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A bit of background
Originally inspired by the Lockheed P-38 Lightning, this twin boom glider design has actually been a back-burner project for the past 6 years, and over that time it’s gone through quite a few iterations (eight in total), only some of which are shown above. (An early prototype of the current version can be seen in the lower right corner).
The original versions were all slide pod systems, but I could never get the burn string to reliably release. It would always jam in the hole through which it was threaded. It didn’t matter what the material was either: cotton thread, thin elastic, dental floss – the result was always the same. Enlarging the burn thread hole, changing its shape, or moving its location didn’t make a difference.
I even considered that the internal motor pod could’ve been twisting and trapping the burn thread in place, so I used a wire and aluminum tube setup to prevent it. (Once in launch position, the wire would thread into the tube, preventing any twisting of the internal motor pod).
It finally worked in a ground test and the maiden flight of my last slide pod version, but by then I’d lost any confidence I had about the reliability of using a burn string. Another thought (inspired by the Apogee Rockets Texas Twister) was to use an internal slide pod system.
However, after mulling it over for a few weeks, I thought about the added weight of using this method and how I’d have to add more wing area to compensate, and decided to go with something far simpler: a BG that ejects the motor on a streamer to shift its CG. I’ve since decided to use unswept wings with a straight taper, making it easier to attach the twin boom at the wing’s dihedral break.
I also decided to revise the stab and rudder configuration. I just felt too uncomfortable about having the stab so close to the path of the ejecting motor and hot exhaust plume, so I lowered it. It now spans the dual fuselage rods for better clearance and adds more support to the aft end of the rods. The rudders were also relocated to the stab ends
Sketch of the final design:
Final cardboard and balsa prototype.
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