Bubble Canopy Idea - Anyone want to try to build this?

[TacomaD]

Hi, David talked about the difficulty of building the bubble canopy for the FT_Racer/Slinger. I had a couple of ideas and decided to try one out today.

I modeled a bubble canopy (not any specific design) in my 3D app (LightWave 3D) and loaded into Pepakura Designer to break up into foldable pieces. I did go back and forth between the apps quite a bit to simplify the model quite a bit.

Unfortunately, I don't have a printer handy to print out the pattern to see if this is a viable construction method for myself right now. I'm uploading the pattern here if anyone wants to give it a go. It might be best to try with regular paper first.

Pepakura is software for turning 3D models/object into patterns to reconstruct the model out of paper. I don't have the full version, so I couldn't export or save the pattern, but I was able to "print" it to a PDF file. You can add textures to the object so your object can be in color.

Basically, Cut the solid lines. Fold on the dotted lines. The white pieces are tabs. I set the tabs up so the frame and the canopy could be assembled separately and then glued together at the end. I should probably have extended the sides further.

This is based on the FT_Racer plans. I'm not sure if the scale carried over through the whole process.



Thanks.

 

[eagle4]

wow, Pepakura seems like a cool piece of software, I'm a 3d artist and never come across this before. thanks for the tip, as for your bubble canopy, i have no comment yet, still reading the Pepakura website

 

[TacomaD]

I finally got a chance to print this out and try it, and I think it might actually be a viable method.

You'd, of course, want to use a stiffer paper and you'd probably want to cover it all with tape or some kind of film.



One thing I learned was that interlocking tabs are your friend. I had manually moved some of the tabs thinking I could build the canopy and frame separately and just slip the one into the other. It turns out that the interlocking tabs that the program automatically builds in help to slot the pieces together and make for a stronger structure.

Yeah, I should have extended the frame edges to cover more of the fuselage.

Now if only I had built the plane to put this on.

 

[Tritium]

Waterproof what you have, pour it full of plaster, then use it for a vacuum form for a clear canopy made from 2 liter pop bottles.

Thurmond

 

[TacomaD]

Not a bad idea. Vacuum forming was my other idea for this. I hadn't thought of filling this with plaster to make the buck. Of course I'd want to fill/sand it until it's smooth. Oh, and I'd have to build myself a vacuum former, but that's already on my projects to do list.

I don't think I'll be getting to that soon, though.

 

[epic.engineering]

TacomaD all you have to is take the plastic bottle stick it in the oven at about 300 degree for a few minutes. Take it out care fully and with gloves you can push it down over the buck and it will harden in seconds. Its a decent method when shaping small pieces like this.. works great with thicker plastic/ acrylic like plexiglass.

Also if you have a heat gun you can do it even more precisely when heating, It may take a few minutes to figure out how long to leave it in to get the right temp. It should be good when it feels pliable like a piece of soft leather. Just an idea that I've used when fabricating custom full size automotive parts.

 

[epic.engineering]

Also as far as making the mold/ buck goes I've made some pep models before and to harden them we used fiberglass resin. Just mix fiberglass resin (can be found at walmart or auto supply store) buy some cheap paint brushes because there single use.

Mix the resin and hardner, paint it on thin (don't mix to much at once). Let it harden, do it a second time (keep it thin). Let that dry. After a fer hours it should be stiff, but it will remain semi flexable. Now use a small pack of fiber glass cloth , cut into small pieces and now apply to the inside of the canopy. Once this dries it will be a solid mold/buck. and relatively light.

Side note: you could just paint on the two layers of resin on the outside of the canopy, then paint it and stick it on the plane. In all honesty it won't weigh much more than the pop bottle canopy and it can be painted.

 

[TacomaD]

Thanks for the tips!

I'm interested in learning how to build/sculpt/mold/fabricate things.

I'll probably have to build a new plane anyway. I parked my FT_Flyer in a tree yesterday.

 

[xuzme720]

Is it retrievable? Or did you already get and now it needs a replacement?

 

[epic.engineering]

I may build one of these this week. If I do I'll try the canopy, or may try to find a way to make an easy to make plastic canopy.

 

[TacomaD]

I could possibly retrieve it with a 40 foot pole or knock it down with some kind of projectile. The problem is that it's in a public dog park, so I don't want to go in with a big ladder or a firearm or something that could potentially land on someone or their dog.

It has rained a few times in the last few days, so it will be interesting to see how well it holds up to the wetness. The body was minwaxed although I did miss a small bit on the tail. The engine pod was not minwaxed, but the outside is covered in extreme packing tape. The inside of the pod is untreated. It may be okay, but I'm not counting on it. My guess it's that some or all of the electronics with be okay, but I don't know about the rest. I expect the battery to be dead. Of course, I don't even know if I'll get it back.

I visited it today and the weather did push it around. It used to be pointing nose down, and now it seems to be flat on its back. I'm hoping the wind knocks it out of the tree. I have my phone number and email address on the plane, so if it does come down and someone finds it they can contact me.

 

[andy_spoo]

Plastic sheets for vacuum forming always seem pretty expensive to me. Using a pop bottle seems like a great idea, and good recycling as well ;-)