raymod2

this is the idea behind them...... Winglets in other applications After reading that article and looking at the pictures of the winglets on the Nitro and Blade I suspect they are a gimmick. How can they recover energy lost by wingtip vortices when they aren't even located at the wingtips?

I just received my copy today.

I believe it. I've only got 35 jumps under a Stiletto but I wasn't impressed with how it swooped. It wants to turn so fast that I found it difficult to manage my turn rate during my final approach. I frequently found that I was coming around too fast and if I tried to slow down the turn the riser pressure would become unmanageable. I also got the impression that it loses lift quickly towards the end of the swoop and requires you to put your feet down too early. Then again, maybe I just wasn't flying it right. I learned to swoop on a Sabre.

I would love to share my input on this book. However, I have been checking my mailbox for the last 7 weeks and I still have not received a copy. I mailed my check on May 6th. Has anyone else had any better luck?

My opinion, which isn't worth much, is that it would have shown more "style" to try your best on both rounds.

There's a difference between opinion and speculation, in that the latter is even more worthless.

This is good advice. The most satisfying swoops are not the ones that go exactly as planned but the ones where you learn something new.

It looks like we hit a nerve with some of the people here. I guess the lesson of the day is: don't question how many cells a cross-braced canopy pilot has. He has plenty and you can be sure he has more than you.

And I thought the definition of a cell was an enclosed pocket of fabric that inflates independently from neighboring cells. My Sabre has 18 openings but there are cross ports between every 2 of them. Hence it is a 9 cell canopy.

Just rotate your shoulders forward. This brings your front risers closer together and takes the tension off your chest strap so that you can loosen it.

Stating 1.2:1 as a "recommended minimum" could easily be taken to mean it is unsafe below that It seems to me that is an unfair assumption. Let's say I design a sports car engine that redlines at 15,000 RPM and has peak horsepower at 13,500 RPM. A lot of my design effort went into fast closing valves and lighter engine parts that allow such a high RPM. When I sell the car I might recommend that you don't let the RPMs drop below 10,000 because the power drops off considerably below that. Does that mean that you can't safely drive it around town at 4,000 RPM? No, it just means you won't reap the benefits of many of my design efforts if you drive it that way.

Like fingernails on the chalkboard. Homonyms really aren't so difficult. break - something you do to a femur brake - something you do to slow down

If you go down that road then why not apply the same principle here in the United States?

Did you PLF?

I would not jump to the conclusion that an outdated CYPRES is better than no CYPRES at all. Did you consider the possibility that a malfunctioning CYPRES could *cause* a fatality by firing when it shouldn't?

you can wheelie a shaft cycle, but saying you can't is basically a motorcycling equivalent of saying you can't swoop a sabre. I was going to use the "can't wheelie a shaft cycle" defense in traffic court but the cop didn't show up.

What? You're trying to swoop a Sabre? It can't be done. You also can't wheelie a shaft driven motorcycle.

This is not done by the flaps on an aircraft. It's done by the tail. Since we don't have a tail, it is the light high drag wing that decelerates and the heavy, low drag pilot that swings forward, thus changing the angle of attack when the brakes are applied. Since you are the second person to comment on my flaps analogy I will elaborate. The most commonly accepted definition of angle of attack is the angle between the chord line and the direction of flight. The chord line is an imaginary line drawn between the leading edge of the wing and the trailing edge. When you lower the trailing edge of a wing (by extending flaps or pulling on toggles) you are moving the chord line and increasing the angle of attack. This (usually) causes an increase in lift and drag. It creates more drag than lift, however, so the lift-to-drag ratio goes down. The decreasing lift-to-drag ratio is generally a bad thing for airplanes (which is why they don't fly around all the time with flaps extended). But for canopy pilots this produces a secondary effect which is very desirable. It tilts the T.A.F. rearwards which creates a moment that rotates the canopy/pilot system. This tilts the entire wing and causes an even greater increase in the angle of attack. Note that this has nothing to do with deceleration or "swinging forward". Since the canopy and pilot are connected they both experience the same deceleration. And if the pilot simply "swung forward" then the lines in the front would go slack and there would be no change in the angle of attack. What you perceive as "swinging forward" is actually a rotation of the entire canopy/pilot system.

I've put a lot of thought recently into the principles involved during a high performance canopy approach and landing. I figured I'd write them down, share them here, and solicit comments. A canopy pilot is flying at full glide with the toggles all the way up against the guide rings. The canopy is flying a straight line path towards the ground at a constant airspeed. The canopy/pilot system is in perfect equilibrium: there are no unbalanced forces and no rotational moments acting on the system. The total aerodynamic force (abbreviated T.A.F.), which is the sum of the lift and drag vectors, is equal and opposite to the gravity force and colinear with the center of mass. The pilot reaches up, grasps both front risers, and pulls them down a few inches. This shifts the center of mass of the system forward. Now the T.A.F. is no longer colinear with the center of mass. A moment has developed which causes the canopy/pilot system to rotate counterclockwise (as viewed from an observer to his left) until the center of mass again lies on the same line as the T.A.F. At first, due to inertia, the direction of flight and the airspeed remain unchanged. Due to the rotation of the canopy its angle of attack has decreased. This causes a decrease in lift and drag. The canopy now experiences an unbalanced downward force. The system seeks out a new glide angle and airspeed that produces equilibrium in the new configuration. The result is a steeper glide angle, a higher airspeed, and a lower angle of attack. As the ground approaches the canopy pilot begins the roundout (this is the phase of the landing where descending flight transitions to horizontal flight). First he eases off the front risers. The center of mass shifts backwards, the system rotates clockwise, and the angle of attack increases. The increased angle of attack causes an unbalanced lift force which alters the direction of flight (making it more horizontal). This tends to decrease the angle of attack but it also causes the lift and drag vectors (and the T.A.F.) to rotate clockwise. The canopy/pilot system must also rotate clockwise to keep the center of mass colinear with the T.A.F. This tends to increase the angle of attack again. Thus, once initiated, the roundout is a self-sustaining process. There are two other processes, however, which will oppose the roundout. (1) The component of gravity which opposes lift will increase. This will tend to eliminate the unbalanced lift needed for the roundout to continue. (2) The component of gravity which opposes drag will decrease. This will cause the airspeed to decrease which also tends to eliminate the unbalanced lift. The pilot may need to apply some toggle input to complete the roundout. As he pulls down on the toggles the tail of the canopy deflects downwards. This inherently increases the angle of attack of the wing (similar to lowering the flaps on an airplane). In addition the new shape decreases the lift to drag ratio of the canopy. In other words the T.A.F. rotates clockwise. The canopy/pilot system also rotates clockwise to keep the center of mass colinear with the T.A.F. This rotation further increases the angle of attack. The higher angle of attack provides the extra lift needed to complete the roundout. At the end of the roundout and the beginning of the surf (horizontal flight) the lift force must be equal to the gravity force. If there is too much lift at this point the canopy will continue past horizontal flight and transition to ascending flight. The pilot can ease up on the toggles (decreasing the angle of attack) to correct for this. During the surf all of gravity opposes lift and none of it opposes drag. With nothing to oppose drag the airspeed will steadily decrease. As the airspeed decreases the pilot steadily pulls down on the toggles (increasing the angle of attack) in order to maintain constant lift. Before reaching the stalling angle of attack the pilot touches down and completes the landing.

I am not refuting the veracity of this statement but would you care to elaborate why?

I think you're forgetting the fact that lift is perpendicular to the line of flight. It does not always point up and it does not always oppose gravity.

Letting up on your brakes results in accelerated flight which decreases your apparent weight and decreases riser pressure. It is the same principle that causes riser pressure to increase when pulling out of a dive except the direction of acceleration is reversed.

Here are a few thoughts on the subject: Riser pressure is related to the weight of the canopy pilot. If you are a fatass then you are going to have to pull harder to lift yourself up. Similarly, you can alter the apparent "weight" of the pilot through various flight maneuvers. The recovery arc is a perfect example of this. During the recovery arc the canopy is accelerating upwards. This makes the pilot "weigh" more and it will increase riser pressure. Furthermore, a shorter recovery arc translates into a stronger acceleration and more riser pressure. Decreasing the size of the wing, in and of itself, should have no direct effect on riser pressure. However, it can have indirect effects by changing the way the canopy flies and altering the apparent weight of the pilot during various maneuvers. I imagine that canopy design can also affect riser pressure directly by moving the center of lift and changing the weight distribution between the front and rear risers.

> I said NOTHING of swooping. This is for those that > don't know what the rock point is. > > What I said makes perfect sense. You might not > understand it but the principal is sound. And I am > in fact correct. The purpose of my post was to demonstrate that you were talking straight out of your ass and that you don't have a clue about the basic principles of flight. I think I succeeded at that.

> It is the point during the flare that you have > swung directly under canopy. Where you have > entered the slow speed flight of your canopies > airfoil. At your rock point your descent has ceased > and you are just moving forward bleeding off > airspeed. Does that make sense? No, that doesn't make sense. You can arrest your vertical descent at nearly any airspeed. This has nothing to do with "slow speed flight". To the contrary, the primary goal of a swooper is to plane out at the highest possible airspeed. > Weight wise under canopy you have shifted > slightly in front of your canopies center of gravity > allowing the canopy essentially to canter upwards > acting as a brake and slowing down. The purpose of flaring (or rear-risering) is to increase the angle of attack in order to maintain lift while airspeed is decreasing. Yes, this also increases induced drag (canopy acting as a brake) but this is an (undesirable) side effect. Also, this is a continual process and not well described in terms of a discrete "rock point". > In an airliner. When the plane slows down, flaps > drop. The moment that nose starts to point above > the horizon with the plane still flying straight and > level could be considered the rock point. Most planes can takeoff, fly their entire flight plan, and land without ever extending the flaps. Also, extending the flaps increases the angle of incidence so it is usually accompanied by a *downward* pitching motion. That is one of the reasons flaps are used on jump run. It allows the plane to slow down without pitching the nose up (and increasing the risk of exiting skydivers hitting the tail).