Warbirds in my Workshop

David Glen BSc (Hons) MSc, Model Maker, Journalist and Author

Formerly Spitfire in my Workshop

The wing tip skin

Monday, 7th November, 2016

The Spitfire’s wing tip (which is detachable in the full sized machine) has two skin parts plus a narrow fore-aft reinforcing strip per side, and compared to the leading edge they are easy to do. As before, a little heat annealing is helpful around the outer periphery of the plates but after that the metal, if closely trimmed, snugs down nicely along and around the fining out wingtip.



The navigation light fairings do not overlap the wing skin. So by making these first (as described on my previous page), I was able to use them as templates for scribing and cutting the underlying litho plate, thereby obtaining neat and tidy abutted seam lines (the seam is actually toggled in the real aircraft).



The only thing to say about the bracing strips is that they are made of thicker material, so that they stand perceptibly proud of the surrounding wing skin. I used 0.75mm aluminium sheet.



The single perceptible difference between the wingtip skin and that covering the rest of the main-plane is that in the full size aircraft the former is secured to a wooden framework by no fewer than 80 wood screws per panel.  The above-mentioned reinforcing piece is also perforated by a row of 24 larger screws. This is not only time consuming for the model maker but also costly: Tiny 16 and 14 BA screws purchased in their hundreds run up a hefty bill very quickly.



There is also another drawback: Making neat and consistent countersunk holes in thin aluminium sheet (the litho plate I use is no more than 11 to 12 thou thick at most) is not easy. And if the countersinks are not consistent, especially where closely spaced, and the screws do no present perpendicular to the metal surface, the finished work can look ghastly.  (For anyone interested, I will be posting a brief description of the techniques I use for this on my ‘Aired and Shared’ pages of this website shortly).

Back to Spitfire Mk IX Diary

The smaller of the two upper wing tip skin panels showing the embayment cut into the leading edge for the nav light fairing.
The same piece after gluing onto the wing.
The larger rear skin plate after forming to shape. The curved edges are left very slightly overly deep. Once the panel is emplaced the model can be turned over and some very thin superglue run in along the trailing edge. This results in an extremely solid bond, enabling the slight excess of metal fringing the underside of the wing tip to be cleaned flush with a file or abrasive block ready for the application of the counterpart plate on the under-wing.
There are rivets in the wingtip skin but the bulk of the fasteners are screws, for which holes have by now been drilled.
You have to look carefully but some of the tiny 16BA brass 'wood screws' can now be discerned in the skin. Larger steel countersunk screws are visible in the reinforcing strip and along the join between the two skin panels.
Mustang in my Workshop book cover

Mustang in my Workshop

A book to inspire, encourage and empower the enthusiastic model maker to scratch build a masterpiece.