HPA

No not the Earl of Norton but a device to help sanding strip into trailing edge stock because one is much more likely to  have some sheet the right thickness, grain and density than to find a commercial piece of TE that suits!

Today I started making another rubber powered plane. I'll tell you more about it when I am more advanced in the build (still waiting for a package of balsa from Balsa Central in Adelaide to get here so that I can start cutting ribs).

However, my balsa stock did have some suitable timber for the trailing and leading edges for the wing and I bent the bamboo wingtips using my usual heating-soaked-bamboo-around-a-template method.

However, I realised that I had not shown you guys my trailing edge sanding tool. I think I stole the idea (and improved it a bit) from something I read in Aeromodeller (it may even have been John Stroud's Golden Wings column in the mid-70s.

Here are a couple of photos.
Tilted sanding block 1.jpg
Basically, as you can see, the heart of the device is a piece of 50 mm x 25 mm aluminium rectangular tube 150 mm long  (I think it's 3 or 4 mm wall thickness).
Tilted sanding block 2.jpg
To each side. I have created two sliding "legs" which have 3 mm wide slots cut in them. 150 mm long. The slots are about 35 mm from each end. Then in the middle of both sides of the centre section at the 35mm point I so that a 3 mm cheesehead  screw can hold the legs solidly to the side.

In fact, one leg of the device could be just a piece of aluminium strip glued to the side with 1.0 or 1.5 mm projecting since normally the rear of the trailing edge edges that I use come down to about 1.5 or 1 mm. The other side, however, does need to move so that the block is angled to create a nice triangular piece of trailing edge stock.

If the trailing edge is 12.5 mm wide, the long leg needs to be set four times the thickness of the trailing edge because the block is 50 mm wide and 12.5/50 = 4.

Of course, I forgot to mention that a piece of 120 grit sandpaper is stuck to the wide side of one face of the centre piece.

I tend to take off 70% or so of the balsa using a razor plane and then use the tilted sanding block to take it down closer to finished dimensions.

Maybe sometime soon I will do a 3D printed version of this

Thanks for sharing your setuo. I tend to break many wing ribs when sanding trailing edges after assembly. So, I am a big fan of sanding prior to assembly.