masher

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Everything posted by masher

  1. Thats also a function of how big your DZ is, and how many students vs "I'm too good to jump with you " people there are. Not that I can comment first hand here... -- Arching is overrated - Marlies
  2. Probably more like driving on P-plates... Slower top speed, lower blood alcohol level et al. -- Arching is overrated - Marlies
  3. masher

    Threesome ??

    Why does everyone assume that a funny photo is photoshopped? -- Arching is overrated - Marlies
  4. To get your B licence with the APF, you need to complete the B-rel table. That teaches you how to fly your body. It sound like what Shark was talking about, but a bit more formal. There are 10 stages involved (12 jumps if you pass first time). They go from a straight pin, to 3x 3 point four ways. -- Arching is overrated - Marlies
  5. I would like to see one. I managed to do one of my approaches wrong a couple of weekends ago because I couldn't see our wind vanes clearly until about ~150 ft. That, and the fact that the wind at the LZ was about 180deg different to the main airport windsock about 400-500 m away... (thank god for flat turns and student canopies) -- Arching is overrated - Marlies
  6. V nice. Where can I find some more? -- Arching is overrated - Marlies
  7. Anyone got a picture? -- Arching is overrated - Marlies
  8. masher

    Physiology

    You need the physics to figure out the physiological effects. Plus, I didn't want to do any work at uni. -- Arching is overrated - Marlies
  9. Read the 'physiology' thread.... It's mind numbing. Unless you're a physicist, that is... -- Arching is overrated - Marlies
  10. masher

    Physiology

    I had another brain fart. Here we go. This should work. The velocity for a conical pendulum is given by v=sqrt(r*g*tan(theta)). The velocity for a driven conical pendulum is given by v=sqrt(r*g*tan(theta)) + x, where x is the constant velocity of the parachute. Centripital acceleration is given by a=v^2/r, so after all the maths, the acceleration that you experience is given by the equation: a = g*tan(theta) + 2*x*sqrt(r*g*tan(theta)) + (x^2/r) a = centrepital acceleration g = acceleration due to gravity theta = angle between the vertical and angle of revolution x = forward speed of you canopy -- Arching is overrated - Marlies
  11. masher

    Physiology

    The theory is too hard for me to figure out at the moment (the book that I need is at home). To do it experimentally, you need a gyroscope setup and 3 accelerometers. You can integrate the z data twice to get your displacement (altitude loss). the z data should give a zero accel'n. The reason for this is the same as that behind freefall velocities. The only difference is that under canopy you have a larger surface area. So, once you start your turn, after the initial accel'n period, you should stay at a constant velocity. So, the path that you describe in that air is that of a driven conical pendulum falling at a constant velocity, and because you're falling at a constant velocity, we don't need to worry about it. (Eintein said so) So we only need to worry about accel'n in the horizontal plane. Convert the x and y accel'n to a radial accel'n. and you have the g forces that you are under. . There's no acceleration in the vertical (once you reach equilibrium). All of the acceleration is contained in the horizontal plane. Sorry about that, but I actually did some thinking before I wrote this post. -- Arching is overrated - Marlies
  12. masher

    Physiology

    Thats true for circular motion in the absence of a gravitational field. A spinning parachutist is an example of a conical pendulum. More exactly, a conical pendulum with a constant driving force. For a normal conical pendulum, the only driving force is that of gravity. For a small body of mass, m, suspended from a string of length L, the body revolves in a horizontal circle of radius r. The angle, theta, describes the angle between the vertical and the string. Do the maths, and the period of revolution is 2*pi*sqrt((L*cos(theta))/g) This problem is 'easy', as the only acceleration is in the horizontal plane, and the source of the acceleration is gravity. With a parachutist you have the additional problem of acceleration in the vertical direction, as well as a driven osccilator; the parachute gives you forward speed, as well as gravity. That makes things hard. -- Arching is overrated - Marlies
  13. masher

    Physiology

    The maximum that accel'n due to gravity will add is 1 g. The inertial forces that you experience are made of two components: the circular motion of yourslef under the canopy, and the pull of gravity. Now, measuring these two components is fairly difficult, as you need two accelerometers that are (at all times) perpendicular and parallel to the ground (to measure centripital and gravitational accel'n). Measuring the force on you body is a bit easier. Taking an idea frp, Push, you can mount something like a fish scale, with a thingo that records the highest weight (like a tag that goes down, but not up) and attach a weight to the end. This is mounted vertically on your leg, so the the weight is pulled down to your feet. After you deploy (you may have to reset the scale, I don't know about g-forces on deployment), just put yourself into a spin, making sure to keep you legs pointing straight. After landing (softly) look at the max weight. That will tell you how many g's you experienced. ie. if you put a 100g mass on the spring, and the max weight is 200g, then you experienced 2 g's. -- Arching is overrated - Marlies
  14. masher

    Weekend Numbers?

    0:4:0 Not bad for only the Saturday... btw, I still owe two cartons from the last time I was down... They're being paid off this weekend. -- Arching is overrated - Marlies
  15. Somewhere in the northern hemisphere? . Hey, 50/50 chance... -- Arching is overrated - Marlies
  16. Your velocity overall will be zero. Velocity is displacement/time. Your displacement is zero, as you've ended up where you started from, and the time doesn't matter. -- Arching is overrated - Marlies
  17. Talk about unlucky..... -- Arching is overrated - Marlies
  18. found it.... http://www.wannaplaygames.com/skyball/ -- Arching is overrated - Marlies
  19. where was that freefly web game? The one where you have to dodge the flatflyers? -- Arching is overrated - Marlies
  20. Techniquely, you can't do that either, as 'their' and 'they' represent a group of (in this case) people. It's been accepted practice to use 'they' instead of 'he' or 'she', but it's not right. . What you should use is "he or she or it", commonly abbreviated to "h'orsh'orit" -- Arching is overrated - Marlies
  21. mmmm How did you manage to do that? -- Arching is overrated - Marlies
  22. It doesn't work..... http://www.google.com.au/search?q=Google+help+me+for+I+am+ill&ie=UTF-8&oe=UTF-8&hl=en&meta= -- Arching is overrated - Marlies
  23. This list has also done the rounds as the Royal Marines (well, British military at least...) officers apprasials. The one from that list I like is: His men would only follow this officer out of curiosity. -- Arching is overrated - Marlies
  24. Looks to goods to me... What container have you got? -- Arching is overrated - Marlies
  25. slow enough? I wouldn't call 200km/h slow. How about aircraft.... They're a bit louder, and they get hit... -- Arching is overrated - Marlies