Modelling-ABC by Wilfried Eck
Textile Structure (a reminiscence)
Only a few and moreover not quite young
modelers (m/f/d) will remember the then revolutionary P-40 from Revell. Not only
the 1/32 scale was new, but also a cockpit with a real seat (in 1/72 it was
often just a crossbar), an instrument panel with instruments and pointers and
other things. But the abundance of previously unseen details was crowned by
rudders with textile structure. Finally, one could see what was sheet metal and
what was fabric in the original. The enthusiasm of the kit reviewers knew no
bounds, so that subsequently no manufacturer could afford to do without this
important detail. The fact that in 1/72nd scale this turned out to be rather
coarse hardly bothered anyone.
So it remained for quite some time until it was replaced by a new trend (I think it was removable flaps, the more the better). Now it was discovered that in reality there was no textile structure to be seen in the real aircraft, because the result of several layers of pore filler, primer and stretching varnish made the whole thing as smooth as glass. How glossy the aircraft appeared in the outcome depended on the topcoat, which was never dull.
On WW I aircraft with (two-stroke) rotary engines, the engine oil was expelled along with the exhaust gas, which at least gave the fuselage an additional layer of gloss that protected it from weathering. Unfortunately, word has not gotten around to this day. Textile covering also does not sag in waves, but is tight like a drumhead. See photos on the German page B, "Bespannung".
The other mistake is to let textile covering sag. In reality it was taut, only the ribs and stringers protuding only slightly. See page F, fabric covering
Excluding some types with blunt or even concave trailing edges on wings and control surfaces (i.e. F7U Cutlass) these parts are knife edged.
Contrary so in many plastic kits. Due to manufacturing restrictions most trailing edges in kits are too thick and rounded, especially in 1/72 or smaller scales. But even in larger ones I've seen models with trailing edges scaling to log thickness in the real plane.
To achive this required sharp edge it isn't sufficient to sand the very last part of the surface, the resulting kink making it even worse. To retain a flat profile sanding has to begin further towards the leading edge, the sandpaper being held flat by a suitable piece of wood or plastic (fixing the sandpaper with double sticking tape is no bad idea). Naturally this procedure begins with coarse and ends with very fine sandpaper.
It doesn't matter if during this process the gaps around ailerons and rudders are reduced considerably for they usually are too wide and rounded too. In any case rescribing (with the rear of the pointed edge of a sharp knive) should be done so that the rescribing tool points to the front to create a sharp edge there.