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Sky_doggy

Main vs. reserve size

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6 hours ago, shadeland said:

 

I know this is an old post, but in doing some research on the subject, I believe this to be incorrect based on the information I've obtained. 

Both the PDR and PD Optimum both have waivers (though I've never been able to find a copy of the waivers). Same for Aerodyne Smart and Smart LPV. Anything over 1.3 WL is going to exceed the maximum descent rate as specified in the various TSO standards (C23b/c/d/f). If you look at the maximum recommended weights of the PD and Aerodynes, they clearly go over this. 

Icarus World, however, you'll note that their maximum weights for the Icarus Reserve or Icarus Nano are pretty much exactly at 1.3. They don't have a waiver and specifically mention the ~1.3 WL limit in the reserve manual. I talked to an Icarus representative at the 2019 PIA regarding this.

I don't know what other reserves have or do not have them, other than the 3 listed above. 

 

Hi shadeland,

Re:  Both the PDR and PD Optimum both have waivers

My post, which you quoted above your post, was based upon a discussion held in 2005.  I was told in that discussion that the PDR line of canopies had no such waiver.

I have nothing factual to present on this matter.

Jerry Baumchen

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2 hours ago, JerryBaumchen said:

Hi shadeland,

Re:  Both the PDR and PD Optimum both have waivers

My post, which you quoted above your post, was based upon a discussion held in 2005.  I was told in that discussion that the PDR line of canopies had no such waiver.

I have nothing factual to present on this matter.

Jerry Baumchen

I think there was a misconception that PD Optimums descended faster than the PD Reserves, which is why I brought it up. I don't believe that's the case. I believe that there's no real difference in descent rate given the same size and wing loading. 

The only difference (again, as far as I can tell) is some companies have maximum recommended weights well above 1.3 (Aerodyne, PD) and some don't (Icarus World). Whether that involves an FAA waiver, I don't know. I've never seen it. And I've never gotten a firm answer from anyone on it. 

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5 hours ago, mark said:

This is unlikely to be true.

As a consumer, I rely on a company's representations as to the performance of their products.  If there is a secret waiver, it might allow a company to produce a product, but it will not shield them from liability for failure to meet published standards.

PD and others are free to placard their canopies at less than the TSO-limited weight, but this is no different than publishing maximum weights based on experience.

I've "heard" that there are waivers, but never seen them. 

Perhaps it's an interpretation of the rules. There's the maximum weight the gear has been rated at, and then there's the maximum weight that will put a canopy faster than 24 feet per second descent rate, 36 feet per second total speed (usually around 1.3 WL) which would be significantly below the tested load weight (i.e 254 lbs). 

As an example, the PD Reserve 143 size has a maximum weight of 254 lbs, which would put it at about 1.8 WL. An Icarus Reserve 149 reserve has a maximum suspended weight listed of 199 lbs, which is about 1.3 WL. 

Is a waiver required by PD to list a maximum weight above 1.3 WL? I don't know. 

That's the regulatory part of it, so what of the actual performance? 

I don't think there's a significant difference in descent rate between the PDR, PD Optimum, Aerodyne Smart/SmartLPV, etc. with the same wing loading and canopy size, so I don't think that's a relevant factor in choosing between them. I think that there was the idea that there was, based on Optimums having some time of waiver, and PDRs not. But I don't believe that's actually the case. 

And of course what's the safe thing? 

Most, if not all of the C23 testing standards (NAS, SAE, PIA) list a maximum 24 ft/s descent rate and 36 ft/s total velocity for a deployment configured (i.e., brakes stowed and no flare) landing, and that roughly translates to 1.3 WL. Does that mean you're safe below 1.3 and dead above 1.3 if you land unconscious with no flare? Of course not. The higher the WL you are, the more danger there is. There's also the issue of canopies getting aggressive, regardless of the design, when loading them highly. But in choosing between the various reserves, I don't think descent rate variability given the same size and wing loading is an issue. 

That would be interesting to test. 



 

 

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Good points dear shadeland,

Also consider that USPA, and many canopy coaches consider any canopy smaller than 150 square feet to be "heavily-loaded" because their short suspension lines allow fast turns. ... turns faster than some skydivers' brains can comprehend.

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2 hours ago, shadeland said:

There's the maximum weight the gear has been rated at, and then there's the maximum weight that will put a canopy faster than 24 feet per second descent rate, 36 feet per second total speed (usually around 1.3 WL) which would be significantly below the tested load weight (i.e 254 lbs).  

No.  The descent rates are measured at the maximum operating weight.  See AS8015B para 4.3.7.

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1 hour ago, mark said:

No.  The descent rates are measured at the maximum operating weight.  See AS8015B para 4.3.7.

Ah. Both PD Optimums and PD Reserves (after a certain date) have, on their data panels, maximum operating weights well above 1.3 WL. I just saw a photo of one for a PD-R 106 with a maximum weight of 220 lbs, which would be over 2.0 (I would not want a reserve loaded the high, personally). 

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