sirenoremac

Can't wait! I'll be there August 3rd doing my FFC so anyone who wants to come make fun of me or try to get me to buy them beer can come say hello!

Skydive El Paso will let you do static-line at 16 with parental consent. Technically it's not in Texas, but just barely across the border in New Mexico. http://www.dropzone.com/dropzone/Detailed/817.shtml Check it.

A Pilot is noticably faster in the turns than an original Sabre. As for the glide, I would say they are pretty similar, although I haven't jumped a Sabre in a while, so it's a little hard to compare. Front riser pressure is a little lighter on a Pilot as well.

But will the ceiling change it's angle? This is very simple physics people...

It's a podcast... it's on the web.

Being on a 12-way with Craig G. and Eliana at Eloy, diving behind Eliana having her glance at me as I flew down the hill, take a sort of analyzing look, and then nod. Hehe... felt real nice.

No I do! edit: crap....

Perhaps you were just pulling your outermost cascades?

I really like the idea of rigging up a cool something or other, changing the altitude on the unit and having it fire in freefall. Maybe even on your main, although you would need to turn it on at a higher than field elevation since the altitude adjustment only goes up 1500 ft. And you would have to have a ripcord and spring-loaded pilot-chute. And be willing to sacrifice a closing-loop. And there are probably other things to take into consideration. But with a good rigger and a little cash, along with a little training to re-learn ripcord rigs, as well as the awareness that you should definitely be ready to pull for yourself, it could be a lot of fun. I would do it if I was confident in the planning. Or you could toss it in a pressure chamber and try to activate it and get to watch. That would be mildly entertaining.

I jump a Pilot 150 and I weigh about 180 out the door. I'm loading it around 1.2:1. I have close to 300 jumps, with about 70 on this canopy. At this wing-loading, much less at 1.3 or more, you have to be flying your canopy confidently all the way to the ground. Everything from the turns to the landings are going to be completely different from the 280. Think of a toggle turn where you can't pull the toggle past your elbow, and after a 360 your legs start to hurt. In landing you have to be able to judge your altitude accurately and quickly and account for your forward speed at the same time. It's certainly not a cross-braced hankerchief, but it is beginning to be in the realm of high-performance flight. I would not have been comfortable flying this at 100 jumps. Things just happen faster, and there's more to think about. This is something you learn to handle through experience. So here's my opinion. And it's just my opinion. You need to be comfortable under whatever canopy you are flying. You need to be confident, not wondering as you make your final "Am I gonna biff it? Am I gonna flare right?" You need to be able to have a certain percentage of these factors down-pat as instincts, so that your mind can focus on other things, like traffic. Hopefully your instructors will get you ready before letting you fly this canopy. But if YOU are not comfortable, the final veto power lies in your hands. If YOU feel like the 190 is what you want instead, that's your choice. It's your money, and if you call Aerodyne at this point and tell them the deal, I'd bet there would be no problem in changing it. Remember, this is YOUR life. You have the right to be as safe and cautious and take as much time as you want, so that you can assure that you will have time in your future.

yummmmmm... gamy....

No need, I already said I was mistaken. That is not what I wanted him to say. I just like the prof's way of explaining things.

At The Drive-In, The Mars Volta, and Sparta are all from my hometown, and people I know. If you've never heard of any of them... you need to!

Mine is a Suzuki GN400 '81. Old, and solid. I like it because I can do every bit of maintenance/repair on it myself, and I know very little about that stuff. Also, it gets 50+ mpg. Perfect for getting to and from work and around town, but it's definitely not something to take on a long trip. It suits me well, but you have to figure out what you need out of your bike.

A canopy collapse occurs when the airspeed of the canopy becomes too low to support inflation. A deep stall, turbulence, lazy eights (turning fast one way and very quickly reversing direction) can all cause this condition but for different reasons. A deep stall will stop the parachute from flying, and directly cause airspeed loss and therefore pressurization loss. Turbulence may effect a canopy many different ways, but a collpase can occur when different portions of the canopy are flying through distinctly different types of air masses, i.e. the sides of the canopy get caught in a solid up-draft, but the center does not. This will cause part of the canopy to lose inflation. Lazy eights can induce slack in your lines, causing a brief loss of your gravitational force on the canopy, and possibly leading to some type of collapse, although this would be difficult to induce. Basically anything that you can picture to make the air flowing into the front of your canopy or part of your canopy can cause some type of collapse. Turbulence is the most likely to cause an accidental collapse, while holding a deep stall is the easiest way to induce a collapse.

I have tried very hard to keep anything I've said from being personally negative, 'cause I really don't have anything against you or your idea or you rright to share your ideas. All I've tried to do is point out the things about your ideas which I believe would make them impractical or non-beneficial. It's nothing personal, really, and it certainly is not an attempt to kill creativity for the sake of physics. It's merely an application of my knowledge of physics and aerodynamics to a presented thought toward which these fields are applicable. Because when it comes down to it things obey the laws of physics. Creativity isn't discouraged, you merely have to apply that creativity toward exploiting those laws as opposed to wishfully trying to ignore them. Not that that's what you are trying to do, but you do keep coming across as willing to let the aspects of physics which don't seem to work well with your idea slide on by. As for the three-ring system, I agree, it CAN be mis-assembled, and while that is something that is considered a design flaw in complicated mechanisms, there are really only four parts to this mechanism, and any misstep in assembly is easily caught with a cursory glance. Not to say that it's perfect, but it is a well tried system. If you have an idea for an improved system, or feel like you could come up with one, more power to you. That's where innovation comes from, not from whining about poor design, but from fixing it. Three-rings are an improvement from older systems, and we will keep using them until there is another clear improvement. I also would like to invite you to return arguement, instead of poo-pooing what we've said. If you still think your ideas have merit, tell us why. Like I said, I'd like some discussion, to get a better grasp on an idea that I have thus far only had a few lines of written description on. I may still not fully get what you're trying to put across, so explain it in more detail, and explain why you believe that you could create a benefit with the system. I've explained why I don't think you can. Return the favor.

Allright, back to civilized discussion. Thank you. As has already been said, the biggest flaw in your idea, and the one that I believe would kill any possible benefit is the production of extra parasite drag. In a prior post, it was mentioned that flaps on an airplane produce MORE drag than lift. The general figure thrown around is %30 more lift and %300 more drag. A 10:1 ratio. Remember that the key to making swoops longer is essentially making them faster. Clean up the drag, streamline the system, and more of your speed will be available to convert into lift. In more depth, your flap idea is essentially a more clumsy and complicated method of applying the same idea that canopies already use. When you put flaps down on an airplane, you are changing the chord of the wing. The same exact thing happens when you flare a canopy. In an airplane, in a no-flaps configuration on landing, the pitch, and angle of attack are controlled with the elevator. A parachute does not have the luxury of an elevator, and therefore must change the actual shape of its wing to control its pitch and angle of attack. When you flare, look at your canopy and notice (which I'm sure you're aware of) that the trailing edge is pulled down, creating a very similar visual to that of lowering the flaps on most small aircraft. So essentially, parachutes already come with flaps. We just happen to use them as our elevator and ailerons as well. Oh, and these flaps have been very precisely designed by the manufacturers to do their job as best they can for the type of canopy that they are on. As for your original idea, once again, without any kind of model to go on and couldn;t say for sure, but I can pretty much guarantee that the added prasite drag, as small as it may seem, wouldn't kill any potential lift benefit. With a parachute we only have so much energy to work with, and we really have to figure out ways of more efficiently using that energy, so good for you on thinking forward. But the solution is not likely to be found in fairly complex systems, and much more likely to be seen as very clever small improvements to increase efficeincy a little bit at a time. Think cross-bracing for more rigid wings, think HMA lines for lower drag in the line system, think collapsible slider and pilot chute. And remember, there's the matter of skydivers liking soft openings. Adding to material in strange places or putting holes in a canopy are most likely not going to benefit a nice 500-700 ft on-heading opening. But then I guess we are really just talking about the pure aerodynaimc possibilities here. Oh, as for your point about using the air that is simply being wasted in making the wing more rigid, I don't believe that there is any wasted pressurizing air while a parachute is flying. Hence the need for cross-bracing, air-locks, and even better forms of internal bracing (PD's up-and-coming Z-bracing). In other words, there isn't any excess pressure in a RAM-air wing. If there was, perhaps some type of system could be implemented to use it more effectively, but I get the feeling that it wouldn't be putting holes in the bottom-skin of canopies. Anyway, keep tossing those ideas out, just don't get so defensive when people offer their expertise on why it probably wouldn't work. Life is learning. Let's keep up the discussion.

Okay, I'm going to take another whack at this, and try to explain, NOT shoot down for no reason, but explain WHY your idea doesn't make sense. I am not an enemy. Clear? Okay. Here goes. First off, the principle that a ramjet operates on is simple. It is in essence just a venturi with a fuel injector. The venturi itself adds NOTHING to the system. It's the energy from the combusting fuel that gives a ramjet the ability to accelerate. Otherwise it is as Kallend said, just a funnel being dragged through the air. Now what you suggest is to use gravity as your powering force, and use flare of a canopy as an example. Conservation of energy not only allows for that, but it is also a very simple and good example of the law. When a canopy is flying at 100 feet, it has both gravitational potential energy, and kinetic energy. The idea behind a swoop is to convert as much of that potential energy into kinetic energy with as little energy lost to friction as possible. Then, if the timing is perfect, when the kinetic energy of the skydiver-parachute system has reached its peak, and the canopy is in a dive with forward movement, you then use the remaining kinetice energy (speed) to generate lift. Then as the canopy slows, the swoop comes to an end, setting the skydiver down. Are we good? Make sense? Wonderful. Now here comes the biggest problem with your little thought. Remember how I mentioned that for a perfect swoop you want to convert potential into kinetic with as little loss to friction as possible? What do you think adding holes is going to do? Besides the fact that it will weaken the pressurization of the wing and therefore be non-beneficial, you are also presenting more parasite drag to bleed energy away. Enough to immediately equal and quickly outweigh any possible hope of adding lift to the system. You were hollering about dynamics assuming a perfect world. You are the one assuming perfection. You have to remember to account for non-conservative forces as well. Besides that, which is the most obvious mis-step in your plan, you still haven't said anything about what will happen with the topskin forces of the airfoil, or how you think the loss of rigidity on the whole will affect performance. Short answer: negatively. Your net lift will only increase by adding energy into the system, or by making the system more efficient in and of itself. Adding holes to the bottom of a RAMair wing will NOT increase it's efficiency.

First, I wouldn't reccomend getting into a physics arguement of any kind with the professor. Second, this is extremely old news in aerodynaimcs. Ten years plus. Rest assured that if it could be applied as effectively as the article makes it seem, it would have already been done. The aerospace industry is always looking for anything, ever so slight, that is truly beneficial. It doesn't take much cost saving to make a huge difference in an industry where a single product cost $100 million. And as far as applicability to ram-air flight goes, there is zilch. Systems of this type are very complex, even on a rigid wing. As far as this venturi effect idea goes, I'm not sure I understand what you're suggesting, but if I'm picturing it correctly, just the manufacture of such a system, made completely from fabric, would be absurd. But perhaps I am not getting the idea right.

Started static-line at 15. Now 19. I miss the good old days

I believe Johnathan's new record is ~494 ft. Not positive, can't remember where I read it.

Yeah, it's definitely a complex issue, and one that is more than likely very canopy dependent. However I would be willing to bet that the added momentum has a greater effect than the induced drag. The real issue is how the wing's performace changes at higher velocities, and at higher wingloadings. That is bound to be the hardest thing to analyze, with the only practical option being to do so empirically. Now if canopies were completely rigid wings, we would be in much better shape performance-wise, but I imagine the openings would be slightly uncomfortable .

Its a similar issue to fall rate. Momentum v. Friction. If you keep the same profile presented to the wind while increasing your mass, you will go farther than if you were going the same speed with less mass. The friction or drag that the wind creates is proportional to velocity, and surface area (coefficient of drag as well). If these stay the same, but mass increases, you have more energy, therfore more "cutting power" through the wind. Assuming the canopy performs exactly the same, which it won't, you will go farther by having more weight.

Go static-line! graduated on jump 9 and did my first two way on jump 10! Beat THAT turbine babies!

Lol! Let's hear it for REALLY young skydivers! Heck, I've been jumpng for close to three years, and I dont look a day over sixteen Eric Cameron