Bomber Navigation—The Blind Led the Blind

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qua r^e 1941

Navigation is an art and a science in­herited, by those who fly, from those who sail the seas. It is fascinating, and some­times even glamorous, but it is intricate and demanding. At sea, the bones of wrecked ships testify to the consequences of lack of skill in it, and in the air it levies penalties for incapacity which are not less severe. Indeed, during the Hitler years, poor navigation came perilously close to losing a war.

When World War II broke out in 1939, there were two diametrically opposed theor­ies of using airpower. One of them, the prime exponent of which was the Royal Air Force, saw aircraft as totally independent weapons, able to fight their own private war. The other school, which included Germany,

A lone Lancaster—one of 719 bombers that par­ticipated—is the only aircraft visible in the photo­graph on the preceding page of Bomber Com­mand’s historic attack on Wuppertal on 29-30 May 1943.

France, and Russia, considered aircraft to be nothing more than another weapon, best vised to support the traditional arms. The Luftwaffe, in particular, used its planes for the first two years of war as flying artillery) with its fighters devoted to making the skies safe for the Stukas and Heinkels that if> turn supported the army directly, largely i'¹ helping prepare for tank and infantry as­saults. An inordinate amount of Luftwaffe re­sources was devoted until the very end if attacking tanks, ground fortifications, and enemy troops in the field. It is significant that one of Hitler’s most-decorated airmen, Hans Rudel, gained his fame by attacking tanks.

Neither the Germans nor the Russians put much stock in strategic bombing. Although they killed 60,000 Britons during the 1940' 41 Blitz, the Germans never put a four- engined aircraft into service against British cities, and after 1942, their strategic bombing efforts were desultory. The Russians devoted practically all their aerial efforts to tactical targets, scarcely touching German cities with their bombs until they came into the actual combat zone.

On the other hand, the Royal Air Force (including the Dominion air forces) believed in strategic bombing with religious fervor. After Dunkirk, when the only offensive action that Britain could take was by bombing, ques­tioning its efficacy was almost heresy. The U. S. Army Air Forces joined them in be­lieving that no sacrifice demanded by the effort to put bombers over the Reich was too great, no price too high to pay. Yet, when the U. S. Strategic Bombing Commission studied the effect of the Allied air offensive against Germany, it found that on balance it had been unsuccessful. For at least the first four years of the war, the strategic assault had been run at a loss—each bombing attack cost the Allies more in fuel and aircraft, effort and lives than the damage it inflicted on Germany-

Part of the reason for the initial belief U¹ the efficacy of strategic bombing lay in a gross overestimate of the damage bombs can do- At the beginning of the war, it was believed that the lethal pressure against human targets was about five pounds per s inch; experiments carried out in late by Professor Sir Solly Zuckerman and his Oxford team proved the lethal pressure to be

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, the private secretary to Churchill’s p 'ef Scientist, F. A. Lindemann (later Lord _a ^erwell). Cherwell told his secretary to tnaly_Ze tp_e photographs statistically. It took ^ni,h until August 1941.

, .i^s report astounded Bomber Command’s 'els, who although they had earlier seen the otographs, had been unable to bring them-

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^es to believe the evidence of their cameras, aircraft recorded to have attacked their

400 to 500 pounds per square inch.

Such overestimates led the Royal Air e°rce to dispatch a force of aircraft to drop ^°nte 30 tons of bombs on the Saarland at the ^le>ght of the Battle of France, in the belief that this would blunt the German offensive. Four years later, more realistic planners were to drop 400 tons of bombs on a single factory.

. British belief in strategic bombing was re- ‘nforced by the German blitz against British ^fJties, the best example being the attack on ^oventry, the center of the British automo- ^tlVe industry. Out of 450 German aircraft dispatched, 449 dropped 503 long tons (of >240 pounds each) of explosives and 881 'acendiary canisters during the night of 14-15 ovember 1940, killing 380 people, burning °Wn the cathedral, and costing the British '^var effort the equivalent of 32 days of the ^c'ty’s production. The next month, a special ^urnmittee, analyzing the results Bomber ornrnand had achieved by then, discerned j^'ne success against German oil production, his led to a War Cabinet directive, issued on January 1941, to destroy the 17 major oil Plants in Germany.

Bomber Command went to work, and soon jhaps were being carefully inked in showing ,°w German refineries were being flattened. ^ccording to reports from the aircrews doing ^e Job, supported by a few target photo- ■Phphs, the targets were being blasted accord- to plan.

Shortly before, on 16 November 1940, a j. ^fl°tographic Reconnaissance Flight was ^rmed. Just after Christmas, certain officers the flight unofficially showed their slim

^tection of photographs to David Bensusan- Butt,

gets (by no means all of those dispatched), fiv ^ °^ne'third had in fact bombed within ^e miles; while against well-defended tar- I ^e*^s> such as the Ruhr industrial cities, ^CSs than a tenth of the crews put their bombs

within five miles, the average bomb missing by some 13 miles. It was now all too clear that German claims, trumpeted to neutral news­men, that British bombing was doing negli­gible damage, were all too true. Despite crew reports such as that made regarding the 10-11 November 1940 attack on Ruhland, near Dresden, of “great fires giving off dense clouds of black smoke,” German claims, that no bombs had fallen on the target or near it, were considerably closer to the truth.

There were, of course, a number of per­fectly good reasons for this state of affairs. At the beginning of the war, the Royal Air Force had intended to fly over Germany in formation, as the U.S.A.A.F. was later to do. The bombers, equipped with power-driven turrets, were expected to be able to defend themselves against fighters, partly because of a mistaken belief that a bomber crossing the sights of a fighter would be moving at so high a relative speed that the fighter would not be able to bring its guns to bear. British fighters then (and later) were too short-legged to be able to provide escorts for any distance.

Within the first month of war, the Royal Air Force found that aircraft venturing over German territory in daylight without fighter escort suffered prohibitive losses. The situa­tion was made worse by the fact that many of the British bombers were slow and had low ceilings. The Wellington cruised at 130 knots, the Hampden at 140, and the Whitley, which stayed in combat service for at least two years, had a cruising speed of less than 100 miles an hour. The Manchester had trouble climbing over 10,000 feet, and the Stirling stuck at 15,000. Long before the first winter of the war was over, the Royal Air Force was forced to admit that its bombers were simply incapable of operating in hostile air in day­light. As a result, operations over Germany during the “phoney war” period, when only leaflets were dropped, were all done at night. After France fell, of course, any possibility of fighter escort completely disappeared. Bom­ber Command had no choice but to follow a policy of night bombing if it wished to do any bombing at all.

The Royal Air Force, unfortunately, like every other air force of the day, had not been trained to operate at night. Night flying was more a tour de force than a serious job. Tak-

ing off and landing was bad enough. Navi­gating turned out to be all but impossible.

The prewar R.A.F. had some highly skilled navigators, but they were not taken very seriously except in Coastal Command. Ob­servers were often air gunners who had been tions by means of his own direction finder (DF) loop. The sample navigation log, pub­lished in 1941 as part of Air Publication 1234, the R.A.F. Manual of Air Navigation, made use of both these techniques.

Unfortunately, the ground-direction-find­Wide World

taught the rudiments of navigation, and whose primary job was to observe the fall of artillery shells. The Royal Canadian Air Force, which was to send more than 40 squadrons overseas, entered the war without a single full-time observer.

The tools of air navigation had scarcely changed since 1918. The prime navigation aid was map-reading—“pilotage” in Ameri­can terms. The most sophisticated instrument was the drift sight. The standard method of navigation was to carry a dead-reckoning plot of airspeeds and headings flown, apply the meteorological winds forecast for the route, and rely mostly on pinpoints (ground positions obtained by map-reading) plus oc­casional drift readings obtained either by the drift-sight or by the rear gunner for en route information. Some use was made of radio. Between the wars the chief method of navi­gating commercial aircraft was to use ground- based direction-finding, where the airborne radio operator transmitted a long dash, and Adcock stations on the ground took bearings on the aircraft and retransmitted the bearings to the aircraft. The airborne radio operator could also take bearings on the ground sta-

ing technique was extremely dangerous, since it advertised the aircraft’s position to the ' German defenders. DF bearings were highly inaccurate, suffering from crude equipment, compass errors, and coastal refraction. Both techniques proved worthless for navigation outbound, although until the end of the war both were used for homing on the return trip’ Dead-reckoning using the meteorologies winds was inaccurate, since the average error in the estimation of the wind was some - knots, which would cause a 100-mile error n¹ five hours. Correcting it by observing the drift was difficult at night, the only effective method being to throw out flame-floats an take bearings on the light with the rear turret' This was of some help over the sea, althoug¹ it attracted fighters. After the first few years, the bombers began flying in cloud cover to avoid the rapidly improving skills of th^e German night fighters, and soon, even this minor piece of navigational information was denied.                                                    . ,

Some attempt was made to stress celestia navigation—“astro” as it was called in the R.A.F. Here again, the path was full ⁰ stumbling blocks. The R.A.F. had become

inder seriously interested in celestial navigation °ⁿly in 1938, and many of the flights over Germany during the first years were made by aircraft that carried neither sextants nor men ^Capable of using them.

Effective celestial navigation, moreover,

^Cannot be learned overnight; it requires fears of practice. Even experienced sea cap- ^lains occasionally add when they should sub- ^lract, or take a value from the wrong page of Air Almanac. Working under cramped e°nditions, on a tiny chart-table in a poor ^I,ght, the hurried navigator could not be ex­pected to obtain optimum results in his calcu- ^abons. Even if he had, the sights he took had an average error of some seven miles, accord­ing to Bomber Command figures collected

er m the war. The process took a long time, minutes for a fix, since pre-computation not yet been thought of.

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Successful sextant sights require a steady platform, which meant that gunners had to ^S|°P swinging their turrets during observa­tions. They were extremely reluctant to do so, ®*nce a constant search was imperative in the ghter-infested German skies. This pressured ⁿe navigators into taking the bare minimum sights, and to hurry the ones they did take, "ath a resultant reduction in accuracy.

The navigators also had a few cards stacked against them that they did not even know ^D°ut. Phenomena such as jet streams were ^st'll unknown, and when they found 100-knot

winds, the navigators would not believe them, and would use instead a more “common sense” wind, which would get them lost. Compasses, airspeed indicators, and altime­ters were often inaccurate. Maps were often out-of-date. And finally, the Germans cam­ouflaged well their most attractive targets.

Then, as now, navigation required calm, precise work, with every calculation double­checked, together with a considerable amount of judgment, which still takes years to ac­quire. Usually, this demanding task was the duty of a man in his early twenties, with ten years of education, who had first flown per­haps 18 months before, and who, within the course of any hour of a mission, had been badly frightened. He was seldom experienced, since the average crew lasted only 14 trips. Records, gathered in the last ten years, of the results of professional transatlantic naviga­tors, working in comfort in commercial trans­ports, show that not even these veterans are immune from blunders. The wartime naviga­tors were naturally far more vulnerable to mistakes.

Navigation in the target area, leading to the bombing run, had to be done by map reading. This also is a difficult art, which is not learned at once, and where mistakes are easy to make, especially when one’s position is uncertain, owing to the human tendency to make the features on the ground fit one’s preconceived idea of where one ought to be.

of

bombs at random over Germany, most

At night, except in bright moonlight, ac­curate visual checks were almost impossible, and the R.A.F. soon stopped operating in bright moonlight, because of heavy losses in­flicted by German night fighters. Before long, the R.A.F.’s top navigators were teaching

Imperial War Museum

their students that the only reliable map­reading feature was water. In bad weather, not even that was visible.

The actual bombing was expected to be done by sighting on the target through a visual bombsight. This in turn required that the target be identified, a task difficult enough in broad daylight over unfamiliar terrain. To identify a small target at night over blacked- out country proved all too often to be com­pletely impossible; what the crews often did was to drop on a fire. If the general target area was obscured, the crews would usually drop their bombs “blind” at their Estimated Time of Arrival. Needless to say, they seldom hit their targets. Some of the bombs, indeed, landed in the wrong country.

Being human, however, the navigators were reluctant to admit that they did not know where their bombs had gone. The pilots were equally reluctant to admit that they had not recognized the target area either. Target photographs taken by the light of a single flare are usually featureless and hard to interpret. The reports went up to Headquarters that the targets had been bombed as ordered.

Although it was not realized at the time,

nor for a long time afterwards, the success of the Luftwaffe fighters in making dayligW raids prohibitively expensive for the British was a major German victory. It is even poS' sible that the fact that British bombers could do nothing more than mount nuisance raids'' l

Wide Wortt

which cost the British more than the Get' mans—may have encouraged Hitler to attack Russia. He obviously had little to fear on th^e Western front.

For some six months, Lindeinann studied his secretary’s report, which told him that, n¹ effect, Bomber Command was scattering

them exploding in farmers’ fields. Two of h>^s colleagues, Professor P.M.S. Blackett, th^e Chief of Operational Research at the tim^e> and Professor Zuckermann, told him that th^e bombing offensive was useless. Blackett esti' mated that a ton of bombs would cause 0-2 deaths, and a proportionate loss in produC' tion. To deliver 40 tons would cost about St* British aircrew dead or captured, and an ait' craft; eight dead German civilians wef^e scarcely a reasonable trade-off. Lindemanni undeterred, analyzed the German attacks on such cities as Hull and Coventry, and wrote ³ report in which he stated that an area-bomb' ing attack could break the spirit of the Get' man population, provided that it was aime at the working-class areas of 58 Germ³*¹ towns, each having a population of over 100,000. He estimated that each 40 tons ⁰

^J°rnbs (a bomber’s loads during its lifetime) ^°uld destroy 800 to 1,600 houses and “turn jOOO-8,000 people out of house and home.” his would make a third of the whole German Population homeless in the next 15 months.

This report became the center of a con­troversy which has been reported by C.P.

now in his book Science and Government, derived

°m his Godkin lectures given at Harvard in

fri

^60. Snow blasts Lindemann’s proposal, '^vhich necessarily called for an area-bombing ^ahack on the houses of the civilian popula- ''on, as a cold-blooded example of pure ^rightfulness, coupled with mathematical irre­^sPonsibility and self-delusion. The barbarism ^Was clear from a minute written by the Chief the Air Staff, who wrote, in February 1942,

. wcf. the new bombing directive; I suppose it clear that the aiming points are to be the ^u'lt-up areas, not for instance the dockyards °^r aircraft factories.” The mathematical ^lrrcsponsibility became apparent when the ^Port was given to Professor Blackett and Sir ^enry Tizard for comment. Tizard estimated at Lindemann’s estimate was five times too T§h. Blackett gave it as six times too high. _Bⁿ°w says that the report of the Strategic cuibing Survey, made after the war, con- ^uded that the estimate had been ten times ^tQo high.

hlackett based his conclusion partly on the ^act that German bombs had killed 0.8 per- ^s°ns per ton dropped. Knowing that the Ger- ^a,an bombs had been proved by experiment ^ be about twice as lethal as British bombs, a ^r'tish bomb would therefore kill about 0.4 P^ersons. The rest of his argument centered ^ar°und navigation.

The Germans used an automatic dead- ^r,'^ck°ning computer (Kurskoppler, course com­Puter) and two different ground-based fixing ^a,1(i guidance aids called X-Gerat (X-Gear) ^"⁽T^erat (Y-Gear). Y-Gerat was virtually ^e same as the British Oboe, and very like Uay’^s Distance Measuring Equipment ^E), i_n that a transceiver on board the air- it echoed a ground-originated pulse, which lh ^0rn'^ec^ ground station the distance of ^e craft from the station. Readings from two j ^atl°ns gave an excellent fix, which was re­fed to the aircraft, or was used to allow the ' ^r°^uud station actually to control the air- ^rah. The nearest British equivalent, “Gee,”

was installed in very few planes, and Blackett knew that over enemy territory it could easily be jammed and made useless. He therefore came to the conclusion that German naviga­tion was at least twice as good as British; this differential would cut German losses to 0.2 deaths per ton of bombs dropped. His conclusion was that bombing Germany would be a waste of time, money, and blood, and Great Britain’s aircraft re­sources would be much better em­ployed on antisub­marine patrols.

Keeping in mind that Lindemann had set a time­limit of 15 months on his endeavor,

Blacket and Tizard were absolutely right —the bombing effort over that whole period was futile. The Battle of the Atlantic was very nearly lost in the dark winter of 1942-43 and the frightful spring that followed it. British naval his­torians considered that the war was almost lost for the lack of two squadrons of very long range aircraft; 24 Lancasters would have filled the bill. Twenty-four aircraft was a common night’s loss, during a raid in which the bombs usually plowed farmers’ fields. There is no doubt that the decision was wildly wrong and nearly catastrophic.

The matter does not end there, however, and it warrants more examination. First of all, it must be emphasized that both the plan and the objections to it—although Lindemann hardly mentioned it—revolved about one main point, navigation. No matter how poor British bombs were with their 25 per cent ratio of explosives to total weight, they were far from useless. Furthermore, 40 per cent explosive and 80 per cent explosive bombs were rapidly being developed, and were quickly being put into production. The 4,000-pound “blockbuster” light-case bomb was available after July 1942.

British bombs, put into the right place, could do a great deal of damage. The trouble was that they were simply not being dropped where they would hurt. Lindemann, when he put forward his proposal, actually bit the sour apple—he admitted that the Bomber Command policy of precision bombing was useless because navigation was so poor, and he sought a policy that would choose targets Bomber Command had some chance of hitting. This was, indeed, the first realism that had permeated bombing planning since 1939. Furthermore, it must be stressed that in early 1942, when Russia was in extremis and calling for help, Britain had no way to hit back at Germany proper except to employ the bombing offensive. It was very nearly bomb­ing or nothing. With Churchill at the helm, it could never have been nothing.

Lindemann’s chief mistake was that he did not downgrade bomber navigation enough. He estimated that half the bombs would fall in built-up areas, whereas Blackett would not go higher than a quarter. Actually, only about an eighth did, at least during the rest of 1942. But to someone who had been hearing about feats of precision bombing, proudly described by senior officers and repeated in the press, Lindemann’s estimate was an extreme case of independent thinking.

Thus, the new policy was formulated to overcome defects in navigation; the objec­tions to strategic bombing revolved around navigation, and the fact that it did not work, again must be chalked up to navigation. Lindemann based his plan on hitting cities; Bomber Command, for at least another year, could not even consistently hit the cities.

Meanwhile, of course, scientists and engi­neers were working feverishly to provide the tools for accurate navigation, and R.A.F. planners were working out methods of making the best use of them, and of improving their tactics to overcome the fatal effects of naviga­tion inaccuracy.

The first, and easiest, action was to change the composition of the crews. Bomber Com­mand had started the war with its planes manned by two pilots, an observer (a naviga­tor-bomb aimer), a wireless operator, and one or two gunners. Before long, the number of pilots was cut to one. The duties of the ob­server included navigating the plane to the target and back, dropping the bombs, and sometimes firing a gun. Making the transition from doing the navigating to dropping the bombs was, however, too difficult, particii' larly since it required night-adaptation of the observer’s eyes. The solution was to employ ^a specialist bomb-aimer (who could not be called a “bombardier,” since this term de­noted an artillery rank corresponding to \ corporal.) These “air bombers,” as they were ^ officially called, acted as co-pilots during take­offs and landings, but their chief task was that of assistant navigator, a function later ac­complished mostly by operating the radar- They also took sextant sights and obtained ¹ drift checks by using the bombsight.

Tactics were also changed drastically. For the first three years of the war, crews were allowed to reach and attack their targets any­way they wished, and usually were allowed to choose their own routes. This was abandoned for “bomber stream” tactics, in which the aircraft were carefully briefed to stay close to a specified track and to make good specified timing points. A good part of the objective, in thus concentrating the fleet en route and at the target, was to saturate the defenses, as well ^aS _f to allow an elaborate campaign of spoof raids and doglegged approaches designed to mis­lead the enemy as to the selected target. Con­centrating the raid was also designed to over­load the enemy fire-fighting and civil defense organizations.

Another highly important change was to | form the Pathfinder Force, under the com­mand of Air Vice Marshal D.C.T. Bennett, an irascible Australian who was the “compleat airman”—he was a qualified pilot, air gunner, ; bomb aimer, flight engineer, and wireless operator, and he had written a book on navigation. The Force was composed of elit^e crews, initially selected personally by Bennett from the most successful and experienced men in Bomber Command, who were given special training and provided with the most advanced navigational aids. The function of the Force was to mark the targets for the main force crews to bomb.

Nevertheless, in 1942, Pathfinder Force started its career by marking Harburg instead of Hamburg (some ten miles away), missing Flensburg completely, and failing to find Saarbriicken. On 10 December 1942, Bennett

sent out one of his crack crews, captained by Squadron Leader S. P. Daniels, to mark Frankfurt, a city of half a million people Seated on a distinctive river, after which Daniels was to inaugurate a new technique by acting as “Master Bomber.” The weather was Fad, however, and after the raid the Police President of Frankfurt reported that “al­though the sirens sounded that night, not a single bomb fell within the city boundaries.” Darmstadt, 17 miles to the south, received its heaviest raid of the year; four people were Filled. Far from being able to locate factories, bomber Command proved, after three years °f war, that in this raid its most highly skilled ^Crews could not be relied upon even to find a specific city, and that if they did, their raids could be virtually harmless.

Aside from finding the right target, one of 'he main objectives of the Pathfinder techni­que was to concentrate the bombing. The original tactics called for the targets to be Marked with incendiaries, dropped in two Passes to form a cross, after which the main ‘°rce would bomb the fires. The incendiaries '''ere always scattered, however, and the Germans countered them by setting dummy Fres. The British answer was to drop brilli­antly colored flares that Bennett christened Paramatta” (ground markers) and “Wan­ganui” (sky markers, to be bombed as they boated down by parachute over cloud-ob­jured targets) after two towns in his Austral- ^lan homeland. The Germans called them Christmas trees.”

The Germans tried to imitate the flares ^also, but by ringing in changes on color codes, the British were usually able to out­guess them. In the Normandy campaign, however, the Germans used colored smoke from artillery shells to simulate Pathfinder flares and brought bombs down on Allied troops.

The Pathfinder crews were highly trained and determined, but the Frankfurt affair and similar embarrassments proved that the best navigators in the world cannot reach precise ^targets without sophisticated navigational ^a>ds. British scientists and engineers set about developing them. They began to be installed *n aircraft and the co-operating ground sta­tions in 1942, although they were by no coeans common until well into 1943, even in aircraft performing the function of Pathfinder.

The first of these, the Air Position Indi­cator, was designed to help the navigator with his plotting. Previously, most of the naviga­tor’s time was taken up by drawing lines on his chart to represent the aircraft’s path through the air. To do this, the pilot had to be relied upon to main­tain predictable air­speeds and head­ings, tell the navi­gator whenever he was about to alter heading, and fly straight and level most of the time.

If he began to ma­neuver without tell­ing the navigator what he was doing (as he would have to do if he were at­tacked by a fighter, or forced to dodge flakbursts), the navi­gator would be unable to keep track of the aircraft, simply because he could not work fast enough to do a “real time” job. In addition, the navigator was unable to plot curved lines, and had to approximate the aircraft’s path by means of straight segments. Furthermore, working under the greatest tension, the navigator was extremely vulner­able to mistakes.

Automating what had been the navigator’s most onerous job regained for the pilot his ability to maneuver freely without immedi­ately throwing the dead reckoning position into grave doubt; in other words, it gave him “tactical freedom.” The navigator could now devote most of his attention to fixing his position and finding the wind, which was always his greatest worry and absorbed most of his ingenuity. Squadrons equipped with APIs immediately exhibited greatly improved navigation.

The next task was to give the navigator something with which to fix his position. The two most successful devices for general use in the bomber fleet generally were Gee and H2S. Gee was a ground-based aid, working on the same principle as Loran, which provides

hyperbolic lines of position by comparing the time of receipt of two pulses received from two ground stations. These position-lines, plotted on an airborne map, allowed the navigator to fix his position to something under a mile. Gee (still in use in Europe) allowed Bomber Command to make some spectacular attacks, but the Germans quickly devised means to jam the Gee beacons, which were located in Britain, with the result that, by 1943, the navigator found the trace-presentation of his “Gee box” a solid fence of unintelligible “railings” by the time he reached the French coast. With Gee alone, the navigator could get a good start for his trip, but over France and Germany, he was back where he had been in 1941. Indeed, the chief enroute means

Wide World

A Canadian flight sergeant inserts a flare into the flare-chute of his Wellington bomber so that the "air-bomber” in the nose can set his sights and drop his bombs "somewhere over Germany” in March 1942.

of navigation taught Bomber Command crews in 1943 was to take bearings on flak- bursts directed at other aircraft, estimate the city from which they came, by means of the dead-reckoning plot, and calculate a “Most Probable Position,” which was hopefully ex­pected to be within ten or 15 miles of the air- , craft’s actual position.

To queries from student navigators, as to how sure they could be that these flak bursts would be around for observation, the answer was, “There’ll be some poor devil off track over the big towns along your route—you can depend on that.”

The other aid was H2S—airborne search radar, giving the map-like Plan Position In­dicator view of the area over which the air­craft was flying, with built-up areas and coast­lines (and sometimes lakes) showing up on it- Since this was in the infancy of radar, service­ability was only fair, definition was poor, range was limited to about 20 miles (or 40 if a good target such as Heligoland was available) interference from other aircraft was a nui­sance, and the techniques required for ac­curate radar-return interpretation (later brought to perfection by the U.S. Air Force) had not yet been developed. Nevertheless, fixes from an unjammable device were noW available, and though it was by no means im­possible to mis-identify towns or coastlines, , accuracy to about a mile or two was achieved—town-accuracy, not factory-ac­curacy.

Supplying these aids was a magnificent technical feat, especially since they were con­ceived, developed, debugged, and put into production within a period of about two years. To perform a comparable task today takes seven years.

The Pathfinders received the equipment first. Using it, they marked the targets, and under the eyes of a “Master Bomber,” a highly experienced veteran who acted as master of ceremonies for the raid, they re­placed the flares as they burnt out, corrected badly placed flares, cancelled German dummy targets by specially colored flares, and changed the aiming-point if the Master Bomber so decided.

It was still by no means precision bombing, however, since the average marker fell 0.7 of a mile from the aiming-point, and the actual

had

always previously gone through the mo-

bombs fell farther away than that, largely because of the tendency of raids to creep back ^as the attack progressed. The bomber crews '''ere under a strong temptation to drop on the first fires they saw, since the rest of the crew shorted the bomb-aimer to “Pull that bloody P^fg and let’s get out of here!” Against Berlin, ^lbe creep-back stretched for 30 miles. In ?b°rt, it was a precise kind of area bombing, bomber Command by 1943 could count on mtting the right town; its navigators were ^coming better trained and its aircraft bet­^ter equipped. Still, the technique was im­perfect and remained so as late as February 1945 when Chemnitz was attacked.

There were two schools of thought among fbe Pathfinders themselves. Bennett favored ⁿⁱgh-altitude flare-dropping using radar, '^vhile Air-Vice-Marshal The Honorable ^^alph Cochrane, the head of No. 5 Group of °mber Command, which had its own Path- mders, favored finding the target with radar ’>nd dropping flares on it from Lancasters, ^and then having a high-speed Mosquito duck ^0vvn to a few hundred feet to drop the actual ‘barkers.

Tile new techniques took time, however, ^a‘id Lindemann’s 15 months passed without Pc achievement of even one-tenth of what he Predicted. German production showed no induction; German morale was steadfast.

ben, on 29-30 May 1943, the new equip­ment, tactics, training and skill all came to­gether in an attack on Wuppertal, a city in Ruhr.

I For the first time the crews were actually ^Jrtefed to attack built-up areas instead of the ‘bdustrial targets which Bomber Command ^tlons of designating as targets. Seven hundred ^ar‘d nineteen bombers were despatched to ^<r°ss the city on a heading of 068 degrees, '''here any bombs prematurely dropped would pl hit the city. The first markers were red _i(^ares dropped by means of the radar aid I Oboe” controlled from the ground in Eng- ^n<l, and the first bombers dropped incen- jbaries that started brilliant fires. It was the . ^Csl raid Bomber Command had ever ^abtiched, but even at that, only 475 of the bbews dropped their loads within three miles the aiming-point; 40 per cent of the air- t-baft still scattered their bombs more or less at random. Despite this, the attack set back Wuppertal-Barinen’s production for 52 days and killed 2,450 people for 1,900 tons of bombs dropped, including incendiaries. This was some six times what Blackett had pre­dicted. One hundred and eighteen thousand were made homeless; Lindemann’s estimate would have set a lower limit of 190,000, using his yardstick of “100-200” homeless per ton of bombs dropped.

A little less than two months later, Bomber Command launched a four-raid attack on Hamburg. In addition to their new skill at navigating, the bomber crews were using “Window” (Chaff) to jam the German gun­laying radars. Since Hamburg is located on a conspicuous estuary, with Heligoland acting as a prominent radar signpost to tell the Pathfinder aircraft where to turn, the bomb­ing concentration was excellent.

The bombers achieved a macabre bonus. During the second raid, in which 969 tons of incendiaries were dropped, the fire services were overwhelmed, and 40 minutes after the first bomb fell, the first fire storm which Ger­many suffered was in progress.

When the four raids were over (the fourth was launched in poor weather, and had little effect), more than 43,000 people were dead (30 times Blackett’s estimate) and 753,000 were homeless (Lindemann’s bottom limit was about 800,000). Of 524 major factories, 163 were destroyed, and 4,118 of 9,068 smaller ones. In the harbor, 180,000 tons of shipping were destroyed.

Two months later, it was Kassel’s turn. On 22-23 October, the center of German tank and locomotive production received 1,824 tons of bombs from 444 bombers, of which 380 (85 per cent) put their load within three miles of the aiming point. A fire storm developed and destroyed 27,000 homes, killed 5,800 people (Blackett’s estimate was 360), and made 150,000 people homeless (Lindemann’s lower limit was 180,000). The entire gas, electricity, and water system was put out of action, and the entire city’s production paralyzed. Some 70 per cent of the casualties were asphyxiated or burned to death. Nobody in Britain had anticipated this; it accounted in large measure for the inaccuracy of Black­ett’s predictions in the murderous raids which began in 1943 and lasted until the war’s end.

In 1944, the area attack on Germany slackened, partly because bomber activity was concentrated for most of the year to bombing railway targets (largely in France) in prepara­tion for D-Day, and after D-Day in supporting the ground troops, but it did not cease. Ger-

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man defenses were making it expensive, however; on the night of 30-31 March 1944, 95 of the 795 bombers that attacked Nurem­berg did not return.

A new Pathfinding technique was used against Munich on 24-25 April 1944, when 260 Lancasters belonging to Sir Ralph Coch­rane’s No. 5 Group dropped 1,100 tons of bombs, 90 per cent of which were in the target area. Despite Air Vice Marshal Bennett’s insistence that low-level map-reading was impossible, No. 5 Group’s aircraft, crewed by such super-experts as Group Captain Leonard Cheshire, VC, DSO, DFC, repeated the exercise on 12 September against Stuttgart, wiping out the center of the city. A technique of briefing three streams of bombers to use the same markers, delaying the dropping of their bombs for a specified number of seconds, thus obtaining the effect of three aiming-points for the price of one, was tried out against Konigs- berg on 30 August. On 11 September, Darm­stadt was smashed, with 12,300 dead (against Blackett’s estimate of 175).

The whole process culminated during 13 to 15 February 1945, when an R.A.F. double­blow at Dresden (two raids three hours apart)

followed by a U.S.A.A.F. raid, killed 135,000 people, made 400,000 homeless, and dev­astated 16 square miles (as compared with the six square miles of London smashed dur­ing the whole war). The raid was a bombing and navigational tour de force; spoof raids at

Wide World

four other cities drew off German fighters, Lancasters dropped flares on radar to lig^¹ the target, Mosquitoes dashed across the city at low level to drop the red target markers by the light of the Lancasters’ flares, and th^e Master Bomber kept the target markers re­placed and controlled the raid. The effect was murderous. More people died than were kill⁰ at Hiroshima.

When Bomber Command tried to folio" the Dresden raid with an attack on Chemnitz, however, the target was covered by cloud which kept the Pathfinder markers from re' maining visible long enough to allow ac curate bombing, the crude radar of the da> failed to distinguish the target with any cer­tainty, and the raid was a comparative failure’ The deficiencies of airborne radar were also demonstrated by the fact that 40 B-17s, briefe to attack Dresden that day, missed the city completely although they were equipped wut APS-15 radar, and bombed Prague instead-

This incident illustrates the fact that the Americans suffered from the same difficult"'⁸ as did Bomber Command. When the B-C^s and B-24s first went to England, their coin manders were committed to a policy of day

1'ght bombing, using the famous Norden "‘pickle-barrel” sight. The U.S.A.A.F. bomb­^ers received two rude shocks in a row, how­ler. First, their navigation, learned in the ^clear air of Texas, proved even weaker than that of Bomber Command when the For- aircraft to maintain their tracks and their timing, and if enemy opposition was light enough not to force the bombers to jettison their loads prematurely. The task was still so difficult, however, that Bomber Command and the Eighth Air Force were never able to

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hght

^•S.A.A.F. B-17

hesses began to fly over smoky, cloud-covered Germany. Next, they found that German %hters were able to inflict crippling losses on Unescorted bombers, despite the fact that the ®'17s carried, in the words of a rude R.A.F. ^s°ng, “Ten tons of ammo and one teeny ^b°mb.” It was the development of the Mus­^tang and Thunderbolt long-range fighters 'hat made the daylight offensive workable.

„ Adherence to the classical tenet of air war- obtaining air superiority, allowed day­bombing to be carried out without pro­hibitive losses. Nevertheless, the U.S.A.A.F. generals greatly overestimated their crews’ navigational ability, and underestimated the navigational task. Furthermore, although 'heir targets were ostensibly precision objec- '^lves, at Hamburg, Dresden, and many other j-hies, the U.S.A.A.F. joined in the area- ^0rnbing attack.

the end of the war, the aircraft of Bomb­^er Command and the U.S.A.A.F. had some Solidly barbaric achievements to their credit.

. hey had proved they could wipe out cities, If the weather was clear enough over the tar- ^^et to allow accurate marking, if the weather '^vas good enough en route to allow attacking put attacks on two cities back-to-back, one following the other closely enough to create a crippling, cumulative drain on German war production and morale.

Despite their successes, the task was so difficult that the Strategic Bombing Com­mission concluded after the war that the stra­tegic bombing offensive had been a failure. On balance, the attacks had cost the Allies more in men and planes and money than it cost the Germans in war potential. In fact, German war production reached an all-time peak in September 1944. The really effective part of the bombing was not the attack on cities, but on German transportation and oil supplies.

There is no doubt that it would have been far better during 1942 and 1943 to have de­voted the lion’s share of airborne effort to patrolling the seas against submarines, to pro­viding extensive support for the Army in Africa and Italy, and mounting more of the special attacks such as the one that breached the Mohn and Eder dams. The attack on German morale never succeeded, since the German will to fight never cracked until the Allied armies met on the Elbe. In many ways,

despite sporadic successes, the strategic bomb­ing campaign is almost an object lesson in how not to fight a war.

But the big bombers came a lot closer to their objective than it has been fashionable lately to admit. After Hamburg, Alfred Speer, Germany’s economics minister, told Hitler that six similar raids close together would leave him unable to maintain arms produc­tion. Bomber Command did not, however, have the means to mount the raids.

There actually were sufficient aircraft if they had been able to place their bombs close enough to the targets. What made the task impossible was the same thing that had made the first three years of the campaign a hope­less failure—lack of navigational ability, largely owing to their lack of sophisticated equipment, particularly electronic navigation aids. When successes came at last to be achieved, they were the result of actually finding the correct target, unquestionably a navigational task; of concentrating the actual bombing, a task shared between the navigator and the bomb-aimer; concentrating the bombing in time (at the end of the war, a whole attack could be completed in ten minutes), the task of the navigators; and keep­ing on track out and home, which saturated the defenses and allowed aircraft to survive to drop their bombs or to bomb another day, again the job of the navigation team.

The area campaign itself, ironically, was “justified” because of the German area at­tacks on cities such as Coventry, which were in turn “justified” by the Germans on the grounds that the Allies had on 10 May 1940 bombed Freiburg, killing 57 civilians includ­ing 22 children. The attack had in fact been made on Freiburg by German Heinkels, be­cause of a navigational error.

The navigational state-of-the-art led the strategic planners along a path of miscalcula­tions, each of which unhappily involved a belief in one’s own propaganda. When Ger­man fighters made it impossible to operate bombers by day, the Royal Air Force con­vinced itself that night bombing was as ac­curate as day bombing, mostly because of mistaken faith in optimistic crew reports, but largely because night bombing was all they could do. After clinging to this belief for two- and-a-half years, a conversion to area bomb-

Mr. Emmott enlisted in the R.C.A.F. in 1937 as a store­keeper and spent five years in the ranks before assignment to aircrew and service as a navi­gator in Halifax heavy bomb­ers, RCAF Squadron 433, in Group No. 6 out of Yorkshire. Graduating from R.C.A.F. Specialist Navigation Course in 1950 and from R.C.A.F. Staff College in 1954, he served largely in positions dealing with the development of navigational elec­tronic gear during his last ten years of service. He re­tired in 1963, with the rank of Squadron leader, and has since been employed with the aerospace industry in California. He is now a senior engineer, Guidance and Control Division, Litton Industries, Inc., Wood- i land Hills, California. He received his B.A. in Mathe­matics from San Fernando Valley State College.

ing was forced on them, once again because the bombers could do nothing else. The Wat Cabinet convinced itself that area-bombing would, in fact, be effective; that it would break German morale and cripple German production. The planners also had to force themselves to believe that the bombs could hit the cities, which for 15 months they could not. In the last year of war, moreover, when navigation aids and better techniques allowed precision bombing to be carried out even at night against such targets as marshaling yards, factories, and dockyards, so wedded were they to the area-bombing concept that they continued to stir up the rubble of Essen and Hamburg rather than go after the noW- reachable factories. When, in 1944, the Ger­man armies in France were being crippled by their smashed railway system, bombers were only grudgingly allotted to pounding the transport system, which later proved to have been decisive; instead, they were sent against German cities at every opportunity.

Either better navigation, or better knowl­edge of how bad the actual navigation was, would have kept the planners on the rigid track. If the bombers could have navigated to a quarter of a mile or so, they need not have been launched at cities. Having been launched at cities, if they had been able consistently to find them despite bad weather and darkness, and if the bombs had fallen within a mile or two of their targets, it is quite conceivable that they might have destroyed enough of the

^cities to break either the German will or Power to fight. If the fact that the new Path­finder Force could not even be sure of finding the right town had been recognized in 1942, ^lfie aircraft needed by Coastal Command ^could have been provided, thus hastening the Pre-invasion buildup. If the pitiful lack of success at night had been evident after 1940, the British could have developed a longer- kgged fighter, which could have made day- fight bombing possible again; after all, the Mustang was built to a British specification ^and powered with a British engine. There are many “ifs” here, but all of them revolve ^around navigation.

Some of the lessons have been taken to heart. Two concurrent ones—the fact that navigational accuracy is crucial to a bombing Ulission’s success, and that the best-skilled human being in the world is helpless to ^achieve it without sophisticated aids—have been recognized by an outpouring of money ^and effort to develop a series of intricate navigational devices, including digital com­puters, automatic sextants, doppler radar, hhran, Shiran, and many other variants of the ^0riginal Oboe, and inertial navigation sys- ^tfuns, which have been installed in military ^a>rcraft.

Navigation training has been greatly im­proved. Immense efforts have been devoted to •ntproving the navigators’ maps. The em­phasis on accurate bomb-aiming has been kept at concert pitch for 20 years.

The results have been apparent in recent reports of B-52 bombers dropping bombs within a few hundred yards of Marine posi­tions at Khe Sanh, despite cloud cover, by the skillful use of radar, ground beacons and re­flectors, and airborne computers, plus highly skilled men to use them.

Other lessons can be learned. One is that courage and determination—50,000 of Bomber Command’s 100,000 men lost their lives—are no substitute for technical excel­lence. A continuous effort to improve capabil­ity and techniques is always needed, and parallel equipment and methods often prove themselves and sometimes save the situation. Those who receive criticism when they strive to improve military equipment which already seems good enough should remember that in 1939 the R.A.F.’s marshals were convinced they could win the war all by themselves, and that the equipment they had at the time was good enough.

The final lesson, that facts should always be looked in the face without being clouded by preconceived ideas, is probably as hard to learn as it ever was.

Nevertheless, it is still true, as historian Edward Gibbon said, that “the winds and waves are on the side of the ablest naviga­tors,” and this applies also to the winds aloft.