weight and Speed to which a component or system is certificated to. I call that performance rating. To me "load" is in pounds force.

BTW: You understand that is is not possible to properly match components for strength using the weight and speed system of certification.

One more point: A Parachute Labs Reserves are marked with the "Maximum" Force encountered during testing rather than the "Average" which is called for. It seems foolish to me to list the Average force encountered when you are trying to assure the strength of the matted component won't be exceeded. If one were to match a harness with a capability of 2000 pounds to a canopy with and average of 2000 pounds then a max force would exceed the harness strength.

[RiggerLee 61]

And for the most part this has not shown it self to be a problem.

However just recently we blew up an upper junction on a base rig. It had "integral risers". Think reserve risers. They used a slightly lighter confluence wrap and did not have the advantage of a three ring or any thing surrounding the stack to help prevent catastrophic failing. Still reserve risers are built in the same way some times with no confluence wrap at all.

So we just had an almost catastrophic failure of what was in essence a reserve harness from a hard opening. I just wasn't sure if you had followed it or not.

Waving arms! FAILURE, FAILURE, FAILURE!

Just saying.

Lee

Lee
[email protected]
www.velocitysportswear.com

[Deyan 31]

Here is what's written on the Techno reserves. The only missing size is 98, but I have never seen that size reserve in my life. Maybe they have made only 2 canopies from it :)

Techno 115 - 2100 daN
Techno 128 - 1520 daN
Techno 140 - 2100 daN
Techno 155 - 2160 daN
Techno 190 - 1260 daN
Techno 240C- 1120daN

Some other reserves

PDR 113 - 3639 lbs
Optimum 106 - 3951
Optimum 126- 3951
Optimum 218 - 2123
Smart 120 - 5.36 G
Smart 190 - 5.59 G

Few years back I did collect all that info because I thought that it's interesting to know. Then I find out that it's actually pretty useless since stuff don't fail on their "average" force. Then my computer crashed and I didn't care to recover that info.

Some other things to think about. Decelerator reserve from 2003 ( I think) it's TSO C23d tested , but doesn't have any average force written on the label.
Maybe there are more TSO C23d items without that info printed.

I hope any of that helps

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

[pchapman 261]

Nice data!

The info we have here is all still a bit fragmentary, but shows how much variation there is, between brands, between sizes in the same brand. Sometimes the smaller canopies open harder, sometimes the variation with size looks almost random.

[RiggerLee 61]

Lets say you had a design with a number of sizes but only three slider sizes. You might get the largest opening a bit hard, then the next size down a bit softer, and a bit softer for the next. Then a sharp spike upwards in opening force as you went to a smaller slider size, and again a decrease for the next few canopies. Not saying this is the case. I'm just pointing out a possible reason. And then some time you just build a hard opening canopy.

Lee

Lee
[email protected]
www.velocitysportswear.com

[dpreguy 14]

Can someone explain an "Average" peak force, as distinguished from a a "Measured" peak force?

I haven't visited TSO D for a while, so could someone post the paragraph or two (not the whole thing) where "average" peak force is discussed?

Average and peak are contradictory terms. (Unless what is being done is to simply average the 'measured peak forces' tests as observed.) I get that. Guess I need to figure out the SAE or FAA definition of an "average peak force".

[mark 102]

dpreguy

Can someone explain an "Average" peak force, as distinguished from a a "Measured" peak force?

"Peak force" is measured on a single test. "Average peak force" is the average over a series of tests.

Mark

[JerryBaumchen 1,048]

Hi Deyan,

Nice work.

Here is the Techno values in lbs:

Techno 115 - 2100 daN = 4721 lbs
Techno 128 - 1520 daN = 3417 lbs
Techno 140 - 2100 daN = 4721 lbs
Techno 155 - 2160 daN = 4856 lbs
Techno 190 - 1260 daN = 2832 lbs
Techno 240C- 1120daN = 2518 lbs

The converter is here:

http://www.convertunits.com/from/daN/to/pound-force

OK, more info to keep track of.

To get the Smart values in lbs you will need to know some more info on the weight of the drop test dummy.

Jerry Baumchen

[dpreguy 14]

Average a series of measured peak forces. Got it.

[Deyan 31]

JerryBaumchen

Hi Deyan,

Nice work.

Here is the Techno values in lbs:

Techno 115 - 2100 daN = 4721 lbs
Techno 128 - 1520 daN = 3417 lbs
Techno 140 - 2100 daN = 4721 lbs
Techno 155 - 2160 daN = 4856 lbs
Techno 190 - 1260 daN = 2832 lbs
Techno 240C- 1120daN = 2518 lbs

The converter is here:

http://www.convertunits.com/from/daN/to/pound-force

OK, more info to keep track of.

Jerry Baumchen

Hi Jerry,

I posted the numbers the way they were written on the data label, so people can see that even something so simple like writing data can be left for interpretation from the manufactures. Pounds, Decanewtons, G's....you name it

Quote

To get the Smart values in lbs you will need to know some more info on the weight of the drop test dummy.

I would guess that would be the max weight on the label X 1.2

Cheers

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

[JerryBaumchen 1,048]

Hi Deyan,

Re: "To get the Smart values in lbs you will need to know some more info on the weight of the drop test dummy."

Quote

I would guess that would be the max weight on the label X 1.2

I left it sort of open-ended because I don't know those numbers.

Anyone????

Jerry Baumchen

[Deyan 31]

Hi Jerry,

From the manual:

Smart 99, 110, 120, 135 are listed as 220lbs max. exit weight
Smart 150, 160, 175, 190, 220 are listed as 265 max exit weight
Smart 250 is listed as 300 lbs max. exit weight.

Based on those numbers, the dummy weigh should've been no less than 264 lbs. on the small sizes and 318 lbs on the sizes till 220 sq ft.

Am I correct, or did I miss something?

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

[JerryBaumchen 1,048]

Hi Deyan,

Quote

Am I correct, or did I miss something?

The problem IMO is that these numbers are what they list in the manual. They may be less than the numbers that would result from the actual testing.

Jerry Baumchen

PS) Using the 5.36Gs and the 220 = 1179 lbs for the 120 canopy. Using the 5.59Gss and the 265 = 1481 lbs for the 190 canopy.

[Deyan 31]

Hi Jerry,

I think you forgot to multiple the listed weight X 1.2

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

[JerryBaumchen 1,048]

Hi Deyan,

Quote

: Hi Jerry,

I think you forgot to multiple the listed weight X 1.2

And you would be correct.

Note to self: Do not post when you are just waking up.

Or better yet: Do not do calculations when you are just waking up.



Jerry Baumchen

PS) Once again) Using the 5.36Gs and the 220 (1.2) = 1415 lbs for the 120 canopy. Using the 5.59Gs and the 265 (1.2) = 1777 lbs for the 190 canopy.

[JerryBaumchen 1,048]

Hi folks,

And to add to this vast quantity of knowledge; I have a well-worn Reflex harness/container here and it is placarded:

AVERAGE MAX SHOCK LOAD 1920 LBS

Jerry Baumchen

[pchapman 261]

JerryBaumchen

Reflex harness/container here and it is placarded:
AVERAGE MAX SHOCK LOAD 1920 LBS

Wow, that low?
They must have found a nice soft opening reserve!
C-23d does allow using any reserve that still meets the 3 second opening rule. (Ref: AS8015B, sec 4.3.4 and 4.3.6, with slight mods for higher weights)

In this thread we've seen the opening forces at max weight & speed (*1.2) can vary a lot.

Is it correct there's no requirement for a C-23d harness to withstand the loads listed for a C-23d canopy installed in it? So they can test the rig with a soft opening canopy but you can put in a canopy that opens a whole lot harder? (at the maximum limits)

The rules looks similar in TSO C-23f / TS-135.

I recall some discussions about stuff like this but not the details.

[Hooknswoop 19]

PDR 113 - 3639 lbs
Optimum 106 - 3951
Optimum 126- 3951

So what happens if you put one of these reserves into a container that was TSO'd under C23b, Low Speed (3000lbs) category?

Does that mean the reserve is capable of producing more force during opening than the harness is certified to?

Derek V

[RiggerLee 61]

Some people are arguing that.

Lee

Lee
[email protected]
www.velocitysportswear.com

[JerryBaumchen 1,048]

Hi Derek,

Quote

more force during opening than the harness is certified to?

As Lee says, some people are 'discussing' that.

I would suppose, after reading all of John Sherman's thoughts, it would depend upon who is doing the certifying.

In TSO C23(b), while there is 'supposedly' testing to some load(s), the FAA does not have any req'ment for any placarding on any component, certifying it to any load carrying capability.

Does that sound sufficiently 'lawyer-ish' to you?

I contend that no component that is certificated under C23(b) carries any rated load.

Others have other thoughts,

Jerry Baumchen

[mark 102]

JerryBaumchen

I contend that no component that is certificated under C23(b) carries any rated load.

Nor is there any maximum deployment speed. (The 150mph limit for low speed category is aircraft speed, not freefall speed.)

Mark