29-02 -> 04: First Joining of Major Components (then take them apart again!)

Chapter 29 started with a bang - the joining of the Lower Mid Fuselage (baggage compartment) to the Lower Forward Fuse (Cockpit & Firewall). 

A momentous occasion! 

In preparation for this join I reconfigured my workshop - assuming once the join had occurred i would be unable to move the assembly around very easily.  I moved the main workbench (on wheels) over to the end, and in the centre placed my aluminium saw horses. I bolted on some 12" x 2" timber from the fuselage shipping crate and surprise surprise it was exactly the right length! I then added some padded foam (actually a mattress topper chopped up) to protect the bottom skins and provide somewhere for the cleco tails to stick into. 

The extra foam hanging off the ends is for rolling up to support the aft end of the fuselage bottom skins (as the skin curves upward and is not flat).

 It was then a simple matter of man handling the baggage area through the doorway, sliding it in place, then clecoing it to the forward skins! 

A note here for anyone following however: If you read ahead to Page 29-04, you need to put sealant between the aft skin and the aft flange of the stainless centre tunnel top - we did not do this when we cleco'd together the skins on Page 29-02 - it is much easier to do this without making a mess if you do it at the time you initially cleco the skins together on Page 29-02. 

Preparing to Stand the Fuse on its Side

To rivet the bottom skins together, the plans call for standing the assembly up on its side. However, to do this the assembly has to be rigid, meaning the upper and lower drag fittings need to be drilled and bolted in and the side plates need to be clecod in. 

Work started here by bolting the upper and lower drag fittings in place - i did not want to use the locknuts specified, so needed some 3/8 nuts - so back to the bolt shop! (we don't just have imperial nuts laying around down here - especially not UNF). 

Once in place the side plate is clecod on, the upper drag fitting is clamped in place and the upper drag fitting is match drilled to the side plate. These are some well made and hefty components! I made sure to mark the left and right components permanently, so they don't get put in the wrong sides.

Lower drag fitting

Such a satisfyingly nice fit.

Once all these parts were drilled, everything was removed and all parts deburred. For the next step, everything is bolted and clecod back in place for the riveting of the bottom skins - the lower drag fittings included. So these were primed before being bolted back in. As always on bolts, TefGel was used as an anti-corrosive on all bolts. 

Lower drag fitting primed ready to be bolted in.

A wooden support leg was made up and bolted in place with some temporary 3/8 bolts. We carefully lifted the assembly up, and used some pillows to stop it flexing in the forward and aft axis, and a ratchet strap and bolt used on the roof of the shed to hold the assembly up.  

A leg much longer than the plans was made up to span between the 2 long boards i am using for a 'bench'

Don't let go dad!

Cushions and a ratchet strap keep the assembly pretty stable.

DOH!

So here we were about to start riveting the lower skins, and i saw this:

Yes - there is a rivet installed already in the skin underneath these 3 rivet holes 

So what happened? As you can see from the image, on each side of the airframe there is a nutplate location. These are used when the aircraft is a nose-wheel machine, for a cover plate which goes around the landing gear. 

For the taildragger, on Page 26-11, instead of installing nutplates in these locations, you simply fill the nutplate holes with -3 rivets. Page 26-11 Step 11 says "Fill the nutplate holes in the centre bottom skin with rivets". 

However, it does not mean ALL the nutplate holes! What it means in that step, is fill the nutplate holes where nutplates are shown in the image. However, there is one set of nutplate holes which do not receive a nutplate in Chapter 26, as this location is the overlap between the forward bottom and centre bottom skins. For the nosewheel, this location gets a nutplate in Chapter 29 (and rivets for the taildragger). 

Turns out i set rivets in ALL the nutplate location holes back in Chapter 26 - not just the ones with nutplates pictured, but also the holes circled in orange. DOH!

So the whole assembly had to be lowered back down, unclecod and unbolted, the forward and aft sections pulled apart and the 6 rivets drilled out. The only saving grace, is that by this time we had figured out we needed sealant under the stainless tunnel flange, so we did this at this time and re-clecod and bolted the assemblies all together once again. 

Back apart again!

Goodbye rivets.

There was 2.5 hours of work, and we did not move ahead in the project at all! C'est La Vie!