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OneFaller

Reserve opening speed

Question

At typical belly to earth freefall speeds (110-120mph) in how many feet will a reserve typically open?  The goal here is to figure out the G's one might encounter during a reserve deployment.  
Will a reserve open faster than, say, a Sabre2?

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I have no specific experience with a Sabre2, but in general reserves are designed and packed to open reliably and quickly. Thus, a typical model reserve parachute will open faster than a typical model main parachute.

My personal experience is comparing a PDR193 reserve canopy (two rides, both ~1.2WL) with a Lightning, and the deployment speed was similar. A Lightning is known for quick openings, and I opened my reserve while still at sub-terminal speeds.

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13 hours ago, OneFaller said:

At typical belly to earth freefall speeds (110-120mph) in how many feet will a reserve typically open?  The goal here is to figure out the G's one might encounter during a reserve deployment.  
Will a reserve open faster than, say, a Sabre2?

My understanding is that reserves are required to be open within 300 ft of deployment no matter what the airspeed when they are deployed. If you are going faster that would equal less time and a harder opening than if you had just cutaway from your main. But 300 ft either way, the distance should not change, just the time.

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1 minute ago, gowlerk said:

My understanding is that reserves are required to be open within 300 ft of deployment no matter what the airspeed when they are deployed.

Hi Ken,

That is incorrect.  The urban legend of the infamous 300 ft req'ment is simply wrong.

Some versions of the four TSO standards* do have an optional test for a 300 ft opening.  It is NOT a req'd test.

Jerry Baumchen

PS) * You can buy modern, current, up to date gear** built to one of four TSO standards.  I do not know of any current production reserve canopies being built under C23(b).

**  That means with all the latest bells & whistles.

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1 minute ago, JerryBaumchen said:

Hi Ken,

That is incorrect.  The urban legend of the infamous 300 ft req'ment is simply wrong.

Some versions of the four TSO standards* do have an optional test for a 300 ft opening.  It is NOT a req'd test.

Jerry Baumchen

PS) * You can buy modern, current, up to date gear** built to one of four TSO standards.  I do not know of any current production reserve canopies being built under C23(b).

**  That means with all the latest bells & whistles.

Ya Jerry, I kinda knew it was much more complicated than that. But it's the only standard I know of and is likely in the ball park. As far as I know there is no way to accurately answer the original question.

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Having a few dozen jumps on a reserve packed as a main I can tell you they open fast. Faster than most modern canopies. So far the only canopy I've ever jumped that opens faster than a reserve is a BASE canopy. So yes, reserves will open faster than a Sabre 2. If you have a terminal reserve ride, dont expect it to be present.

Edited by 20kN

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I've opened a reserve at terminal twice. Once was a PD193 when I couldn't shake my pilot chute off my back, the other time was to demo a PD 176 Optimum as a main canopy. Both openings were quick, but not what I would call hard. More like comfortable. There's a hole in the slider on those things for a reason !

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(edited)
On 9/5/2019 at 6:22 PM, gowlerk said:

My understanding is that reserves are required to be open within 300 ft of deployment no matter what the airspeed when they are deployed. If you are going faster that would equal less time and a harder opening than if you had just cutaway from your main. But 300 ft either way, the distance should not change, just the time.

Hi Ken,

As I recall [ and, I am not going to look it up ], the 300 ft altitude loss is an optional test during the certification process.

Now, it seems that many, many people think that is a req'ment; I do believe that it is.

If I am wrong, I will happily be corrected.

Jerry Baumchen

PS)  So much for my memory - see my post of nearly 4 yrs ago -> #2

 

Edited by JerryBaumchen

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