Three
ON 13 APRIL 1945, less than a month before the end of the war in Europe, the advancing American forces had stumbled across one of Germany’s best-kept aeronautical secrets. On the western outskirts of Braunschweig, near to the village of Völkenrode, they found a collection of buildings, sixty or more, scattered across a wide area of woodland. At first glance many of the buildings appeared to be nothing more than innocuous-looking farmsteads. Only a few rose above the tree canopy, and those that did were hidden beneath concrete platforms covered with several feet of earth and planted with trees to blend in with the forest. This explains how the Germans had managed to hide their most advanced and extensive research establishment: the Luftfahrtforschungsanstalt (LFA) Hermann Göring, otherwise known as Völkenrode.
In the aftermath of the First World War German aeronautical research had been left in the doldrums, shackled by the terms of the Treaty of Versailles and lacking either support or funding from the Weimar government. That situation changed abruptly following Hitler’s rise to power and his appointment as Chancellor in January 1933, and only months later the RLM had been formed. Suddenly the importance of aeronautical research was being officially recognised by the state and millions of Reichsmarks were poured into expanding the existing educational establishments and research facilities. Huge wind tunnels were constructed at the main centres, the Deutsche Versuchsansalt für Luftfahrt (DVL) at Berlin-Adlershof, and the Aerodynamische Versuchsanstalt (AVA) at the University of Göttingen. One of the wind tunnels at Göttingen was so big that the Lufthansa pilots were said to use it as a navigational aid because they could easily spot it from the air. However, with the prospect of a war on the horizon, these highly visible city-based institutions might prove vulnerable to aerial reconnaissance and attack by hostile aircraft. What was needed was something altogether more discreet. A little place in the woods, perhaps.
Groundwork on the 1,000-acre site near Völkenrode began in October 1935 and construction of the first wind tunnel commenced in November the following year. A road running between Völkenrode and Bortfeld was diverted to clear the area and the buildings were widely spaced among the trees, grouped into the five main areas of activity that made up the LFA. The Institute of Aerodynamics with five wind tunnels, and the Institute of Gas Dynamics which had a high-speed wind tunnel of its own, were both located at the southern tip of the site. The Institute of Strength Properties, with facilities for static testing, was on the western side, while the Institute of Engine Research was in a detached area on the eastern side. The Institute of Kinematics, which would undertake weapons and ballistic research in its laboratories and using a specially constructed 1,312ft (400m) ballistic tunnel, was in the north-west corner. The buildings were spread out in this way not only to reduce the risk of being observed by enemy reconnaissance aircraft, but also to ensure that the scientists working in any one institute would not be aware of the research going on in another. This was a physical manifestation of the paranoid tendency which permeated the Nazis’ weapons programme. An unintended negative result of this policy was that individual teams, be they aircraft or weapons specialists, or even manufacturers for that matter, were unable to benefit from similar work being undertaken by others within the same field.
In addition to these facilities, around 400 houses were constructed at Völkenrode, a little away from the main site, to accommodate a nominal force of 1,500 workers and scientists. There were also various other support buildings such as administration offices, a telephone exchange, electricity generators, canteens, guard houses and so on. To avoid the risk of detection there were no railway lines leading into the site, no overhead power cables and no tell-tale chimneys. All services were brought underground from Braunschweig; even the steam used to heat the buildings. An airstrip was constructed on the outskirts of Braunschweig but was carefully disguised by the planting of patches with several different types of grass seed. So thorough and effective was the subterfuge that the location of LFA Völkenrode remained secret until the fall of Germany. The Allies did have an idea that such an aeronautical research facility actually existed but had no idea where, as Fedden himself noted:
The ‘broken back of the Luftwaffe’ – British and American personnel examine the remains of a Ju 88 at the Braunschweig, or Brunswick, airfield. (USAF)
British engineers, who had been in the habit of visiting Germany prior to the war, had heard rumours that the RLM was setting up an entirely new research organisation, but nobody knew exactly where it was, or the extent of the equipment and personnel. In fact, rumour had it that it was in East Prussia, whereas other statements were to the effect that such a laboratory had been planned but never started.
Secrecy aside, it was the extent of the site that astounded Fedden and his team when they arrived at Völkenrode on the morning of Thursday 14 June 1945. By then dozens of CIOS technical teams had already pored over the site and the Americans had made themselves at home, even though it was within the British Zone of occupation. As Fedden put it, ‘the whole LFA Laboratory seems to have been very finely combed by the American authorities’. The place even had the feel of a US Army base with dozens of white-starred trucks and Jeeps negotiating the maze of wavy tracks that ran through the woods. Some visitors became so lost on the extensive site that signposts were erected in English to help them reach their destinations.
The most obvious jewels at Völkenrode were the wind tunnels, of which there were several, each designated by the Germans and allocated with an ‘A’ number (as shown on the site map).
A1 was a medium-sized tunnel of the Göttingen type with a circular nozzle 8ft 6in (2.5m) diameter and a maximum air speed of 123mph (55m/sec). It had been in operation since 1937.
A full-size Messerschmitt Bf 109 undergoing testing in the A3 wind tunnel at the secret Völkenrode aeronautical research centre in 1940. (LoC)
Plan of the Hermann Göring Research Institute (LFA) at Völkenrode. Incredibly this 1,000 acre facility remained secret to the Allies through concealment and the apparent randomness of the layout. On the western side, left, starting at the top there is the weapons research area, then structural research with munitions at the bottom. The main aerodynamics area with wind tunnels is central, and engine research is located on the eastern side.
A2 was a high-speed closed-return tunnel with a cylindrical test section of 9ft 2in (2.8m) diameter and 4ft 4in (4m) long. Work on this tunnel had started in 1937 and the first tests were run in 1939. The A2 was especially interesting as it had a maximum airspeed – with test model in place and depending on the dimensions of that model – in the transonic range around Mach 1 to 1.2. (The model was held in place by two carefully profiled struts which were swept back and unshielded.) The return circuit, with provision for cooling air, was located above the working section. The air was supplied by a two-stage compressor driven by a pair of DC motors, each one of 600kw rating. Interferometer and striation apparatus was fitted for visual examination of the airflow characteristics.
The inner surfaces of the A2 tunnel were coated with an application of Keratylene for smoothness and to prevent erosion. However, the tunnel was found to suffer from air vibrations or flutters when operating in the critical range passing from subsonic to supersonic conditions. Because of these problems the scientists at Völkenrode had obtained a free-flight research rocket which was launched almost vertically via a gantry. The model to be studied was attached to the front of the rocket and three cine-theodolites, geared together and fitted with a timer, recorded the flight and provided data to calculate the drag coefficient along the whole trajectory. The rocket Fedden would have seen at Völkenrode was the Rheinmetall-Borsig F25, a single liquid-fuelled engine rocket designed for high-speed research initially, although with the potential for development as a weapon. This had side wings, or fins, and a high-mounted tailplane at the rear. Curiously, the photographs published in the Fedden Mission’s final report are labelled as a ‘Free flight model for drag investigations at sonic speeds’, but actually show the bigger F55. This was a guided anti-aircraft missile known as the Feurlilie (‘fire lily’) which was 15ft 9in (4.8m) long and had a pair of wings at the rear with fins on the tips. Like the F25, the F55 was designed originally to be powered by a single liquid-fuelled rocket engine, but on its first test launch, during which it attained Mach 1.25, it flew with four Rheinmetall-Borsig 109-505 solid fuel rockets instead. So it seems almost certain that for his report Fedden borrowed some photographs of the F55, probably taken as it was being prepared for its first test flight at Pomerania in May 1944, but definitely not showing the smaller F25 research rocket seen at Völkenrode.
The mission report states that this is the Rheinmetall-Borsig F25 liquid-fuelled free-flight research model seen at Völkenrode, but in fact Fedden had appropriated a photograph of the test launch of the F55 Feurlilie anti-aircraft missile.
The biggest wind tunnel, but by no means the fastest, was the A3; a full-scale Göttingen type with a lateral return, a 26ft 3in (8m) diameter nozzle and a maximum airspeed of 215mph (95m/sec). Importantly, the open working section had a length of 36ft (11m), which was big enough to test a full-size small aircraft. Photographs from around 1940 show a complete Messerschmitt Bf 109 suspended in position in this wind tunnel. The compressor was operated by two 6,000kw DC motors, placed one behind the other and contained in a fairing in the return circuit. This fairing acted as an air intake, continuously removing about 10 per cent of the air in circulation which was then replaced by fresh air for cooling drawn from the measuring chamber.
Fedden was informed that this tunnel had proved very useful in practice, in particular with designing the pressure cowling for the BMW 801 radial piston engine fitted on a number of Junkers aircraft and also on the Messerschmitt Me 264 which had been a potential candidate as an Amerikabomber.
THE AMERIKABOMBER PROJECT
The Amerikabomber project had called for a long-range aircraft capable of delivering a useful bomb load, say 4.5 tons if we disregard the possibility of an atomic bomb for now, across the 3,600-mile (5,800km) expanse of the Atlantic Ocean. The intention was twofold; to hit back at the Americans and also to tie up their resources in defending the homeland. A number of scenarios were put forward including a return flight, a Huckepack or piggy-back configuration in which a larger aircraft would carry a smaller one as far as possible before releasing it, or a one-way trip with the aircraft ditching in the Atlantic afterwards for pick-up by U-boat.
Several aircraft were considered for the Amerikabomber project, including the Focke-Wulf Fw 300 which was based on the existing Focke-Wulf Fw 200 Condor long-range maritime patrol and reconnaissance aircraft, the Focke-Wulf Ta 400, the Junkers Ju 390 which was another heavy transport long-range bomber, the Heinkel He 277 – the nearest the Luftwaffe had to a long-range heavy bomber in production – and the Messerschmitt Me 264. In addition the Horten brothers and the Arado company had put forward proposals for large jet-powered flying wings (see Chapter 10). In the event, a more conventional Ju 390 was selected.
One of two supersonic wind tunnels at Völkenrode housed side-by-side in the building shown as A9 on the site map. By coupling the motors from both tunnels Mach numbers of between 1.0 and 1.5 could be maintained.
Photograph from the mission report showing Dr E. Scmidt beside an engine test-bed in the engine laboratory at Völkenrode.
Three prototypes were constructed and some sources have suggested that the second aircraft actually made a transatlantic flight to within 12 miles (20km) of the US coast, although this claim is generally discredited. In the end the Amerikabomber raid on the USA was never realised, not through any insurmountable technical barriers but through a lack of will and, by the latter stages of the war, the strain being put on the Nazis’ war machine.
Another way of attacking America also under consideration by the Nazis was to deploy rocket-powered aircraft or inter-continental ballistic missiles. Even before the war the scientists Eugen Sanger and Irene Bredt had proposed a winged sub-orbital transatlantic bomber in the form of a lifting body, which they christened Silbervogel (‘silverbird’). This would have been launched from a 2-mile (3km) track by rocket-powered sled, and once airborne its own rocket engines would have accelerated it to around 13,800mph (22,100km/h) at an altitude of 90 miles (145km). As it gradually descended the Silbervogel would have gained lift in the denser air to bounce, like a stone on the surface of the water, in ever decreasing arcs until it had reached it target. The Silbervogel never made it off the drawing board.
Plans for a conventional rocket attack were also never put into operation. The A9/A10 Amerika-Rakete (‘America rocket’) was to be developed from the A4 (V2) rocket family as a two-stage missile with inter-continental capability. Another alternative would have entailed launching an A4-type rocket from a U-boat stationed near the American coast, but the problem of fuelling and launching such a complicated weapon from an unstable sea-borne platform were considered too great.
Returning to Völkenrode, the A3 wind tunnel was also used in the development of the Argus pulsejet engine found on the tail of the V-1 flying bomb (see Chapter 7).
Of the other wind tunnels, the A6/7 worked in a different way. An air storage tank with a 35,500ft3 (1,000m3) capacity would be evacuated to about one-fifth atmosphere with the help of a 1,000kw pump. On opening a valve air was sucked through the small working section, less than 16in2(40cm2), for a duration of about 20 seconds. The A9 building housed a pair of supersonic tunnels, side by side. Each one was operated by a 4,000kw motor, and by coupling these motors together either tunnel could be operated with 8,000kw, making it possible to sustain Mach numbers of between 1.0 and 1.5 in continuous operation. However, the working sections were still relatively small at 31.5in2 (80cm2) on one, and the open section on the other had a diameter of 35.5in (90cm).
THE SWEPT WING
One of the most important areas of the aerodynamic research conducted in the wind tunnels at the three main research centres, Völkenrode and Göttingen as well at DVL Berlin-Aldershof, was in the development of the swept-wing platform for Germany’s new generation of jet-powered aircraft. As the speed of an aircraft increases the effects of the compressibility of the air become more pronounced. When the Mach number – defined as the ratio of the flight velocity to the speed of sound – approaches Mach 1 the aerodynamic characteristics of a wing are radically changed. The lift decreases and the drag increases. For conventional straight wings, as featured on just about every propeller-driven aircraft, this radical change in wing efficiency doesn’t occur generally until Mach 0.74 and hence it is not an issue. But for faster jets the critical Mach number had to be pushed to higher limits.
Göttingen’s big wind tunnel under construction in 1935. It is said that Lufthansa pilots used it as a navigational aid. (DLR)
The swept-wing, referred to as the Pfeilflügel (‘arrow wing’) by the Germans, was first proposed by Adolf Busemann at an aeronautical conference held in Italy in 1935. Busemann was a professor of aerodynamics at Göttingen University and went on to run the aerodynamics research department at Völkenrode during the war. However, the young engineer’s paper was received with only mild interest as it was thought that there was little prospect of any aircraft attaining Mach 1 for some considerable time to come. It was only with the advent of the turbojets that the swept-wing configuration was revisited and wind tunnel testing soon confirmed Busemann’s theories.
Of all the Luftwaffe’s jets of the Second World War, the Messerschmitt Me 262 is undoubtedly the most famous. But the oft-repeated assertion that this was the first jet to feature swept-wing geometry is incorrect. The truth is that as a result of his wind tunnel research Busemann had suggested that the Messerschmitt designers should use a 35° sweep – the same angle as the later US F-86 Sabre and the Soviet MiG-15 incidentally – but this was not adopted. Instead the production aircraft had a leading edge sweep of only 18.5°, too slight to afford any significant increase in the critical Mach speed. This sweep on the Me 262 was a modification made to counteract the higher than anticipated weight of the jet engines and to realign the centre of lift with the centre of mass of the aircraft. Another claim, that an Me 262 obtained Mach 1 in a steep dive, has never been proved. The maximum level speed of the Me 262 was more in the region of 560mph (900km/h); far short of the nominal speed of sound which is given as 768mph (1,236km/h) in dry air at 20°C. Indeed, tests with series production versions of the Me 262 revealed that a loss of control would occur in a steep dive at Mach 0.84.
Newly completed, Göttingen’s massive wind tunnel 6 photographed in 1936. (DLR)
Members of the Fedden Mission with Dr Encke, in the white coat, at the AVA Göttingen. Second from the left wearing glasses is Dr W.J. Duncan, next to him is Mr Stern of the Control Commission for Germany.
The Messerschmitt company did attempt to create special Hochgeschwindigkeit (HG) high-speed variants of the aircraft. The Me 262 HG-I V9, fitted with a low-profile Rennkabine (‘racing cabin’), is reputed to have achieved 606mph (975km/h). The next version, the projected but never built HG-II, was to have had a 35° sweep and a butterfly tail, while the HG-III would have gone even further with a 45° sweep and turbojets jets embedded within the wing roots. The top speed of the HG-III was anticipated as Mach 0.96 at 20,000ft altitude, but this is still below Mach 1. For comparison the rocket-powered Messerschmitt Me 163 B-1 Komet exhibited phenomenal rates of climb but even this still had a relatively modest maximum speed of only 596mph (1,060km/h).
Messerschmitt’s first true swept-wing jet fighter was to have been the experimental P.1101 which was nearing completion at the Oberammergau works at the time of Germany’s surrender (see Chapter 10).
Naturally the Allies showed great interest in the German research into swept wings, and at one point Fedden’s team had got one of the wind tunnels working with an airflow model of a swept-back wing aircraft in place when an American delegation arrived on the scene. The Americans frequently included civilian experts from within the aircraft industry in their technical exploitation teams and among this particular delegation was George Schairer. Schairer was involved with Boeing’s design work on a new six-engined long-range bomber for the USAF and he showed great interest in the tests. The next morning the airflow model had gone and Schairer later admitted that he couldn’t have left it behind. He sent word back to his design team in the USA to halt all work on a straight-wing design for the bomber and to switch to a swept-back wing instead. Boeing’s modified design for the bomber was accepted by the USAF and it became the swept-wing B-47 Stratojet which first flew in December 1947 and went on to become the mainstay of the USAF’s Strategic Air Command (SAC) throughout the 1950s and well into the early 1960s.
Rare air-to-air photograph of a Messerschmitt Me 262A. The shallow sweep of its wings was introduced to realign the centre of gravity and was not sufficient to increase the aircraft’s critical Mach speed.
Model of the Junkers Ju 287, with its unusual forward-swept wing geometry, undergoing testing in the Göttingen wind tunnel. (DLR)
As this incident with the swept-wing model shows, Britain’s closest allies were not against a little ‘midnight requisition’ of equipment when it suited them. In American Raiders, author Wolfgang W.E. Samuel quotes one of the Americans based at Völkenrode at the time: ‘The trick was to get whatever test equipment out of the place without the British noticing. As soon as everybody was in bed and the lights were out, we’d spring into action.’ The ‘requisitioned’ items would be taken to the airfield where the Americans ran a pair of B-24 and B-17 aircraft like an airline, shuttling back and forth from Völkenrode. At the Potsdam Conference the British complained about these surreptitious appropriations to the USAF’s representatives, only to be met by earnest pleads of innocence.
The design of Boeing’s post-war B-47 Stratojet bomber was modified to incorporate swept-back wings as a direct result of Germany’s wartime research. (US DoD)
THE FORWARD-SWEPT WING
A radical alternative to the conventional swept-back configuration which was assessed in the wind tunnel at Göttingen was the forward-swept wing. The principle benefits claimed for this were reduced drag, resulting in extra lift at lower speeds during take-off and landing, plus improved manoeuvrability. Unlike with the swept-back wing, the airflow on the forward-swept wing is from the wing tip towards the wing root and fuselage, thus delaying a stall at the wing tips. Shock waves at the wing root do not spread outwards although, conversely, there was a tendency for a stall to occur first at the wing root in a high angle of attack, causing a pitch-up moment further exacerbating the stall. Another advantage of mounting the forward-swept wings further back on the aircraft was that it also freed up space within the fuselage for an unobstructed bomb bay to carry greater loads.
Only one Luftwaffe aircraft featured the forward-swept wing: the Junkers Ju 287, which was developed by Dr Hans Wocke as a testbed for a bomber fast enough to out-run any enemy fighters. The Ju 287 was by no means the Luftwaffe’s first jet-powered bomber as the Arado Ar 234 had made its maiden flight more than a year earlier, in June 1943. However, the Ar 234 was too small to be an effective bomber as it was only marginally bigger than the Me 262, and its straight unswept wing limited its speed. The prototype Ju 287 V1 – the V designation on German aircraft standing for Versuch (‘test aircraft)’ – was produced from a mishmash of donor parts. The main fuselage came from a Heinkel He 177 bomber, the tail was from a Junkers Ju 388 and the heavy-duty nose wheels were actually salvaged from crashed American B-24s. The aircraft was powered by four Junkers Jumo 109-004B-1 jet engines, one hung under each wing and the other two in nacelles mounted to either side of the forward fuselage. This unorthodox and unfamiliar configuration looked all wrong, but when flight tests began at Junkers’ works at Dessau in August 1944, the aircraft demonstrated good handling characteristics, although further tests suggested that it would benefit from placing more of the engine mass under the wings. Accordingly the second prototype was to have six of the Heinkel HeS 011 turbojets, but because of delays in development the BMW 003 jet engine was selected instead and arranged in groups of three under each wing. It was proposed that a third prototype would have had two engines under each wing plus one on either side of the forward fuselage.
Early in 1945 the advancing Russian forces captured the Ju 287 V1 prototype, which had suffered bomb damage at the Rechlin test centre, as had the unfinished V2 aircraft. Working for the Russians, a large team of Junkers engineers utilised parts from the Ju 287 V2 to create the EF-131 and this was dismantled and taken by railway back to Russia. Test flights with the EF-131 commenced in 1947, but the programme was terminated the following year as the design was already obsolete.
In the decades since the end of the Second World War there have been very few manifestations of the forward-swept configuration. Notable exceptions being Grumman’s X-29 research aircraft, of which two were built in the USA in the 1980s, and the Russian-built Sukhoi S-37, later redesignated as the Su-47 Berkut (Golden Eagle), which first flew in 1997. Unlike the Ju 287, both of these designs featured additional canards ahead of the main forward-swept wings.
The Fedden team spent two days at Völkenrode initially, followed up by a second visit to the site by a sub-group ten days later. While their primary interests were focused on the development work carried out in the wind tunnels they also inspected the structures and engine departments. In the Structures Laboratory – shown on the site map as being on the western side – they discovered equipment and samples still in the testing machines, indicating that the research had been directed towards strength of materials and components under alternating stresses, although there appeared to be no strength testing of larger aircraft components. This work was supplemented by photo-elastic research as well as research of stress cracking lacquers, with a view to understanding the phenomenon of stress concentration, which is an important factor where fatigue stress is concerned. Unfortunately, Fedden was unable to interrogate any of the laboratory staff on this matter. Included on his inventory of equipment in the lab were 60 ton and 20 ton Schenck-Erlinger horizontal push-pull pulsators, plus other vertical pulsators and impact and fatigue testing equipment. In the main this equipment was in good condition, although Fedden did observe that most of the recording instruments had been damaged prior to their visit.
The Messerschmitt Me 264 four-engined long-range maritime reconnaissance aircraft was a candidate for the proposed Amerikabomber project capable of attacking New York.
The team members were then guided around the Motor Laboratory by Dr E. Schmidt, who seemed to be in frail health. In the photograph of Dr Schmidt standing beside an engine test-bed he looks drawn and he is shown resting on a stick. In contrast with the other laboratories Fedden thought the engine department was generally lacking in modern equipment. It did contain an altitude test bed, however, which he suggests was ‘better than anything we have in this country’ but not as advanced as the equipment they would later see at BMW in Munich. Like the remainder of the Völkenrode departments, the Motor Laboratory gave every appearance of being under-staffed in Fedden’s opinion: ‘On the other hand a considerable volume of work had been in progress on basic research of a more ambitious nature than has been attempted in this country during the war.’
The extent of this work covered turbine and stator blade forms, including research using optical interferometers to make airflow around wings or turbine blades visible, temperature measurements at high altitude at Mach 2, the conductivity of liquids at varying temperatures, heat exchangers, ceramic turbine blades, hollow liquid-cooled turbine blades, plus the study of plain bearings for rotor mountings, piston cooling, air-cooled finning on cylinders, liquid cooling, turbulence and detonation. The tests on various materials and methods of cooling turbine blades were of special interest given the shortage of certain strategic materials towards the latter stage of the war (see Chapter 4).
Dr Schmidt was pleased to show them the equipment used in developing water cooling for his turbines. Fedden considered Dr Schmidt to be one of the leading authorities on heat exchangers for different types; air-to-air, gas-to-air, oil-to-air, and air-to-liquid. This work was very important as the heat exchanger’s effectiveness would be a critical factor in future high-performance turbine power plants. In terms of specific equipment in the Motor Laboratory, Fedden was particularly impressed by an interferometer used in the optical investigation of high-speed flow phenomena in connection with turbine blades. However, as he curtly commented in his report, ‘It is understood that the instrument has since been removed by the Americans.’
On the Friday evening, 15 June, the team departed from the Braunschweig airfield at 7.15 p.m. for the 80-mile flight to Kassel, south-west of Göttingen, and overnight they billeted at the American Intelligence Centre, Camp Dantine. The next morning the party split into two; one group going to the Junkers jet engine factory in Magdeburg, while the remainder returned to Göttingen where they made arrangements for Professor A. Prandtl and his colleagues to be available for interrogation the following day. At Göttingen Fedden’s team inspected another impressive collection of wind tunnels; the mission report lists more than ten, plus several water tunnels which were used in fluid motion research. The largest of the wind tunnels had a large working section, which could be used either open or closed, 15ft 5in (4.7m) high by 23ft (7m) wide. One of the smaller tunnels working on the vacuum storage tank principle was capable of supersonic speeds up to Mach 3.2.
Weapons testing inside the Institute of Kinematics K1 1,312ft (440m) ballistics research tunnel at Völkenrode, 1940. (DLR)
The line-up of scientists they met at the AVA included Prandtl who was in charge of the laboratories, A. Betz who worked with the wind tunnel equipment, J. Stüper who was an expert pilot as well as a scientist, L. Ritz who was working with heat exchangers and low temperature research, specialising on jet-engine projects, W. Encke a leading authority on compressor and turbine design, and H.G. Kussner who was an expert in flutter. It is interesting to note that Fedden always uses the term ‘interrogate’ in regard to the German scientists and engineers, even though he had known many of them personally from before the war. The term is an extension of the language of the soldier, the language of a victor talking about the defeated. Of the Göttingen people he readily admits that they were, ‘a first class team of experimental aerodynamic research workers’. And in general the mission concluded that it was preferable to interview the Germans at their laboratories or works rather than take them to London for questioning:
… it is better that engineers and scientists should be interrogated on their own ground, where they can refer immediately to drawings, samples and to the workshops, and where information given by one man can be checked up with that given by another on the same job. The mission has interrogated many technicians in Germany and in particular cases, it is believed, have got different stories from those which have been given by senior executives sent over to London. It was found possible to check up by referring the problems to the factory, and by interrogating two or three people on the same job. The information that it was able to glean directly in Germany may be nearest to the truth.
Despite this note of suspicion, the mission found that most of the German engineers were more than willing to cooperate with the Allies:
Generally speaking, and with a few exceptions, the mission believes that the engineers, technicians and executives who were interrogated, and who showed them around the laboratories and plants, wished to be helpful, and to give constructive answers to the points raised … It was sensed that there was considerable apprehension on the part of the German scientists and engineers as to their future. Several spoke of their desire to move their staffs and equipment to America, or particularly to Canada.
Their concern was understandable as the Russians, for their part, had no qualms about taking any scientist or engineer they thought might be useful back with them to the Soviet Union. In contrast the other Allies, especially the Americans, had to find ways to legitimatise any transatlantic brain drain, lest they should be accused of bringing former Nazis into the country. And while it was simple enough to load the captured equipment and documents straight on to a truck or aeroplane and take it out of Germany, moving people would take a little more time to organise.