Rear Risers - Be serious

[sprtdth 0]

Re-read Sparky's post. Yes, you slow your forward speed, BUT, you also decrease your rate of descent. IMHO, rate of descent, not forward (or rearward) speed is what makes for a softer landing.

CRW Skies
Frank
CRW Diva #58

[mjosparky 3]

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Maybe someone who really remembers what jumping those old rounds was all about will help me out here.

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Up until the first of this year I was still jumping rounds on a regular basis doing testing for Irvin, Simula, Cold Lake Canada and other clients both civilian and military. I assure you I am aware of the different ways to control a round canopy, both modified and un-modified.

Maybe with you limited number of jumps you never learned some of the finer points of canopy control?

Sparky

My idea of a fair fight is clubbing baby seals

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[MikePelkey 0]

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Up until the first of this year I was still jumping rounds on a regular basis doing testing for Irvin, Simula, Cold Lake Canada and other clients both civilian and military. I assure you I am aware of the different ways to control a round canopy, both modified and un-modified.

Maybe with you limited number of jumps you never learned some of the finer points of canopy control?

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Having a greater number of jumps does not automatically make you right. There is only one correct answer. Pulling rear risers on landing in a holding orientation either slows you down or speeds you up. Slowing the descent by moving the apex off center by a foot or two doesn't make a tiny bit of sense to me.

Why don't you act like the senior guy here and explain the physics in detail instead of trying to pussyfoot around it by pulling rank? Assuring me that you are right because you know what you're talking about and I don't isn't my kind of adult approach. How about explaining it?

In theory, there is no difference bretween theory and practice. In practice, however, there is. -

"RIP Forever Brian Schubert. Always remembered, Never forgotten" - Leroy DB
http://www.johnny

[ripcord4 0]

I am truly surprised that no one has stepped up to the plate to agree with me on this.

[SkymonkeyONE 3]

Mike, I have to stay with Sparky on this one. My first sport jump was under a 28 foot 7-TU and my dad, Buddy Blue D-597, taught me to pull down on my rears just prior to landing. I used that technique my entire 21 year military jumping career with the same, satisfactory results. Likewise, all the jump meets and demos my dad took me to in the 1960's and early 1970's lead me to believe that was what everyone was doing back then; not the opposite as you state. Maybe it was the fad where you were jumping, but definitely not in the old Cottonbelt Parachute Council.

Cheers,

Chuck Blue, D-12501

[steve1 5]

Mike,
Maybe I should reword my reply. I shouldn't have said I always used rear risers when jumping a round. Hell, that was so many years ago it's kind of hard to remember all that.

I always thought of pulling the rear risers as a way to put on the brakes. On really windy days I didn't pull them down. I hated rear PLF's with a passion and I figured I'd do anything to get a little more drive into the wind. I don't know how many times we jumped in way too much wind, but there was a bunch of these. So, on those jumps I either left the rear risers alone and turned slightly, so it would be easier to get to my side when I slammed into the ground. Prior to that I did a lot of feet, rear, head landings. God, my head still hurts from that.

But later I learned to run with the wind and then hook it into the wind at the last moment (on my para-commander). With the long lines and big oscillation from a turn, you could land without backing up. But then again you had to time it just right.

I recall one jumper who was jumping a para-comander in Utah (back in the 70's). The wind came up, and he was probably knocked out on landing, then he was drug to death. There was a reason everyone wore a heavy duty helmet back then....Steve1

[mjosparky 3]

You asked why people pulled down on rear risers when landing a round canopy. I responded with:

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“Two things happen when you pull down on the rear risers. First you move the apex vent off center increasing the drag coefficient, a little, which will slow the decent rate. Second you lower the rear of the canopy skirt in relation to the front skirt and this will reduce forward drive. If timed right at landing you will land softer with less forward speed. Results vary with canopy design.”

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I said nothing about “holding” or “running”. And you respond with:

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“I'm ready to give up on this. I feel like I'm talking to the old proverbial brick wall if you "most certainly know the difference between running and holding", and you are proud to claim there is something to be gained in pulling rear risers when landing in a holding orientation.

I am truly surprised that no one has stepped up to the plate to agree with me on this”

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I explained to you my history (resent) with jumping rounds and come back with:

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“Having a greater number of jumps does not automatically make you right. There is only one correct answer. Pulling rear risers on landing in a holding orientation either slows you down or speeds you up. Slowing the descent by moving the apex off center by a foot or two doesn't make a tiny bit of sense to me.

Why don't you act like the senior guy here and explain the physics in detail instead of trying to pussyfoot around it by pulling rank? Assuring me that you are right because you know what you're talking about and I don't isn't my kind of adult approach. How about explaining it?”

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I explained it to you in post #21. And you are right, have more jumps does not automatically make me right. But on the other hand because it “doesn’t make a tiny bit of sense” to you does not make it wrong. Just how long has it been since you have jumped a round canopy or any canopy for that matter?

Now I have tried to answer your question and explain my position. You can agree, disagree or hold your breath until you turn blue. I don’t really care.

My idea of a fair fight is clubbing baby seals

[MikePelkey 0]

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But later I learned to run with the wind and then hook it into the wind at the last moment (on my para-commander). With the long lines and big oscillation from a turn, you could land without backing up. But then again you had to time it just right.
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Yes Steve, now you're talking. Thank you. If you dissect hooking it in in a high wind you get the following:

1. You are approaching the target in the holding orientation to keep from flying to the next county.

2. At (hopefully) the perfect distance above the ground you execute a 180, turning into the running orientation.

3. The canopy surges forward and you swing out behind it.

4. When you are stretched out behind the canopy as far as you are going to stretch you pull another quick 180 turn. You swing hard under the canopy and higher up than you were on the first turn.

5. Now in a pendulum approach you are swinging forward (toward the target). The canopy is still being blown back with the wind, but you are countering that movement by simultaneously swinging forward. It is a good idea to pop one half shot of one of the capewells at this point.

6. As you touch down you are at the maximum drive against the wind, considering that you are in a holding position and you are subtracting the pendulum drive from the difference between the wind speed and the parachute's inherent airspeed. Pop the other half of the half-popped capewell as soon as you touch down. This is the greatest air speed you can possibly attain in the holding position. Decreasing either the speed of the pendulum effect or the inherent speed of the canopy will obviously cause an increase in your landing speed.

6. You will land at the lowest ground speed possible 100% of the time if you land in the holding orientation with respect to the wind. In a zero wind condition holding speed will be equal to running speed. For any non-zero wind speed, holding groundspeed will be lower than running groundspeed. In my day no one in their right mind landed running with the wind on purpose, unless they were in accuracy competition.

ParaCommanders were constructed differently. The peg lines were called brake lines, and had a different effect than the old modified T7A military chutes.

If anyone disagrees with my description of the function of a full 180 degree hook landing, please let me know. If I am missing out on any part of it, I'd love to be corrected. I doubt if it would work at all if it didn't work exactly the way I explained it above.

Please note that the description above is intended as an example of why it is better to maximize your ground speed when holding and to minimize your ground speed when running.

Also note that what I objected to from the very beginning of this thread was the premise that "pulling rear risors" made for softer landings. Obviously in zero wind conditions it doesn't matter whether you are running or holding, and pulling rear risors would soften your landing. That is because in zero wind there is no such thing as holding; you are always running no matter which direction you are facing. Whenever you are running, slowing down the groundspeed contributes to a softer landing. However whenever you are holding, slowing down the groundspeed contributes to a harder landing. The moment wind becomes non-zero, a holding orientation exists, and theroretically there is an optimal orientation to approach the target.

In theory, there is no difference bretween theory and practice. In practice, however, there is. -

"RIP Forever Brian Schubert. Always remembered, Never forgotten" - Leroy DB
http://www.johnny

[ripcord4 0]

In my day, no one in his right mind did anything with his Capewells in the air other than than an intentional cut-away.

No one in his right mind would ever jump a modified T-7A as a main. That was a 24 ' diameter twill reserve than was bad enough to land as a reserve.

Gravity is a constant. It makes no difference whether you are running or holding when you land - your rate of descent is the same. Only your ground speed will vary.

[steve1 5]

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In my day, no one in his right mind did anything with his Capewells in the air other than than an intentional cut-away..

I agree... There may have been some jumpers that did that, but not me. The though of having one side coming loose close to the ground didn't sound like much fun.

I recall one jump where I had a really hard opening on my PC, and my arm brushed one of my shot and a half covers...popping the cover off. Scared the hell out of me. I knew a lot of jumpers that had one shot capewells in the early 70's. Those too were scary to me. But then again, maybe I'm just a big scaredy-cat....Steve1

[MikePelkey 0]

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I recall one jumper who was jumping a para-comander in Utah (back in the 70's). The wind came up, and he was probably knocked out on landing, then he was drug to death. There was a reason everyone wore a heavy duty helmet back then....Steve1
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Steve,

You're probably right about the inherent danger in messing with the capewells close to ground. I was thinking of the more severe high wind conditions where you may not make the maneuver quite right and need to release your canopy before touchdown to avoid getting drug to death if it looks like you may end up being knocked cuckoo. It was almost never necessary to do a full 180 hook landing. I have only done it once that I recall in an extremely windy landing. In that particular case I did half release my capewells just prior to landing. I was very fortunate to land like a feather standing up as one of the airport's wind socks flew past me, and completed the capewell release as soon as I touched down.

Most of the time the bigger winds let you get away with the diagonal hook approach you brought up in your post.

Releasing capewells was not the main part of my post. I'm only trying to get someone else to agree with us that reducing airspeed in the holding orientation didn't really make for easier landings.

In theory, there is no difference bretween theory and practice. In practice, however, there is. -

"RIP Forever Brian Schubert. Always remembered, Never forgotten" - Leroy DB
http://www.johnny

[ripcord4 0]

need to release your canopy before touchdown to avoid getting drug to death if it looks like you may end up being knocked cuckoo.
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Releasing your canopy PRIOR to touchdown? That's a sure way to get knocked cuckoo and probably worse.

If you are worried about being dragged to death, I would say you are jumping in winds well above the safety limit.

[GreenLight 5]

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And I do most certainly know the difference between running and holding as I am still jumping rounds twice a month at Z-Hills.
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I'm ready to give up on this. I feel like I'm talking to the old proverbial brick wall if you "most certainly know the difference between running and holding", and you are proud to claim there is something to be gained in pulling rear risers when landing in a holding orientation.

I am truly surprised that no one has stepped up to the plate to agree with me on this.

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I'm ready to give up on this.

Sounds like a good idea.

Green Light
"Harry, why did you land all the way out there? Nobody else landed out there."
"Your statement answered your question."

[skypuppy 1]

Seems to me there's a whole range of wind-speeds between no wind and coming straight down, and once you throw in a hook turn, even higher wind speeds still give your body forward speed on landing. So in any of these lower wind speeds, it would help to pull down on the rear risers to bleed off forward speed (and slow rate of descent).

In higher wind speeds where you're backing up, it was sort of a trade-off, if you timed it right, you could reduce your rate of descent WITHOUT too much of an increase in backwards ground speed -- if you held them down too long, your ground speed (backwards) picked up and you went ass over teakettle.

If some old guy can do it then obviously it can't be very extreme. Otherwise he'd already be dead.
Bruce McConkey 'I thought we were gonna die, and I couldn't think of anyone

[pchapman 261]

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In higher wind speeds where you're backing up, it was sort of a trade-off, if you timed it right, you could reduce your rate of descent WITHOUT too much of an increase in backwards ground speed -- if you held them down too long, your ground speed (backwards) picked up and you went ass over teakettle.

Yeah, same as when backing up under a big square canopy in high winds. A short, sharp flare just before touchdown reduces the vertical speed without making one accelerate much backwards. (The dynamic swing-forward during a flare also helps in that regard.)

[cutaway1 3]

I jumped a 28' round with a tu mod from 63 thru 70, we didn't hang on to our rear risers, but pulled on them hard the instant before landing to decrease our verticle speed, doing stand ups in moccasins most of the time, it kind of cushioned your landing.

SCR-21