Dive Bombing.Pdf

JANUARY 25, 1940. Equipment and Tactics for DIVE-BOMBING Specialised Aircraft : Diving Brakes : Heavy Bombs : The Human Element By H. F. KING NTEREST aroused by an article Germany's Dive Bombers appearing in Flight of September 28 last year I suggested a review of international practice in this form 01 attack with reference to the specialised aircraft required and the problems presented. Both the Spanisn and the Polish struggles demonstrated that dive-bombing has a very definite place in modern warfare. They established that diving attacks made with specially designed aircraft will give excellent results not only against small individual targets on land (e.g., build- ings, cross roads, railway junctions and " pill boxes ") but against moving objects like ships, tanks and mechanised columns. Previously dive-bombing with heavy projectiles, particularly as fostered in America, was regarded as being chiefly of use against ships and it is significant that, despite the fact that several squadrons of the Luftwaffe are equipped with Junkers Ju 87 and Henschel Hs 123 dive- bombers, the great majority of American, British and French machines designed primarily for diving attacks operate from the decks of airciaft carriers. Reference has already been made in Flight to the exten- sive and successful employment of Ju 87s in Spain. They were introduced into the conflict early in 1938 and were used on the drive to the Mediterranean coast, during the fighting on the Ebro front and on the Catalonian offensive. They met with particular success in the final phase of the Spanish war when they bombed ports and ships on the Mediterranean coast. The havoc wrought in Valencia, A German Henschel Hs 123 single-seater dive-bomber Taragona and Barcelona was due chiefly to their activities. releases a salvo of four 50 kg. bombs One pilot is said to have accounted, single-handed, for three large steamers off Taragona, each time securing a Dive-bombing as we shall consider it entails the release direct hit. of a bomb or bombs while an aircraft is diving steeply to- In Poland, German dive-bombers, particularly the Hen- wards a target. Obviously there is only one point of re- schel Hs 123 single-seater biplane, were used in close sup- lease for a given dive, for after leaving the aircraft the port of the infantry. As already inferred, such aircraft bomb will not follow a straight path. Special sights to give good results against tanks and other obstacles to facilitate aiming have been evolved but it is believed that ground forces. these are not in general use. The speed of the dive increases the vertical velocity of the bomb so that its penetration is equivalent to that of A study of the German Junkers Ju 87 two-seater dive-bomber a similar projectile released in level flight at a greater showing how the single large bomb carried beneath the altitude. Although dive-bombing with bombs of 500 or radiator is swung outboard before release. There are diving- brakes under the wings. '.}?? JANUARY 25, 1940. (Left) An American bomb-displacing gear shown diagrammatically. It is believed that this is essentially simi- 6000-70O0FT. lar to the type used by the U.S. Navy. anti-aircraft defences. Converging tactics may also be profitably used by formations, while single machines 2000-3000 FT may adopt evasive measures before their final aiming dive. It is reported that Japanese tactical dive-bombers approach obliquely at 2,500-3,500ft., then turn sharply through 35-40 deg. before diving on the target at 60-70 deg., recovering at 1,300ft. With present machines the From left to right the diagrams above \ speed rises from 90-200 m.p.h. The illustrate possible dive-bombing approaches in (i) clear weather, (2) when there are escape is made in a turn. some clouds, and (3) when there is an un- Apart from keeping his machine on broken layer of cloud. the target the pilot of a dive-bomber must allow for wind which will tend to cause the bomb to 1,000 lb. would give good results against destroyers, light fall short on up-wind approaches, wide on cross-wind cruisers and fairly heavily armoured cruisers (e.g. the attacks and over the target on down-wind dives. pocket battleships), its effectiveness against very large capi- On its final aiming dive a dive-bomber is an excellent tal ships is often questioned, for the thicker the bomb target for anti-aircraft gunners on the ground and may casing (necessary to ensure penetration) the smaller the be subjected to all kinds of " hate " in the form of shrap- explosive charge. nel, multiple pom-pom shells and large and small-bore As an interesting sidelight we may recall that it is neces- machine gun bullets. The French expert, Rougeron, sary to dig down through four feet of solid earth to retrieve recommends the use of shrapnel against dive-bombers, a small practice bomb after a diving release. each 10 cm. shell containing about 240 bullets. These are The tactics of dive-bombing vary considerably according expelled inside a relatively small cone and at a distance of to the nature of the target and efficiency of its defences, about 100 yd. from the burst one bullet may be expected the state of the weather and the type of aircraft employed. per square yard, whilst at 650 yd. the proportion is one Diagrammatic representations of attacks under various bullet to about 3 sq. yd. Even should the bullets be conditions of weather are given on this page. It is advis- met at an appreciable distance from the point of burst able where possible to attack out of the sun to handicap the impact velocity, due to the high speed of the diving aircraft, will accentuate the damage. Precise details of the tactics used by Royal Air Force and Fleet Air Arm units are, for obvious reasons, not available for publication. A Continental author- ity, however, has set out the following stages of a modern dive-bombing attack. Phase 1 is a spiral from 10,000 m. down to 1,500 m., the time being about 90 sec. if a speed of 120 m./sec is assumed. In Phase 2 the horizontal speed is reduced to 40 m./sec. while getting into position for the attack. The course during this phase is usually at 30 to 40 deg. to the direction of the final dive and the time is 10 seconds. Phase 3 is the actual dive at about 70 deg. on to the target and lasts 7 seconds. At the beginning The highly efficient flaps on the Blackburn Skua fleet fighter dive-bomber which not only improve take-off and landing quali- ties, but restrict the diving speed. JANUARY 25, 1940. of the dive the target is 1,500 m. away and at the end only 600 m. The release of the bomb and the pull-out (Phase 4) is said to occupy 2 sec. and the spiral get-away and gradual climb (Phase 5) 90 seconds. It is considered that during Phases 1 and 5 the dive- bomber has complete manoeuvrability and is therefore difficult to hit with anti-aircraft guns. The sudden reduction in speed in the second phase is also disconcerting to the artillery. It is in Phase 3, when the flight path of the dive-bomber must necessarily almost coincide with the tra- jectory of the bullets and shells, that the chances of its being hit are greatest. Phase 4 is said to be too short for consideration by the anti-aircraft artillery. Testing in America Dive-bombing and the pilots who do it have been heavily over-drarnatised by pen and camera, mainly because the 9-G '' pull-outs required until fairly recently of prototypes for the U.S. Navy sometimes subjected test pilots to rather unpleasant strains. Referring to this test a writer in an American contemporary once said: '' We are told that in one of these sharp pull-outs from a terminal velocity dive to meet the current rigid Navy requirements the pilot is absolutely without control as to the amount of force of pull-out he puts on a ship, as the only physical or mental reaction possible under these circumstances is to decide The Fokker G. 1 multiple-purpose machine can be fitted with when he is going to pull out, pray, pull like hell, pass out, diving brakes shown above in their "normal flight" and and hope that when he does come to he and the airplane "diving" positions. will still be intact." To minimise the effects of sharp pull-outs American test It is said that German dive-bombing pilots used to adopt pilots sometimes gird themselves with a corset-like belt a crouching position to minimise the effect of " G " during and tie a scarf tightly round their throats. There is a the pull-out, a special sighting window being fitted in the natural desire to yell during the dive and this is also bottom of the fuselage. Certainly this position enables a considered beneficial. man to withstand a greater acceleration, but it is not so An American Service pilot, discussing dive-bombing, efficient as the prone position. writes: '' The average pilot is uncomfortable only in pro- longed dives from extremely high altitudes ; under io,oooft. Design Difficulties the sensation is exhilarating, even in a terminal velocity Design requirements as affecting dive-bombers are often dive. No other sport offers such a feeling of projection, very difficult, for, apart from considerations of structure, for the very attitude of your 'plane, which becomes only an aerodynamics and view, it is often necessary to limit extension of yourself, is the factor which determines your dimensions and landing speeds to such figures as can be accuracy." He goes on to say: "A lot of bilge has been tolerated for carrier operation and to provide for folding written about the tremendous bodily stresses that pilots wings and alternative loadings.

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