Attach right hand fuel tank to main spar

All rough marks on main spar flange edges smoothed off and alodined

Fay sealing with Sikafex Pro+

rib 5 bolts torqued to 39 in-lbs. I used AN3-4A bolts to attach the fuel tanks rather than the supplied AN3-3A bolts so that I could use a standard AN4 washer under the bolt head. With repeated attachments and removals during testing the washer served to reduce wear on the spar surface. The washer aluminium interface was smeared with Duralac yellow, keeping the threads clean. Importantly, the grip of the bolt extends into the tank brackets sufficiently to ensure accurate positioning of the tank.

rib 4 bolts torqued to 39 in-lbs

rib 3 bolts torqued to 39 in-lbs

rib 2 bolts torqued to 39 in-lbs

Close tolerance AN173-13A bolts were used - with standard AN3 washer under nut. The bolt grip and washer aluminium interface was smeared with Duralac yellow, keeping the threads clean.

And a thin AN3 washer under the head, torqued to 39 in-lbs

Fay sealing with Sikaflex Pro+ with every effort to remove any squeeze out from the rivet holes

Install stainless steel rivets as per SB14 with Durlac yellow

and remaining rivets with Duralac green

The last 8 rivets are 4x13mm, 7 of which owing to the camera power supply mount bracket, and the eighth due to the total thickness of material

Finished result - underside

Breather hole

Fay sealing and stainless steel rivets installed as per SB14, with Duralac yellow

and remaining rivets with Duralac green

Finished result - top side

Finished result - top side

Laser level line - tip end, with all clamps released

Laser level line - root end - absence of twist confirmed

0.63mm shim made to break 1.1mm transition on the underside at rib 7 into two smaller steps (left hand wing shown here)

Appearance of shim - smaller skin steps