The Auto UnionGrand Prix racing cars types A to D were developed and built by a specialist racing department ofAuto Union'sHorch works inZwickau, Germany, between 1933 and 1939, after the company bought a design by Dr.Ferdinand Porsche in 1933. The Auto Union type B streamlined body was designed byPaul Jaray.[1]
Of the fourAuto Union racing cars, the Types A, B and C, used from 1934 to 1937 had supercharged V16 engines, and the final car, the Type D used in 1938 and 1939 (built to new 1938 regulations), had a supercharged 3L V12 that developed almost 550 horsepower. All of the designs were difficult to handle due to extreme power/weight ratios (wheelspin could be induced at over 100 mph (160 km/h)), and markedoversteer due to uneven weight distribution (all models were tail heavy). The Type D was easier to drive because of its smaller, lower mass engine that was better positioned toward the vehicle's center of mass.
Between 1935 and 1937, Auto Unions won 25 races, driven byErnst von Delius,Tazio Nuvolari,Bernd Rosemeyer,Hans Stuck andAchille Varzi. Auto Union proved particularly successful in the 1936 and 1937 seasons. Their main competition came from the Mercedes Benz team, which also raced sleek, silver cars. Known as theSilver Arrows, the cars of the two German teams dominated Grand Prix racing until the outbreak ofWorld War II in 1939.
Having been made redundant fromSteyr Automobile, Dr.Ferdinand Porsche foundedPorsche inStuttgart, with engineering colleagues includingKarl Rabe, and financial backing fromAdolf Rosenberger. Unfortunately, car commissions were low in the depressed economic climate, so Porsche founded the subsidiary companyHochleistungsfahrzeugbau GmbH (HFB) (High Performance Car Ltd.) in 1932 to develop aracing car, for which he had no customer.[2]
In 1933, Grand Prix racing was dominated by French and Italian marquesBugatti,Alfa Romeo andMaserati. In early 1933, governing bodyAIACR announced a new formula, with the main regulation that the weight of the car without driver, fuel, oil, water and tyre was not allowed to exceed 750 kg (1,650 lb). This was created to restrict the size of engine that could be used, with the authority estimating that this weight limit would allow around 2.5-litre engines.[3]
Based onMax Wagner'smid-engined1923 BenzTropfenwagen, or "Teardrop" aerodynamic design, also built in part by Rumpler engineers,[4] the experimentalP-Wagen project racing car (P stood for Porsche) was designed according to the regulations of the 750 kg formula. On 15 November chief engineer Rabe submitted the first draft to the planning office of a racing car for the new formula, with Josef Kales responsible for theV16 engine, while Rabe also held responsibility for the chassis.[2]
In 1932Auto UnionGmbh was formed, comprising struggling auto manufacturersAudi,DKW,Horch andWanderer. The chairman of the board of Directors, BaronKlaus von Oertzen wanted a show piece project, so at fellow director Adolf Rosenberger's insistence, von Oertzen met with Porsche, who had done work for him before.[2]
At the 1933 Berlin Motor Show,German ChancellorAdolf Hitler announced two new programs:[2]
German racing driverHans Stuck had met Hitler before he became Chancellor, and not being able to gain a seat at Mercedes, accepted the invitation of Rosenberger to join him, von Oertzen, and Porsche in approaching the Chancellor. In a meeting in theReich Chancellery, Hitler agreed with Porsche that for the glory of Germany, it would be better for two companies to develop the project, resulting in Hitler agreeing to pay£40,000 for the country's best racing car of 1934, as well as an annual stipend of 250,000Reichsmarks[2] (£20,000)[5] each for Mercedes and Auto Union. (In time, this would climb to £250,000.)[6] This highly annoyed Mercedes, who had already developed theirMercedes-Benz W25, which nevertheless was gratified, its racing program having financial difficulties since 1931.[6] It resulted in a heated exchange both on and off the racing track between the two companies until World War Two.
Having garnered state funds, Auto Union boughtHochleistungs Motor GmbH and hence the P-Wagen Project for 75,000Reichsmarks, relocating the company toChemnitz.[2]
Therear mid-engine, rear-wheel-drive layout was unusual at the time. From front to rear the layout comprised radiator, driver, fuel tank, and engine. The layout would return to Grand Prix racing in the late 1950s by British manufacturerCooper Car Company.
The problem with early mid-engined design was the stiffness of the contemporaryladder chassis andsuspension. The car's turning angle changed as the momentum of the centrally mounted engine increased on thechassis, causingoversteer. All Auto Unions hadindependent suspension, with paralleltrailing arms andtorsion bars at the front. At the rear, Dr. Porsche tried to counter the tendency to oversteer by using a then-advancedswing axle suspension on the early cars. On the later Type D, rear suspension was ade Dion system, following the lead ofMercedes-Benz, but thesuperchargedengines eventually produced almost 550horsepower, which exacerbated theoversteer.
The original Porsche-designedV16 was modified as aV12 when in 1938 the Grand Prix regulations set a limit of 3 litres on supercharged engines. Originally designed as a 6-litre, the first Auto Union engines displaced 4,360 cc and developed 295 PS (217 kW). They had two cylinder blocks, inclined at an angle of 45 degrees, with a singleoverhead camshaft to operate all 32 valves. The intake valves in thehemispherical cylinder heads were connected to thecamshaft byrocker arms, while for the exhaust valves the rocker arms were connected to the camshaft bypushrods that passed through tubes situated above the spark plugs; thus the engine had threevalve covers. The engine provided optimumtorque at low engine speeds, andBernd Rosemeyer later drove an Auto Union around theNürburgring in a single gear to prove the engine's flexibility.
The body underwent wind-tunnel testing at theGerman Institute for Aerodynamics, a scientific organization that still exists. With the fuel tank located in the centre of the car directly behind the driver, the front-rearweight distribution remained unchanged as the fuel was used; the same location is used in modern open-wheel racing cars for the same reason. The chassis tubes originally piped coolant from the radiator to the engine, but this was eventually abandoned owing to leaks.
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The development of Auto Union racing cars began 1933 by specialists ofHorch works. The first cars ran in the winter 1933/34, on theNürburgring,AVUS andMonza. Further development was stopped completely in 1942.
Unlike Mercedes, who had former racing driver turned designerRudolf Uhlenhaut, who could provide excellent feedback on the car and required developments; Auto Union were forced to create in-car measuring systems to provide additional feedback. Auto Union used aclockwork mechanism and a paper disc to record data such as engine revs while the car was being tested, allowing the engineers to study the collected data at a later date.[3] It was found that additional work was needed on the car's cornering behaviour, as accelerating out of a corner would cause the inside rear wheel to spin furiously. This was much abated by the use of a Porsche innovation,limited slip differential, manufactured byZF, which was introduced at the end of the 1935 season.
Co-operation between Porsche and Auto Union continued through the Types A, B and C,[7] until the 750 kg (1,650 lb) formula ended in 1937, as engineering developments had resulted in engines producing great horsepower in lightweight vehicles, and hence high speeds and excessive accidents. Dr. Ing.Robert Eberan von Eberhorst was responsible for the new Type D car,[8] which while still retaining the 750 kg (1,650 lb) minimum weight, also restricted capacity to 3 litres with a supercharger, or 4.5 litres without. The Type D employed a12-cylinder engine, while the hillclimb versions, where the capacity limit was not enforced, used a different gearbox and final drive to retain the 16-cylinder engine of the Type C.
This section includes only results of second or better.
The list of drivers for the initial 1934 season was headed byHans Stuck; he won theGerman,Swiss andCzechoslovakian Grand Prix races (as well as finishing second in theItalian Grand Prix andEifelrennen), along with wins in a number of hill-climb races, becoming European Mountain Champion. (There was noEuropean Championship for the circuit races that year).August Momberger placed second in the Swiss Grand Prix.
In 1935, the engine had been enlarged to five litres displacement, producing 370 bhp (280 kW).Achille Varzi joined the team and won theTunis Grand Prix inCarthage and theCoppa Acerbo inPescara (along with placing second in theTripoli Grand Prix). Stuck won the Italian Grand Prix (along with second at the German Grand Prix), plus his usual collection of hill-climb wins, again taking the European Mountain Championship. The new sensation,Bernd Rosemeyer, won the Czech Grand Prix (and managed a second at the Eifelrennen and Coppa Acerbo).
Hans Stuck also managed to break speed records, reaching 199 mph (320 km/h) on an Italian autostrada in a streamlined car with enclosed cockpit.[9] Lessons learned from this streamlining were later applied to Stuck'sMercedes-Benz T80 land speed record car.
For 1936, the engine had grown to the full 6 litres, and was now producing 520 bhp (390 kW); and reaching 258 mph (415 km/h) in the hands of Rosemeyer and his teammates, the Auto Union Type C dominated the racing world. Rosemeyer won theEifelrennen, German, Swiss and Italian Grands Prix and the Coppa Acerbo (as well as second in theHungarian Grand Prix). He was crownedEuropean Champion (Auto Union's only win of the driver's championship), and for good measure also took the European Mountain Championship. Varzi won the Tripoli Grand Prix (and took second at theMonaco,Milan and Swiss Grands Prix). Stuck placed second in the Tripoli and German Grands Prix, andErnst von Delius took second in the Coppa Acerbo.
In 1937, the car was basically unchanged and did surprisingly well against the newMercedes-Benz W125, winning 5 races to the 7 of Mercedes-Benz. Rosemeyer took the Eifelrennen andDonington Grand Prix, theCoppa Acerbo, and theVanderbilt Cup (and well as second in the Tripoli Grand Prix).Rudolf Hasse won theBelgian Grand Prix (Stuck placed second). Von Delius managed second in theAvus Grand Prix.
In addition to the new 3-litre formula, 1938 brought other challenges, principally the death of Rosemeyer early in the year, in an attempt on theland speed record. The famedTazio Nuvolari joined the team, and won the Italian and Donington Grands Prix, in what was otherwise a thin year for the team, other than yet another European Mountain Championship for Stuck.
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In 1939, as war clouds gathered over Europe, Nuvolari won theYugoslavia Grand Prix in Belgrade (with a second place in the Eifel).Hermann P. Müller won the1939 French Grand Prix (and took second in the German Grand Prix). Hasse managed a second place in the1939 Belgian Grand Prix, andGeorg Meier a second in the French.
(key) (results inbold indicate pole position, results initalics indicate fastest lap)
| Year | Entrant | Chassis | Engine | Drivers | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 1935 | Auto Union AG | Auto Union B | 5.6V16 | MON | FRA | BEL | GER | SUI | ITA | ESP | |
 Achille Varzi | 5 | ||||||||||
 Hans Stuck | Ret | ||||||||||
| 5.0V16 | Bernd Rosemeyer | Ret | 4 | 3 | Ret | 5 | |||||
| Hans Stuck | 2 | 11 | 1 | Ret | |||||||
| Achille Varzi | 8 | 4 | Ret | Ret | |||||||
| Paul Pietsch | 9 | 3 | DNS | ||||||||
| 1936 | Auto Union AG | Auto Union C | 6.0V16 | MON | GER | SUI | ITA | ||||
| Bernd Rosemeyer | Ret | 1 | 1 | 1 | |||||||
| Hans Stuck | 3 | 2 | 3 | Ret | |||||||
| Achille Varzi | 2 | 2 | Ret | ||||||||
| Ernst von Delius | DNS | 6 | 3 | ||||||||
| Rudolf Hasse | 4 | 5 | DNS | ||||||||
| 1937 | Auto Union AG | Auto Union C | 6.0V16 | BEL | GER | MON | SUI | ITA | |||
| Hans Stuck | 2 | Ret | 4 | 4 | 9 | ||||||
| Rudolf Hasse | 1 | 5 | Ret | ||||||||
| Hermann Paul Müller | Ret | Ret | 5 | ||||||||
| Bernd Rosemeyer | 3 | Ret | Ret | 3 | |||||||
| Luigi Fagioli | DNS | 7 | |||||||||
| Ernst von Delius | Ret | ||||||||||
| Tazio Nuvolari | 5 | ||||||||||
| Achille Varzi | 6 | ||||||||||
| 1938 | Auto Union AG | Auto Union D | 3.0V12 | FRA | GER | SUI | ITA | ||||
| Hermann Paul Müller | DNS | 4 | Ret | Ret | |||||||
| Rudolf Hasse | Ret | Ret | |||||||||
 Christian Kautz | Ret | Ret | Ret | ||||||||
| Hans Stuck | 3 | 4 | Ret | ||||||||
| Tazio Nuvolari | Ret | 9 | 1 | ||||||||
| Ulrich Bigalke | DNS | ||||||||||
| 1939 | Auto Union AG | Auto Union D | 3.0V12 | BEL | FRA | GER | SUI | ||||
| Hermann Paul Müller | Ret | 1 | 2 | 4 | |||||||
| Tazio Nuvolari | Ret | Ret | Ret | 5 | |||||||
| Rudolf Hasse | 2 | DNS | Ret | Ret | |||||||
| Georg Meier | Ret | 2 | Ret | ||||||||
| Hans Stuck | 6 | Ret | 10 | ||||||||
Source:[10] | |||||||||||
Very rarely were racing cars of the period kept, as components of early cars if required were scavenged for later models and repairs. Secondly, what did remain was often scrapped to provide funds for additional development.
During the latter part ofWorld War II, an estimated eighteen Auto Union team cars were hidden in acolliery outsideZwickau, Saxony, where the Auto Union race shop was based. In 1945 the invadingRussian Army discovered the cars, and they were retained as war possessions. As Zwickau post-war was located in Soviet controlledCommunistEast Germany, what little of the Auto Union racing cars existed were shipped back to theSoviet Union, distributed to scientific institutes and motor manufacturers includingNAMI for research. The Auto Union company itself was forced to relocate toWest Germany, where it was re-incorporated inIngolstadt in 1949, ultimately evolving intoAudi as it is known today.
Today, it is believed that most of the cars were probably reduced to scrap, and that no Type A or Type B cars still exist. Presently it is believed that only one Type C car, three Type D cars, and a Type C/D hill climbing car remain.
The sole remaining Type C was originally left to a German museum by Auto Union, after the death ofBernd Rosemeyer resulted in only two or three of these historic cars running. Damaged by bombing during the war, its body today still shows these marks. In 1979/80,Audi commissioned restoration of the car, undertaking a preservation-level overhaul to the body, engine and transmission.
Another car was taken to Moscow to study its technology. In 1976, it was at theZIL factory in Moscow and scheduled to be cut up for scrap metal when Viktors Kulbergs, president of the Antique Automobile Club of Latvia, brought it for theRiga Motor Museum.
After the collapse of the Soviet Union, Audi engineers authenticated the car as a 16-cylinder hill-climbing Auto Union that combined types C and D. Audi acquired it in exchange for a replica, on the condition that all non-replaceable parts were kept on the original car and the replica was built with replaceable parts plus one-off made parts that were originally on an Audi-made replica. Purchase/exchange was done for an undisclosed sum of money, and in 1997 British engineering companiesCrostwaite & Gardiner ofBuxted andRoach Manufacturing ofOwer were commissioned to restore the original and create the replica. The original, which now resides in the Audi Motor Museum, appears at car shows and is also demonstrated at race meetings by long-time Audi racing driverHans Stuck Jr., son of the original driver Hans Stuck. The replica, which was unveiled at the 2007Festival of Speed atGoodwood House, England, withPink Floyd drummerNick Mason as driver,[11] is exhibited inRiga.[12]
American car enthusiast Paul Karassik tracked down chassis No.19 in Russia, adding an original engine from a separate D-type carcass and handing it over in 1990 toCrosthwaite and Gardiner to restore to its original form. In February 2007, it was due to be auctioned byChristie's in Paris.[13] Although expected to be the most expensive car ever sold at auction at more than $12 million, the car did not find a buyer in the sealed auction. This was because of a discrepancy that was found with the chassis and engine numbers and the fact that they did not correspond with the numbers expected to be found on the car that it was believed to be.[14] The car went onauction in August 2009, withBonhams estimating a sale price of around £5.5million.[15] During Bonhams 2009 Monterey auction, the bidding stalled at $6 million, and the vehicle was not sold.[16]
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For 2000, Audi commissioned a Type C Streamline, which in May 2000 raced around the banked curve of the famousMontlhéry circuit. This was 63 years after its premier at AVUS in May 1937, when Bernd Rosemeyer took a car of this type to a speed of 380 km/h (236 mph) on the straights.[12] Now resident in the Audi Mobile museum in Ingolstadt, the car has appeared at various autoshows around the world, including the 2009Goodwood Festival of Speed commemorating Audi's 100th birthday.[12]
In 2004, Audi announced the rebuilding of Auto Union Wanderer Streamline Specials. The three cars were built by European car restorer Werner Zinke GmbH. As part of the celebration, Audi Tradition commissioned a limited edition 1:43 scale model of the car, bearing the start number 17.[17] The rebuilt cars also entered theLiège–Rome–Liège long-distance run 65 years after their original Liège-Rome-Liège runs.[18] Two of the cars, owned by Audi Tradition, went on display in its Museum in Ingolstadt, while the third car is owned by Belgian Audi importer D'Ieteren.[19]
In 1947,Automobiltechnisches Büro (ATB) created theSokol Typ 650Formula Two racer in theGerman Democratic Republic, using the talents of chassis designer Otto Seidan and engine designer Walther Träger (both former Auto Union employees), along with spare Auto Union parts and resembled the Type D. AsAwtowelo it was successfully tested but never raced.
In 2007, Audi announced the sale of 999 1:2 scale Auto Union Type C pedal cars. The car was designed at Munich design studio. It features hydraulic dual-disc brake and its speed is controlled by the 7-speed hub gear with back-pedalling brake function. The car was made from aluminium space frame and the aluminium body panels. The seats, framing and steering wheel have been upholstered in leather by a bag-maker, as in the Audi TT, while the spoke wheels were custom-made. The steering wheel can be removed to make getting in and out easier, as in the original. The prototype of the pedal car was unveiled at theParis Motor Show in autumn 2006.[20]
It is a version of 1:2 scale Auto Union Type C made of aluminum and carbon-look material, based on the Type C pedal car. It included rear wheel drive electric motor rated 1.5 PS (1 kW; 1 hp) and 40 N⋅m (29.50 lb⋅ft) (maximum 60 N⋅m (44.25 lb⋅ft)), a lithium-ion battery, a reverse gear. The vehicle has range of around 25 km (15.53 mi), with top speed of 30 km/h (18.64 mph). The battery can be charged at a standard 230 volt household socket.
The vehicle was unveiled in 62nd International Toy Fair in Nuremberg.[21]
| Auto Union Racing Cars | |||||
|---|---|---|---|---|---|
| characteristic | Type A (1934) | Type B (1935) | Type C (1936–37) | Type D (1938–39) | |
image |  | .jpg) | .jpg) |  | |
| engine orientation | longitudinal | longitudinal | longitudinal | longitudinal | |
| engine configuration | V16 | V16 | V16 | V12 | |
| cylinder bank angle | 45° | 45° | 45° | 60° | |
| engine displacement | 4,358cubic centimetres (265.9 cu in) | 4,954 cubic centimetres (302.3 cu in) | 6,008 cubic centimetres (366.6 cu in) | 2,986 cubic centimetres (182.2 cu in) | |
| bore xstroke | 68 mm (2.68 in) x 75 mm (2.95 in) | 72.5 mm (2.85 in) x 75 mm (2.95 in) | 75 mm (2.95 in) x 85 mm (3.35 in) | 65 mm (2.56 in) x 75 mm (2.95 in) | |
| crankshaft | one-piece from Cr-Ni steel | one-piece from Cr-Ni steel | slidingstored (Hirth) | roll-stored | |
| valvetrain, ignition system | single camshaft | single camshaft | single camshaft, 2x ignition magnetos | triple camshaft | |
| aspiration | 1xRoots supercharger | 1x Roots supercharger | 1x Roots supercharger | 1 or 2x Roots supercharger | |
| compressor pressure | 0.61bars (8.8 psi) | 0.75 bars (10.9 psi) | 0.95 bars (13.8 psi) (max) | 1.67 bars (24.2 psi) | |
| motivepower | 295 PS (217 kW; 291 hp) @ 4,500 rpm | 375 PS (276 kW; 370 hp) @ 4,800 rpm | 685–820 PS (504–603 kW; 676–809 hp) @ 5,000 rpm | 420–460 PS (309–338 kW; 414–454 hp) @ 7,000 rpm | |
| torque | 530 N⋅m (391 lbf⋅ft) @ 2,700 rpm | 660 N⋅m (487 lbf⋅ft) @ 2,700 rpm | 1,182 N⋅m (872 lbf⋅ft) @ 2,500 rpm | 550 N⋅m (406 lbf⋅ft) @ 4,000 rpm | |
| transmission gears | 5 | 5 | 5 | 5 | |
| maximum speed | 280 km/h (174 mph) | 340 km/h (211 mph) | 340 km/h (211 mph) | ||
| brakes | 400 mm (15.7 in), system Porsche hydraulic | 400 mm (15.7 in), system Porsche hydraulic | 400 mm (15.7 in), system Porsche hydraulic | 400 mm (15.7 in), system Porsche hydraulic | |
| shock absorber | friction absorber | friction absorber | friction absorber | front: hydraulic rear: hydraulic/friction | |
| frontsuspension | Crank semi-trailing arm (seeVolkswagen Beetle) | Crank semi-trailing arm | |||
| rear suspension | Swing axle with torsion bar suspension (in the back) | De-Dion-axle with torsion bar suspension | |||
| chassis | steel tube ladder framework, main pipe diameter: 75 mm (3.0 in) | steel tube ladder framework, main pipe diameter: 75 mm (3.0 in) | steel tube ladder framework, main pipe diameter: 105 mm (4.1 in) | steel tube ladder framework, main pipe diameter: 105 mm (4.1 in) | |
| wheelbase | 2,900 mm (114.2 in) | 2,800 mm (110.2 in) | |||
| axle track width | 1,420 mm (55.9 in) | 1,390 mm (54.7 in) | |||
| dimensions length × width × height | 3,920 mm (154.3 in) × 1,690 mm (66.5 in) × 1,020 mm (40.2 in) | 4,200 mm (165.4 in) × 1,660 mm (65.4 in) × 1,060 mm (41.7 in) | |||
| fuel capacity | 200 L (44.0 imp gal; 52.8 US gal) | ||||
| dry weight | 825 kg (1,819 lb) | 825 kg (1,819 lb) | 824 kg (1,817 lb) | 850 kg (1,874 lb) | |
| notes | Type D brought about by change of rules | ||||
