Feb 11, 2002, 7:19 AM
Post #1 of 20
Rear Risers During Swoop
In that article on swooping in Parachutist this month it mentioned using rear risers to help with reducing drag. Anyone know what it meant? I use them a lot but not during the swoop (unless the steering line broke).
A few (don't know exactly how many) of the competetitors at the swoop meet were using rear risers to plane the canopy out, and then transitioning to toggles to finish the flare. It has to be done just right, I have watched people slide on their face or land on their back from either not quite enough or a little too much rear riser input. The idea is you can get the canopy to plane out w/o having to pull the tail down with the toggles. This reduces drag and you surf farther/faster.
Do not try this without getting instruction. I wouldn't try it unless I was over water as well. I want to learn this technique but I won't untill I have the oppertunity to so it right. The landings I have seen using this technique seem to be very sensitive. I saw a very good canopy pilot break his back trying to learn it.
Well now that I know that it seems like it would be less prone to stall due to air speed increase.
Yes, just like a normal toggle flare, a rear riser flare is less prone to stall with a higher airspeed than with a lower airspeed.
In reply to:
Not that I'm going to try it yet but what is going on aerodynamically?
Your steering lines attach only to the trailing edge of the canopy. Therefore when you flare using the toggles only the tail of the canopy comes down thus providing increased lift and drag. (For all the technical nazi's out there I realize it's more complicated than this and that it actually changes the AOA thereby increasing...etc, etc...I'm trying to keep it fairly simple. )
The rear risers are attached to both your C and D linesets therefore when you pull them down you're pulling the entire back half of the canopy down. Since you're affecting so much more of the canopy you don't have to pull the risers down nearly as far as you would the toggles in order to generate the same amount of lift....and, since you're not 'cupping' the tail of the canopy downward by pulling on the steering lines, there's less drag.
If it still doesn't make sense the best way to learn what's going on is to watch the tail of someone's canopy as they're flaring (with toggles AND with risers if possible).
One big difference between the two (toggle flare vs. rear riser flare) is the way the canopy stalls. I've found that when you stall a canopy using rear risers it's a more sudden and violent stall than it is when you stall one using toggles.
It also seems to me that I have more 'feel' for when the canopy is going to stall when using toggles than I do when using rear risers however this could very well be due to the fact that I have tons more experience using the toggles and I'm simply more accustomed to receiving and interpreting feedback through the brake lines/toggles tham I am the risers.
I believe one reason people tend to stall the canopy when trying to learn to flare using rear risers is because of the muscle memory they've acquired over hundreds or thousands of jumps using toggles. When you flare using toggles, depending on the length of your steering lines, you typically bring your hands down to about shoulder level and then contine down to arms' length which is about hip level. However, when flaring with rear risers, your hands stay much higher...about head level maybe down to shoulder level before transitioning from risers to toggles to finish the flare.
One thing that puzzles me is that it seems (from some of the posts both here and in other threads) that some people are trying to learn to rear-riser flare for the first time during a swoop. When I decided to try and learn it I waited for a fairly windy day (about 15mph...so my forward ground speed wouldn't be terribly high if I screwed up and biffed in) and then I just flew the canopy straight in and flattened out the glide using rear risers. I didn't transition to toggles (wanted to keep it simple for the first try) and just had to slide out the last bit of forward movement on my feet. From there it's simply a matter of gradually increasing landing speeds while perfecting the rear-riser technique. Granted I was on a Vengeance 120 loaded at 1.5 and not a Velocity 80 loaded > 2.0. I would think that someone flying a highly loaded canopy would either want to borrow a larger canopy to practice a few rear-riser landings or would learn over water! And they definitely (hopefully!) would not try to learn by using the rear risers to get around the corner (as I believe Chuck put it) during a hook.
Chuck, and any other super-swoopers out there who use rear-risers, I'm curious to know how you learned to flare using rear risers.
When you flare with the toggles, you are increasing the camber (curvature) of the canopy, which increases lift. Increasing lift in creases drag. Also by pulling th tail down, you are increasing drag. By increasing the drag of the canopy, it rocks back and the angle of attack increases. As you continue to slow down, you have to flare more to keep the canopy over your head and keep increasing the camber to produce the same amount of lift (and decreasing the stall speed) at continually slower airspeeds. So the initial part of the swoop you don't need to increase the camber of the wing by pulling down on the tail because you have so much airspeed. If you pull down on the rear risers just enough to change the angle of attack enough to plane the canopy out across the ground, it is more efficent because the canopy is still "clean", the tail isn't pulled down. The canopy will stall at a higher airspeed because the tail isn't pulled down, increasing the camber. So before it stalls, you have to transition to the toggles and the rest of the swoop is the same. A canopy will stall at the same angle of attack (unless you change the shape of the canopy w/ the toggle) regardless of airpseed. You can do a front riser turn, honk on the rear risers and stall the canopy at high speed.
i think I confused myself.:-) A bit jumbled-sorry
It cracks me when people say a small canopy has to be hooked to land it. If the canopy has a normal foward speed of 40 mph, and hots say 95 mph in the hook, you don't land doing 40, at some point in the swoop you slow back down to 40 on your way to a slower airspeed for landing. So why can't the same canopy fly straight in at 40 and land from that point forward identically to the one that hit 95 and slowed down from there? The canopies are at the same alititude with the same airspeed with the same amount of tail deflected to maintain altitude.
My next rant will be about people that say "go to half brakes in turbulence" :-)
The simple answer to your statement about people complaining about not being able to land a parachute straight in is, "yes, of course you can". What you cannot do, though, is get the same distance out of that landing if distance swooping is what you are working towards. I have absolutely no problem landing a 65 square foot canopy straight in with no double fronts or anything, but that is not why I jump that main and those just like it. The swoop purist (and competitor) strives for that combination of speed and distance.
Do a search in this forum and you will find volumes on the subject of rear riser swooping. You cannot be competitive on the pro circuit nowadays without rear risering skills; at least not in PPPB events.
To answer a later post in the thread: I started working on my rear riser swoops at altitude on high hop and pops.
Chuck, I believe he was referring to those who complain about a canopy needing to be "sped up" in order to get enough lift to flare and slow down properly. I have seen these complaints on the forums about the Safire, Sabre and other canopies. These complaints make no sense to me either, and frankly I don't think someone who cannot land a canopy straight in has any business hooking it to "improve the flare." I'm gonna guess that Clay can even land his truck straight in if he wants to!
"I'm gonna guess that Clay can even land his truck straight in if he wants to!"
I can....if there is no wind...I really don't like to. It's F-111 so it lacks a little in the flare department without some added speed. I'm with that though. If you can't land straight in(especially on ZP) you have no business hooking. You obviously don't know how to fly your canopy. I haven't even attempted to surf with rear risers. In fact.....the thought of it kinda scares me...... I'll get there some day though....
"I only have 131 jumps, so I don't know shit..right?"-Clay
Rear riser swoops are Very dangerous. True, to win at PPPB in distance, you have to do them. It is just something for very advanced canopy pilots. I am a pretty good canopy pilot, but I won't even bother trying to land that way. Unless I had too. Then I could, But It would be a life saving thing. Not a swoop thing.
Anyway, good question. If you look in some of the back threads, like Chuck said, you can get more of the dynamics of what is going on when you are planeing out and swooping on the rears. Just be careful.
With everything that has being said. It basically seems that if you can already safely rear riser land you are ahead of the game. Seems like the same stuff applies to in a swoop as to that as rear riser flares in general stall much easier.
Not sure if I said so already, but when I was test jumping parachutes for FTS (later APS), I had to land all variety of crazy shit. Brake lines crossed so that you pull right and go left. Mains hooked up backwards. Toggles coming off in your hands because they were improperly installed forcing you to land rear riser, etc, etc.
Straight-in rear riser landings under larger parachutes are not that big a deal. I have landed as small as a 135 with pure rear risers; no toggles at all. It is definitely a good skill to master. The rear risering we are doing in competition is completely different. We throw big 180 (or bigger) riser dives and then plane out with the risers at speeds in the 60mph range. At that speed, the riser input is VERY touchy. Pull too much or off to one side more than the other and you are DONE. I have seen MANY, MANY bad wipeouts because of botched rear riser swoops. Once again, this is completely different than rear riser landings for survival; straight in and without trying to build speed for a surf.
I think Chucks last post sums up what I am talking about. To pull a fast canopy out of a dive onto plane/swoop, is a totally different animal then landing straight in on rears, if I had too.
As it is. If I nail my 270 I can almost go coast to coast on our pond. That means, that I am starting to plane out over land anyway. So for me to use rear risers and try to get that extra bit of distance that would give me the full coast to coast treatment of the pond isn't worth the risk. I would be trying to pull it out of the dive over land. If I miss. Say goodbye to one piece femurs, or worse.
I don't seriously compete, but I love to swoop, and learn from some of the best. Besides I am still exploring my new canopy and smaller size. So, for me, I will just leave the rear riser swoops to "those guys". Learning about them, and what is going on is great for anybody though.