Match Drilling The RV-12’s Longerons Begins

The upper row of holes in the F-1270 fuselage side skins are used as the template for match drilling the rivet holes into the side of the F-1255-L&R longerons. As such, the side skins need to be Clecoed onto the side of the fuselage assembly.

Securing the F-1270-L left fuselage side skin in position on the side of the fuselage assembly with Clecos.

After placing the fuselage’s F-1270 side skins and F-1270A skin stiffeners in position, the three holes pointed out in the photo below were match drilled into the F-1275F corner skin. The F-1270A stiffeners have been added recently to the RV-12 as part of a service bulletin, so the F-1275F corner skin does not have all the necessary holes.

Positioning the F-1270A skin stiffener onto the F-1270 side skin to secure with Clecos.

The three holes above my fingers are the holes that need to be match drilled into the F-1275F corner skins.

I know it is hard to tell from the photo below but the forward end of the right longeron does not have quite enough twist … the inside edge is still a little high. Before match drilling the longerons, thought it best to place the instrument panel bottom onto the forward portion of the longerons to check the fit and get a good visual on how the pieces mate up.

Both F-1270 fuselage side skins in position for match drilling the longerons … note the forward inside edge of right longeron (on left in photo) is still high.

Placing the instrument panel bottom across both longerons confirmed the right longeron still required a little more twist to allow the bottom of the instrument panel to sit flat across the top of the longeron. Using a couple of Crescent wrenches, a little more twist was added to the forward portion of the right longeron and now the panel fits nicely on top of the right longeron. Ended up with a slight bump where the Crescent wrench was, but the overall fit looks very good. Time to move on.

Instrument panel bottom sitting in position straddling the tops of the F-1255 longerons checking fit after right longeron twist was adjusted … overall fit is now flush with the top surface of the longeron.

Final shape of forward end of the right longeron … the left longeron was perfect and now the right longeron looks almost identical.

Bernie happened to stop by and was surprised to see how well the longerons we formed in his basement fit on the fuselage. Both sides are now very symmetrical and I’m now very pleased with the overall fit. Knowing the forward portion of the longerons are correctly positioned for the base of the instrument panel, it was time to begin match drilling the right longeron. Decided to begin by match drilling the holes in the roll bar attach plate because it will lock the aft portion of the longeron in position. The vertex or corner of the longeron needs to be flush with the side of the F-1205B roll bar attach plate. The top of the longeron needs to be flush with the top edge of the F-1270 side skin.

Match drilling the F-1255-R longeron to the roll bar attach plate … this will lock the aft portion of the right longeron in position.