Posts: 6909
Joined: 12/7/2001 From: Andover,
MN, USA Status: offline
This mold will be all glass. They will be made shortly by Wayne Seiwert, owner of Aerotech Models. I was at his shop yesterday, and his molds for his warbirds looked fantasic with all the details built right in. A friend of mine works for Wayne, and I got to watch him lay up a P-47 tail which was pretty interesting. I was amazed at the amount of Carbon that goes into that tail.
Posts: 691
Joined: 6/21/2003 From: San Diego, CA, USA Status: offline
I haven't used MDF for anything but the flange splitter plates, but my answer to you would be "lots of lacquer sanding sealer, sanding between coats." That's what I use on my splitter plates and I've never had a problem.
-David
< Message edited by davidfee -- 7/20/2004 11:17:40 PM >
Posts: 1425
Joined: 1/14/2002 From: San Jose,
CA, USA Status: offline
I posted a note over in the pylon forum too, but you can also try Spyder Foam as a replacement for rohacell. I've used it on many occasions where it provided a better bonding surface to kevlar. Even though it has a vertical grain structure that you can use to your advantage, it still will dent like rohacell and easier. It is cheaper, but you have to hot wire it into thin sheets.
Posts: 1425
Joined: 1/14/2002 From: San Jose,
CA, USA Status: offline
It can be done... I was using a cnc cutter to do so, but first tried hot wiring it from wood templates and shifting the foam up by 2mm on each cut. Obviously, the cnc cutter fared better.
Posts: 6909
Joined: 12/7/2001 From: Andover,
MN, USA Status: offline
Lots of hard work, and trial and error, but I finally have a wing ready to test today.
The first wing I pulled 2 months ago was not flyable, but made a great tool for me as I cut it apart and looked inside as to what I did. I screwed up the hinge on the first one, but that helped me with this one.
Although not perfect, this wing turned out pretty darn good (better than I expected so quick). I new it was going to be heavy, and it is at 20 oz ready to go (with servo). I know I can easily cut 2 oz, and probably 3 in resin alone.
Heres a couple pictures, I'll let you know if it survives the 160 mph "nelson" test this afternoon.
Thanks to everyone for your help, it really was a good learning experience that I can see will take years of practice to perfect.
Posts: 2438
Joined: 1/19/2002 From: Anchorage,
AK, USA Status: offline
Congratulations.
Let us know what your results are. (And on this forum, I think it's safe to say that we'd all enjoy seeing some photos of what you did, and/or what you'll do on the next set.)
Good luck with the test flights!
_____________________________
Mike James RC Design and Building - www.nextcraft.com
Posts: 6909
Joined: 12/7/2001 From: Andover,
MN, USA Status: offline
Test flights were this past Saturday, and they went very good. I originally flew it with an O.S. .46 AX and it handled 125 mph with ease. After two trim flights, I removed the O.S. and put a Nelson .40 Q500 motor on. I flew it twice with the Nelson, approaching speeds of 170 mph. I had plenty of elevator throw and really snapped some turns and the wing held up great.
Everything is still solid, so I think I have a winner. Now I just gotta cut 3 oz minimum. I think I can easily get 1-2 out of the next wing, and finding that last oz may take some time.
I found that laying up glass on Rohacell is a pain in the rear. A friend suggest laying the glass up on wax paper, and then flipping it onto the rohacell. I think I will give this a try, if it works, it will save me quite a bit of resin right there.
Posts: 6909
Joined: 12/7/2001 From: Andover,
MN, USA Status: offline
Not like a fuse. I lay up each wing half in a female mold and let dry in a vacumm bag. After each half is dry, I fit all the internals (spar, torque rods, blocks for wing hold downs, etc).
I then lay a bead of Pro Set Epoxy mixed with Colladial silica around the perimeter of the mold halves. After this, I flip one mold half on top of the other, clamp and let dry. The glue forms the seam, there is no flap of fiberglass or anthing to join them.
Printable Version
All Forums >> RC Airplanes >> Composites Fabrication And Repair >> RE: Wing Mold 
RE: Wing Mold - 
RE: Wing Mold - 
