I shifted over to the DLG flying wing I had dreamed up a couple of weekends ago and after doing some CG calculations decided that I had no choice but to add a pod to it. The other option is to load up the leading edge with lead but that kind of negates the purpose of a glider...
I grabbed a likely bit of scrap and marked out a shape based on what I kind of had in my minds eye. The initial design had a square taper at the back which I wasn't too happy with.
I planned to use the 'lost foam' technique to build this which is why it's covered in packing tape.
After deciding that the square end was both ugly and very poor from a aerodynamic perspective, I peeled all the tape off and worked a nice taper into it. Colour me happy!
I cut out some bi-directional glass from scraps to go around the mould and laid them out within easy application reach.
Turns out that laying out glass on something that small is a proper pain the in proverbial especially around the ends where it tapers in. The glass I used was pretty heavy weight because I wanted it to be pretty sturdy when I accidentally dart the poor thing into the ground, but heavy glass doesn't like tight curves. Still after much swearing and glass manhandling I managed to get the little sucker into a vacuum bag! My hope was that the bag would make up for all my layup inadequacies.
In the interim I attacked the tail. I had done a flat glass layup the night before and it turned out quite nice but seemed a bit too flexible for my liking. I turfed it in the oven to heat treat it, commonly known as a post cure, and it takes a little of the elasticity out of the layup. It still wasn't enough so I had some carbon fibre strands lying around (this stuff isn't cheap so I even hold onto the individual strand groups that pull out sometimes!) and used that to provide some added stiffness.
I cut the tail out and then cut a slot into it for the CF rod to go into leaving a little guide 'flange' at the back and then just used some two part 5 min epoxy to glue it on. After that had set I grabbed the CF strands and some very lightweight glass and used some quick curing epoxy to stick it on. I was going to leave it at that but it kept lifting off the CF rod (grrrr). Enter panic mode and chucking the tail into the bag with the pod (yeah not a great idea to open the bag halfway through the cure but I had little choice).
END RESULT! Yay! Not bad at all!
3kg is just an outside projection of what sort of thrust I should be gunning for. Whatever under that it weight is just added performance really.
