Date: Wed, 2 Jun 1993 17:15:29 -1000 From: plepez@ulb.ac.be (Lepez Philippe) Message-Id: <9306021915.AA14047@is1e.vub.ac.be> Organization: Division of Applied Sciences, Harvard University Subject: SkySharks ? Hi all, In a recent posting Marty Sasaky told us he uses Skyshark spars. I know these are very lights (11, 13 and 15 g.). I would like to ask what about stiffness compared with other spars and how does Marty interconnect them because their outer diameter is not constant. Where can we obtain tube, ferule adapted for these spars, preferably in Europe (Vlieger-op has the spars but not the associated material to the best of my knowledge). Good winds. -- Philippe Lepez (CP 125), | | Good kite Universite Libre de Bruxelles, | Email: plepez@ulb.ac.be | + Good wind 50 av. Roosevelt, | Phone: 32.2.6503553 | ---------------- 1050 Bruxelles, Belgique. | Fax : 32.2.6503323 | = A lot of fun ! = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Date: Thu, 3 Jun 1993 06:34:16 -1000 From: sasaki@das.harvard.edu (Marty Sasaki) Message-Id: <1993Jun3.163416.6854@das.harvard.edu> Organization: Harvard University Subject: Re: SkySharks ? In article <9306021915.AA14047@is1e.vub.ac.be>, plepez@ulb.ac.be (Lepez Philippe) writes: >In a recent posting Marty Sasaky told us he uses Skyshark spars. >I know these are very lights (11, 13 and 15 g.). I would like to ask what about >stiffness compared with other spars and how does Marty interconnect them >because their outer diameter is not constant. Where can we obtain tube, ferule >adapted for these spars, preferably in Europe (Vlieger-op has the spars but not >the associated material to the best of my knowledge). I've promised the data to Simo and I will post it here when I remember, but I've forgotten the bast few days. However, here is some rough data to use until I remember... As a point of comparison, an Advantage 250/2 weighs 14 grams for a 32.5 inch length. The Sky Shark 3p is 11 grams, the 5p is 13 grams, and the 7p is 15 grams. The "p" stands for ply. Sky Shark claims that they use thin plies of graphite and another material to give the spar toughness and stiffness. The 3p is roughly the same stiffness as the Advantage 250/2. The 5p is a little more flexible than the Advantage 250/3. The 7p is somewhere between the 250/3 and 250/4. Remember these are just from memory. There are two ways to connect them, one is the recommended way, and the other is the way that I connect some tubes. The tubes are reinforced on the outside. The reinforcing is then ground down. The outside diameter near the ends are the same for all of the rods. An anodized aluminum tube is used to join the tubes together. This is the recommended way. The inside diameter of all of the tubes is the same. I'm not sure what the exact diameter is, but a Beman 6.3mm rod will slide into the center of the tube nicely. Since the tubing is reinforced near the ends, a short length of 6.3mm can be used as an internal ferrule. I wouldn't use this in high stress situations, but it works quite nicely in other applications. One nice thing about these tubes is that the 6.3mm rods slide easily into them. This past weekend in Wildwood, I slipped 6.3 rods into the Sky Sharks to increase the weight of the kites. This made stopping much easier and strengthened the wing tips which gave me much more confidence for doing tip stands and such. Remember too, that I'm biased. Health Sciences Technology Group sponsors Storm Front... -- Marty Sasaki Harvard University Sasaki Kite Fabrications sasaki@noc.harvard.edu Network Services Division 26 Green Street 617-496-4320 10 Ware Street Jamaica Plain, MA 02130 Cambridge, MA 02138-4002 phone/fax: 617-522-8546 = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =