Friday, August 21, 2009

KR2S Flaps 03

When we left the last post I had finished shaping the flap, it has a very strong spar and now has the hinge spar attached.

Next it is time to encapsulate the hinge spar and harden the outer surface. Here I am tracing the outline of the pieces of glass I need onto a piece of builders plastic.

Here is the underside all glassed over. Note the rib extensions I had on there earlier to ensure I replicated the original placement have been cut away. The hinge now serves this purpose.

Here is the top surface (will be facing down when fitted). You can see a little 3m sanding guide coat (the black areas) to help ensure a perfectly flat surface.

This shot shows the relief I added to ensure the flap did not interfere with the aileron cable.

I have marked two lines to indicate the flap extension limits. The one on the right aligns with the flap surface when deflected to 60degrees, the left one where the top of the new fillet will be. What I am trying to do here is mock up the end of the fillet so that it can slide in behind the fillet on the wing as it deploys.

Here is the fillet partially formed. I will attach it before finishing the shape.

This is where I formed the back surface to support the fillet up against the fuse side. There are a number of layers of packing tape against the fuse to ensure adequate clearance.
2 things in this shot. 1st the back surface of the fillet is facing down, will back this up with a little flox later. 2nd I have marked out where I will cut the spar and lower surface back to to attach the rod end.

Nicely prepared and ready for the rod attachment bolt that will be floxed into the centre of the spar.

This is the rod end I will be using. It will be embedded 2.25" into the spar and floxed in place. Plenty strong enough.

This block was to align the pivot bolt parallel to the spar centre line. It is covered with packing tape to ensure I can get it off when the epoxy sets.

The final result ... a thing of beauty. Believe me you could lift a truck on this (well almost).

This next one is a mock up of the actuating arrangement. It will be embedded within the trailing edge fillet once finished. The pivot is 1/2 way along the 11" flap, ie. 5.5" from the hinge. To raise the flap 60 degrees i will need to lift the pivot about 5.5". To retain reasonable alignment on the arm without going over centre at either end of this travel I need at least 7" of arm. If I faced the arm the other way I will be on top of the aft spar of the wing, this way I am in a clear area in the first bay behind this spar. Later I will fabricate a torque tube from this side to the other and actuate it with a 12v linear actuator something like the like the Jabiru.

Here it is in the extended position. (in the background the 3m guide coat powder)

Fillet foam and front glass attached.
In place this time. With a little filling and sanding it will look as if it all belongs. I'm pleased with the result. Now all I have to do is build another just like it.

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