Bend fuselage skins & drill longerons

This week I focused on more fuselage work. The first task was to fit the huge skins to the center fuselage section but to do that the skins needed bending at the aft intersection to follow the contour of the fuselage.

After much research on the net I finally felt confident enough to make a start. I clamped the skin to the workbench and a piece of scrap aluminium. Then I drilled and cleco’d another scrap piece of ali.

Then carefully and methodically I coaxed the skin round to roughly the right shape.

Once it was pretty close I then offered it up to the fuselage and checked. It took several iterations before I was happy with the fit.

Once one side was done I repeated all the above with the other side and then cleco’d the lot to the rest of the fuselage.

Now that was done the next job on this weeks list was to match drill the longerons to the fuselage. Pretty boring stuff and nothing to get too excited over. I simply started at the back of the fuselage and drilled every hole… one… at… a… time!

I decided to stop drilling at the front section because I wanted to get accurate alignment of the longerons. To do that I would need to start building to forward fuselage.

That’s it for this weeks installment.

Working on seats

With the main structure now riveted together and the seats clamped in place, I fitted the baggage floors to the ribs.

Next up was to work the outer ribs into place. This involved fluting the ribs so that they curved to match the outside skin. I then drew a centre line mark for drilling.

With everything in place I carefully started drilling all the holes on the top and sides. I was working alone today so I couldn’t flip it over to drill the underside holes so I improvised!

Using my full face mask I laid on my back and drilled the belly skin to the rib using the centre line I drew earlier as a guide. Worked out pretty well in the end. Lastly I drilled the end holes up to final sizes for rivets and the bolt.

Next on the list was to drill all the seat and baggage floors to the ribs. That was one of the easier jobs on the list. Once the seat and baggage floors were drilled I enlisted the help of my two kids to help me join this section to the rear fuselage. I’ve finally found a use for teenagers!

After what felt like an eternity for the kids (7 minutes for us humans) the two sections were now one and I admired the structure over a well earned coffee. Finally, I fitted the side skins to help keep everything square and to give the whole structure a bit of strength while I’m away from the workshop.

It’s really rewarding to see this structure take shape.

Continued riveting fuselage centre section

This weeks work was split into lots of different sessions working on the same section, riveting the fuselage centre section.

I decided to work in small sections and set small goals, like riveting the ribs to the main (gold) spar first, then working on the centre baggage ribs outward with the seat back spar in place.

Once that was done I cleco’d on all the skin, marked what should NOT be riveted at this stage. That was the centre section skin ready to rivet but there is no way I can rivet this alone.

So I asked my Dad to help. He was on the gun and I was on a wheely mechanics trolley with the bucking bar from the other side. Once again, good communication is key here. He would say ‘On It’ when the gun was in place and then I would say ‘ready’ when the bucking bar was in place. He would then give it a short burst with the gun. That method was taught to me by another builder and works really well when two people are working together.

After a couple of sessions we managed to get the entire skin riveted in place and on the bench upright ready for the next phase. I couldn’t resist popping the seat trays on though to check that everything was square. It was.

Overall, quite a productive and rewarding week.

Crotch Brackets & Seat Ribs

So now the centre fuselage parts are all primed and cured it is time to fit start final assembly of those parts. I started by riveting the nutplates and doublers onto the cutout for the control sticks. This cut out makes it possible to fit and service the control sticks once this area is all fully assembled.

I also decided to top coat the crotch strap brackets with white Plastikoat. This stuff is really hard wearing and given that I expect the straps to rub over time due to vibration I thought it was best to give these parts the best possible coating. I only top coated the visible and wearing parts though to save weight.

Once the top coat was dried I started final assembly of the seat ribs and crotch strap brackets by riveting the brackets to the ribs and then the ribs to the main spar.

That was a good start to the seat ribs. Like various other builders I started with these ribs to make it easier to solid rivet the brackets and to make access to the other ribs easier.

That’s it for this weeks work sessions.

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