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Wednesday, December 12, 2007

DG500 ELAN part 7

The block of white foam that I started with is a distant memory and that first adrenaline rush as this beauty takes to the sky draws near, so here are more steps in the build which will be posted right until the maiden flight.

The next task is wing cutting and in this regard both Evan and Peter have been invaluable and a great help. I have always cut wings by hand and it was always a hit and miss affair, the last wing I cut like this, was the JART and its very thin profiles made it a nightmare.

But this has all changed, what a revelation own feather cutter and it works like a dream.

The DG 500 is based on the HQ 3/12 profiles well proven on large scale sailplanes , I cut some

balsa templates for panel planning and
layout , these will be cleaned up and transferred to Formica sheet as templates.

The white extruded foam is cut into 600mm x 360mm blocks which once profiled will be bonded together using Alcoline extreme (tip: wipe the areas to be glued off with a damp cloth)

The foam ceiling boards have a lap joint which needed to be removed.

I had to check if it worked and the wire heat is was ok.. The results far better than I can ever cut by hand.. to master the taper cutting I will use the foam calc program which is on the Jart Blog.

This weekend the wings need to be bagged or close to that

In the meantime two new challenges (notice I dont use the word problem) have presented themselves.1. the servo tray is exactly in line with the wing joiner box, so running braided steel control cables to the rudder is a problem. The solution is to install small ball bearing pulleys (I have some)and go over or under , or scrap the servo tray and mount the single servo on plywood blocks lower down on the belly , option two probably better but could pose a problem if I ever fit a retract.

2, the elevator servo is to mount in the tail fin(much like the CMP discus featured recently)

this may compromise the strength of the fin . It now makes sense to install the servo into the fin from above, would be a neat solution with equal strength both sides , option two seems more likely unless I can think of any down side.

more later,

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