sfw2523

Introduction:

I built this to experiment some more with this wing design. The idea is to try different battery sizes and then cut the wing down to test different sizes.

Components:

• Foam board (with foam pipe insulation for fuselage)

• 2x sg90 servos

• Velotech Magic 20a esc w/ 5v BEC

• Cobra 2205 2300kv motor

• DSM receiver

• Eachine battery strap

Conclusion:

189g dry. The build took about 4 hours not counting the time I spent at the end replacing the motor after everything was done. I decided to replace it because it had some resistance and I thought the shaft was bent. During the whole replacement process, I was careful to inspect it to make sure there was no binding anywhere. However, after I replaced it and powered it on, I realized that the binding was there again. Baffled, my only explanation was that there was still some sort of magnetic field in the windings which remained even after the battery was unplugged. I verified this by waiting a few hours and saw that there was no binding again. However, when I powered it on and started the motor, the binding was there again.

Update 11/15/20: The maiden was rather uneventful. I flew it on 3s and then 4s. I was hoping 4s would give more thrust than it did. Then I flew the 2204 2300kv version instead and realized that it was much slower. I have been desensitized to the speed now, so I need to build something faster.

Update 11/21/20: Swapped to the gemfan floppy proppy to see how it performs. I don't like the sound they make, but from the 2 packs I put through so far, they may be a bit more efficient. I'll need to do more testing to be sure.

Update 11/25/20: I cut a hole in the front for the battery and this thing flies amazing. Unfortunately, I was pushing it to the limit on a 4s and smashed it full speed in the ground. The center spar snapped and the duct tape ripped all over the fuse. It may still be repairable? If not, I'll build a new airframe.

Update 12/3/20: Wing loading calculations are as follows. Wingis 6.6oz dry. With a 3s 1000 adding 6.2oz, the final weight is 12.8oz. Since the wing area is .5 sq ft, the total comes to 25.6oz/sqft. Unfortunately, 4s has proven to be too much for the one spar on this wing. Even flying 3s now, the wing bends easily on turns and is causing quite a bit of instability. I'm gonna build another with a stronger spar.