Main vs. reserve size

[Sky_doggy 0]

Hi all,

I have been reflecting on some of the posts in the incidents forums regarding ADD and landing under a reserve unconscious. My current setup is a Pilot 168 & PDR 176 and I am considering replacing the PDR 176 with an Optimum 193.

Please correct me if I am wrong, but as I understand it conventional wisdom suggests that your reserve should be close in size to your main in case you have a two out situation. The thought being that if the canopies are close in size then this would be a more controllable situation.

My question is, is there any data or empirical testing that supports this, or is it just a hypothesis?

[pchapman 279]

I personally see it as something that is theoretically nice, but because of other factors, something one largely ignores in practice.

If I jump a rig with a 282 Parafoil, I don't want a huge ass reserve. If I jump a rig with a ground hungry crossbraced 79, there's nothing that small and fast in reserves. And I'd rather have something bigger than a PD 99 reserve (or even PD Optimum 99).

So just jump the main you want, and if you have a choice, the reserve size you want. If by some chance the sizes and performance are not too dissimilar, then that's a bit of luck in the rare case of a two out.

In your particular case, if you want a bigger reserve, go for it. While someone might say it is bigger than you really need, the extra area is probably more of a benefit that the liability of less compatible canopies -- especially as one tends to see a lot more reserve rides than two outs.

I'm not sure off-hand to what degree the rare two-out studies actually tested much in the way of different size combinations of canopies...

[mjosparky 4]

I have never seen someone land a reserve and say they wished they had a smaller one. Go with the biggest reserve will fit in your container without over packing it.

Sparky

My idea of a fair fight is clubbing baby seals

[Quagmirian 40]

Sky_doggy

Please correct me if I am wrong, but as I understand it conventional wisdom suggests that your reserve should be close in size to your main in case you have a two out situation.

Similar in size means less than a 50% size difference. Current evidence suggests that total line length may be more important than area. So in general, you could probably get away with a much bigger reserve than main.

[Trev_S 0]

Didn't the army do extensive 2 out tests and released a fairly comprehensive report finding that similar sized canopies were greatly advantageous in a 2 out situation?

[JeffCa 0]

I made the same decision. Got an Optimum 218 with a Pilot 188. I figured that the odds of me having a 2-out are very low compared to the odds of having a regular reserve ride, so I made the decision to go with the bigger reserve and I'll cross the 2-out bridge in the unlikely event that it ever happens. I think even if I downsize the main, I'll be keeping the same reserve.

"So many fatalities and injuries are caused by decisions jumpers make before even getting into the aircraft. Skydiving can be safe AND fun at the same time...Honest." - Bill Booth

[JerryBaumchen 1,364]

Hi doggy,

Quote

My current setup is a Pilot 168 & PDR 176 and I am considering replacing the PDR 176 with an Optimum 193.

IMO an informed jumper is a better jumper.

I had a discussion with one of the major players from PD at the 2005 symposium. He told me that the Optimum canopies were TSO'd with an exception/variance/waiver ( take your pick ) to the TSO standard.

These canopies have a higher total velocity than what is in the TSO standard.

The standard PDR reserve canopies were certificated in accordance with the TSO standard; no exceptions.

I am thinking that your total velocity under a PDR 176 may just be less than your total velocity under an Optimum 193.

That would mean that with a landing with no jumper input under the OP 193 would do more damage to you.

Before you make any decision I would suggest that you contact PD and have a long discussion with them about this.

JerryBaumchen

[Sky_doggy 0]

JerryBaumchen

Hi doggy,

IMO an informed jumper is a better jumper.

I had a discussion with one of the major players from PD at the 2005 symposium. He told me that the Optimum canopies were TSO'd with an exception/variance/waiver ( take your pick ) to the TSO standard.

These canopies have a higher total velocity than what is in the TSO standard.

I am thinking that your total velocity under a PDR 176 may just be less than your total velocity under an Optimum 193.

That would mean that with a landing with no jumper input under the OP 193 would do more damage to you.

JerryBaumchen

Jerry this is very valuable information, thank you for sharing. I will talk to the PD folks before I go any further down this road.

[pnuwin 0]

JerryBaumchen

the Optimum canopies were TSO'd with an exception/variance/waiver ( take your pick ) to the TSO standard.

These canopies have a higher total velocity than what is in the TSO standard.

The standard PDR reserve canopies were certificated in accordance with the TSO standard; no exceptions.

According to the PD Optimum explanation video on youtube, PD wanted approval for higher maximum weights. Wouldn't this be the reason for the TSO exception?

Surely with the same exit weight the Optimum would be slower or at least the same total velocity as a PDR. ( ie. a PDR-176 and OP-176 at the same exit weight) What's the point in having standards if you can just make exceptions that are less safe?

[JerryBaumchen 1,364]

Hi pnuwin,

Quote

PD wanted approval for higher maximum weights. Wouldn't this be the reason for the TSO exception?

In our discussion in 2005 I was told it was because of the 'total velocity' req'ment. However, at that time they only had approval for the smaller Optimum sizes.

It is very possible that the later, larger Optimums had a waiver for 'higher maximum weights.'

However, TSO C23d allows the mfr to test for any weight that they want. I know of no upper limit on weight in that standard. But I may be wrong.

In TSO C23d there is a minimum weight that products have to comply with.

Quote

What's the point in having standards if you can just make exceptions that are less safe?

I could not agree more.

JerryBaumchen

[RiggerLee 61]

Now that we have this total velocity standard. What do you think the smallest reserve will be that we will see in the future? I'm assuming that it's measured at the maximum weight that the canopy is approved for. So with the... min maximum requirement in the TSO there should be a practical lower limit to the square footage. And I think it was you that said that the FAA had no intention of permitting another such waver. So, do you think we will ever see another reserve under 126 sq ft? Or will it be more like 143? How many of the optimums needed a waver? The small ones? The very big ones that have a higher max? Interesting how PD managed to sneak this shit in right before every future manufacturer is locked out. Or do you think it's just a product of the design? The trim and the break setting? Maybe it was another compromise that they made along with opening time to allow the canopy to survive at higher terminal speeds?

Lee

Lee
lee@velocitysportswear.com
www.velocitysportswear.com

[pchapman 279]

I think someone needs to ask PD to clarify / dispel rumours, since this is a significant thing when it comes to certification. (My thought was that they didn't get a waiver in the end but I don't know what is true.)

[JerryBaumchen 1,364]

Hi Lee,

I can only speak for myself. I do not represent PD.

I do know what the 'major player' in PD told me & a friend when were talking with him in 2005.

From what I understand, when PD submitted the req'd paperwork for the larger Optimum canopies, it took a long time for the FAA to give them the OK. There is no reason in holy H*** why it would take more than 30 days to obtain certification on the newer, larger canopies; PD already had many canopies in production that were certificated; and their Quality Program was already FAA-approved. It seems to me that the only thing ( and I could be very wrong ) is it took such a long time because they were possibly asking for another waiver/exemption/variance.

Quote

What do you think the smallest reserve will be that we will see in the future?

I have not the slightest idea. PD already has a 99 ft canopy certificated. It really comes down to canopy design in the future; and none of us know what might be out there.

Quote

And I think it was you that said that the FAA had no intention of permitting another such waver.

I have never made such a statement.

Quote

How many of the optimums needed a waver?

Actually, I do not know.

Quote

Or do you think it's just a product of the design? The trim and the break setting? Maybe it was another compromise that they made along with opening time to allow the canopy to survive at higher terminal speeds?

Again, I do not know.

IMO PD is one of the very best gear mfrs out there. They will always take the time to talk to just about anyone regarding their products.

It is my thinking that anyone buying a product should really know just what they are getting.

IMO ( and I am no longer jumping ) anyone jumping a square reserve loaded at more than about 0.8:1 is probably going to be rather seriously injured if they land it with no control inputs; i.e., if the jumper is unconscious.

Back in the late 70's I bought a StratoFlyer; which eventually morfed into the first certificated square reserve, the SafetyFlyer. My first landing on that thing was one of the hardest landings I have ever experienced. At the time I weighed about 175 lbs naked and it was a no wind day.

JerryBaumchen

PS) I have 'heard' that a number of canopy mfrs were doing some testing for higher total velocities with the idea of getting certification if the FAA had not removed that section in TSO C23f.

[IJskonijn 45]

JeffCa

... and I'll cross the 2-out bridge in the unlikely event that it ever happens.

Please, do think about how you can cross that bridge well before it happens. Knowing what your options are (and what isn't an option) is very valuable, because you do not have the time to thoroughly think through every possible case when it actually happens.

As for me, I've made basically the same decision. My rig has a Raven II reserve (218sqft), and I alternate between a Silhouette 190 and Lightning 176 (thinking of switching to a Lightning 160). In a two-out situation, I'll ride it down if I think it's stable enough. Only when it feels wrong and unstable, I'll try to go into a down-plane and cut away the main, provided the risers appear not entangled and altitude is plentiful.

[AlanS 1]

IJskonijn

My rig has a Raven II reserve (218sqft), and I alternate between a Silhouette 190 and Lightning 176 (thinking of switching to a Lightning 160). In a two-out situation, I'll ride it down if I think it's stable enough. ...

So, is a 218 reserve compatible with a 176 main in a two out situation? I'll soon be buying a rig with canopy sizes in this range.

Is there any information of even videos show how a larger reserve interacts with a smaller main?

[Southern_Man 0]

AlanS

So, is a 218 reserve compatible with a 176 main in a two out situation? I'll soon be buying a rig with canopy sizes in this range.

There are no guarantees. Depends not only on the size of canopy but also the type of main as well. Something more square is going to be better and more stable than something more elliptical or w/ a higher aspect ratio. But even then there are too many factors to give a simple yes or no question.

"What if there were no hypothetical questions?"

[JeffCa 0]

IJskonijn

***... and I'll cross the 2-out bridge in the unlikely event that it ever happens.

Please, do think about how you can cross that bridge well before it happens. Knowing what your options are (and what isn't an option) is very valuable, because you do not have the time to thoroughly think through every possible case when it actually happens.


I have thought about it. I know that if I try to cutaway the main without disconnecting the RSL, my Racer could kill me. First thing to be done in 2-out situation is to release the RSL.

"So many fatalities and injuries are caused by decisions jumpers make before even getting into the aircraft. Skydiving can be safe AND fun at the same time...Honest." - Bill Booth

[Calvin19 0]

I have been jumping for a decade and I cannot imagine a situation, especially on my JVX 79, where I would want anything smaller than my PD 149 reserve.


I have a tertiary rig, I think I will give myself a 2-out deployment with my Safire2 149 and my JVX. It sounds like a good practice, and I want to know why people justify a dual parachute system where the total area of reserve + main is below 200 square feet.

[erdnarob 1]

I have experienced a two out at Perris Valley when my AAD popped out the reserve while being at the early phase of my main opening. I had pulled too low.
Fortunately, the result was a very nice biplane. I undid my main brakes but kept the reserve brakes on. My landing was fine.

I had hesitated to cut away my main but since the biplane was flying OK I finally let everything as is. Moreover there is still some chance that the main risers do a whipping effect and get entangled with the reserve lines in case of cut away.

Later on, I discovered that I had taken the good decision by keeping both parachutes in a biplane configuration. My main was a Sabre 170 and reserve a PD 160. I believe that a reserve should have the lines shorter than the main to facilitate a biplane, which is the safest configuration with a two out.

BTW the Sabre 2-170 has the suspension lines about 10" longer than a PD reserve 176. I would not recommend using a Optimum 193 when using a Pilot 168 because I believe that the reserve suspension lines might be longer than the main ones.
The rationale is that, in my opinion, the parachute with longer lines will have the tendency to lead the other canopy.
The discussion is open.

Learn from others mistakes, you will never live long enough to make them all.

[Mickochet 0]

I had the same thing happen to me. The AAD fired and I had a side by side with a 99FX and a swift plus 145. I kept them both and landed just fine.

If you never fall down you aren't trying hard enough.

[DocPop 1]

Sky_doggy

conventional wisdom suggests that your reserve should be close in size to your main in case you have a two out situation.

I take the following view:

- two-outs are largely preventable by gear maintenance and checks, and not pulling low/respecting your hard deck.
- the chances of me having a two-out are way less than me having to fly a reserve normally.
- I should prepare, and choose my equipment for the safest landing with the commonest reserve scenario, not some unlikely event.

Finally, I would really encourage people to demo a reserve as a main. I did and it changes the reserve question from guesswork to "I flew that and I am happy" or "I flew that and I think I need to go bigger". i.e. it is based on your own empirical dataset.

Hope to see you at the DZ soon, buddy.

"The ground does not care who you are. It will always be tougher than the human behind the controls."

~ CanuckInUSA

[JerryBaumchen 1,364]

Hi Doc,

Quote

I would really encourage people to demo a reserve as a main.

IMO good advice. I would also advise them to try to land that 'reserve as main' with the brakes still set and no input from the jumper. I seriously doubt that anyone flying a reserve at 1:1 or higher will walk away from the landing unscathed.

I've been fortunate to have done a number of drop tests with square reserves ( not a lot, but some ) and have watched that 170 lb dummy bounce across the ground. He does not just land, he bounces.

Just a thought,

JerryBaumchen

[lyosha 50]

JerryBaumchen

Hi Doc,

Quote

I would really encourage people to demo a reserve as a main.

IMO good advice. I would also advise them to try to land that 'reserve as main' with the brakes still set and no input from the jumper. I seriously doubt that anyone flying a reserve at 1:1 or higher will walk away from the landing unscathed.

I've been fortunate to have done a number of drop tests with square reserves ( not a lot, but some ) and have watched that 170 lb dummy bounce across the ground. He does not just land, he bounces.

Just a thought,

JerryBaumchen

Click on drop test video in link below ;)

http://www.paratec.de/en/products-parachutes/57-2/

[shadeland 5]

 

On 5/2/2014 at 9:15 AM, JerryBaumchen said:

These canopies have a higher total velocity than what is in the TSO standard.

The standard PDR reserve canopies were certificated in accordance with the TSO standard; no exceptions.
 

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. 

 

[mark 107]

3 hours ago, shadeland said:

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.

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.