17-02->05: Leading Edge Parts Prep

Chapter 17 began in earnest since i was not able to begin the riveting of the wing skins - these have been put on the top shelf, primed and ready to go.
This section started with making up 2 cradles for the leading edges, from the plywood crate tops - the template for 2 of these were traced onto the top of the crate by the factory.

A few of the ribs needed to be modified to fit around the "step bars" on the spars - these were done by drilling a hole in the corner, then a dremel to do the cuts. They were fine tuned with a file by test fitting to the spars themselves. The ribs were laid out and labelled "L1" to "L7" etc, from the inboard most rib to the outboard one. I will use the same metal tags as the wing ribs to ensure they are not mixed up through the prep and priming process.

A #30 hole was drilled the correct distance from the corner..

The hole was enlarged with the step drill

The ribs were test fit in-situ to ensure a good clearance from the spar step bars

Rib Preperation

The rib prep sequence was similar to the wings:

• Smooth the flange edges with a vixen file, scotchbrite wheel and sandpaper
• Smooth the front of the rib flanges to remove the "faceting" with the scotchbrite wheel
• Smooth the lightning holes with a drill-press mounted rotary scotchbrite / sandpaper flapper wheel (this thing is fantastic)
• A small round file is used to smooth the edges of the outside of the flange notches - and a flat file to adjust the shape of the cutout where the J-Stiffner will go
• Sandpaper is used to debur inside each of the rib flange notches
• Flute the rib to ensure all the holes are in a straight line
• Straighten the flanges of the ribs to 90 degrees using the homemade flange tool. 

Heavy fluting was needed at the nose of each rib

Before fluting..

After fluting

Next was to remove the "splice strips" from the fuel tank skins and prep these. As well as clean up the edges of the landing light cutouts, the skin edges (including a small break on the edges where it will be riveted to the spar), and deburring all the other little parts (access hatch ring, cover, light lens retainers etc). 

The dremel standing drum did a good job on these cutouts.

The J-Stiffners were marked up and match drilled and I used a small stick to hold the stiffner against the skin - i cleco'd every hole as i drilled. 

The hole where the tie-down rings get screwed in were enlarged with a step drill

These things take a lot of clecos!

I plan not to install the stall-warning vane, however i will prep all the parts for it and put it together (just not install it). 

Finally, all the parts were prepped and primed as per previous procedure. I am not using Alumiprep for the etch step, as i ran out of EkoEtch and it is very expensive to get it to Australia. The EkoEtch was around $50 AUD per litre, but i can get Alumiprep Gallon (4 litres) for around $75. Andy from Stewart Systems recommended it as an alternative product.

All parts ready for priming

Parts were primed in batches