Saturday, 1 April 2017

Main fuselage continued.

Back from holiday and I started by preparing another load of fuselage parts in anticipation of a big assembly session.

To start with, I installed the wing spar box closure pieces and fitted the wing-spar rollers which aid quick wing removal and installation.

 This is the left side of the spar box.  The cockpit roll bar will fit on top of the box-pillar.  The taped-off holes are the large bushes where the wing securing pins are fitted.  I masked them to keep then free of paint when originally priming the parts and will leave them masked until the cockpit has been finally painted grey.

This picture shows the left wing-spar roller.  There is an aluminium tubular spacer inside the roller to ensure it doesn't stop rotating when the securing bolt is tightened.  In this view you can also clearly see the brackets which hold the seat-belt lap-straps for both occupants.

A view from the right side of the fuselage through the spar box showing both rollers and the spar guide blocks.  Note that the rollers fit in opposite directions.

Next job is to assemble to control column bulkhead with the front stub-spar pockets, control column bearing brackets etc.  I didn't take any stage pictures so here is the finished product!

Aft side of the left wing front stub-spar pocket showing the reinforcing structure. 

Looking into the pocket for the left wing front stub-spar.  In this view you can see the additional bracing structure on the forward face of the bulkhead.

Final view of the stub-spar pocket reinforcing, looking aft on the left side on the 
fuselage.  The holes with red edges are where rivets mustn't be installed at this stage,
so it's my way of making sure I don't put them in by mistake!

Left-side control tube bearing bracket.  The bearing bracket is assembled before being riveted to the bulkhead.  Trying to flush-rivet the four rivets around the bearing was a challenge and took several attempts.  I do wonder how you'd change a worn bearing as a maintenance action in the future - quite a lot of dismantling would be required.
The two horns on the plate in the centre of the bearing bracket are the elevator control limit stops.

This is the reinforcing plate around the control column aperture.

Looking down on the seat pans with the control bulkhead cleco'd in place ready for riveting.  You can see how many anchor nuts are needed for removable access panels.  I still have a few hundred in the parts bin! 

 A view on the control bulkhead looking aft .  The next job is riveting this to the seat base ribs before adding six more ribs and the cockpit floor step.

Final view for this section, with a view that covers the front and rear stub-spar pockets and the main spar box.    If you've followed what's gone on so far, you'll realise that the left side of the picture is the front of the aircraft.  Not long now before I can sit in the seat and make aeroplane noises and push a control column around even if it won't actually look like an aircraft!
Having worked on Cessnas and Pipers from the last 25 years, the RV12 cockpit floor seems to be a much more complex structure (perhaps for crash-worthiness?) even if the materials seem much thinner.

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