IN THE AIR: Bomber Tactics

Big surprise to most of the world in the Nazi drive through the Lowlands and northern France was the terrible accuracy of German dive bombers. Except for the U. S. Naval Air Service (which originated dive bombing, still works hard and ably at it), few of the world’s air forces had fully realized the sharpshooting possibilities of a heavy bomb projected straight & true from a diving airplane.

Last fortnight across the Atlantic came details of another brand of German attack from the air: high-altitude, level-flight bombing, which the U. S. Army Air Corps uses to the exclusion of the diving attack. Returning travelers who saw the daylight raid on Paris, hundreds of other attacks through France, told of hearing raiders so high that they were out of sight in the clear sky. Yet these planes, starting out their campaign by smashing up France’s airfields and pursuit resistance, methodically and unspectacularly brought a creeping paralysis to France’s communications. Road junctions were reduced to craters, railroad junctions and yards were smashed and littered with wreckage. Military headquarters were knocked out by sharpshooting bombers almost as soon as they were set up. Apparently few bombs were wasted by bad shooting. Harold Francis McEnness, European representative for big, research-wise Bendix Aviation Corp. (aircraft carburetors, magnetos, instruments, other accessories), told of a raid on the Citroen automobile plant outside Paris.

“There were about 250 planes in the attack,” said he. “They were so high you couldn’t see them but their number was estimated by the number of bombs dropped. Their accuracy was terrific. Of all the bombs dropped . . . the majority plunked right into the factory.”

Quick was Harold McEnness to surmise that the Germans either had learned the secret of the closely guarded U. S. bombsight, or had developed one of their own. Quick were Army Air Corps officers to say that the U. S. sight was still a U. S. secret. But none doubted that German ingenuity had developed a bombing sight for World War II that was modern, scientific, accurate. Typical level-flight bomber in the medium range (24,900 Ib. fully loaded) is the sleek, two-engined Heinkel He. in K which carries a crew of four, makes bombing a highly coordinated job for two men, the pilot and the bombardier. These, with other types (Dornier, Junkers, etc.), were the ships that were trying to soften up Britain with intensified raids all last week (see above). A Heinkel He. in K is pictured on the opposite page during a hypothetical attack on the vital Thames Estuary and London docks.

The advantage of level-flight bombing from high altitude is that it keeps bombers out of effective range of anti-aircraft batteries, forces defending pursuit to climb higher and farther to give battle. Its only limitation in good weather is the accuracy of the bombsight.

Unless German scientists have developed a sight allowing accurate bombing out of turns, glides or climbs, maximum danger period of a Nazi level-flight bomber is in his approach to his target. For coming up to his bomb-release line he must fly in a straight line and at a constant altitude for about 60 seconds (more than three miles at 200 m.p.h.), to give his bombardier time to draw a bead. It is there that he is the best target for the antiaircraft guns. On likeliest directions of approach anti-aircraft guns are most heavily established. The batteries are so placed that the tops of their inverted cones of effective fire (see lower cut) overlap. Because it is better to wing a bomber beforehe drops his load than after, fire cones are heavily overlapped ahead of the lines where enemy bombers are likely to drop their eggs.

On a bombing raid, a Heinkel bombardier, who is also second pilot, rides up forward in the nose (“meat-can” to U. S. Air Corps big-ship crews). There he has a machine gun, convenient in case his ship is jumped by enemy pursuit. Back of him sits the pilot, still farther back two machine-gunners to deal with pursuit attacking from behind. The top gunner rides in a wind-screened cockpit looking for attacks from above. The gunner on the bottom rides in a “dust-bin,” on his belly, to range his guns on pursuits attacking from below.

Approaching the target, the bombardier leaves his seat, crouches or lies down flat over the bombsight just below his machine gun. Quickly he checks the spirit levels to be sure that the ship is parallel to the ground, other settings that correct for the speed of the plane and the wind drift (which slows a bomb, speeds or deflects it). Then he puts his eye to the eyepiece and takes his sight on his target. From that point until the bombs are dropped the bombardier is in charge of the ship. Training his sight on the target he may well find (and usually does) that the pilot is not flying straight toward the target. On the pilot’s board an instrument signals that he is right or left of the sighting line. Providing he holds the true line and keeps constant altitude the rest is up to the bombardier. Down the groove flies the Heinkel with its belly bomb-bay doors open. As it gets into range, the bombardier presses the bomb-release button. If he has set his selector for one bomb, only one falls toward the target. If he has set it for salvo-bombing, all drop. Air Corps enlisted men call this “opening the tail gate.”

What changes the Germans have added to such fundamental procedure the Germans are keeping to themselves. One possibility is that they have done away with the bomb-release button, use a photoelectric cell built into the sight to drop the bombs when the sight is on the target. Purpose of mechanical dropping is to avoid a lapse sometimes as long as one-fifth of a second between the time a bombardier sights the target and the time his mind has telegraphed the button-pushing impulse to his fingers. Split seconds in the releasing operation make yards of difference on the ground.

Because of the forward speed of the plane, bombs travel forward as well as down when they are released from the racks, head for the ground in a sweeping curve. Bombs from a ship flying at 200 miles an hour at 10,000 feet travel roughly 13-miles in horizontal distance before they get to the target. If a ship continues in its same flight line (as it does if it has an objective just beyond), it will be almost directly over the first target when the bomb hits. But more popular with bombing crews is a single objective. Then a pilot can turn and climb after the bombs are released, scramble out of fire from batteries below, and make himself a hard target by varying course and altitude.