Fixed Guns vs Free

by Robert A Winston

Heavy armament is the backbone of Europe's war in the air. A major problem in future development is the decision between movable and fixed plane guns.

Not very many moons ago, the world's aviation experts were unanimously proclaiming the end of the fighter era. "The fighting plane is obsolete," they announced with pontifical finality. "The advent of the modern high-speed bomber has ended the day of the dogfight. From now on, invincible armadas of bombers will rule the air."

This edict, it appears, was a bit premature. The experts were making the fatal mistake of comparing horizontal speeds. "If we have a bomber that is 50 mph faster than the enemy's fighters," they reasoned, "the bombers will be able to outrun the fighters."

This is quite true as far as it goes, but there are several other factors to be taken into consideration. The first is that the mission of the bomber is offense. For this reason it is not always necessary for the fighters to be able to outrun the bombers. If the fighters are waiting between the bombers and their objective, as is usually the case, the superior speed of the bombers usually brings on the real showdown that much faster.

All things considered, the fighter's task is simple compared with the horizontal bomber's assignment. The bomber's most vulnerable moment is just when it is closest to accomplishing its mission. In order to get hits, the horizontal bomber must be flying straight and level long enough for the man at the bombsight to get his aim. At this stage the bombing plane must not deviate from its course, or its bombs will miss. The pilot is busy making a smooth "run," the bombardier is lying flat on his stomach with his eye glued to the bombsight and both hands full of adjusting knobs correcting for altitude and drift. Only the rear gunner is protecting the plane.

At such a time, the bomber is dead meat for the average fighting plane, even if the fighter is slower. If the fighter is waiting at the same altitude he can meet the bomber head-on. In this case, the fighter's objective is accomplished, for the bomber's run is spoiled. The man at the bombsight must drop his vital work of directing the bomber's course to that pinpoint in the sky where his plane must be at a certain precise second in order to get hits. He must pick up his machine gun and defend himself for, in his exposed position out in the transparent nose of the bomber, he is the most vulnerable of any of its crew. The pilot of almost any kind of airplane flying directly at him would be able to spoil his aim — even in a Curtiss pusher with only an armful of bricks for ammunition.

Remember that the only place the bombs can be released on any given run is in a direct line from the nose of the bomber to its objective. If the bomber is flying in a slight skid, or if the bombs are released half a second early or late, they will miss the target by hundreds of yards. Thus any obstacle in the bomber's path must be removed once the aiming approach is begun, or the bomber must circle and come back for another try. And if enough defending fighters are sniping at him, the pilot may give it up as a bad job, jettison his valuable cargo of bombs at random and head for home. At this point he may be able to outrun the fighters — if they do not have an altitude advantage. If they happen to be at a higher level, the bomber may still be out of luck, for a diving fighter can quickly convert an altitude advantage into sufficient air speed for overtaking the fastest bomber.

When this occurs it is a duel between fixed guns and free guns. Here the fighter with its fixed guns has a definite advantage over the free-swinging guns of the bomber. Almost any sort of fighter used today will have the advantage of superior firepower, with at least four machine guns and sometimes as many as eight. In addition, the fighter is a fairly small target while the bomber is a big target which can be put out of commission if the pilot, bombardier, or engines are hit.

The fighter pilot can shoot comfortably from almost any position. Even if his plane is banked steeply, upside down, diving or zooming vertically, all he has to do is press his thumb on an electric trigger button when the bomber enters the field of his gunsight. He can change his position instantly by leaning one way or the other, ducking under the bomber's tail or wing, or diving at it with the sun behind him to blind the rear gunner. The bomber's free guns are definitely limited in radius of action. It is very difficult to shoot free guns straight up or directly astern, which are the fighter pilot's favorite approaches. Also, the free gunner has to swing his guns in order to train them, where the fighter pilot does not. Even if the free gunner has a power-operated turret, the fighter pilot still has a much easier job of aiming his guns. The power turret cuts down the fighter's advantage, but does not nullify it. If two fighters try for the bomber, one will probably get it even if the other is shot down &# 151; and fighters usually attack in groups.

Various formations of bombers have been tried out in an attempt at mutual protection against fighters. In the recent Russo-Finnish war the Russian bombers started out with large flights of 70 or 80 bombers in massed V of V formations. These bombers, copies of our Martin and Douglas types manufactured under Russian license, were faster than the Finnish fighters which were "obsolete" Fokkers equipped with fixed skis, carrying only four small-caliber machine guns. Using these planes the Finns shot down over 700 Russian planes, most of them twin-engined bombers.

Their method was simple. Using an efficient warning system of outlying listening posts, the fighters took off as soon as the bombers were reported heading inland. The fighters then climbed to the reported altitude of the bombers until the latter were sighted, then headed in the same direction in which the bombers were heading, climbing as fast as possible. By the time the bombers overtook them the fighters had enough of an altitude advantage to catch the bombers by diving. Their usual procedure was to dive at the Russian rear gunner, give him a burst from all four guns and duck under the bomber's tail. With the momentum of the dive they could zoom up and ahead for another pass at the bomber. If they got the rear gunner on the first dive, their next aim was for a burst at the bomber's engines.

As simple as this procedure seems, it was very effective. Using these tactics one Finnish pilot, Captain J Sarvanto, shot down six modern twin-engined Russian bombers in four minutes. The Russians finally changed their formation from a V of Vs to a line formation — but the Finns still picked off the planes on the end of the line.

Recently the Germans varied their tactics from the V formations they used in Belgium and France, trying out a follow-the-leader formation. Still the Spitfires and Hurricanes are reported to be shooting them down or chasing them back before they reach their objectives. The English are also using patrols of night fighter planes with encouraging results. These fighters patrol over vital objectives, circling in the critical radius where the bombers must come before releasing their bombs. Their method of locating the bombers has not been revealed but it is significant that the English will no longer accept fighters which are not equipped with electrically illuminated reflector-type gun sights, as the telescope sight is no good for night work.

Coincidental with the use of night fighters is the slackening of the protective anti-aircraft barrage around the London area. At the peak of the recent night raids on London, the English were using an estimated half million anti-aircraft shells at a cost of almost $1,000,000. Even with this ruinously expensive barrage, the anti-aircraft was credited with only three per cent to five per cent of the total number of German raiders shot down. In view of this comparative ineffectiveness of anti-aircraft fire, it might be more profitable to eliminate the anti-aircraft and use fighter patrols exclusively. The fighter patrol has several advantages:

  1. The fighters are mobile, while the anti-aircraft is limited by a fixed base.
  2. The fighter patrol costs only a fraction of the cost of an anti-aircraft "box barrage.”
  3. The moral effect of the fighters is worse than the anti-aircraft to the enemy. A bomber pilot may ignore anti-aircraft bursts in his vicinity as long as his plane is not struck. But when he sees a fighter headed in his direction, or tracer bullets zipping past him in the dark, he will probably forget all about his bombing run in his efforts to escape.
  4. The damage on the ground from anti-aircraft shrapnel and duds often is considerable. In addition, it hampers the operations of the defending fighters.
  5. Fighters at high altitude make very little noise, whereas the racket of the anti-aircraft batteries makes sleep impossible for the civilian population, undermining morale and curtailing the efficiency of workers.

Superiority in the air depends upon fighting planes. Poland was helpless after her air force was eliminated. France resisted until her fighters were outnumbered. England was helpless until the Spitfires hit their stride and warded off an expected invasion. Fighting planes will probably decide England's fate, and perhaps even America's. What, then, is the best type of fighting plane? We can only judge from the results observed in the proving grounds of the recent wars in Europe.

In the Spanish civil war Russian-built Boeing fighters ruled the air for a time and gave the Germans their idea for the dive bombers they used so effectively against Poland, Holland, Belgium and France. In the latter part of their war with Russia, the Finns had an assortment of Italian Fiats, Dutch Fokkers and Koolhovens, French Moranes, English Hurricanes and Gloster Gladiators and an export model of a US-built fighter (probably the Brewster —Ed). Although the American fighter had a top speed of only 300 mph, which was somewhat slower than some of the other foreign fighters, several top-ranking Finnish aces told me that they preferred it because:

  1. It was faster in a climb.
  2. It picked up speed faster in a dive.
  3. It was more maneuverable at close quarters, due to the absence of the wingtip stall characteristic of low-wing, taper-wing monoplanes.
  4. Its armament was heavier; .50-caliber guns would pierce Russian cockpit armor, which repelled bullets from lighter guns.

English pilots now in this country who have seen action recently tell me that the old dogfight tactics have not changed much since the last European war. They say that massed fighter formations still break up into grand mélees consisting of individual dogfights, and that a dogfight still ends up with two planes circling for an opening, with the fighter which can fly the tightest circle winning.

Judging from what we have learned from these last three wars, the ideal fighting plane should have the following accessories and characteristics:

  1. Self-sealing oil and fuel tanks.
  2. Bullet-proof glass windshields.
  3. Armor behind the pilot's seat.
  4. Electric reflector-type gun sights.
  5. Absence of wingtip stall.
  6. Fast action maneuvering flaps for dog-fighting.
  7. Fast rate of climb. This is more important than excessively high horizontal speed.
  8. Fast diving speed.
  9. Instrument equipment which permits takeoffs with zero-zero visibility.
  10. Modern oxygen masks.
  11. Heavy guns with explosive projectiles.
  12. Turbo-driven supercharged engines. Maneuverability should not be sacrificed for high horizontal speeds.

The above qualifications can easily be met by several US fighters now in production, with a few minor changes. By the addition of turbo-driven superchargers the top speeds of these same models can be increased as much as 50 mph, with no reduction in maneuverability or change in handling characteristics.

Most of these items are already incorporated in the fighting planes of the Axis powers. Unless we give our pilots similar equipment at once, we may be caught short — just as France was — and sooner than we expect.

This article was originally published in the January, 1941, issue of Flying and Popular Aviation magazine, vol 28, no 1, pp 16-17, 79-80.
The original article includes 3 photos.
Photos credited to British Combine, Acme.