Aircraft material

(Adam X) #1

I’m looking for suggestions on a sheet good to use for cutting aircraft (multirotor) frames. I’d prefer to stay away from metals. Ideally a material around .125" thick and in at least 12x12 sheets. I can get a high-ply hobby plywood, but it’s most common in 6x12 around here and is very expensive for what it is.

Needs to be stiff and durable, not flexible like an ABS or UHMW. Maybe some other sort of polymer I’m not aware of?

(William Adams) #2

Is carbon fiber an option? G10 or Garolite? I’d go w/ the plywood myself, much less problematic to cut.

(Adam X) #3

Carbon Fibre is hands down the superior material. Issue is, as you say, cutting it. As I understand, it’s pretty lethal stuff if you don’t have perfect dust extraction.

(William Adams) #4

Best option rather than dust extraction is just putting it in a pan of water and cutting it there.

(William T Stokes) #5

What about cutting the door skin materiel from the big box store then laminating(vacuum bag) it with a layer or three of Carbon FIber-I have used that with great results in several projects… I tried balsa with a carbon fiber core(alternating the grain), and it was good unless there was an impact, the balsa sometimes gave up along its grain-encapsulating the balsa worked terrific, but the door skin was $7-9 a 4’x8’ sheet, and the balsa almost infinitely more… basically what I ended up with was a torsion panel with cheap wood as leave in place jig for the carbon fiber, cut the complicated parts in easy materials and easy states(fit the fiber dry, then do the layup)…more work, but other than time no cutter wear, noxious dust issues, and you can get exactly what you want. formulate a composite to your needs.

(mikep) #6

This can be done with thin foam as well, just need to be careful about the foam/epoxy capability. I’ve also done the same using a rope core (lay the rope in an open matrix over glass or carbon then lay another layer over the top, and push it down into contact in between. Forms a pretty stiff matrix with a reasonable weight.)

In general, I’ll say carbon isn’t worth the effort over well laid glass unless you have some really extreme needs. They both have the same issues with cutting, but the glass is a lot easier to lay up.

@Adam_Xett , out of curiosity, why no metal?

(Adam X) #7

Metal is essentially out due to weight. I could use an aluminum alloy, which partly gets around the weight issue, but it then bends in crashes. The “modern” race frames for multirotors are made out of 4mm thick laminated carbon fiber.

(mikep) #8

“Bends” can be a little easier to deal with than “shatters.” Don’t underestimate the real strength you can get out a well designed aluminum part. That said, if you’re willing to deal with the extra precautions of cutting carbon/glass, it’s pretty easy.

(Adam X) #9

@mikep that’s a good point, maybe I’m underestimating the strength of an aluminum part. I’m looking for a ~1/8" thick sheet to cut from - any recommendations on alloy? And corresponding recs for cutting it?

(Adam X) #10

and @WillAdams, I’m not familiar with Garolite… what’s a product I’d know made from it?

(mikep) #11

2024-T3 is very stiff, very light. You might have to dress the cuts a little by hand. These ribs were done with -very- simple geometry. They could easily be lightened with a little work. (the two rightmost ones are fabricated from brass rod…ignore those) You can easily make things like I-beams out of thicker material, and so forth. I think you would be surprised how light an aluminum structure can be (I’ve build full size airplanes out of this material). I use a lot of .020" sheets of this for all sorts of things. It’s not terribly expensive.

2 side “clad” is more durable to corrosion (it’s clad on both sides with pure aluminum, which provides protection to the core)

(Kelly Taylor) #12

An alternative to a one piece frame of one material is main frame of aluminum, and arms of printed plastic. There are several open source designs available at thingiverse, and team blacksheep sells a dual material design too. Browse thingiverse for some other options like this maybe

(mikep) #13

It’s an epoxy/fiberglass phenolic. A lot like a printed circuit board, technically it’s a “phenolic.”