The Guided Missile

A number of experimental types, designed to achieve the same basic function of surface-to-surface bombardment and also a limited surface-to-air capability against German airships, were built in the UK under the cover designation Aerial Target by a team under the supervision of Professor A.M. Low at the RFC Experimental Works and then the Royal Aircraft Factory at Farnborough. These types lacked the gyroscopic control system and were therefore designed for command guidance by radio.

Germany undertook the experimental development of remotely piloted glide bombs in the course of World War I. Resulting from an initiative of Dr Wilhelm von Siemens of the Siemens-Schuckert Werke, these SSW types were tested in 1915 as glide bombs with guidance commands transmitted to the control surfaces (powered by an onboard battery), via fine copper wires that were unreeled as the weapon departed from its launch aeroplane. The concept was fully and successfully evaluated in a number of monoplane and biplane test models, but plans to use such glide bombs were overtaken by Germany's defeat.

Other such types were mooted in the 1920s and early 1930s by far-sighted designers, but foundered on a dearth of military enthusiasm for such weapons at a time of straitened finances, and on the lack of a powerplant other than the piston engine whose use would result in a weapon that was not appreciably faster than current warplanes and was therefore comparatively simple to intercept and shoot down. The turning point in the concept of the guided missile, from being a feasible but not necessarihpractical or desirable weapon, came in the mid-1930s with the rise to power in Germany of the Nazi party and the first development of effective reactiontype engines such as the turbojet, pulsejet and rocket motor. The German military at last began to appreciate that unmanned but guided weapons using such reaction motors offered hitherto unrealisable performance, and the leaders of the Nazi parry saw the opportunity not only to redress the overall weight of the military balance in favour of Germany - which was denied the right to develop advanced weapons during the currency of the Treaty of Versailles that had signalled Germany's defeat in World War I - but also to overtake Germany's potential enemies through the mass production of weapons that resulted from the German `genius'.

A major development effort was started in the later 1930s and during the first years of World War II, and from 1942 was progressed as a matter of high priority as Germany's conventional forces were checked for the first time in the nation's aggressive quest for territorial and political expansion, and particularly as the Allied powers began to drive the German forces back towards Germany.
The German research and development effort had strategic as well as tactical ambitions, the two strategic weapons to enter large-scale service being the Fieseler Fi 103 flying bomb or cruise missile, and the Peenemunde A-4 ballistic missile.

The first guided missile to be used operationally in large numbers, the Fi 103 was a pilotless flying bomb for the bombardment of large urban areas. Development of the weapon was authorised in June 1942, and the Fi 103 began to take shape under the leadership of Dipl: Ing. Robert Lusser as an aeroplane-shaped weapon with a circular-section fuselage carrying, from nose to tail, the master magnetic compass, the warhead, the fuel tank, the two high-pressure air tanks used to power the control surfaces and feed the fuel to the engine, the battery, the master gyro assembly and guidance package, and the pneumatic servos controlling the elevators and rudder. The rest of the airframe comprised the flying surfaces, which included the cantilever mid-set wing and a plain tail unit whose vertical surface provided the rear support for the pulsejet engine whose forward end was carried by a pylon over the battery section.

The first unpowered test vehicle was launched from a Focke-Wulf Fw 200 Condor motherplane in December 1942, and the first powered ground launch took place later in the same month. There were a number of development problems, but the weapon was ready for use in the summer of 1944 after some 300 Fi 103s had been fired in trials. The weapon was dubbed V-1 (Vergeltungswaffe-1, or reprisal weapon-1) by the Nazi party, and the first was fired against London on 12 June 1944.

The offensive that followed saw the launch by the Luftwaffe of 8,617 standard missiles against London and other British targets in the period up to the end of August 1944, when the programme was taken over by the German army, which fired 11,988 weapons against a range of European targets in the period up to the end of March 1945. Another version of the weapon had wooden wings and a smaller warhead for longer-range attacks, and 275 of these weapons were fired by the SS against British targets between January and March 1945. Finally, the Luftwaffe fired 865 missiles from adapted Heinkel He 111 bombers between September 1944 and March 1945.

Generally known by its Nazi designation V-2 (Vergeltungswaffe-2, or reprisal weapon-2), the A-4 weapon was in every respect a prodigious achievement for its period, and marked the emergence of the ballistic missile as a new type of weapon for strategic purposes. The unsuccessful first launch was attempted in June 1942, the successful second launch following in August. There were considerable development difficulties with the missile, and no fewer than 265 test launches were made before the type entered service.

The weapon was based on a tapered circular-section body carrying, from top to bottom, the warhead, the guidance package of gyroscopes and integrating accelerometers, the tank for 8,3111b (3,770kg) of alcohol fuel, the tank for 10,8021b (4,900kg) of liquid oxygen oxidant, the fuel and oxidant turbopumps powered by hydrogen peroxide and calcium permanganate, and the rocket motor. Round the base of the missile was a cruciform of swept fins each carrying a control surface, and four graphite vanes were fitted in the exhaust to control the missile by vectoring the thrust of its engine before the weapon had reached a speed at which the aerodynamic control surfaces became effective. The first A-4 was fired operationally on 8 September 1944, and in a programme that lasted to 27 March 1945, a total of 3,165 A-4s was fired against British and European targets.

The Germans also expended considerable but not altogether successful effort in the creation of a number of tactical missiles of the air-to-air, surfaceto-air and air-to-surface types. It was only weapons of the last category that reached operational service, and then only in limited numbers and mainly for the anti-ship role. The two most important of these weapons were the Ruhrstahl SD-1400 X and Henschel Hs 293. Otherwise known as the X-1, Fritz-X or FX-1400, the SD-1400 X was designed by Max Kramer for a first test launch in 1942, and scored its greatest success on 9 September 1943 when two such weapons hit and sank the Italian battleship Roma as she was steaming to Malta after the Italian armistice with the Allies: each weapon was a guided version of the SD-1400 armour-piercing bomb with an arrangement of four fixed wings on the centre of gravity and a lengthened tail section carrying an ovoid ring tail embodying spoiler controls that moved under control of the operator in the launch warplane. This weapon was fully practical in the technical and operational senses, but only about 100 of the type were used in real missions because of losses to the launch warplanes, which were heavily laden and vulnerable when flying to the target area, and then slow and vulnerable as they cruised in the target area during the attack, R7 for which the operator used the standard Lofte 7 bombsight as the pilot 8e+r straight and level until weapon impact. A variant with Telefunken FuG 208/238 wire command guidance did not enter service.

The Germans displayed a keen interest in the development of standoff weapons even before the outbreak of World War II, and one of the first fruits of this enthusiasm was the Hs 293A air-to-surface missile designed under the leadership of Herbert Wagner. The core of the weapon was a standard 5511b (250kg) SC-250 bomb to which were added a mid-set wing of the constant-chord type with inset ailerons and also a cumbersome tail unit that was designed to accommodate the autopilot and guidance package (not yet available) as well as the horizontal tail surface, the deep ventral portion that stabilized the missile in the directional plane even though there was no rudder, and the large flare that facilitated optical tracking of the missile by its operator. It was in this form as a glide bomb that the weapon was first tested, but then a powerplant was added in the form of a Walter liquidpropellant rocket extended below the body of the weapon on short struts and exhausting obliquely downward and to the rear.

The first warplane selected as launch type for the Hs 293A initial production model was the Dornier Do 217E bomber, and the relevant aircraft were modified with an operator position in the starboard side of the forward crew compartment. This meant that the Hs 293A had to be released as the launch warplane paralleled the course of the target off to its right, and that the pilot had to hold a steady course as the operator kept the flare on the tail of the missile superimposed over the target image until impact. 'Ibe Hs 293A was used operationally over the Mediterranean, Atlantic Ocean and North Sea (its first success was the sinking of the British sloop Egret on ?a August 1943 in the Bay of Biscay), and a number of the missiles were also expended in attempts to destroy the bridges being used by the Soviets to cross the Rivers Vistula and Oder in the spring of 1945.

Variants of the Hs 293 series that proceeded no further than the prototype or project stage were the Hs 293B with the Staru FuG 207/237 wire-guidance system; the Hs 293C intended to penetrate under the surface of the sea before hitting the underside of a target ship's hull; the Hs 293D with Fernseh T<' guidance; the Hs 293E with spoiler controls; the Hs 293F proposed tailless model; and the He 293H with the Schmidding 109-503 or Schmidding 109•5L rocket motor for carriage by the Arado Ar 234 Blitz jet powered bomber