drop-bear

Members
  • Content

    19
  • Joined

  • Last visited

    Never
  • Feedback

    0%

Community Reputation

0 Neutral

Gear

  • Main Canopy Size
    150
  • Reserve Canopy Size
    193
  • AAD
    Cypres 2

Jump Profile

  • License
    B
  • Licensing Organization
    USPA
  • Number of Jumps
    650
  • Years in Sport
    4
  1. Another option that may work without wheels is Sydney Skydivers down at Picton. Haven't been there in a few years, but they used to run a free shuttle bus from Central. Give them a call and see if they still have that. With an express from Newcastle, that could work out well.
  2. If anyone else is looking for the UPT product improvement notice that is referred to in the Sun Path one, it doesn't seem to be available on the UPT website, but there is a copy at http://www.aeroclub.at/download/SM090101.pdf (though it is missing images and links). The tandem incident it then refers to is http://www.dropzone.com/cgi-bin/forum/gforum.cgi?do=post_view_flat;post=3331658.
  3. Thanks for taking the time to clarify that for me Lee. Now that i look at the Lingard paper again, it does on that very page up the top have equations (when rearranged) showing lift squares with velocity, as does drag. Face palm, it was on that very page. And the coefficients of lift and drag mainly only vary with the angle of attack as you mentioned (equations 5 and 6). Though one other variable that effects the coefficient of lift is the anhedral angle (which makes sense since as that angle decreases, the lift vectors from the edges of the wing change direction to better align upwards). Could the higher internal cell pressure from an increased velocity flatten out the wing a little and reduce this angle? That's completely wild arsed speculation, and i really don't know. Maybe any change is too small to be relevant, or maybe my thought process is just wrong. In the real world highly loaded canopies do look flatter, but that's more to do with their construction (ie crossbracing). Think you are right that the comment in Sobieski was probably talking about angle relative to the ground, not the moving air mass. It was more a side comment he made, not the main point he was discussing, so could just be a mistake. Technical writing even, when you really know the subject deeply, can be difficult to make sure every statement is perfectly accurate, and yet as a whole everything remains readable. You also brought up the scaling of wings. That's something i've just skipped over at the moment, still trying to get a grasp of the basics first. Still would love to hear any thoughts you had on it though. Thanks again, -Luke
  4. This thread has been a gold mine of information. Though now i'm a bit confused on the effect (if any) of wing loading on glide ratio. Two of the links seem to contradict each other. http://www.aerodecelerator.org/PDF/Lingard.pdf page 22 says "Consequently, in still air conditions, a given parachute will travel the same distance for a given height loss whatever the altitude or wing loading, but velocity down the glide path will increase with increasing altitude and wing loading." http://skysurfer.com.au/hosted/highperf.pdf page 41 says "This increase in wing loading provides still greater thrust and con- sequently greater airspeed, which in turn contributes to the manueverability and glide ratio of these canopies." Are they both correct and maybe talking about something slightly different from each other? Have i just gone mad and completely misunderstood them? Lingard seems to be basing that statement on the assumption that lift and drag increase in the same ratio as the velocity increases. Seems perfectly plausible, but also not immediately obvious that it must be true. Is this a well known fact, or was it shown earlier in the paper and i missed it?
  5. In the early 80s Wayne Allwood skydived onto Centrepoint Tower in Sydney, cut away his main, then BASE jumped off it with his reserve. Absolutely legendary jump, http://www.youtube.com/watch?v=AVDlu7dvzGM .
  6. You can sign up to get an AIAA login without becoming a member and without being a student. The couple papers i bought where then $25 non-member price. But you are not meant to then share these; the pdfs are watermarked with your name and the time you downloaded it. ETA: Why the hell am i at home on DZ.com, and not at the boogie jumping right now? Damn i am lazy sometimes
  7. Thanks guys. There is a lot of interesting looking papers at AIAA, though they're not exactly cheap, basically one jump ticket each (then again, maybe i'm just being cheap here). They do have Lingard, "The Aerodynamics of Gliding Parachutes", 1986. Haven't read it fully yet, but layout and content looks extremely similar to the freely available PADS link above. The free Cockrell paper looks like it has a lot of information. I've got absolutely zero background in anything aero related (and barely any more jumps than zero), but i just find trying to understand this a little better to be really interesting. Thanks again.
  8. Para Publishing has Lingard, "Gliding Parachutes", technical report (http://www.parapublishing.com/sites/parachute/information/reports.cfm), but the year is different (1990, not 1981). Will order that when they fix their expired SSL certificate.
  9. Hi Lee, That thread was actually the one that got me interested in trying to track down "The Performance and Design of Ram-Air Gliding Parachutes". The link there is for the "Precision Aerial Delivery Seminar, Ram-Air Parachute Design", which was a really interesting read, and lists "The Performance and Design of Ram-Air Gliding Parachutes" as reference 3. Poynter volume 1 also says it is worth reading. Thanks, - Luke
  10. Does anyone know where to get a copy of J.S. Lingard, "The Performance and Design of Ram-Air Gliding Parachutes", RAE Technical Report TR 81103 (1981)? Was hoping that the National Aerospace Library would have it available for purchase, but it is not listed there, and all my googling attempts have come up with nothing. Thanks.
  11. The 2012-2013 Para Gear catalog lists RR2006 and RR2006C rig racks which looked pretty good (page 165), but searching for these part numbers on their website draws a blank. Maybe these have been discontinued? Anyone used these before? Had been considering ordering one soon myself.
  12. My first chop was caused by a few small mistakes adding up, all of them mainly due to inexperience, so hopefully it's relevant to this thread. Rented gear, Spectre 210 (WL 1.07), Mirage G4, PDR (not sure if it was a 193 or 218). 97th jump, 5th of the day. 11-way tracking dive. Altitrack deployment altitude says 2240, so pins out around 2700. Had been having really poor heading performance on openings that day, so was steering the snivel straight, when the slider grommet hit my hand really hard (first mistake, had grabbed risers a little too high). As a reflex reaction pulled my hand away from the riser quickly (second mistake). Think this hand movement is probably what caused the unstowing of the excess control line. Grabbed the toggles and went to unstow them, but ended up with one unstowed, and the other knotted up. That was the third mistake, i remember the toggle grab feeling a little odd (wasn't wearing gloves), so should have paused and looked. Tried to figure out how to undo it for a while, but knot was tight, and not easy to tell how to get it undone (no hook knife on this rig either). Was not going to attempt to land with one toggle and one riser (yeh, yeh big pussy :), so chopped at 1830. Freefall felt a lot longer than i expected, but really it was only 3 seconds and about 180 feet. Had the RSL connected, and think it must have beat me to the silver, though reckon it was close. Followed main and free bag as best as i could, but wind separated them. Very soft landing sinking it in, on DZ property, but waaay off in the sticks. Got the main, but lost the free bag and pilot chute.
  13. http://www.youtube.com/watch?v=49Kw0ZafG4c, from about 3:25 onwards in this UPT video it shows the bridle routing method. Also like the trick of putting your knee through the shoulder strap, hadn't seen that one before.
  14. To answer part of my own question, no, a MARD doesn't work at terminal since the main isn't out, so it won't cause hard opening problems.