Seven league boots

by William S Friedman

Like magic boots of old, drop tanks make penetration of the enemy's heart one great step from Allied bases.

The tale is told that Luftmarschall Hugo Sperrle, high Nazi airman charged with safeguarding the Reich from air attack, has just begun dreaming about breaking up Fortress and Liberator formations with some of his pet Rube Goldberg devices (flying doughnuts, bombs-on-cables, air-to-air bombing, etc) when he was kicked by a horse and rudely awakened. The equine involved was the North American Mustang.

Like the cavalry of old, which led, flanked and rear-guarded bodies of troops, Mustangs arrived over Berlin, riding herd over tight-packed Fortress and Liberator formations, keeping Focke-Wulf 190s, Messerschmitt 109s and interceptor-equipped Junkers Ju-88s at a respectable distance.

The Luftwaffe's general armament plan called for weapons that could stay outside the range of the Fortress' murderous .50-cal fire, yet break up the formation. Junkers Ju-88s, rigged with long-range droppable tanks, clogged formations most of the way home, swooping in, vulture-like if a wounded ship couldn't keep pace with the gang.

Early in the war, day bomber tacticians learned that, over a well-defended target area, bombing planes required fighter escort for operational safety. The size of the airplane did not seem to matter as much as the proportion of the total weight it could invest in air-to-air offensive firepower. The bomber could be invulnerable if bomb load were sacrificed for .50-cal guns and ammunition. This technique was mechanically possible but totally impractical from an offensive point of view. During the Fortress' early operations over Europe, American ships attempted comparatively short daylight operations, their runs being limited by the relatively short range of the Spitfires sent out to accompany them. Later, when our own Lockheed Lightning's with increased ranges, began operations, the thrust went deeper.

With dramatic suddenness, the Republic Thunderbolt arrived, possessing a towering service ceiling, and a droppable belly tank, which allowed it to escort the Fortresses to most targets in Western Germany. The final blow landed when the Mustangs, equipped with two huge gas tanks, which looked for all the world like spare fuselages hung under their slim wings, arrived over the Reich's capital, to battle with the Luftwaffe, while the bombers shattered Hitler's war industry.

Now the Luftwaffe was caught with its flaps down and decimated by these fighters for two reasons. One was the superior maneuverability of the Mustang, even at high speeds, an asset endowed it by its laminar-flow wing and Edgar Schmeud's (North American's No 1 genius) design skill. The other was the fact that most of Germans' dog fighter strength had to be regunned to fight a "standing target," a block Fortress formation and not a twisting, diving fighter. The German fighter had been loaded with armament, while the Mustang came in, light as a feather, having burned off the fuel in their streamlined droppable tanks. If the enemy came in for attack, they dropped these "eggs," faced the foe with a lower wing loading and twice the fuel needed to get home. Thus, German defenders, armed to fight bombers; were at a disadvantage against the escort fighter.

What About Drop Tanks

The American public first became conscious of drop tanks when the Zeke or Mitsubishi Zero became the first-rate terror of the days after Pearl Harbor. A major portion of the credit for the development of drop tanks goes to the Nips. Having been faced with the problems resulting from homicide and mayhem a full decade before the rest of the world, it is not surprising that Jap airmen made the earliest use of this device.

The earliest drop tanks were not created as a range-stretching idea, but as a safety measure. Some fighters, built for the Navy during the middle '20s, had their tanks incorporated into both sides of the (Continued on page 70)

This article was originally published in the June, 1944, issue of Air News magazine, vol 6, no 5, pp 20-21, 70.
The original article includes 8 small photos and a map showing ranges over Europe.
Photos credited to British Combine, Air News.

The Score Sheet

The striking effect of droppable tanks on range can best be shown in tabular form. Most of these figures are estimates, some are shown in percentage, but all will serve as a general index to how this simple device has increased the fighter's effective radius of action. As indicated, built-in and droppable tankage can only be given on enemy aircraft. Figures on US craft are still restricted.

PlaneBuiltin tankage
and range
Droppable tankage
and total range
P-381400+ miles
P-39425 miles800+ miles
P-40430 miles800+ miles
P-47650 miles1000+ miles
P-51Unstated unit1200+ miles
F4F780 miles1300+ miles
F6FUnit52% increase in range
Hurricane IIB  480 milesapprox 1200 miles
Spitfire460 miles1030 miles
Zeke141 gal, 980 miles87 gal, 1820 miles
Fw-190138 gal, 440 miles78 gal, 820 miles
Me-109GUnit 50% increase in gal
miles45% increase in range
Me-110336 gal, 920 miles216 gal, 2120 miles
Me-210660 gal, 1280 miles  144 gal, 1700 miles

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