Mdf is great to mill out cheap one off molds... it really cuts nice. However as a core I can't imagine it having any advantages. But until it is tried out who knows!
Awesome video as always! I'm wondering how thin you can go. To me it feels like racing wings might be over built and thicker than they need to be. Second question does laying the carbon fiber fabric at an angle change the flex characteristics?
Some of the smaller high aspect wings I am designing will be a little thinner than this current one. Fiber orientation does matter if you want optimal performance. However this wing had a plain weave with half of the fibers going along the span. Optimal fiber direction would have been a lot more unidirectional fiber going tip to tip.
The cores of these wings in the video is a hardwood ply. My other thicker wings are milled out of 2lb EPS. I believe these wings are to thin to use foam, and the trailing edge would be an issue getting so thin.
I just checked out of curiosity the density of UL MDF. What I found was 480-550 kg/m³ for the MDF but poplar has only 350-500 kg/m³ and most pines fall below 500kg/m³. At the end I wouldn't use MDF for anything else than maybe plugs or molds. A high performance PET or PVC core would be better suited. As the forces decrease towards the center (into the core, not along the wing) the core is simply a compression-seeing placeholder to keep the wing from collapsing under load. A good wood alternative would be standing grain Balsa. Speaking of high performance here. Plywood is a good alternative as it's cheap, easy to work with, easy to get and fairly strong in most directions as the wood fibers are still long and intact. Because of that, you can use a slightly lighter laminate and offload some forces to the core to compensate for the higher weight.
@@0xhexdec Exactly! I am debating trying out some high density PVC but the cost becomes prohibitive. Especially when having to ship. Those thin and delicate trailing edges would require a snug foam cut out for protection (which I do with my EPS wings). But then the box size goes up, shipping costs get pricier, and so on... For now the ply core is stellar!
I wonder how Ultralight MDF might work as a core material. Might need to use a sanding sealer to keep the epoxy from soaking up too much though.
Mdf is great to mill out cheap one off molds... it really cuts nice. However as a core I can't imagine it having any advantages. But until it is tried out who knows!
Awesome video as always! I'm wondering how thin you can go. To me it feels like racing wings might be over built and thicker than they need to be. Second question does laying the carbon fiber fabric at an angle change the flex characteristics?
Some of the smaller high aspect wings I am designing will be a little thinner than this current one. Fiber orientation does matter if you want optimal performance. However this wing had a plain weave with half of the fibers going along the span. Optimal fiber direction would have been a lot more unidirectional fiber going tip to tip.
what is the thickness of fiber glass on the foam core?
Wow that looks strong... 3/8 plywood ?
I glue up two layers of 3/4 to get a 1.5" block. I need the thick stock to capture the anhedral (wing curve) from tip to tip.
What foam do you use for the inside of the wings ? Can you put link
The cores of these wings in the video is a hardwood ply. My other thicker wings are milled out of 2lb EPS. I believe these wings are to thin to use foam, and the trailing edge would be an issue getting so thin.
I wonder how Ultralight MDF might work as a core material. Might need to use a sanding sealer to keep the epoxy from soaking up too much though.
I just checked out of curiosity the density of UL MDF. What I found was 480-550 kg/m³ for the MDF but poplar has only 350-500 kg/m³ and most pines fall below 500kg/m³. At the end I wouldn't use MDF for anything else than maybe plugs or molds. A high performance PET or PVC core would be better suited. As the forces decrease towards the center (into the core, not along the wing) the core is simply a compression-seeing placeholder to keep the wing from collapsing under load. A good wood alternative would be standing grain Balsa. Speaking of high performance here. Plywood is a good alternative as it's cheap, easy to work with, easy to get and fairly strong in most directions as the wood fibers are still long and intact. Because of that, you can use a slightly lighter laminate and offload some forces to the core to compensate for the higher weight.
@@0xhexdec Exactly! I am debating trying out some high density PVC but the cost becomes prohibitive. Especially when having to ship. Those thin and delicate trailing edges would require a snug foam cut out for protection (which I do with my EPS wings). But then the box size goes up, shipping costs get pricier, and so on... For now the ply core is stellar!