Sunday, August 11, 2013

Saab's two-stroke heritage


In the world of streamlined cars, few have been as efficient or built with such singularity of purpose as the Saab. That the car should have demonstrated such aerodynamic qualities should come as no surprise when one considers Saab, the Swedish Aeroplane Company Limited (Svenska Aeroplan AB) was first and foremost an aircraft manufacturer.

Sweden had long pursued a strict policy of neutrality in European affairs, but with Europe sliding slowly towards the Second World War, the government recognised the need to develop military self sufficiency. In 1937 the Svenska Aeroplan AB was established to build military aircraft. Their first project was the Saab 17 fighter-bomber, which took to the air in 1940. The Saab 17 would remain in service until 1955. Saab went on to build single and multi-engined fighters and bombers throughout the war years and by the end of the war were experimenting with jet aircraft.

As the Second World War drew towards its close, Saab's management recognised that there would be little post-war demand for their aircraft and began casting around for an alternative business opportunity. After considering a venture into the exciting world of fitted kitchens, they decided to investigate motor vehicles. Ironically however, almost no one at Saab knew much about motor cars. In fact, in the twenty man team assigned to the project, only three had a drivers license.

Project 92, led by engineer Gunnar Ljungström, commenced in 1945 in the greatest secrecy. To provide the team with some practical experience with motor vehicles several pre-war German cars were purchased for study. These included a DKW F8, a Hanomag, an Opel Kadet and a Volkswagen. Although the team didn't really know how to go about building a car, there was absolute clarity about what that car should be - it would be a budget car, costing less than 3200 Swedish Kroner, economical to run, modern and streamlined.

Ljungström turned to a former Saab employee, Sixten Sason, for the styling of the car. Sason had left Saab in the 1940s to become a futurist illustrator and he sketched out a number of futuristic design concepts, one of which was eventually turned into a 1/10th wooden model for wind tunnel testing. The testing returned an outstanding drag co-efficient of 0.32. In April 1946 a full scale wooden model was built for presentation to Saab management. The wooden body was coated in black shoe polish in lieu of paint. The response from management however wasn't as positive as the project team would have liked, but Ljungström's response has gone down in Saab legend "...if it can save 100 litres of fuel a year, it doesn’t matter if it looks like a frog."

Because look like a frog it did. This photo of the first test car was taken at Saab's Linkoping factory and airfield. The car would undergo significant modification.

Ljungström's view prevailed and the project pressed ahead. The next step was to build a functioning car; something Saab were still struggling with. A decision had been made to use a two-stroke engine but the design of the engine had not yet been finalised. Nor had the car's ladder chassis been built or tested, so a working mock up was constructed using a DKW F8 chassis and 688cc engine with a hand beaten steel body-shell. This became the Ursaab - the first Saab.

Saab's decision to use a two-stroke engine is often attributed to their unconventional and idiosyncratic approach to automobile design, but it was nothing of the sort. Firstly, two-stroke engines were simpler to build, having fewer moving parts than a four stroke, and were therefore well suited for a budget vehicle. Secondly, in terms of power output to size, two-strokes substantially outperformed four-strokes, and they were more economical to run in terms of fuel consumption and maintenance. Lastly, because two-stroke engines were lubricated through their fuel system and did not rely on oil sumps and pumps, they could be trusted to start even during Sweden's sub-zero winters.

Inside the engine bay of Saab 920001. The petrol tank comes directly from a DKW F8 and is stamped with the four rings logo of Auto-Union.

Under conditions of top secrecy the car underwent road testing. Although the first car was more DKW than Saab, there were lots of lessons to be learnt from the testing. By mid 1946 Saab's two-stroke engine was finally ready and was swapped into the car. Saab's two-stroke was based on DKW's trusty design and included a DKW style freewheel. The engine was a two cylinder 748cc engine delivering 25 horsepower and was mounted transversely driving the front wheels through a three-speed gearbox.

Four more prototypes were built and subjected to rigorous testing under the most trying of conditions, bashing through the trackless Swedish forests in all seasons. The cars survived their mistreatment and in 1947 Saab began adapting their Trollhatten factory to automobile production.

The lessons from the Ursaab testing were incorporated into design of the production vehicle. The fully enclosed wheel arches, which were a key feature of the Ursaab's aerodynamic streamlining, were dropped. In driving conditions they had proved to be a snow, sleet and mud trap. The steel bodywork was also found to be too heavy, especially on the doors. This was the result of Saab's unusual technique of stamping the entire body in a single pressing. The doors and bonnet were then cut from the pressing. Doors and bonnets were lightened and the bonnet and front-end was restyled and widened to allow easier removal of the engine. The bonnet was also hinged from the front instead of the rear in the Ursaab. Suspension was via Volkswagen style torsion bars.

Saab 92

Almost five years after Saab first initiated the Saab 92 car project, the car went on sale on 10 June 1949. The car came in only one colour - dark green; the paint was surplus from Saab's aircraft factory. 700 cars were built in the first year but production quickly ramped up and 20,000 had been built by the time production ceased in 1956.


Saab 93

In 1956 the Saab 92 was replaced by the Saab 93. Nicknamed the 'bullnose' because of its distinctive radiator styling, the car featured a new three-cylinder 748cc two-stroke engine. Although of no greater cubic capacity than the earlier two cylinder engine it was a better engine and developed 33 horsepower. The engine was longitudinally mounted but still had only three gears. To fit beneath the bonnet the engine was rotated some 15 degrees from upright.


Saab 96

Some 56,000 Saab 93's were built until the car was replaced by the Saab 96 in 1960. The new car was virtually identical to its predecessor baring minor improvements and changes to the instrumentation. In 1963 the 748cc engine was replaced with an 841cc engine developing 42 horsepower.

By 1965 two-stroke engines were generally viewed as old fashioned by the motoring public and Saab's sales began to ebb. Like DKW, Saab had built its name and fortune on its two-stroke engine and within the company there was strong resistance to changing the engine, especially from management who did not relish the cost to develop a new engine while Saab was enjoying outstanding success in racing and rallying. Nevertheless, the automobile department could see the writing on the wall and initiated a secret project to replace the two-stroke engine. Several different engines were trialled in secret locations around the country and in 1967 the new 95 V4 was released with a Ford Taunus V4 four stroke engine, bringing an end to Saab's two-stroke heritage.


All the two-stroke Saab's won fame in racing and rallying, but that's worth an article all to itself.

http://jalopnik.com/5747058/vintage-saab-rally-documentary

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Links
http://saabmuseum.com/en/saab-model/ursaab/
http://www.saabisti.fi/
http://www.vintagesaabclub.org/
http://www.vintagesaabmanuals.org/
http://www.vsaab.com/
http://www.swadeology.com/2012/01/for-sale-the-cars-at-the-saab-museum/
http://saabworld.net/f85/low-mileage-1962-saab-96-garage-find-garaged-but-not-driven-since-1978-a-1134/
http://saabworld.net/
http://heinkelscooter.blogspot.com.au/2013/09/1961-saab-96-modern-motor-review.html
http://heinkelscooter.blogspot.com.au/2013/10/the-saab-story-1965-us-promotional.html
http://heinkelscooter.blogspot.com.au/2013/10/saab-95-and-95-road-test.html

Thursday, August 1, 2013

Auto-Union Streamliners


Former Zeppelin engineer Paul Jaray was at the forefront of streamlined automobile design in the 1920s. He lodged his first automobile patent in 1921 and the following year he had built a series of prototype vehicles for Audi, Ley and Dixi. Unfortunately, none of the these radically new vehicles proved practical enough to go into production. In fact the negative reaction to the 'Ugly Ducklings' set back the streamlining movement almost ten years. Despite this failed experiment, Paul Jaray continued working on improving and refining his designs and in 1927 he founded Stromlinien Karosserie Gesellschaft in Switzerland and became a consulting engineer.

Paul Jaray's early streamlined car designs were clearly influenced by his work at Zeppelin and featured cramped seating and poor use of interior space.

By the 1930s automotive streamlining was back on the agenda and numerous car companies initiated experimental projects. Auto Union, the Saxon automotive conglomerate was again in the forefront of developments, with several interesting projects based on Paul Jaray patents. The company pursued two tracks - a traditional front-engined layout and experimental rear-engined project.

The rear-engined project resulted in a the construction of single research vehicle which borrowed some design styling from the Czechoslovakian Tatra T77. The rear-engine layout was not pursued, but the streamlined wooden bodywork was applied to the DKW Schwebeklasse of 1935.

The front engined Jaray prototypes were an improvement over the 1921 experiment. Several examples were built, including this Audi model above.

In 1935 DKW fitted a Jaray patented streamlined body to an F5 Sonderklasse. The result was a handsome, modern looking vehicle with fully enclosed wheel arches and headlights. The body was built by Hornig-Karosserie.


The Wanderers

With a successful concept in hand, Auto Union returned to motorsport in order to develop the design further. For the 1938 Liege-Rome-Liege endurance race, Wanderer constructed three streamlined racers. The cars were something of a hybrid, combining Wanderer's W-24 chassis, mounting a DKW schwebeklasse floating axle and powered by a 2 litre W-25K engine with triple carburetors. The engines were not supercharged however and rated only 40 horsepower, but the aerodynamic effect of the lightweight aluminum bodywork delivered the cars the performance equivalent of 70 horsepower. Although the cars had a top speed of 160 kilometres per hour breakdowns prevented any of the cars completing the race.

The cars performed better the following year with better tuned engines. One car tying for 4th and another gaining 11th position.

The DKWs

For the 1938 Berlin to Rome endurance race chief DKW designer William Werner fielded three streamliners based on the Wanderer design. The cars were fitted with 700cc four-cylinder twin-V engines with priming cylinders. Strikingly, these little engines delivered 40 horsepower - the equivalent power output of Wanderer's 2 litre engines - and could push the cars along at 140kph.

For the 1939 Berlin to Rome race the DKW team trialed different engines in the cars, including a tuned two-cylinder 700cc two stroke from the contemporary F7, the four-cylinder 1000cc engine of the DKW Schweberlasse and their new three cylinder 900cc engine. Further improvements were planned for 1940, but were put on hold by the war.

This DKW Rome-Berlin stromliner was photographed in Baden-Wurttemberg after the war but then disappeared.

Production Vehicles
Auto-Union's central design team in Chemnitz took the lessons learned on its streamlined endurance racers to develop a series of modern, streamlined passenger vehicles. The result was three exceptional machines, two of which never really made it passed the prototype stage and one that went on to become the foundation of DKW's post-war success.

Horch 930S

Horch unveiled its new luxury limousine, the 930S, at the Berlin Auto Show in 1939. Designed by Günter Mickwausch, Georg Böhm and John Hufnagel, the chassis was based on the 930V of 1935 and mounted a V-8 3.9 litre engine. The hand crafted bodywork was closely modeled on the DKW-Wanderer endurance streamliners of 1938. The car was a sensation, with all the luxury fittings, such as a fold out washbasin behind the front wheel, that were the trademark of the Horch brand. Performance tests on the Dessau racetrack clocked the 2300 kilogram car at 178 kilometres per hour. Only three cars were built before the war intervened.


DKW F9 Hohnklasse

Meanwhile, over at DKW, William Werner's design team were working on a budget version of the design. The F9 Hohnklasse (high class) was also based on the DKW-Wanderer design and featured the new three-cylinder two-stroke engine. The car shared styling with the Horch 930S, which is especially apparent when the vehicles are viewed from the rear quarter. Ten pre-production examples were built before the war. http://heinkelscooter.blogspot.com.au/2012/12/1939-dkw-f9-prototype.html


Wanderer W-31

The ultimate aim of the 'Hohnklasse' project was to establish a single Auto-Union type which would have variants across the brands' market segments. The DKW F9 would be the budget, entry level version. A Wanderer version, powered by a Wanderer 6 cylinder engine, would be offered to the middle class  The car was originally designated the W-31, but was then renamed either the W-4 or W-6, depending on whether a four cylinder or six cylinder engine was installed. The car barely made it past prototype stage. A four door sedan and two door coupe prototype were built and presented in May 1939, before all further development ceased when all Auto-Union civilian car production shut down in 1940.


The War and its Aftermath
In 1940 Auto Union shut down its racing department and placed all the cars in storage. Amongst the horde were all six DKW and Wanderer streamline endurance racers, the Silver Arrows, and the AVUS record breaking car. When the war turned against Germany and Auto Union's factories came under attack, the collection was distributed to more secure locations. Some cars were moved west, while others were hidden in underground bunkers and mines. Despite this the cars were found and seized by the Soviets after the end of the war and shipped back to Russia for study. With assistance from Auto-Union engineers, a number of V16 racers were built and tested. After trials, the project was abandoned as the Soviets opted not to compete in the international Grand Prix circuit. The seized racers were originally intended to be scrapped symbols of Nazism, but several were sent for exhibition in Czechoslovakia and Latvia and escaped destruction. They were eventually put in storage and largely forgotten. After the Fall of Communism they disappeared in mysterious circumstances before eventually re-emerging and were recovered by Audi Tradition, who spared no expense restoring these extraordinary machines.

The Wanderer W-31 and the endurance racers, along with all plans and blueprints were destroyed during the war. A handful of photographs are all that remain. Audi Tradition decided to recreated the trio of Wanderer endurance racers as exhibition vehicles. Without blueprints or documentation for the original cars, these cars were modeled off original photographs with modern running gear underneath.



A single Horch 930S escaped destruction in hands of race driver Tazio Nuvolari, who took it to Switzerland. The car was returned to Germany after the war and was preserved by Audi Tradition in Ingolstadt. It now resides at the Audi Museum. The Soviets found six 930S chassis at the Horch factory at the end of the war and between 1948 and 1952 complete cars were constructed using spare and scrounged parts. The cars were distributed to Soviet and East German communist party officials, who were so pleased with the results that VEB, the East German automotive collective, officially commissioned Horch to build limousines. These were known as the Sachsenring P240 and the unique Horch 950S. One of each of these cars is on display at the August Horch Museum in Zwickau.

The surviving 1948 Horch 930S was found in Riga, Latvia and restored for the August Horch museum in Zwickau. The post-war 930S' had a different front end to the prewar models.


Only the F9 survived the war to be resurrected as both the DKW F89 in the West and the IFA F9. Although most of the car's blueprints were lost during the war, three examples survived. One complete car was found in Leipzig and became the template for the IFA F9. A body shell was found in Spandau and shipped to Ingolstadt where it became the template for the DKW F89. DKW however did not have complete car or engine, so the new DKW car used a modified F8 chassis and 700cc engine. The third car escaped intact, was commandeered by the British and later shipped to Australia, where it was later recovered by Audi Tradition. The F9, in all its guises, proved to be an outstanding success, both in the West and in the East. For more information see https://dkwautounionproject.blogspot.com/2017/07/dkw-germanys-post-war-wonder-car.htmlmanys-post-war-wonder-car.html and http://heinkelscooter.blogspot.com/2011/02/veb-sachsenring-east-germanys-peoples.html

The first post war F9 is unveiled at the Leipzig Motor Show in 1949 by IFA.

A DKW F91 and IFA F9 parked side by side highlights both their similarities and differences.