Build Progress

1. Set up first 3D printer

2. Iterated on printing parts

3. Machined and assembled mount for pusher motor

4. Built inverted v-tail

I was amazed with how much leverage a 3D printer gives me. It's literally a factory-in-a-box!

For $300, I have a machine that can replicate high strength polymer components (such as for VTOL motor mounts) with 100 micron precision. And it can print parts while I work on other things or even sleep.

This is huge leverage! After a few hours of experimenting, I had a workflow where I was iterating on designs for several parts while printing other parts. I was iterating practically as fast as I could have writing code.

1. 3D printer set up

This is my first 3D printer and I wanted the easiest to use and fastest to get ramped up on. I went with the Bambu A1 and it did not disappoint. The hardest thing about the set up was to adjust my shelving height to fit the printer vertically.

The first test print was a PLA scraper which came out flawlessly. I was printing test sections of parts using PETG within a couple of hours. PETG is often used in 3D printed RC planes because of its higher impact resistance, lower brittleness and stronger layer bonds than PLA.

1. Iterating on printing parts

Check out the first photo - I was able to iterate at a 30 to 60 min cadence on the 3 parts labeled. Tests ran from left to right. For part 1, the boom/spar connector, you can see the stringing of the material circled top left and how subsequent versions fixed this. Top middle of the pic, see how the slotted hole snapped, which I fixed by reinforcing it.

A stomach bug slowed me down the last couple days but I'm iterating on these parts again. The motor mount, labelled 3 in the pic, is now I think ready for load testing.

In pic 2, you can see testing of the full boom/spar connector parts in the wing. I realized after my thrust test crash, I overengineered the T shaped connectors. I've separated them in CAD and will reprint shortly. The main spar connector (middle) also does not need fasteners to secure it, as I think torsional loads will be managed by having two spars secured to the wings (second spar lower right).

1. Pusher motor assembly

I adapted a 3mm aluminum L bracket to mount to the tapered aft fuselage. Positioning the motor mounting holes for drilling required a lot of spot checking. But once I had the workflow, it took less time to machine the 3 other holes than the first.

Many such cases when learning new things!

1. Inverted v tail build

I put together the 5"/127mm foam tail including 2"/51mm control surfaces. Inverted v tails have the benefit of yawing in the same direction as roll, ie when turning the VTOL in forward flight.

Radio controlled foam tails are often only one layer of foam with duck tape, but I bent mine over along the leading edge for a little extra lift and stabilization.

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With the 3D printed parts enabling me to build a more solid structure, I'm closing in on a maiden hover! Still need to finalize boom and spar connectors, join the wings, integrate servos for wing and tail control surfaces, and do final bench testing before taking her out.