Sweden Under the Attack of V-weapons

In the full accordance with the well-known proverb, when the great powers begin to sort out their relations, the other countries suffer for it. During World War 2 neutral Sweden was balancing between warring military blocks with the agility of a tightrope walker but German missiles also blew up on its territory. However, the enterprising Swedes were able to benefit even from those unfortunate incidents.

Went astray

Today German missiles V1 and V2 (“Fau 1” and “Fau 2” in German) are widely known. In the end of WW2 the Allied anti-Hitler coalition got numerous samples of those cruise and ballistic missiles. Moreover, even the German scientists who took part in their creation became a kind of “trophies”. The best known among them is Wernher von Braun, who was A4 (V2) missile architect, a NSDAP member and SS-Sturmbannführer (Major) and who later became one of the “fathers” of the American space program. It is generally recognized that the German scientists achievements were of great importance for the rocket science of Great Britain, the USSR, the USA and France.

It is a much less known fact that German missiles made an invaluable contribution to the rocket technology development of neutral Sweden. And oddly enough but the reason for the fact was mostly a certain imperfection of German rocketry.

The thing is the German V1 cruise missile guidance system was a rather primitive autopilot by today’s standards, which included three gyroscopes, barometric altitude sensor, and a magnetic compass. The latter aimed the missile at the target before a launch and the gyroscopes together with the barometric sensor provided the missile with stabilization along the course and pitch. It is interesting that V1 had no roll control – they believed that a cruise missile aerodynamics gave it a sufficient stability relative to the longitudinal axis. The British Royal Air Force pilots used such a property in the fight against V1 when with a wingtip of a plane they toppled V1 in the air and after that a missile immediately fell down.

The autopilot ran the elevators and rudders by means of a compressed air pneumatic system. However, with all the guidance system ingenuity, V1 accuracy left much to be desired and it did not exceed fifteen kilometers. Advanced, but still very imperfect weapons caused a lot of troubles for the Germans themselves: around 20% of the missiles failed or exploded when launched. A significant number (according to various estimates about 20% more) out of the 10 000 missiles, launched by the Germans, fell in various areas of the North and Baltic seas. And on the 17th of June 1944 one of the V1s that had deviated from its course even fell down on Hitler’s bunker in Margival.

On the 15th of November 1943 the remains of V1 cruise missile were found in a Swedish län (“län” in Swedish means an administrative-territorial unit, county) Blekinge, 20 km south-east of the center of Karlskrona Municipality. Briefly after that on the 30th of November another missile was found in Scania County, 7 km east of the town of Ystad. It is characteristic that the Swedes began to find such German “gifts” long before their combat use on the territory of England because some experimental samples flew into Scandinavia, and they had been launched by the Germans from the research center on the island of Usedom at the mouth of the Order.

After that there was an almost six-month pause during which the German “vengeance weapon” stopped falling on the territory of the hospitable neutral state (or fell where it was never found). On the 11th of May the Swedes found a well-preserved V1 near Brosarp in Scania. The same year on the 13th of June a V2 ballistic missile “landed” on the Swedish land in Smoland that was 30 km north-west from Kalmar. On the 17th of June the Germans began massive V1 missile attacks on London and before the 1st of November the Swedes discovered three more German V1 missiles on their state territory. Thus, in total the remains of seven German missiles were found in the south of Sweden-six cruise V1s and one ballistic V2.

German missiles that crashed in southern Sweden 1943-1944

1. November 15, 1943 V1 missile, Utlängan (20 km south-east of Karlskrona), Blekinge
2. November 30, 1943 V1 missile, Nybro (7 km east of Ystad), Scania
3. May 11, 1944 V1 missile, Bertilstorp (15 km north-west of Kivik), Scania
4. June 13, 1944 V2 missile no 4089 (30 km north-west of Kalmar), Smoland
5. July 27, 1944 V1 missile (3.5 km north-west of Karlskrona), Blekinge
6. September 7, 1944 V1 missile, Trunnerup, Scania
7. November 1, 1944 V1 missile Baskemölla, Scania

Swedish anti-ship missiles based on V1

German V1 cruise missiles were studied with great interest by the Defense Aeronautical Experimental Institute (FFA, Flygtekniska försöksanstalten) and the Naval shipyard in Skeppsholmen. In the book “The Rocket and I” (“Robot 50 år”) published in 1997 by SAAB it was told:

The German missiles inspired new ways of thinking within all three branches of defense. The Naval Forces viewed aerial torpedoes as a variant of underwater torpedoes, the Army viewed them as an alternative artillery and the Air Force saw them as an unmanned aircraft with several possible tasks.

The Swedish Navy was the first to order SAAB (Swedish for «Swedish Aeroplane Company Limited») to build “air torpedoes” on V1 basis. In fact, they were the same cruise missiles with a pulsating jet engine improved by Swedish designers. In 1945 after the end of hostilities in Europe, a Swedish delegation visited England where the delegates could get some additional information about V1. The construction of the first SAAB RB310 missile began the same year – 1945 – and its first tests were done in June 1946. The apparent external difference between V1 and RB310 was that the latter had its engine inside the body (instead of mounting it separately on the body top above its tail as on V1) and air entered it through the side air intakes. The autopilot was also improved. The missile length was 4.73 m and its weight was 265 kg, and it could reach the speed of 620 km/h. They built 5 such devises all in all.

The development of RB310 was a larder RB311 missile which had a length of 6.7 m and its weight was about 900 kg. That “aerial torpedo” could reach the speed of 792 km/h. The built 10 missiles in 1948-1949.

The next in the family of created by the order of the Navy was the anti-ship SAAB RB315. The first few such “torpedoes” from 193-piece series were built by SAAB and the main part was built by CVA. The missile weight was 880 kg while its length was 4.7 m, and its diameter was 80 cm; it could reach the speed of 756 km/h. RB315 was tested in 1953-1959 including launches from Swedish Navy destroyers. Despite numerous improvements, the management of the servos controls was still carried out the same way as in V1, using compressed air. The fundamental difference from V1 and the previous Swedish missiles was the presence of four launch rocket engines that let RB315 accelerate to a speed of, sufficient for the pulse jet engine operation without a launch catapult.

Together with the Navy, the Swedish Air Force also carried out its own program for cruise missile development. A series of experimental RB301, RB302, RB303 missile, created within the program framework, was crowned with RB304 missile, adopted as an anti-ship fire-and-forget air-launched missile RB304 (Robot 04). In its creation the developments, obtained during the design of previous samples, were widely used and RB304 with its various modifications was in service in Sweden until 2000s and it can be also called a direct V1 descendant.

The “run-away” A4 adventures

As it was already mentioned above, one of the German missiles, that crashed in Sweden, was a long range V2 ballistic missile. On the 13th of May 1944 there was an overlap with a test missile no 4089 on which there was a radio control receiver unit installed (similar to the one that German anti-aircraft remote control missiles Wasserfal were equipped with). The operator, who was present at the launched for the first time, was so much excited by the sight of the take-off, that for some time he lost control over the vehicle. That moment was enough for V2 to vanish in cumulus clouds, and it was never seen by the Germans again. It was supposed that the missile would crash in the sea outside the Danish island of Bornholm, that had been occupied by the Germans, but everything turned out to be different.

The skittish missile flew 350 km, crossed the Baltic Sea and exploded about 1500 meters above the Swedish Smoland County in front of family of Erlandsson. Later George Erlandsson and his son Ivar recollected hoe the explosion blocked their ears, the horses sank down on their knees and glittering metal fragments started running down.

At first the Swedish military did not understand what happened and by the time the newspapers were forbidden to write about the incident, the Germans already knew where their “run-away” missile had gone. Walter Dornberger, the head of the missile research center in Peenemünde, from where the ill-fated V2 was launched, felt a certain excitement before the report to Hitler about the incident – after all, his brainchild fell on the territory of a neutral state.

However, the führer calmed him down and said that the incident was quite a good thing for the Swedes to realize that the Germans could bombard their country directly from the German territory. In order to comfort Hitler, Dornberger assured him that the secret V2 radio equipment was guaranteed to collapse in the explosion. And that was his great mistake. Most likely the missile exploded as a result the fuel tank malfunction but not the warhead. Therefore, the warhead, V2 engine and the secret radio equipment fell on the ground slightly damaged (almost intact).

The remains, found on the explosion spot and taken from the locals (who picked up the missile parts for souvenirs) were afterwards delivered by the Swedish military first to Air Regiment 12 in Kalmar and from there to the Defense Aeronautical Experiment Institute. Before telling about their further fate it is necessary to make a small digression devoted to the Swedish foreign policy peculiarities at that time.

At the beginning of WW2, the Swedish government treated Germany with a certain degree of sympathy. The Third Reich was a stable (and thanks to the military industry demands almost bottomless) market for Swedish iron ore. In practice the “pro-German” nature of the Swedish government was expressed in the fact that the German troops were allowed a passage through Sweden to Norway, occupied by Germany by that time and to Finland, also allied to the Reich (in total from 1940 to 1943 more than 2 million German soldiers were carried through the country). The newspaper circulation that published anti-nazi articles were often confiscated and eliminated and on the 22nd of June 1941 the country’s most popular newspaper “Аftonbladet” published the article entitled “The European Liberation War”.

As the time went on, it became clear that Germany’s victory chances were decreasing. After the Battle of Stalingrad anti-German articles stopped being confiscated in Sweden and after the Allied landings in Normady, Sweden finally turned the foreign policy vector towards the anti-Hitler coalition. Thanks to the abovementioned, twelve boxes of V2 wreckage were exchanged with Britain for a batch of Supermarine Spitfires.

The British were hoping that having received such detailed information about the German ballistic missile design they would be able to come up with the way to counter it. But the Swedish “discovery” misled the British. On the Swedish island of Öland there was a team of four British soldiers under the command of an officer in a small cabin with radio surveillance equipment that was supposed to help record V2 launches from Peenemünde (that was a flagrant breach Swedish neutrality and it vividly illustrated the drift of Swedish foreign policy towards anti-Hitler coalition). Unfortunately, no more than 20% of the launched German ballistic missiles were equipped with the remote radio control system, which had been found among V2 wreckage.

However, even if the British were able to record all German ballistic missile launches that would be difficult to extract practical benefits from the information. The reliable missile defense system creation that would be able to destroy enemy’s ballistic missiles-it is still a very difficult technical task even at the beginning of the 21st century and it seems to be very far from a complete solution.

Sources:

1. Shirer A. The Rise and Fall of the Third Reich, 1959;
2. Dornberger, Walter. V-2, Ballantine Books, New York 1954;
3. Reuter, Claus. The V2 and the German, Russian and American Rocket Program, S.R. Research & Publishing; 2 edition, 2000;
4. Tyska robotar som störtat i Sverige 1943–1944, dflund.se;
5. The Rocket and I dflund.se;
6. Allmänt om marinens försöksrobotar robotmuseum.se;
7. Zweden — Saab RB 310, Zweden — Saab RB 311 users.telenet.be/.