Effect that difference in size of main and reserve on a system have in a two out scenario

[Beachum 1]

This has probably been discussed plenty, somewhere, please either point me in the direction of some info or weigh in.  
 

In a two out scenario as the reserve gets larger in square footage in comparison to the main involved what effect does it have on the malfunction.  Bi - plane and side by side.  
 

Thanks

 

 

Edited March 17 by Beachum
Make more direct

[rjklein4470 23]

I might be wrong here but if there is a large difference (and I am in that boat) the main will start to stall and move back into a biplane pretty quick I imagine. To me this is the best scenario, I would rather chop the main in this position. 
 

if I was in a side by side I would try to get this into a biplane so I could chop it. 
 

all depends on weather, wind, altitude ect….

at one point I thought about this quite a bit, now I put more thought into making sure it doesn’t happen. 

[Grumpy 5]

PD did some detailed research into this a while back but the report is no longer available on their site. Does anyone know why it was removed?
Here's the bulk of it. Well worth a read.
https://www.skydivemag.com/new/2018-06-06-two-canopies-out/

[sundevil777 98]

Disconnect the RSL before chopping the main to help prevent it snagging the reserve.

[IJskonijn 42]

There's a better way than "blindly" chopping your main in a two-out scenario. For one, if you are unlucky enough to have the main and reserve risers entangled, chopping it can be certain death.

I've had the luck to sit through Jim Cowan's Dual Out briefing recently, and his breakdown of possibilities and options is top-notch. It's also on youtube, so I highly recommend everyone to watch it.

 

As for the specific effect of a much larger reserve than main, I would guess that the reserve is much higher over your head (providing more lift) while the main flies a lot more twitchy. My gut feeling would be that you might have to rein in the main flying it in deep brakes or rears (if half-brake is still set) to keep the two cooperating. Cutting the main away IFF it's not entangled would probably be your best bet, secondary to keeping both canopies nailed together down to landing.

[SCS422 24]

I had a malfunction similar to this, I was jumping a Stratostar at Elsinore with a borrowed rig that was too lose on me, the reserve handle fell out of the pocket and the pin worked its way out of the reserve.  The reserve was a 26 Lo-Po and fell down and  inflated behind me, I watched it fully inflate behind the stratostar and when it bumped the main I cut the main away.  It was a non-event but in retrospect I could see where it could get real bad.

Edited July 2 by SCS422

[chuckakers 406]

On 3/17/2024 at 10:36 AM, rjklein4470 said:

all depends on weather, wind....

What difference would that make?

[IJskonijn 42]

On 7/2/2024 at 11:33 PM, chuckakers said:

What difference would that make?

The choice between keeping a side-by-side or trying to get it to a biplane could well be wind-related. It appears that a side-by-side has quite good lift-to-drag and therefore reasonable penetration into headwinds, while a biplane is a lot more sinky compared. (No personal experience, but based off the seminar that Jim Cowan gave). Thus, I can imagine a situation where you have a two-out, strong headwinds, good landing fields ahead of you and Mordor behind you. In that situation, keeping the side-by-side might be safer than trying to work it into a biplane.

[chuckakers 406]

2 hours ago, IJskonijn said:

The choice between keeping a side-by-side or trying to get it to a biplane could well be wind-related. It appears that a side-by-side has quite good lift-to-drag and therefore reasonable penetration into headwinds, while a biplane is a lot more sinky compared. (No personal experience, but based off the seminar that Jim Cowan gave). Thus, I can imagine a situation where you have a two-out, strong headwinds, good landing fields ahead of you and Mordor behind you. In that situation, keeping the side-by-side might be safer than trying to work it into a biplane.

Not sure that logic would pay off or that it would matter all that much. A two-out in either configuration would have a very light wing loading, so even a side-by-side would have a slow (or zero) forward speed into a headwind

In a two-out scenario (if I chose to keep it), I would be much more concerned with monitoring the stability of the configuration (and having my plan B ready) than I would be about penetration into the wind.

For me, if I can confirmed that the main can be released without conflict, I would likely chop.

I have seen (several times) side-by-side configurations turn into downplanes AFTER flying stable. There have been incidents caused by this.

Just because the canopies fly well together one moment does not mean they will fly well together the next.

2 cents

[IJskonijn 42]

True, better to reach the ground softly anywhere than crash hard in a nice field. So chopping the main if possible remains the best option. However, that was my take on a situation in which the winds might be a factor of consideration.

And if a side-by-side is kept, the advice is to keep it together by actively giving both canopies some inside rear pressure (basically rear-riser turn both canopies into each other) to nail them tight.