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Show HN: I made a 3D printed VTOL drone

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Re: Show HN: I made a 3D printed VTOL drone

#71

Post by stavros »

tsungxu wrote: post #66
stavros wrote: post #51

Earlier quoted context omitted.

PLA is pretty bad compared to foam when it comes to planes, as it's very heavy and very brittle. Any semi-hard landing will break parts off, and heavy planes fly badly. The big advantage is that you can just print the part again, which almost makes PLA worth it. ABS would probably be better, as it's much more durable and lighter, but it's still much heavier than foam, and printing ABS isn't great.

I used single wall foaming PLA which has filament density of ~0.45 g/cm3 at 250 degree nozzle temp, about 64% lower than normal PLA. But it is even worse for impact resistance than normal PLA. Weight was the primary driver for this plane

Yep, I've used that as well, but, as you say, it's just very bad for impact resistance. I think the sweet spot between weight and durability might be ABS or something like ASA.

Re: Show HN: I made a 3D printed VTOL drone

#72

Post by tsungxu »

stavros wrote: post #71
tsungxu wrote: post #66

Earlier quoted context omitted.

I used single wall foaming PLA which has filament density of ~0.45 g/cm3 at 250 degree nozzle temp, about 64% lower than normal PLA. But it is even worse for impact resistance than normal PLA. Weight was the primary driver for this plane

Yep, I've used that as well, but, as you say, it's just very bad for impact resistance. I think the sweet spot between weight and durability might be ABS or something like ASA.

Yes and there is foaming ASA as well which is almost as light as foaming PLA. But I can't print ASA well on my A1 and the weight penalty was still enough that I didn't try, given the mission profile of flight time.

Re: Show HN: I made a 3D printed VTOL drone

#74

Post by tsungxu »

mlsu wrote: post #49

This is the first I've heard of foaming PLA, definitely have to check that out. Did you do the whole airplane with a small printer like the A1 / A1 mini? I would love to print airfoils but I'm struggling to imagine a way to link individual prints together in a way that preserves stiffness. My 100cm wing would need 10x (10x10cm) printed parts somehow attached to one another. Until I figure this out it's foamboard buil…

A1, 256 x 256 mm lets me print these wings in four sections (including a double walled thin section for the boom mounts). With a high AR glider you'd probably need a few more. Carbon fiber spars + CA glue will do the trick for attaching them

Re: Show HN: I made a 3D printed VTOL drone

#75

Post by tsungxu »

aspenmayer wrote: post #65
tsungxu wrote: post #30

Earlier quoted context omitted.

Exactly! Didn't even mention cruise vs dive. But the latest WR for a quad doing 347mph I think, is just insane, even if drawing multi hundred amps for a few seconds only.

Oh wow, that’s even higher than this one I saw from last year @ 298 MPH for a quadcopter, but I’m not sure if this is the same criteria for the WR or build limitations etc? https://www.youtube.com/watch?v=wThmg8Ezm9w

I saw that one too which was also incredible. This latest record was from a few days ago https://youtu.be/8p5eZ4ZRkfY?si=hSxTh5BeSyEwzpy8

Re: Show HN: I made a 3D printed VTOL drone

#77

Post by tonyarkles »

hadlock wrote: post #55
normie3000 wrote: post #46

This is incredibly impressive. I'd love to hear more about what relevant skills & knowledge you started with, and how you worked out what you'd need to know to complete the project. How much customisation did you need to make to Ardupilot? Is your drone's control unique, or somehow standardised?

Ardupilot is very, very mature software. A lot of the drone video coming out of Ukraine, the HUD overlay is likely from Ardupilot. If you can think of it, Arduipilot supports it. Airplanes, helicopter, VTOL, speedboat, even sailboats.

As someone who works with ArduPilot professionally, I have very mixed feelings about it. It’s mature, definitely. It supports all kinds of vehicles, like you say. It’s beautifully modular and supports a crapload of flight control and sensor hardware. And there are definitely pieces of it that are aggravating and exceptionally janky.

The HUD overlay you’re referring to is technically Mission Planner (GCS software), not ArduPilot (flight control software). Mission Planner and ArduPilot both talk Mavlink, and they’re both developed by the same community. MP is flexible. You can set it up to do almost anything you’d ever want. It’s also terrible and exceptionally janky… but extremely powerful. And they’re both free.

I think the problem with both of them is that they’re good enough that there isn’t likely to be a huge critical mass developing a better alternative. On the GCS side there is also QGroundControl and APM Planner 2 (which was a fork or reimplementation of Mission Planner). Both of them have their own upsides and downsides, but neither one of them is as mature or as powerful/flexible as Mission Planner. PX4 on the flight controller side is popular commercially because it’s BSD-licensed instead of GPL, but the net result is that it has nowhere near as many features as ArduPilot because companies build proprietary features and don’t push them back upstream.

This stuff is definitely in the worse-is-better domain. ArduPilot is free, ArduPilot is amazing and ArduPilot sucks. :)

Anyway, off to bed. I’m in a long test campaign right now and we’ve got to be up at 0430 to fly the ArduPilot-based aircraft again before the weather goes sideways.

Re: Show HN: I made a 3D printed VTOL drone

#78

Post by tonyarkles »

tsungxu wrote: post #74
mlsu wrote: post #49

This is the first I've heard of foaming PLA, definitely have to check that out. Did you do the whole airplane with a small printer like the A1 / A1 mini? I would love to print airfoils but I'm struggling to imagine a way to link individual prints together in a way that preserves stiffness. My 100cm wing would need 10x (10x10cm) printed parts somehow attached to one another. Until I figure this out it's foamboard buil…

A1, 256 x 256 mm lets me print these wings in four sections (including a double walled thin section for the boom mounts). With a high AR glider you'd probably need a few more. Carbon fiber spars + CA glue will do the trick for attaching them

Yeah I printed one of the Titan Dynamics airframes (before they closed up at access for the hobby market) on a Prusa MK3S using foaming PLA and CF spars. The fuselage came out in three prints, the wings as one print each, and then the two wing tip extensions got combined into one print.

It would definitely have been tight on an A1 mini but the full size A1 would work great for sure.

Re: Show HN: I made a 3D printed VTOL drone

#79

Post by tonyarkles »

the__alchemist wrote: post #19
tsungxu wrote: post #14

Earlier quoted context omitted.

Not tested! But minimum I would say 70 mph. If designing for speed, I'd be looking at a cruise motor and prop that maximizes the thrust output rather than cruise efficiency edit: at least 70 mph

Probably significantly higher even? A normal quad will hit 100Mph +.

With how many minutes of battery life? :)

Re: Show HN: I made a 3D printed VTOL drone

#80

Post by tsungxu »

tonyarkles wrote: post #78
tsungxu wrote: post #74

Earlier quoted context omitted.

A1, 256 x 256 mm lets me print these wings in four sections (including a double walled thin section for the boom mounts). With a high AR glider you'd probably need a few more. Carbon fiber spars + CA glue will do the trick for attaching them

Yeah I printed one of the Titan Dynamics airframes (before they closed up at access for the hobby market) on a Prusa MK3S using foaming PLA and CF spars. The fuselage came out in three prints, the wings as one print each, and then the two wing tip extensions got combined into one print. It would definitely have been tight on an A1 mini but the full size A1 would work great for sure.

I actually managed to batch print the wing sections which you can see in the video in the rebuild chapter. That works really well for wing sections because each takes up a minimal bed area
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