Reserves and Max weight

[freeflajankie 0]

I have been looking at a whole bunch of different reserves.

Does anyone know how come they differ so much in max exit weight even if they have the same TSO.
The canopies listed below all have the TSO C23D

Example:
PD 99 reserve - Max weight 220lbs
Rmax 108 - Max weight 140lbs
Smart 99 - Max weight 220lbs
Speed 2000, 120 - Max weight 158lbs
Eagle Reserve 140 - Max weight 145lbs

Ankie

Skydivers are a bunch of insensitive jerks...
And that's why I don't skydive anymore!

[EAerodyne 0]

Ankie,

what is even more confusing when you start looking at those kind of numbers is that the wingloading is so much different for each canopy as there are virtually no 2 manufacturers that measure their canopies the same. When the Max is for example 220lbs on a 99 equals a 2.2 wingloading. Imagine what that results in when that 99 square foot measurment is actually 89 square feet just due to different measuring techniques.

I honestly wish that the PIA would standardize a measurement technique that can be applied, regardless of how it is measured it'd at least provide a constant from which to work from and all canopies would be measured equally.

This would provide for a far safer skydiving environment where people can make an educated choice as to what wingloading they want to be loading a canopy at.

kind regards

[Liemberg 0]

Wingload? (i.e. if a manufacturer looks beyond TSO C23D which says something like "so many pounds / that speed / prototype survived in one piece - therefore max weight & max deployment speed" It should be the same for all the canopies you mentioned. Now the young heroin is up in the air with an unscathered parachute above her head, but can she land it? The mfg wonders, the canopies are different, different strokes for different folks....)

"Whoever in discussion adduces authority uses not intellect but memory." - Leonardo da Vinci
A thousand words...

[mjosparky 3]

Quote

I have been looking at a whole bunch of different reserves.

Does anyone know how come they differ so much in max exit weight even if they have the same TSO.
The canopies listed below all have the TSO C23D

Example:
PD 99 reserve - Max weight 220lbs
Rmax 108 - Max weight 140lbs
Smart 99 - Max weight 220lbs
Speed 2000, 120 - Max weight 158lbs
Eagle Reserve 140 - Max weight 145lbs

Ankie

All reserve canopies are test to the following:

4.3.4 Strength Test: No material(s) or device(s) that attenuates shock loads and is not an integral part of the

parachute assembly or component being certificated may be used. Tests may be conducted for either a

complete parachute assembly or separate components. There shall be no evidence of material, stitch,

or functional failure that will affect airworthiness. The same canopy, harness, component, and/or riser(s)

shall be used for all 4.3.4 tests. Opening forces shall be measured on all 4.3.4 tests. The parachute

must be functionally open within the number of seconds calculated for 4.3.6 tests. Parachute

assemblies shall be tested in accordance with the following schedule


a. Test weight = Maximum operating weight limit x 1.2

b. Test speed = Maximim operating speed limit x 1.2

However, test weight must be not less than 264 lb (119.7 kg) and the test speed must be not less than

180 KEAS (333.4 km/h) for reserve and emergency parachute assemblies; for dual harness parachute

assemblies for test weight must not be less than 480 lb (217.7 kg) and the test speed must not be less

than 210 KEAS (388.9 km/h).***


These weights and speeds are what the canopy is tested to take on opening. The max. suspended weight or max. exit weight is what the manufacture feels the jumper can take on landing.


I hope this helps.


Sparky
My idea of a fair fight is clubbing baby seals



			
		

[councilman24 36]

Quote

I honestly wish that the PIA would standardize a measurement technique that can be applied, regardless of how it is measured it'd at least provide a constant from which to work from and all canopies would be measured equally.

This would provide for a far safer skydiving environment where people can make an educated choice as to what wingloading they want to be loading a canopy at.

PIA does have a measurement standard. But manufacturers choose not to use it. Yes, it may be outdated and PIA technical committee is working on a new one.

The way to get what you want is to participate! YOU are PIA as much as anybody. Wishing for PIA to do something is wishing for YOURSELF (in the form of your companies representatives) to do something. Only work done by the volunteers gets acomplished and only the volunteers that participate get input.

The PIA business meeting schedule will be posted shortly. I look forward to seeing Aerodyne's representative at the technical committee meeting.

You really should stop beating up on yourself like that.

I'm old for my age.
Terry Urban
D-8631
FAA DPRE

[DrewEckhardt 0]

Quote

I have been looking at a whole bunch of different reserves.

Does anyone know how come they differ so much in max exit weight even if they have the same TSO.

Some companies rate them at the legal maximum and give lower recomendations (PD)

Some rate them at a reasonable maximum, with different companies having different ideas of "reasonable."

Some measure differently.

[EAerodyne 0]

Hi Terry,

seems like i managed to rile you up. Wasn't intended honestly.

I was employed by PD for 17 years and only recently moved to Aerdoyne last year. I would like to point out that although members of PD have either been members of the said technical committee and possibly even chaired a couple. There is still a very undecided manner in which to measure a canopy correctly. Aerodyne does have members on the committee already (the change from PISA to Aerodyne was done before I even joined Aerodyne) So yes you will see our technical representative at the committee meeting.

The last thing I'd like to comment on is that the PIA is working on a new technique. This has been work in progress for almost (if I am not mistaken) 4 years. The reason it isn't further today than it was then is because of the differences between manufacturers (also present on the committee) to come to a common agreement.

My comments were not so much directed at the PIA but more to those responsible for finalizing this task of adopting a new measuring technique. I believe such frustrations are the same frustrations that have had many a volunteer finally give up attending meetings where nothing is finalized.

I have a huge respect for PIA and all the volunteer work done. I never meant to imply that PIA was solely responsible for the lack of a standard adopted by all manufacturers.

kind regards and see you at the symposium

[councilman24 36]

Didn't mean anything personal. But you did touch a nerve.

See you in January.

Terry

I'm old for my age.
Terry Urban
D-8631
FAA DPRE

[Canuck 0]

Question for you Bushman, seeing how you have worked for both PD and Aerodyne, do those two companies use the same measuring technique? Would the PD 99 and the Smart 99 be the same size?

Also, using the PIA standard, PD reserves are bigger than they are marked as (ie. the 126 is listed at 137 on the PIA chart). Same true then for the Smart?

Thanks,

Canuck

[mjosparky 3]

Bushman,

Could you explain the method PD uses to measure the sq. ft. of their canopies and how it differs from other manufactures?

I am sure this would be valuable knowledge to many who post here. (myself included)

Thanks,

Sparky

My idea of a fair fight is clubbing baby seals

[riggerrob 558]

Quote

Bushman,

Could you explain the method PD uses to measure the sq. ft. of their canopies and how it differs from other manufactures?

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

At the last PIA Symposium, I asked Bill Coe to explain P.D.'s canopy measuring method and never go tan answer.
Somebody else explained that P.D.'s method is roughly equal to bottom skin area.
Maybe if enough of us ask Mr. Coe, we will eventually get an answer.

• Quote

[mjosparky 3]

Quote

Quote

Bushman,

Could you explain the method PD uses to measure the sq. ft. of their canopies and how it differs from other manufactures?

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

At the last PIA Symposium, I asked Bill Coe to explain P.D.'s canopy measuring method and never go tan answer.
Somebody else explained that P.D.'s method is roughly equal to bottom skin area.
Maybe if enough of us ask Mr. Coe, we will eventually get an answer.

Hmmmmm.....Coming up with an answer might be tougher that it looked. You are one of the guys I was counting on knowing.

When I make King, all this will change.
Sparky

My idea of a fair fight is clubbing baby seals

• Quote

[EAerodyne 0]

Hi Sparky,

I will gladly devulge how we measure our canopies however would prefer to let other manufacturers answer the question related to their products. Just don't want to be seen as bashing other companies and so forth and with respect to other manufacturers they can get involved if they feel they'd like to.

Aerodyne Research measures the bottom skin of the canopy. We find that this gives us the most acurate measurement when measuring elliptical canopies and so have chosen it as our standard for all our canopies. From the furtherest point aft to the furtherest point fore and from furtherest point left to right. Excluding the stabilizers.

The other forms of measurement used by other manufacturers include top skin measurement, Inflated projection measurement, and 2 inches back from the leading edge top skin measurement. Some may even have other measuring techniques but these are the most common.

For reference though, the TEMPO which was a PISA product (now Aerodyne Systems) was measured on the top skin.

I hope that this helps

Kind regards

[PhreeZone 15]

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For reference though, the TEMPO which was a PISA product (now Aerodyne Systems) was measured on the top skin.

Am I correct that if you say a canopy is a 150 by measuring the topskin, its smaller then if you say a canopy is a 150 by measuring the bottom skin?

Yesterday is history
And tomorrow is a mystery

Parachutemanuals.com

[mark 102]

Quote

Am I correct that if you say a canopy is a 150 by measuring the topskin, its smaller then if you say a canopy is a 150 by measuring the bottom skin?

That's correct for most canopies these days. The width of the cells is greater at the top than at the bottom. That isn't the case for older canopies, which have top and bottom cell widths the same.

Mark

[mjosparky 3]

Edward,

Thank you for the information. Now I will end spending a couple of days at the shop hanging every canopy I can find and measuring. Thats what happens when you anal.

Sparky

My idea of a fair fight is clubbing baby seals

[PhreeZone 15]

Post what you come up with. I'd be courious to see what reserves are really what size

Yesterday is history
And tomorrow is a mystery

Parachutemanuals.com

[EAerodyne 0]

You are a good man Sparks :-), I don't care what they all say about you.

Bushman

[riggerrob 558]

Only Para-Flite and PISA canopies were measured by the PIA method - seeing as how Manley Bulter wrote the PIA standard while working at Para-Flite and PISA built their first few ram-air reserves (5-cell Swifts) under license to Para-Flite.
The PIA standard involves measuring chord as the longest dimension on the rib (a straight line from the top leading edge to trailing edge). PIA then measures span on the top skin, a little way (2 inches ?) back from the leading edge.

If you measure a Performance Designs canopy with PIA methods, it gets 10% "bigger."
If you measure a Precision canopy by PIA methods, it gets 10% "smaller."

[mjosparky 3]

Quote

You are a good man Sparks :-), I don't care what they all say about you.

Bushman

Thank you.

Most of the time, neither do I.

Sparky

My idea of a fair fight is clubbing baby seals

[koz2000 1]

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If you measure a Precision canopy by PIA methods, it gets 10% "smaller.

Does that include the R-max? It seemed to pack bigger unlike the raven & dash-m series.

______________________________________________
- Does this small canopy make my balls look big? - J. Hayes -