Despite a few spectacular successes, such as the destruction of zeppelin sheds and Strange’s bombing at Courtai, the initial results of tactical and strategic bombing were extremely limited. Of 483 bombing attacks that the British and French launched against German targets between 1 March and 20 June 1915, only seven were considered successful. In addition, bombers proved extremely vulnerable to ground fire, antiaircraft guns, and enemy bombers. By late 1915 experience dictated the development of tactical guidelines for bombing, such as attacking targets downwind and flying in formation to minimize the impact of antiaircraft guns. In addition, daytime bombing raids were increasingly restricted to short runs or to entice enemy fighters into a trap, while nighttime bombing raids were used to fly deep into enemy territory. It should be noted that nighttime flying presented a host of problems because of the lack of training and instruments—obstacles that would not be overcome until the last 2 years of the war.
By far the most significant legacy of bombing in the war—one that would shape postwar air power theory—was the German bombing campaign against Great Britain, which began in 1915 and continued until the end of the war, and was by far the most extensive use of strategic bombing during the war. Although Kaiser Wilhelm II at first proved reluctant to sanction attacks against London and other British cities, the German public clamored for taking the war directly to the British, who had imposed a naval blockade of all items—including food—into Germany. As a result, the Kaiser gradually relented to public pressure and the demands of his military subordinates who saw aerial bombardment as a legitimate means of destroying the English will to fight. The first attacks were carried out on the night of 19 January 1915 by naval zeppelins L-3 and L-4 against Yarmouth and King’s Lynn. The attacks destroyed a few homes and shops, killing six civilians and injuring twenty (including three children) in the process. Although the Germans justified the raid as an attack on “fortified places,” the British denounced them as an act of barbarism. The success of the raid finally led the Kaiser to lift restrictions on London.
Attempting to launch their zeppelins against London was no easy task for the Germans. Attacking at night without adequate instruments was difficult enough; adverse weather only compounded problems. Captain Ernst Lehmann, commander of the newly commissioned Z-12, which could carry a bomb payload of 12 tons, devised an ingenious method of lowering an observation car as much as 2,700 ft beneath his zeppelin so it could remain above the clouds, where an observer below could communicate via telephone to the wheelhouse and guide the airship to its intended target. When Lehmann attempted his first raid against London on 17 March 1915, however, he turned back because of heavy fog, refusing to drop his bomb load on an unseen target below. Because the naval zeppelins were based in Germany and thus were stretching their range, the task of bombing London in 1915 ultimately fell to the army, which could use bases in Belgium. After making several attempts to find London in April and May 1915, Captain Erich Linnarz, commander of the LZ-38, finally succeeded on 31 May. Dropping a payload of five 110-lb bombs and forty-eight small incendiary bombs from 7,000 ft, the LZ-38 destroyed approximately $100,000 of property, killing seven civilians and injuring thirty-five.
Although the attack did not induce the British to panic, as the Germans expected, First Lord of the Admiralty Winston Churchill did order the Royal Naval Air Service (RNAS) to divert resources to defending civilians against further zeppelin attacks. When the Germans attempted their second raid against London on the night of 6–7 June with three zeppelins—LZ-37, LZ-38, and LZ-39—the British were ready. After naval intelligence intercepted German radio signals and notified the RNAS wing stationed at Dunkirk, two Morane-Saulniers and two Farmans were dispatched to attack the zeppelins upon their return. Although Lieutenant John Rose had to return to base after the engine on his Morane-Saulnier malfunctioned, his companions were far more successful. Lieutenant Alexander Warneford, flying the other Morane-Saulnier, intercepted LZ-37 on its return to Ghent, destroying it after releasing six bombs from above as it descended to its base. Lieutenants John P. Wilson and John S. Mills used their Farmans to bomb and destroy LZ-38 as it was entering its shed at Évère. As a result of their losses, the Germans temporarily halted raids by their army zeppelins, waiting instead for Captain Peter Strasser to assembly his fleet of naval zeppelins for a major raid.
In an attempt to carry out a mass raid against London, Strasser postponed further probes of the English coast in June and July, awaiting the arrival of nine new zeppelins, each of which had a gas capacity of 1.1 million cubic ft and were capable of 61 mph with their four Maybach engines. Although Strasser carefully planned his first mass raid against London for 9 August 1915, it proved to be an absolute failure with not a single ship finding its target. In subsequent attacks the Germans enjoyed little success, with the exception of an attack carried out by Captain Heinrich Mathy in L-13 on 8 September. The L-13, which had a payload of fifteen high-explosive bombs and some fifty incendiary bombs, accounted for approximately 25 percent of the damage that London would suffer in the entire war, resulting in $2.5 million of property damage, thirty-five deaths, and thirty-seven injured civilians.
In response to the zeppelin raids, Arthur Balfour, who had replaced Churchill as first lord of the admiralty in the aftermath of the Gallipoli debacle, placed Admiral Sir Percy Scott in charge of London’s antiaircraft defenses. Believing that antiaircraft guns were the key to defense, Scott established batteries of high-angle cannon and a network of high-power spotlights around London. More important, he acquired motorized 75 mm guns from the French, which allowed for a mobile antiaircraft system. In addition, Scott established continual air patrols over London at night and had the RNAS increase its coastal patrols. The improved British antiaircraft defenses led Strasser to suspend attacks in late 1915 until new, improved zeppelins could enter service. As a result, the British enjoyed a 3-month respite until 31 January 1916, when Strasser dispatched nine zeppelins on a raid intended to strike Liverpool. Although only one of the zeppelins, L-21, reached its destination, its bombs did minimal damage. The other eight, however, dropped their loads across the English countryside, killing 70 civilians and injuring 113. Although this was the deadliest raid thus far in the war, it achieved no real military objective. To the extent that the raids had tied up British manpower and resources at an enormous expense, the German raids were worthwhile, even if they did not achieve their intended result.
On 2 September 1916 Strasser launched what he hoped would be the climactic air raid of the campaign, sending a flotilla of twenty zeppelins against England—two in a diversionary attack over the Humber and eighteen (including five of the newest zeppelins) against London; however, British antiaircraft defenses had by then become much stronger. In particular, British aircraft were now armed with much improved incendiary ammunition designed to penetrate the zeppelin’s outer skin and explode the hydrogen. In addition, cryptographers working in Room 40 of naval intelligence had obtained German code books, which allowed them to decode intercepted messages sent between zeppelins on the night of 2 September, thereby providing ample warning to the antiaircraft defense network. Lieutenant Leefe Robinson intercepted SL-11 (Schutte Lanz airship) with his B.E.2 and used his new incendiary shells to shoot it down, for which he would receive the Victoria Cross. Whereas the fiery descent of SL-11 cheered British onlookers, it shook the confidence of the other zeppelin crews who witnessed it in the air, leading all but one—LZ-98 commanded by Lehmann—to turn abruptly around before dropping their payload on their intended targets. On 23 September Strasser carried out a new raid with four of his new super zeppelins (L-30, L-31, L-32, and L-33), which were to attack London, and six older types, which were to carry out diversionary raids. British antiaircraft defenses once again proved their worth against these lumbering giants. Caught in a web of spotlights east of London, the L-32 provided an easy target, as Lieutenant John Sowrey pulled underneath it with his B.E.2 and emptied three canisters of incendiary and tracer bullets fired from his Lewis gun into the belly of the great ship, striking a fuel tank, which then produced a tremendous explosion that brought the L-32 down in a ball of flames. Although the remaining zeppelins completed their mission, dropping bombs that killed 39 and injured 131, the Germans suffered the loss of a second super zeppelin, L-33, after Lieutenant Alfred de Bath Brandon punctured its gas bags so severely that it was forced to land near Colchester.
Although the disasters that befell German zeppelins in September 1916 were held from the public, the German High Command demanded that the Kaiser order an end to the navy’s raids, considering them a waste of manpower and precious resources that could be used elsewhere. The navy naturally resented the army’s interference, but naval leaders did remove the autonomy that Strasser had previously enjoyed. In addition, production of new zeppelins was gradually curtailed. More important, all subsequent zeppelin attacks, which were carried out until August 1918, were limited to the British east coast and industrial midlands in order to avoid the air defenses around London. Nevertheless, German losses continued to mount. Of seven zeppelins launched on a raid against Harwich and Yarmouth on 27 October 1917, for example, only three returned home. Whereas the numerical losses of German zeppelin crews paled in comparison to those suffered by the men in the trenches, the percentages are quite astonishing. In March 1918 Strasser reported a casualty rate of more than 40 percent, as 70 officers and more than 250 crewmen had died and 150 had been wounded or taken prisoner. In the last zeppelin raid of the war, on the night of 5 August 1918, Strasser himself would go down in L-70, the largest zeppelin built during the war.
The Germans carried out forty zeppelin raids during the war, dropping 220 tons of bombs that left 557 dead and 1,538 wounded, destroying $30 million of property. In doing so, however, the Germans paid a heavy price. Of the 140 airships that participated in the raids, approximately two-thirds were destroyed by enemy fire, storms, or accidents. Given the enormous costs of building and maintaining the airships, the zeppelin raids must be considered a failure because each airship cost approximately $500,000 to build, and the monthly maintenance cost for the fleet could have funded four infantry brigades. They failed to inflict the physical damage that the Germans expected and did not create the desired psychological trauma that had been anticipated. They must also be considered a public relations disaster in that attacks on nonmilitary targets led neutral powers, particularly the United States, to sympathize with the British.