tanks for its longest sorties. This teardrop-shaped tank design was long and in diameter at its widest point. Paper-based drop tanks Faced by wartime metal shortages and a need to extend the range of fighter craft, the British came up with drop tanks made of glue-impregnated kraft paper, which had excellent tolerance characteristics for extreme heat and cold necessary for operation on an aircraft as well as being waterproof. Since the glue would slowly dissolve from the solvent effects of the fuel (sometimes developing leaks within a few hours of being loaded with fuel) these were strictly a single-use item, used in typically chilly Northern European conditions, filled immediately before take off, jettisoned in the event of an aborted mission and only being required for the outbound portion of a flight. Such papier-mâché tanks were assembled from three main components, the nose cone, tail cone and the body, each shaped over wooden forms, the center section created by wrapping layers of the impregnated paper around a cylinder, the end caps hand-laminated with petal-shaped pieces sometimes called gores. Before final assembly wooden anti-slosh baffles were installed, pipes and fittings were attached and the interiors coated with fuel-resistant lacquer and the three pieces were bonded together in press. Once the tank had cured, it was pressure tested to and passing tanks were given two coats of cellulose dope followed by two coats of aluminium paint. (British paper drop tanks can be distinguished from outwardly similar metal tanks by colour, paper tanks were silver in appearance, while metal tanks were grey.) Some 13,000 papier-mâché tanks were made and used by the RAF, the vast majority during the war, conserving a considerable amount of metal. Very few examples survive due to their expendable nature, low intrinsic value and the fact that they are not inherently robust. While probably a nuisance for those under the flight path when the empty tanks were released, they were lightweight and comparatively fragile. Though they were likely to cause nothing but anxiety, the German authorities went so far as to distribute leaflets explaining that drop tanks were not bombs. U.S. paper tanks were developed by Col. Bob Shafer and Col. Cass Hough, who spent many hours developing a 110-gallon (416 liter) paper tank, then getting them into series production at Bowater-Lloyd's of London, only to be told by experts at Wright Field "paper tanks are absolutely unfeasible and will