Blackie

I am transforming an ARF (WM SS60) to replicate the Fokker Eindecker,

Let me see if I can explain best I can what I'm trying to do.

Trying to build new elevator, flap and aileron halves, and using solid pieces of balsa. I attempted to do this but was not comfortable with the out come. I started with the flaps but was not sure if I had both sides even with each other.

Took one side of the flaps roughly 2" width and 13" in length, laid if flat on my build table, with a sanding block at an angle to get the taper I started the sanding, swapping it over as even as I could in order to get both sides. I took the next flap and tried to replicate the same angle and movements as did on the first, problem is I'm just not sure if they are both even.

Is there a trick to the method used?
Is there a way to tell if the angle is the same on both sides of each flap?

Help please

Thanks
Blackie

mulligan

This is quite difficult to do without a lot of practice and craftsmanship. I suppose if you had a disc sander and a jig, you could make it work, but...

Why don't you simply buy some of the pre-made aileron stock from your lhs? It comes in varying sizes that you can trim to suit.

If you are forced to do it by hand, you'll want to draw a centerline down the trailing edge of the piece you're sanding, so you'll know when it is "even."

Tall Paul

To get a true tapered trailing edge, lay a piece of music wire, say 1/16" dia. at the edge of your work table. For the other side of the surface, use a piece the thickness you want. Lay the stock wood between the two, and with a long sanding block, taper away!

Blackie

Thanks paul,

This leaves me with another question. Am I to taper both sides of the single block that I"m working on or do I taper one side only?

In your diagram you show to taper only one side of the block.

Thanks
Blackie

Tall Paul

One side is sufficient. The chamfer for the hinge... either on the edge or in the middle will do the rest.

patternwannabee

My Feedback: (1)

Wow Paul, that's exactly how I do it.

Blackie, if your control surface is wider on one end, then you might want want to do it both sides, otherwise, technically, the shape you wind up with won't be symmetrical. So, on one side, taper to half the thickness, then flip over and taper to final thickness.

BMatthews

Hold on Paul. One side is sufficient for constant chord surfaces but if it's tapered in chord but constant thickness then it needs to be done from both sides. For that situation you need to reference to a center line on the rear edge. The wire or rod jig idea will still work but you need a thicker wire for the first cut and then the thinner one for the second. The flex in the balsa will let the surface twist under the pressure of the sanding block.

If you try to do a single cut on a tapered surface the CENTER LINE angle will change from the root to the tip.

Jim_McIntyre

Hmmnnn... I just rip them off stock with my table saw.
Set the negative angle and RIP!, next set positive angle and thickness of root and RIP!.
Touch up with a sanding block and viola!.

Tall Paul

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There are ALWAYS specific exceptions to general situations. Adapt to fit.