freeflyguy

Nice thread One thing nobody has mentioned, is how a front riser turns the parachute. When you pull a front, that side isn't changeing the shape of the wing (camber or planform). Only angle of attack. You are not reshapeing it to have more lift, or drag. But it has less lift because you decreased the angle of attack. It speeds up, as it starts down. Of course the other side of the parachute follows. But it will have more lift, as compared to the other side, so it will be above the risered side, and turn you. Your body follows along as well. But doesn't swing you out as much as the toggle turn.

Nice post Rob. I don't really "Hook", myself. If I call it a hook turn, it meant that it was too low or dangerous. For the reasons you mentioned. The slow carve is the way to go, for safety and speed. It just may seem that it is not so "slow" on some canopies. I agree with the point about it being dangerous to use front risers in the wind. At least more than normal. I had my elbow go to my chest the other day, initiating a front riser turn. But it was a very gusty day. I don't really know, but I think when you pull on that riser, it is possible to decrease the angle of attack on that one side so much, the wind then pushes on top of the canopy. Most people reccomend being conservative in wind anyway though. j

Nah, probably don't know me, unless you have come to Kapowsin. They all call me Cash Money. I jump a white FF suit with bright orange and yellow flames.

I should leave this alone. But what the hell, I am going hunting and won't be around the rest of the week anyway. Trey, I can't promise to be right, but you are thinking the way I am in the first part of your post. But think of these things too. The wings of an F-15 are still generating lift when it is going straight up, It is just the lift is pulling 90 degrees from the line of flight. As always, but that wouldn't be a help in a vertical climb, so in order to keep it pointed straight up, you need something to counter it. Elevator. Also the regular model of Drag, Lift, Thrust, and weight is stll there, but screwed up. Weight and drag are pointed straight down, Thrust is pointed straight up, and lift, ahh. Pointed somewhere, but not really needed, except to say as a component of thrust. But it turns the thing into a rocket, not really a plane. This too, Angle of incidence is the angle the wings are conected to the fuselage of an aircraft, you can't change that unless you are flying a VTOL Osprey, but then you would just crash. Anyway. It is fixed on a cessna. It is on a parachute too, by line trim. But when you are in double fronts, in a dive, you are not allowing the parachute to fly at it's normal trim, or angle of incidence. You are forceing a change in it. That is why it keeps diving. Let it back up, and it will seek the airspeed that it is trimmed to fly at. Until it gets slowed down to that airspeed, it will give you more lift. That is why it pulls itself out of it's dive. This is true even on a high loaded canopy. It is just they may take 500 feet or more to pull out on their own. You can turn too high. One other thing regarding engines. Have you ever seen those scary contraptions where they do connect a parachute to an engine, either a back mounted or trike? I am pretty sure they only have three or four controls. Two toggles, a throttle and wheel brake. Guess how you go up?, add power, guess how you come down? Yep. decrease power. I believe on those they also claim you can't stall them. I just thought I would be a blowhard and beat the poor horse some more. J.

Ok. Just figured I would give my thoughts. Take from it what you will. Talk to you later. james

Hmm. Ya maybe my reply was a bit snide there. Sorry, Paul. You do know what you're talking about when it comes to aerodynamics. Most of what you said is correct and does come straight out of a pilot's manual. I should say where I disagree. Not just poke. That said. I disagree. The original question on this thread was about stall and line trim. That was pretty well answered. One thing not really talked about was whether a person chose to do front riser turns or not, in that persons eqaution of toggle length. Some mentioned they like only a small bow in their lines, at full flight, with toggles up. That is fine. It will work great and is likely close to factory specks as well. But if you have that setting, and choose to start doing front riser turns, it might be a problem. As you pull you're front riser, at the same time, that hand will tighten your brake lines and deform the rear of your canopy. It may not collapse it, but if not, it certainly is not efficient. The point where I disagree with Paul's post is this. He mentioned the dynamics of a stall, using toggles. That is very good, and is likely all true, to a point. In his description, he makes it seem a stall can occur, using toggles only, at some speed above very slow. That isn't true, if we are talking about parachutes, and toggles only. On the vast majority of the parachutes we jump. It is practically impossible stall it, with toggles only, until after it has been slowed down to it's stall speed in that configuration. I wish I had a better way to explain it. Anytime I have ever seen anybody in a full dive, then stab the toggles for all he was worth, the parachute simply does it's best to claw back up. It may be that you haven't really fully stalled it. If it is flying at all, even mushy, it is flying. Although likely partially stalled. The bad air starts at the tail, and as the parachute gets slower, the bad air creeps forward on the top skin. When it stalls, it quits flying and falls off. Usually back. Rear riser stalls are totally different, they can occur at any speed. Although the turbulant air creeping up the top skin is the same. Just likely quicker, and more violent. A major reason why it wont stall on the toggles, is that when you pull them down, you reshape the parachute so much. It is then 'designed' to fly at a much slower speed. Your dive is not likely over more than 90 degrees, it will swing you down, and quite quick to level, then be increasingly resistant to swinging you back up. You and the parachute catch up to each other, then it just climbs until it runs out of speed, and stalls. An airplane is totatlly different. You have the elevator. When you pull back on the stick, it forcibly changes the angle attack of the wing. The wing itself isn't changed, it has no more lift, and you can easily exceed the critical angle of attack. It is stalled. The rear risers do the same, forceiblely change the angle of attack. Where this matters to us, and the only reason I bring it up, is if you are too deep in the corner, pretty much your only choice is stab the toggles. I wouldn't want someone to read something that doesn't completely apply to a parachute and think there is danger of stalling, when you have to stab. That is the last ,and often only, choice that has saved many lives.

That came from experience and honesty. But I wouldn't want it any other way. A full contact freefly and staring at a pond when you are almost 90 degrees to the horizon at 400 feet is part of the game, and refreshing. :)

It would be interesting to see if the fx with those lines and trim was better. Some think that the non cascade causes more drag. Who knows? It would probably take a pretty fancy aerodynamic model to know for sure. What I do know, is those lines, at the first stow, when you have all of them in your hands, seem 2/3 the size of a velocity's. The trim is a whole different deal. Tell us how it works out.

Thoughts, ya, have fun. If there isn't anything allready answered here, ask away. But It shouldn't be tremendously different than the other cross braced you have jumped. It will dive much more than the stilletto though. Do you jump at Mololla?

hrmph. Ya sorry. Sometimes it is hard to resist a bit of a jab. But there has been some good stuff in there. So if it is light, it can be good. Another thing to keep in mind. Look who you are talking too. Traditionally swoopers and freefliers are usually not on the top of the food change, when it comes to reason. They shoud be, those aren't exactly the safest disciplines. But, that is why you need to consider the crowd. Of course we could all just get Blood alcohol lockout devices installed on our computers. You can only post when your BAC is above, .01. But then the forum might get awfull quiet. Of course that is another good reason to carefully evaluate the info dispensed. Pull your strings. j

Sometimes I look at that green grass, then try to say to myself, 'ah, it isn't really that green, it was just painted by the chemlawn people.' That helps keep me from getting snagged on all those fences.

Farrington. I jump at Kapowsin. It's nice to have him and his family around, to learn from. j

Uh, yah. But I think you really meant to talk about the reverse tangent of the square root. Or maybe just the knudsen connector. But I really don't know about that stuff.

I had a cool day of jumping yesterday. -21degrees at 13k. I think I frostbit my nose, but whatever. Anyway. I had to jump my safire again. Because Andy stole my Xaos. Bastard. Anyway, my point in this is this. He has a 69, and a 77 Xaos that he jumps in competition. The one he stole from me is a 100. I think that one gives him a scant wingloading of 2.2. On one jump, he rips it in, hooks the hell out of it, pulls a carve at about 20 feet. The end cell was below his body. Then he whips it back, and lands in the peas. Whatever. Then we had an acuracy contest, for beer. I landed in the peas , 6 feet from the center, the other dude was about the same, Andy landed, and stopped,1 foot from center, on that parachute. Accuracy is where it is at. At the end of the day, he says "I had a blast jumping that parachute today." He just likes to skydive. I guess my point is, high wingloading doesn't equal fun. Also. A high wing loading can be boring in a way. I love to be hanging there in the air. On a high loaded canopy. After it is open all you do is set up to land. Sometimes it is nice to just hang out. Ahh..... Chillin....

hmm. Ya, camber is probably the right term. I don't know much about building wings, or parachutes. To be specific. When you pull down on the toggles, you change the chord line. That is, the chord line moves farther away from the top skin (Chord line is an imaginary line between the leading and trailing edges). It is also the line or direction, the parachute travels when it has 0 degree of angle of attack). So the toggles change the shape of the wing (camber) and chord line. The toggles then effectively change the angle of attack. Not because you move the wing (parachute) in relation to the wind, so much, but because you re-shaped the wing. They pretty much leave the leading edge the same, in relation to the wind, but bring the chord line down, because you brought the rear of the parachute down. That increased camber results in a dirtier wing that, although will have more drag, will also have more lift, and a slower stall speed. That was the point. Pulling rear riser doesn't change the shape of the wing. Since it doesn't change the shape of the wing, the wing itself doesn't have an increased amount of lift. Because of that, you can easily stall the puppy, even if you are cooking. Pulling the toggle is different. It changes the shape of the wing, camber. That results in a wing that has an increased amount of lift, for a given airspeed, and will also stall at a slower speed. So, when in doubt, stab the toggles. If someone is trying to land on rear risers, realizes he is low, or not coming out the dive, more rear riser will do nothing for him. Many a pilot in WWII killed himself because he dove away from the enemy, came out of the clouds, or whatever, saw the ground and jerked back on the stick. That resulted in the high speed dynamic stall. Pulling back on the stick more does nothing. That is why I expect some incident reports this coming year, as people hear more about this "new way to swoop". People will hear the pro's are using the rear risers to swoop farther, try it, get low, pull more rear riser to "save" it, and just bury themselves. Scary and sad. So carefull with it. The whole point of a rear riser swoop is to not increase the drag of making your wing "dirtier", or slower flying because of the increased camber and lift the toggles provide. But at the same time, if you are trying to land with rear risers, and you give it too much, but not enough to fully stall it, you are creating turbulant air on the top skin. That turbulence will slow you down, too. So any gain you may get may be lost, with way decreased margin for safety. Anyway. I probably typed this more for myself and own mental musings then anything else. But whatever, cool forum. j

Huh?

I like the way you guys think. It is true that you all probably could land some cross braced rocket loaded at 2.5. It would probably scare the hell out of you, but if you had too, you could do it. But would it be a good idea. No. People think that because they can land a highly loaded canopy safely a couple times, they can jump it on a regular basis. What about when you have to land out? That guy killed himself a month or two ago, landing out, and makeing a low turn. That is why I completely agree with the above quote. So I agree too, teaching a student on a loading of 1.2 on a zp is proabably not a good idea. The margin for error increases as the loading goes up. There is always time to be a great canopy pilot, later, but only if you are alive later.

ah, you are right on that one. Remi does have it wrong, but that is completely 'believable' don't attack him over it. They don't teach that stuff to skydivers. There really isn't much need too. There is a need for a private pilot to know it though. j

It's raining, so what the heck I mean slow flight mode in the cessna sense. Where you hang on the power of the prop. That is what you where talking about when you mentioned flying at 42 knots. And ya, we cant add thrust, but that is a huge difference. No, the extra speed doesn't really change the angle of attack, if you look at that term correctly. At full flight, the wing is trimmed for a certain speed. It will always seek that speed, same as a cessna. As you increase the speed with the dive, the wing, trimmed for a certain speed, seeks that speed, so the extra speed is burned off in lift that carries you back up, or out of the dive arc, until it reaches it's trimmed flying speed. A wing is a wing, and aerodynamics are some pretty rigid laws, But we don't have an engine, or tail.

Justin The longer brake lines aren't a problem. On our student rigs, the lines are set long on purpose, and the canopies won't stall. That just keeps a student that follows instruction really well from collapsing the canopy on himself. They are taught to flair all the way down. Putting a wrap on your hands would likely get the trim closer to the setting you would have for yourself. I don't know if it is your canopy, but if it was, you would want the brakes to be set so you could just stall it. Play with it, but when you do get it to stall, you would probably not want to just let it flutter forever, you would probably end up in line twists. You can also play with stalling on the rear risers too. It reacts different then when stalled on the toggles. But it is good to know how it flys, and the stall point, in case you have occasion to land on the rear risers j

Quade. intersting spin man. I am not a CFI. and I only have 11 hours, but your cessna analogy doesn't quite work with a parachute. What we fly is more like a B-2 bomber than a 152. We have no tail. Ya we can change angle of attack, and we can change the chord, but what we can't do is add thrust. There is no slow flight mode on our canopies Really, a parachute only has lift, drag and weight. We pretty much can only use weight to increase speed, which on a parachute, results in greater lift :). But you knew that.

I suppose I could chime in. I am not into flame wars. So don't bother. I feel, if anybody is interested in learning to swoop learn it before you downsize. It seems some get the mentality that a 270 swoop landing is only for a higher wing loading. If you can progressively learn how to do that, with accuracy and safety on a lighter loading, you will be able to transfer that to your new canopy. Proper technique and all includes learning to land soft and slow. The Australian Parachute Foundation has a high performance flight manual. One thing I found interesting that they said was something to the affect of "We don't endorse or encourage high speed landings, but if you are going to do it, this is how you should learn..." I think it was nice of them to say that. In this country (US) all the litigation crap often keeps people from saying anything. For fear of being sued. That is sad. So take from it what you will. But we shouldn't create and environment where people are scared to ask for advice. If we do, they may just try to learn on their own. It is really better to be taught. The amount of gain, and the amount you take from this forum is, and should be limited. Because the best teacher is someone that knows what your skill level is, and can watch and critique your progression. So with anything here, be careful with it, think about it, and see how you can carefully apply it. Or come hang out with us for a while. With that in mind. Yahoo. I love to swoop!!!

Oh, I just started jumping one. I had some thoughts on it on a thread titled Xaos-21, last post on 11/28. It might help you. If you have anything specific, I might be able to help. But I am new too it also. One thing that makes me happy about it, I have had line twists something like 4 times. All but one time it popped out of twist just as it fully inflated. The other time, it flew level, and let me kick out. That is much nicer than the scary stilletto stories. That, and turn high for a while. Other than that it flys like a parachute. Sort of...

Cool. Did you have to send in your old canopy before they shipped to you?

Ya, nice Displacement. Once through the risers. You can see my legs extended behind. I stopped just before the shore, then walked up. Nothing hurt. That is nice reminder that a 1.5 wingloading can kill or maim. So don't let anybody try to convince you that you can't have fun on a lighter wing load. I started going to the pond on my Sabre at 1.2 with less than a hundred jumps, and got some nice swoops, as well as learned a lot. Here is a pic of a more succesful swoop. j