Fuel tank cover
Sunday, 29th May, 2016
My apologies for the lengthy hiatus in my web log, and particularly to those who have contacted me about it. I fear the cold, miserable winter we have endured on these islands induced partial hibernation during at least some of the period, and then a resurgence of activity on the model since mid-March has left little time or inclination to write. So, to pick up the thread gently just about where I left off back in January, here is how I tackled one of the less challenging aspects of the fuselage skinning process:
The Spitfire’s designers partially protected the vulnerable fuel tank by covering it over with extra-thick alloy plate, and this gives rise to a subtle but noticeable surface feature: the arched cover sits flush with the rest of the skin at its apex but becomes progressively raised up until it overlaps at the bottom edge. I used 0.5 mm alloy sheet, which is slightly under scale thickness.
Firstly, I needed to make and install the fuel filler cap with its two little lugs and the screw head and breather pipe detail, both of which are clearly visible beneath their individual access holes.
The cover itself was straightforward to mark out and make, particularly since its regular, semicircular form could be achieved easily and without annealing. In situations like this, I tend to make the radius of curvature slightly over-tight so that on installation the metal springs outwards to hug the underlying contours more tightly.
As can be seen from my pictures, the many holes – most of them for steel screw fasteners – were drilled and countersunk prior to fitting. And because the majority of the screws could be self-tapped securely into the numerous plywood members beneath, I was able to omit the use of glue entirely for this operation, thereby making it much easier to infer the very necessary gap between the underside of the cover and the topside of the fuel tank itself.