3D Printed Cargo Plane with 8 ft. Wingspan

[telnar1236]

Over the past few months, I have taken a design for a large firefighting/cargo aircraft created by myself and a few others and turned it into a large 3D printed RC model. When I was looking into sizing the airplane to reduce cost as much as possible, I was very surprised to find that with a few components I already had, a 1/20 scale model with an 8 ft. wingspan and a takeoff weight of 4.5 kg with no additional payload would be the cheapest option at only $164 in materials and electronics, so I went ahead and designed one of the largest 3D printed models I am aware of. It flies on two 5000 mAh 4s battery packs (one per wing) and is the largest airplane I own by a noticeable margin (this is a challenge since it barely fits in my car even without the wings). It flies very well and is exceptionally stable but is also quite heavy and turns very slowly. The STL files for this airplane are not in a usable form so I will not be posting them, but I thought that this was a good example of what is becoming possible with 3D printers and cheap electronics and that I would post it here. The structure is fully 3D printed with the exception of three 10mm carbon fiber spars in the wings, four 3mm carbon fiber spars in the tail, and steel mounting pins and axles in the landing gear. The wings screw on and are removable to make transport possible.

Here are two photos of the plane on the runway and in the air:


And here are several photos from during construction including one showing the internal structure of the fuselage:

 

[WillL84]

You should reprint it with LW-PLA and see if you can get the weight down and make it fly a little better. Either way, great job!

 

[telnar1236]

You should reprint it with LW-PLA and see if you can get the weight down and make it fly a little better. Either way, great job!

At this scale, LW PLA is not really any lighter. The strength to weight ratio of LW PLA is lower than that of normal PLA, so the savings mostly come from cutting out excess strength. At larger scales, you can better optimize the structure, so you don't see those savings. With this design, if it was printed in LW PLA it would not be strong enough to hold together, and if I redesigned for LW PLA it would weigh about the same.

4.5 kg is really pretty expected for an 8 ft. wingspan rc plane with four engines and I should mention that it will fly up to a takeoff weight of 8 kg. My remarks on it being heavy were more relative to the smaller park flyers and EDFs I typically fly; it's larger and a model of a cargo plane so it just needs more space.