Hi, I'm trying to shape an airplane fin and rudder. In the main picture below are three elements: the leading edge, the fin itself, and the rudder. The (yellow) leading edge is a 32mm square piece of Hoop Pine, shaped as follows: Basically, I need to remove the 1.5mm recesses - this is to accommodate the 1.5mm plywood skins for a flush fit. Next I need to round the leading edge (round-over bit?) The vertical fin doesn't present any problems - it is cut from a single piece of 32mm plywood. The rudder portion, however, needs to taper from 32mm at the leading edge to 10mm at the trailing edge. Like this... How does one shave off the yellow bit and then the blue bit? I've never done this before. The rudder is also initially a single piece of 32mm ply, which gets "shaped" and then the cutouts are added (subtracted?) afterwards. So, as you can see - two issues: (1) How to cut the leading edge from a square 32mm x 32mm strip of Hoop Pine (2) How to "shape" the piece of 32mm ply which will become the rudder Any help anyone can provide would be very welcome. Regards, Duncan
I would do the leading edge with a router in a router table. recesses first, roundovers last, and might even use 32x64mm strip and saw it in half after the routing. for tapering the rudder sheet I would mount it on my CNC table with a 'correct thickness' strip under the trailing edge and face off one side. I might go so far as to cut some taper strips to support the sheet, depend show big and how floppy the sheet feels when it is resting the the spacer strip. turn over and 1 - mount it flat and cut the shapes out but leave fairly large tabs to hold it all together 2 - use a new strip of the correct thickness to account for the material already removed and face the 2nd side off for the taper. what is the correct thickness? you have a sketchup drawing, just get it from there (-: I take it this is for a full size aircraft not a model? Take extra time to do it right, you will never regret it.
Thanks David. Sounds like a sensible idea. I have a "Men's Shed" not far from me of which I am a member, and they have a router table. I could do the first part there. Your suggestion re: tapering the rudder sheet sounds do-able. A couple of test runs aught to do it before I tackle the real sheet ($260/sheet)... And yes, a full-size plane.
I would do it like this. I would cut out the rudder and get it to the final outside cuts shape. Then I'll round over the leading edge of the rudder. If you have access to a CNC machine do it like David suggested and flatten it on it. If you don't, do it with a hand planer. First shape the recces of 1.5mm at the leading edge and than the rest. Then do the other side the same way. Once it's in the right shape on both sides cut out the holes. Cutting out the holes first will make it a b*tch to shape the slant next. Too fragile.
