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My First Custom-Built Boost Glider |
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Sunbird II Design First Flight Second Flight Conclusion WAEC Rockets Space Racer SAM-66 Sunbird II Pi Sprint Leviathan Space Racer II Arcturus Mk. 1 Roswell or Bust! Brinley Short March Discovery XW-1 Apollo-LES Sprint II Lone Star Mercury-Redstone Shenzhou Saturn 1B Saturn V Gemini-Titan II Juno I Chrysler Building More Information |
Sometime in October of '99 I was flipping through the book Model Rocket Design and Construction in the Hobby Shop when I happened upon the section about boost gliders. I had wanted to build something with all of the excess junk I had accumulated from past projects. I figured that a boost glider would be the solution to my "problem." I realized that I had an old glider that would work perfectly for this. One time when I flew it it crashed, so it had been sitting on my shelf for several months. Since I would have to rebuild it and customize it a lot, this rocket would essentially be a custom-build. I gave it the name Sunbird II, after a yellow paper airplane that seemed to be immortal. It had landed on the roof of our school twice. The paper airplane was, in turn, named after a can of yellow spray paint. Sunbird II is a conventional boost glider design. The wings are located in front of the tail. Instead of having the vertical stabilizer on the bottom, like many boost gliders, I gave Sunbird II two tail fins on either side of the horizontal stabilizer, sort of like a B-25 or a Beech 18. On the nose a detachable pod holds the engine and all of the things not necessary for a stable glide. At apogee I wanted the pod to fall off, so the glider would level out in a long, spiraling glide. First Flight When the day finally came for launch I was jovial. Over the past week I had finished two new designs, Sunbird II and SAM-66. Because of the more conventional design, SAM-66 flew first. Then the time for Sunbird II to fly came. I placed it on the launch rod and hooked up the igniters. Then I stepped back, counted down, and pushed the button. What happened next was all recorded on 8 mm camcorder tape. I didn't see it all. When the rocket left the pad the power pod detached prematurely. It spun out of control, performing five or six tight loops before falling to the ground. The glider, meanwhile, wasn't at sufficient altitude to level out and glide, so it nose over and rammed into the ground. Luckily, it wasn't damaged. Neither was the power pod. For a while I tried to determine the cause of the accident. (It wasn't a failure. Experiments are never failures. But, it also wasn't a success) At first I thought that it had something to do with the engine I was using, but I eventually decided that the real problem was with the seperation mechanism between the pop pod and the glider. I'm still not certain exactly what the true problem was, but in the end I just decided to up and glue the power pod onto the glider once and for all. This made the whole design simpler but also made it less aerodynamic so it wouldn't fly for so long (which wasn't neccesarily a bad thing). Second Flight I had decided very readily that I would like to use a lower-power engine for the next flight of Sunbird II. I really wanted to aquire a 1/2A engine that was the same diameter as the A8-3 that I had used before. But, I couldn't find any, so I had to settle for a Quest A6-4. On September 26, 2001, I launched two rockets that I had planned to fire off later at my birthday party. The first of these was Roswell or Bust! and it flew quite well. The next one was, of course, Sunbird II, and it was, well... I set up the launch pad exactly as I had for the first flight of Sunbird II, except I used my 12-Volt ignition system instead of the puny 6-Volt Estes version. I tried using the Quest ignitor that came with the engine, but it too seemed to be rather puny, so I decided to swap it out in favor of a more reliable Estes version. The moment I pushed the button, Sunbird II leapt off of the pad like a bat out of Hades and climbed skyward. It weathercocked to the east and headed towards the airspace above some houses. Finally, after several tense moments, the ejection charge fired and a number of pieces fell off of the rocket. Sunbird II executed a successful pullup manuver, then turned south and flew off into the wild blue yonder and out of sight. I never saw it again. Sunbird II will be one for the WAEC history books, since it sure won't grace the skies ever again. After only two flights to its credit, it took off for parts unknown, never to be seen again. I took off after it, but my search efforts were in vain. I looked around in peoples' backyards for about twenty minutes, but I had to head home, lest Mom get worried about my absence (she wasn't even home, it turned out). Besides, I had to get psyched up for the Enterprise premier later that evening. Luckily, for the sentimental value, I was able to recover the pieces that fell off of the rocket (a few strips of balsa and the prized nose cone). With those parts, and other information I have, I was able to construct fairly accurate plans of Sunbird II. Long live Sunbird II. Conclusion As an obsesrvation, it might be interesting to note that I have lost a disproportionate amount of rockets of my own design. This, from a certain viewpoint, can be said to be a good thing. It means that my designs are beginning to transcend the kits that can be bought in the stores these days. Now, they can outperform those wimpy little Estes and Quest designs. They can fly higher, farther (although this isn't always a good thing) and faster than ever before. They are the next step above the storebought kits. They are the rockets of the WAEC. And I think that that was the idea all along. Sunbird II
Plans
image, image: Official WAEC plans
of Sunbird II. These were
drafted more than two years after the loss of
the prototype; inaccuracies to the original design are inevitable.
Specifications:
Glider: Length: 34 cm Wingspan: 30 cm Height: 6.5 cm Wing Area: 150 cm Power Pod: Length: 18 cm Body Tube: BT-20 Engine Mount: 18 mm Nose Shape: Conical Overall: Length: 47 cm Number of Flights: 2
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herein copyright 1999-2008
by Willy Logan willy@wilhelm-aerospace.org |
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