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Slartibartfast

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About Slartibartfast

  • Rank
    no Method in madness
  • Birthday 07/11/1978

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    Adelaide

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  1. I also am a fan of science.

  2. Slartibartfast

    WANTED Kite cloth for testing

    You could try asking for material at a local drop zone (skydiving club). I worked as a packer for several years before getting into kiting and I can assure you most drop zones have plenty of retired parachutes laying about the place. Parachutes are made from F1-11 ripstop nylon and become porous over time, just like kites. Modern parachutes (and by modern I mean made in the 90's or later) are generally made from a material called "ZP", which stands for Zero Porosity (note they actually meant Zero Permeability but got the name wrong). ZP uses strands that are coated in silicone to reduce the permeability of the fabric but over time and not to mention many a violent opening, the silicon wears off and ZP fabric basically becomes F1-11. Another interesting thing to note about parachute material is that the strands that make up the cloth are not twisted. In most cloth the fibers that are woven together are spun or twisted to make circular 'yarns' that are then woven. This makes the cloth stronger but parachute material is woven from un-spun strands such that the fibers are able to squash flat once the weaving is completed. This reduces the porosity of the fabric which in turn reduces its permeability. I'm not sure if the same is done with kiting material but I suspect not. I suspect the additional strength of twisted yarns outweigh the benefits of reduced permeability for kites and certainly the kites I have check appear to have twisted yarns. It might be the case the these new "super fabrics" they use in these deluxe kites do use unspun fibers but I haven't examined any. Using unspun fibers would improve performance but would also reduce the lifetime of the kite. By the way a brand new parachute is incredibly difficult to pack! Packers will generally charge extra for the first 10 or so pack jobs because they're so damn hard to get in the bag. What happens is tiny slithers of air get trapped between all those layers of silicon coated fabric and the whole bundle becomes almost unmanageably slippery. Many a time I have placed my knee on a nicely folded up parachute while attempting to get it into the bag only to have the guts of the stack come spilling out all over the place. It's amazing how easily this happens with brand new ZP canopies.
  3. Slartibartfast

    Skill.

    For those that missed it, it was a video of people flying para-gliders down ski fields, similar in concept to this: The actual video posted above was better than this one but the general concept is the same.
  4. Slartibartfast

    eBay & Gumtree Finds

    Well, my money's been refunded, so I guess all's good. Of course I would have preferred to have the kite but at least I'm not out of pocket
  5. Slartibartfast

    eBay & Gumtree Finds

    Hmm, things went a bit weird... I contacted the guy and asked if he'd be willing to send it to Adelaide and said I would like to pay him through PayPal. He wrote back saying that would be fine, postage to Adelaide would be $33.60 and PayPal fees would be $7.72, so I send him $191.32. He received the money and said he'd send the kite the next day but then later that night I received an email saying: Weird? So at the moment he has $200 of mine which he says he'll return to me rather than send the kite because it's too much of a headache. I hope it works out.
  6. Slartibartfast

    eBay & Gumtree Finds

    Oow, that Venom is exactly what I'm after. Been after another light wind kite since I busted my 13m Venom II and that 16 seems perfect!
  7. Slartibartfast

    Plastic Barrow Rim

    Cool, sounds good. I'll gladly grab one of those of you. Thanks Sinbad (: (:
  8. Slartibartfast

    Plastic Barrow Rim

    Yeah, I have tried both Bunnings and Stratco. They mainly have steel wheels and the few plastic ones they do have are for a much smaller axle diameters. They also don't really sell them on there own. I have been thinking of going to Sysmic rims with Midi XLs, just haven't been able to come at the expense. However, given replacing a plastic barrow is looking like $90 perhaps the $300 to upgrade to Midi XLs is starting to look justifiable
  9. Slartibartfast

    Plastic Barrow Rim

    Anyone know where I can get a replacement rim from? I see Briskites has then but their only listed as a complete wheels (including tyres and bearings) and acutely cost more than the Sysmic 4x8 rims.
  10. Slartibartfast

    Buggy Transport

    Yeah, that's what I was concerned about when I mentioned the "departure angle" above. For my next attempt I intend to bring the rear wheels closer and raise them a little. As it is it already pokes above the roof rack by an appreciable amount and I don't want to push it much higher but a little extra clearance at the back would indeed be welcomed. Also, if I raise the rear axle too much those tyres will start to obscure the taillights and I'll have to look at wiring additional lights to the rack. I'll be able to plug them into the trailer socket, kind of like those towing boards you sometimes see on boats and alike but I'd rather not bother if I can get away with it
  11. Slartibartfast

    Buggy Transport

    So you wheel the buggy up to the car front wheel first, yeah? Then basically you stand the buggy upright with the front wheel in the air, letting the side-rail/swan-next rest on one shoulder (and possibly shuffle forwards a little to get closer to the mount) then, grasping both side-rails, you essentially lift the whole buggy vertically and drop in into the rack, one side first then the other. Is that right? My buggy weighs in excess of 60kg and is an exceedingly awkward shape to lift. While I probably would be able to manage it that way it would be quite an effort and not something I would look forward to :s
  12. Slartibartfast

    Buggy Transport

    I originally planned to mount the bug facing this way too but ended up deciding to mount it 'backwards' so I could simply wheel the buggy up to the mount, lift the axle in then tilt it up. How do you actually lift your buggy in with it facing 'forwards'? Do you kind of stand it up vertically then lift the whole lot, or do you somehow flip it upside down and back it in, or what? My bug's pretty heavy and simply lifting the axle into the cups is best done with two people, I'd hate to imagine how I'd go getting it in the other way round, especially on my own. How do you do it?
  13. Slartibartfast

    Andrew Beattie - first man to reach 100kph

    The trig's not really that important. I'm just pointing out that traveling 10 degreese of straight down wind at 2.5 times wind speed seems infeasible.
  14. Slartibartfast

    Buggy Transport

    It's hard to know. That tube is made from 5mm, 2" square hollow section so it is incredibly strong! The main issue is that 2" hollow section does not mate perfectly with the hitch receiver. It fits in there fine and the retaining pin works as it should but there is a but of slop where it slots in. This means the whole buggy is able to rotate axially a little which on a beast of this size and weight becomes quite significant. To make it stable I have to lash the front wheel to the middle of the roof rack and also use a ratchet strap to keep it all tight. You can see the green ratchet strap in this photo": I'm thinking I will have another go at this. Firstly I'm concerned about the departure angle of the current design, as in how low and how far back the buggy's wheels sit. Fortunately the tail lights on this car are fairly high so I should be able to raise the bug some with out obscuring them too much. The S1 also uses 48mm tube for the rear axle, which is exactly what scaffolding tubing is made from so I should be able to clamp the buggy to the hitch with 90-deg scaffolding couplers: Believe me, these couplers are incredibly strong! So I'm thinking I'll reduce that extension arm to bring the wheels closer to the car making the buggy stand more upright and I'll weld vertical tubes to that cross member and clamp the buggy to the vertical tubes with scaffolding couplers. The advantage of using scaffolding couplers on vertical tubes is 1, it will be incredibly rigid and 2, I'll be able to adjust the ride height of the buggy as I see fit.
  15. Slartibartfast

    Buggy Transport

    Well, after seeing all these I decided to knock something together myself and tell you what, and S1 sure looks pretty big hanging off the back of a car: While it works I sure got a lot of looks driving around Adelaide with that thing hanging off the back
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