Sunday, 23 December 2007

Spiders Web - The Seat Support

In all the time that I have owned IH, I've never been entirely happy with the fit of the harnesses but I could never quite put my finger on what the problem was. Each annual, when inspecting the harness for wear, It would be bunched up in one corner of the triangular attachment rather than a nice even fit along one side of the triangle.

Now that I am able to get at and remove the spiders web that is the seat support I have worked out what the problem is and I think I now know how the support should be located. So before I forget all the detail I must commit it to paper or rather html.

This is the center of the cross support tube with additional straps (not standard) which have been added by a previous owner at some point. This was probably done to stop the support from sagging. Note that the two V shaped wires are held by a U clamp and the U shaped wire on the cross tube is virtually horizontal. This prevents full and free movement of the two triangular harness attachments. This as what caused my problems during each annual.

I decided that I would remove the support and assemble it on the workbench as it should be reinstalled.

The general layout of the support consists the cross tube, a supporting wire at each end of the cross tube and two V shaped wires (one being slightly shorter but made of a larger gauge wire, this was fixed to the rear of the support on the aircraft).

Each cross tube end has a supporting wire looped around it ensuring that the supporting wire goes through the U shaped wire welded to the tube. Note that the U shaped wire now hangs below the tube so that the harness attachment is free to move above the tube.

The center of the cross tube will also have the U shaped wire now hanging below the tube. I have looped the V shaped wires through this so that they will lock in place. If anyone knows if the two V shaped wires should interlock with each other, then let me know, although I already suspect that this is the case.

The frame will now be disassembled so that it can be straightened out a little, cleaned up and repainted.

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