From: Marty Sasaki Subject: Changing the spars and a plug for Avia (was: Anybody flown the Box of Tricks??) Date: Thu, 16 May 1996 06:26:18 -1000 Organization: Division of Applied Sciences, Harvard University Message-ID: <199605161626.MAA12793@pobox.harvard.edu> From: rloiseau@aol.com (RLoiseau) When I got the kite I took it out and flew it in about a 12 mph wind. First hour of flying and one of the lower spreaders broke. So I take it home, and look at the other lower spreader and it is already cracking. You have to understand, I didnt crash the kite, fly it in a heavy wind, nothing. Probably the most agressive thing I did that day was a cartwheel. Anyway, I replaced the lower spreaders with 2300 afc, and beefed up the spars where they go in the tee by gluing some solid fiberglass inside bout 5" in. This was just untill I got the replacement exel from BFK. The next day I broke leading edge, once again not doing anything too agressive. Watch a kite sometime as someone flys it aggresively. You will see that even in light wind the frame is flexing like crazy. Groundwork can really give the sticks a pounding. I sometimes like to do a really hard snap turn or snap stall (or tip stab) which causes the sail to go slack. When I pull back on the lines the sail gives out a popping sound. This moves puts a lot of strain on the frame as well as the sail. Once a small crack develops (it may be so small that you can't see it), the spar will probably completely fail on the next hard jolt. Also, breaking one spar will likely upset the balance of forces in a kite and might cause cracks to develop in other spars. Have fun, the kite is a blast (I just wish I had my spars so I could fly it!!!!) My suggestions is to upgrade the frame to a wrapped graphite frame. If you replace the pultruded frame with a wrapped frame of the same weight, you will end up with a stronger and stiffer frame. If you use a wrapped frame with the same stiffness, you will end up with a much lighter kite. Or, you could choose something in the middle and have a stronger, stiffer, and lighter kite I've found that stiffer frames make kites that fly better in a wider wind range. Precision kites are more precise with faster response and smoother flight. Trick kites are easier to do tricks with. Here's the beginning of the plug... I was out flying recently. I was fine tuning a new design (The Katana Trick Kite, also known as the "Vertigo"). It has the same overall shape as the other Katana kites, but has a deeper sail and a higher aspect ratio than the other kites. It was framed in G-Force Ultra lights. The wind was all over the place, from a low of below 3 to a high around 15. I really bashed that kite around. I slammed it into the ground (damn, turned too late!), bounced the wingtips off of the ground trying to do tip stabs, used the wingtip to bore holes in the ground (tipstands that worked). I wanted to see what the kite could take and how good the overall design was. I had a great time with the kite (the design seems pretty good) and the spars held up to a pretty tough beating. I suspect that most flyers are generally kinder to their kites than I was during the testing. I really wanted to learn what the kite could take. I was surprised that I didn't break anything during this testing. The G-Force spars are tapered, wrapped graphite rods manufactured by Kurt Degener and the folks at Avia Sport Composite, Inc. They are tough and have good stiffness. I've found that all of the kites that I make fly better with G-Force rods than with pultruded or with non-tapered wrapped rods. Paul Shuman (creator of the Stripes and the Speed Limit kites) has told me that his kites also fly better with G-Force rods than will pultruded and non-tapered wrapped rods. I know that BFK has these rods in stock. Hang-em High has them in stock too, and Goodwin's kite probably has them in stock as well. They are more expensive than pultruded rods, but for me, they are worth the extra cost. I also like the new fittings from Avia. Disclaimer: I make and sell kites, and use G-Force rods in many of the kites that I make. My views are probably biased. Gentle breezes... = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =