DKW STREAMLINER - 1938

I was inspired by a photograph offered by Tim Green (the best motorcycle book and ephemera dealer on ebay) to investigate some DKW history, as the photo shows such an intriguing machine; a full 'egg' streamliner with small sidestand, being examined by a host of interested observers.

The photo was taken during 'World Record Week', October 26, 1938, outside Frankfurt-am-Main, which has a fairly straight and flat autobahn (I was there a month ago - which Route did they use, my German readers?). I presume the 'Record Week' meant that the various car and motorcycle factories had access to the autobahn for a period of time during each day, and the timekeeping facilities/staff were kept on hand full-time.

This enclosed DKW was a 500cc model (a supercharged two-stroke twin of course, since that's what the factory was racing at the time - see drawing of the body), and the body was designed by streamlining expert Baron Reinhard von Koenig-Fachsenfeld, the inventor in 1936 of the chopped tail on cars (later called the 'Kamm' tail after Wunibald Kamm developed the idea). The Baron used windtunnel testing at F.K.F.S. (read about it in the link) in Stuttgart - home of DKW - to find a shape with minimal drag.

The tail on this bike (not a 'Kamm' tail - that was designed for cars as a production compromise to 'ideal' streamlining) features a novel 'air brake'; the end of the tail fin has two flaps which can spread out to create drag in the slipstream (see pic of the Baron demonstrating below). And I'd like to know if those flaps are hydraulic, or if the rider had a 'brake pedal' to push, or perhaps even linked braking, like a Rudge.

There were problems with the full enclosure, though, and a combination of handling issues (the record runs in '38 had to be abandoned due to prevailing winds), and poor rider visibility/fumes/discomfort while sealed into the 'egg' put paid to this shape.





Thus, in later runs, the top of the streamliner was cut off, to the level shown on the pic above. This version still had handling issues, and the enclosure was cut down further to the shape seen below; interesting as this progression presages the trend from 'dustbin' fairings to 'dolphin' fairings in GP racing, post-war. Dustbins and other front-wheel enclosing streamliners are extremely sensitive to side winds, and can be dangerous at high speeds. Leaving the front wheel 'in the breeze' makes a huge difference to the ability of the machine to take an angular blast of wind, and remain stable enough to make course corrections.



Several factories in Europe experimented with enclosures on their fastest machines during the 1930s, most famously BMW and Gilera, and put up some very fast speeds before the War - almost 200mph from 500cc ohc engines.

DKW STREAMLINER - 1938

I was inspired by a photograph offered by Tim Green (the best motorcycle book and ephemera dealer on ebay) to investigate some DKW history, as the photo shows such an intriguing machine; a full 'egg' streamliner with small sidestand, being examined by a host of interested observers.

The photo was taken during 'World Record Week', October 26, 1938, outside Frankfurt-am-Main, which has a fairly straight and flat autobahn (I was there a month ago - which Route did they use, my German readers?). I presume the 'Record Week' meant that the various car and motorcycle factories had access to the autobahn for a period of time during each day, and the timekeeping facilities/staff were kept on hand full-time.

This enclosed DKW was a 500cc model (a supercharged two-stroke twin of course, since that's what the factory was racing at the time - see drawing of the body), and the body was designed by streamlining expert Baron Reinhard von Koenig-Fachsenfeld, the inventor in 1936 of the chopped tail on cars (later called the 'Kamm' tail after Wunibald Kamm developed the idea). The Baron used windtunnel testing at F.K.F.S. (read about it in the link) in Stuttgart - home of DKW - to find a shape with minimal drag.

The tail on this bike (not a 'Kamm' tail - that was designed for cars as a production compromise to 'ideal' streamlining) features a novel 'air brake'; the end of the tail fin has two flaps which can spread out to create drag in the slipstream (see pic of the Baron demonstrating below). And I'd like to know if those flaps are hydraulic, or if the rider had a 'brake pedal' to push, or perhaps even linked braking, like a Rudge.

There were problems with the full enclosure, though, and a combination of handling issues (the record runs in '38 had to be abandoned due to prevailing winds), and poor rider visibility/fumes/discomfort while sealed into the 'egg' put paid to this shape.





Thus, in later runs, the top of the streamliner was cut off, to the level shown on the pic above. This version still had handling issues, and the enclosure was cut down further to the shape seen below; interesting as this progression presages the trend from 'dustbin' fairings to 'dolphin' fairings in GP racing, post-war. Dustbins and other front-wheel enclosing streamliners are extremely sensitive to side winds, and can be dangerous at high speeds. Leaving the front wheel 'in the breeze' makes a huge difference to the ability of the machine to take an angular blast of wind, and remain stable enough to make course corrections.



Several factories in Europe experimented with enclosures on their fastest machines during the 1930s, most famously BMW and Gilera, and put up some very fast speeds before the War - almost 200mph from 500cc ohc engines.

RACING DKW'S

by Dennis Quinlan

[I thought it relevant to reproduce Dennis' post on racing DKW's, and his plea for information about these photographs. These are the same machines pictured in my previous post about Ziegler's models.]

These photos are from my archive; I need some help indentifying the places where they were taken, and the dates... so any of you with literature from the period, drop me a line to help out with the ID. The top photo is Walfreid Winkler prewar on his DKW.


Ewald Kluge, 350cc Works DKW, likely during 1951-53 in the photo below. Note interesting headgear! [Machine looks like the 3-cyl 'singing saw' - pd'o]Rider #50 looks very much like Ewald Kluge, and if this is so, and it is the Belgian GP 1939, then he won that race, and continued on to be 'Champion of Europe' after winning 4 out of 7 races towards the championship.

This photo of the DKW and the 'Malmeoy' sign is probably taken at the Belgian Grand Prix at Spa-Francorchamps on July 16, 1939.

These two photos show the same machine, #132. [Note the studded front and ribbed rear tires!]

RACING DKW'S

by Dennis Quinlan

[I thought it relevant to reproduce Dennis' post on racing DKW's, and his plea for information about these photographs. These are the same machines pictured in my previous post about Ziegler's models.]

These photos are from my archive; I need some help indentifying the places where they were taken, and the dates... so any of you with literature from the period, drop me a line to help out with the ID. The top photo is Walfreid Winkler prewar on his DKW.


Ewald Kluge, 350cc Works DKW, likely during 1951-53 in the photo below. Note interesting headgear! [Machine looks like the 3-cyl 'singing saw' - pd'o]Rider #50 looks very much like Ewald Kluge, and if this is so, and it is the Belgian GP 1939, then he won that race, and continued on to be 'Champion of Europe' after winning 4 out of 7 races towards the championship.

This photo of the DKW and the 'Malmeoy' sign is probably taken at the Belgian Grand Prix at Spa-Francorchamps on July 16, 1939.

These two photos show the same machine, #132. [Note the studded front and ribbed rear tires!]

'ROSIE' THE DKW SS350

Perhaps every racing motorcycle has a unique story to tell, but this '39 DKW SS350 production racer has a very interesting tale. When found in Sweden a few years ago, it had previously only had two owners, and was originally a Polish racing machine. 'Why Poland, and how could it have been exported there after the war began?'

The story I heard; a Polish horticulturist (also an amateur racer) had perfected a variety of black roses which were unique. German officers were quite keen customers for his blooms, as they were especially appreciated by their Parisian girlfriends... one well-connected officer asked the Polish fellow how he could reward him for his special efforts on their behalf (the girls must have really liked those flowers!) - he wanted a racing DKW. So, this motorcycle was invoiced to him 'without a petrol tank', but the tank with the bike is from a Works racer, and must have come along with the deal as a special favor.

The DKW was dismantled when things turned sour for his patrons (and for Poland), and was eventually smuggled out of the country to a Swedish collector in the 1980's.

I enjoyed riding near this machine on the Hockenheim circuit; it has no 'ring-ding' of modern two-strokes, but emits a low and raspy bellow. The SS350 is water-cooled and has 'twin cylinders', but four pistons, as the two pistons/barrels for each combustion chamber are used to 'time' the intake/exhaust cycle accurately and push both the incoming and exhaust gases to the right places at the right time. I'll go into how this works in another post, but DKW weren't alone in using two pistons per 'cylinder' - even the last Sears Allstate (Puch) machines used a similar system in the late 1960's - some people call them 'twingles' (twin piston/single cylinder), although I suppose the DKW would be called a 'fourtwin'. These racers also have a Ladepumpe under the the engine, which is a separate cylinder (and crankshaft, on the Works machines) used to compress air into the crankcase - a kind of supercharger for two-strokes. Thus, while this motorcycle is technically a twin-cylinder two stroke, mechanically it is a 5-piston machine - hardly a 'simple two-stroke'. The SS350 produced around 34hp, and used magnesium for the crankcases, gearbox case, and brake hubs, and was what DKW offered to the public for racing. According to Wolfgang Schneider, this complicated multi-piston two-stroke engine is only competitive for racing when the extra 'push' of the Ladepumpe piston is used. The similar Works Ladepumpe 'UL350' racer produced 38hp, but by 1939, the Works machines used a rotary supercharger, and this 'US350' model produced 49hp. And clearly, I need to make a proper timeline for these racers!

DKW joined forces with Audi, Horch, and Wanderer to form Auto-Union in 1932 (making the four 'rings' still seen on Audi), while DKW was the largest motorcycle manufacturer in the world (and Auto Union the second largest motor vehicle mf'r). The DKW archives and many of their works racing machines can be found at the Audi museum in Ingolstadt. Audi also has a small museum in their showplace in Neckarsulm, home of NSU, which was absorbed by Auto Union in the 1969. There is a very nice collection of racing NSU machines in Neckarsulm; photos to come shortly.

'ROSIE' THE DKW SS350

Perhaps every racing motorcycle has a unique story to tell, but this '39 DKW SS350 production racer has a very interesting tale. When found in Sweden a few years ago, it had previously only had two owners, and was originally a Polish racing machine. 'Why Poland, and how could it have been exported there after the war began?'

The story I heard; a Polish horticulturist (also an amateur racer) had perfected a variety of black roses which were unique. German officers were quite keen customers for his blooms, as they were especially appreciated by their Parisian girlfriends... one well-connected officer asked the Polish fellow how he could reward him for his special efforts on their behalf (the girls must have really liked those flowers!) - he wanted a racing DKW. So, this motorcycle was invoiced to him 'without a petrol tank', but the tank with the bike is from a Works racer, and must have come along with the deal as a special favor.

The DKW was dismantled when things turned sour for his patrons (and for Poland), and was eventually smuggled out of the country to a Swedish collector in the 1980's.

I enjoyed riding near this machine on the Hockenheim circuit; it has no 'ring-ding' of modern two-strokes, but emits a low and raspy bellow. The SS350 is water-cooled and has 'twin cylinders', but four pistons, as the two pistons/barrels for each combustion chamber are used to 'time' the intake/exhaust cycle accurately and push both the incoming and exhaust gases to the right places at the right time. I'll go into how this works in another post, but DKW weren't alone in using two pistons per 'cylinder' - even the last Sears Allstate (Puch) machines used a similar system in the late 1960's - some people call them 'twingles' (twin piston/single cylinder), although I suppose the DKW would be called a 'fourtwin'. These racers also have a Ladepumpe under the the engine, which is a separate cylinder (and crankshaft, on the Works machines) used to compress air into the crankcase - a kind of supercharger for two-strokes. Thus, while this motorcycle is technically a twin-cylinder two stroke, mechanically it is a 5-piston machine - hardly a 'simple two-stroke'. The SS350 produced around 34hp, and used magnesium for the crankcases, gearbox case, and brake hubs, and was what DKW offered to the public for racing. According to Wolfgang Schneider, this complicated multi-piston two-stroke engine is only competitive for racing when the extra 'push' of the Ladepumpe piston is used. The similar Works Ladepumpe 'UL350' racer produced 38hp, but by 1939, the Works machines used a rotary supercharger, and this 'US350' model produced 49hp. And clearly, I need to make a proper timeline for these racers!

DKW joined forces with Audi, Horch, and Wanderer to form Auto-Union in 1932 (making the four 'rings' still seen on Audi), while DKW was the largest motorcycle manufacturer in the world (and Auto Union the second largest motor vehicle mf'r). The DKW archives and many of their works racing machines can be found at the Audi museum in Ingolstadt. Audi also has a small museum in their showplace in Neckarsulm, home of NSU, which was absorbed by Auto Union in the 1969. There is a very nice collection of racing NSU machines in Neckarsulm; photos to come shortly.

1937 DKW SB500 A

Sometimes when you're young, you don't really think that you're part of a big cycle, a passing of history from hand to hand. At the time of these photos (1988), I was just excited to have found an unusual old motorcycle for a good price, in great running condition, and totally original. What was also happening was the seller, Hollis Button, was letting go of his lifetime collection of old motorcycles, handing the torch to younger folks to carry on where he was leaving off.

Hollis was having health issues, but had been a member of CAMA (California Antique Motorcycle Ass'n - now defunct) and the AMCA for years, and had restored many motorcycles in his day. I recall a German enthusiast several years ago sending me photos of a 'San Joe Bee', supposedly ca. 1898, and made in San Francisco. Did I know anything about it? I did a little research, and it turned out that Hollis had built the thing out of spares to look 'antique' - he clearly had a sense of humor too!

The top photo tells the tale - there is Hollis looking anxiously on as I (dressed in period gear even at that tender age) acquaint myself with the hand-shift and controls on this '37 DKW 500cc twin-cylinder two-stroke. I had just purchased the machine, and was ready for the test ride. It turned out to be in perfect mechanical condition, and for the few years I owned it, remained so. We had many fun miles, the only bugbear was the prodigious smoke screen laid down whenever I opened up the throttle - I can remember one day going over the Golden Gate bridge, looking back at an enormous blue cloud behind me... not a very 'green' machine!

Second pic shows me under way. The 'Deek' would do 70+ mph, and handled very well. The frame and forks are pressed steel stampings, which can be seen clearly in the bottom photo (note holes in the engine plates below the gear-drive primary cover). I think the machine had come from Verrall's in the 1970's (note tax disc on bottom pic) - it had original paint and pinstriping, although Hollis had converted the original electric start mechanism (yep, 1937 e-start) for a Honda starter/generator. It was a stylish little machine, but ultimately it went away in order to buy my first Brough-Superior, an 11-50 model from 1937. I note that DomiRacer has a similar DKW for sale, and am tempted, but I rarely go backwards...

Some notes about the DKW story; at one time (1936?) they were the largest motorcycle factory in the world, and were amalgamated into the Auto-Union umbrella, which we know now as Audi. Their RT125cc two-stroke single was a huge seller, and immediately after WW2, both the Yanks and Brits 'appropriated' the blueprints and production facilities of the DKW factory - hence we had the Harley Hummer and BSA Bantam, both of which were faithful copies of the little pre-war DKW. After the war the factory in Zschopau ended up in East Germany, and the company became MZ (Motorrad Zschopau). MZ continued to develop motorcycles for road and race through the communist era (I rode a 250cc MZ across the Eastern Bloc in '88).

Their race chief, Walter Kaaden, used mathematical formulae to perfect harmonic resonance in two-stroke exhaust systems ('expansion chambers'), and the little made-on-a-shoestring racers became world beaters. Kaaden's protege, Ernst Degner, defected to Japan and sold Kaaden's secrets to Suzuki, who then went on to world championship status . Degner later committed suicide .... Who says there isn't drama and intrigue in old motorcycle history?

1937 DKW SB500 A

Sometimes when you're young, you don't really think that you're part of a big cycle, a passing of history from hand to hand. At the time of these photos (1988), I was just excited to have found an unusual old motorcycle for a good price, in great running condition, and totally original. What was also happening was the seller, Hollis Button, was letting go of his lifetime collection of old motorcycles, handing the torch to younger folks to carry on where he was leaving off.

Hollis was having health issues, but had been a member of CAMA (California Antique Motorcycle Ass'n - now defunct) and the AMCA for years, and had restored many motorcycles in his day. I recall a German enthusiast several years ago sending me photos of a 'San Joe Bee', supposedly ca. 1898, and made in San Francisco. Did I know anything about it? I did a little research, and it turned out that Hollis had built the thing out of spares to look 'antique' - he clearly had a sense of humor too!

The top photo tells the tale - there is Hollis looking anxiously on as I (dressed in period gear even at that tender age) acquaint myself with the hand-shift and controls on this '37 DKW 500cc twin-cylinder two-stroke. I had just purchased the machine, and was ready for the test ride. It turned out to be in perfect mechanical condition, and for the few years I owned it, remained so. We had many fun miles, the only bugbear was the prodigious smoke screen laid down whenever I opened up the throttle - I can remember one day going over the Golden Gate bridge, looking back at an enormous blue cloud behind me... not a very 'green' machine!

Second pic shows me under way. The 'Deek' would do 70+ mph, and handled very well. The frame and forks are pressed steel stampings, which can be seen clearly in the bottom photo (note holes in the engine plates below the gear-drive primary cover). I think the machine had come from Verrall's in the 1970's (note tax disc on bottom pic) - it had original paint and pinstriping, although Hollis had converted the original electric start mechanism (yep, 1937 e-start) for a Honda starter/generator. It was a stylish little machine, but ultimately it went away in order to buy my first Brough-Superior, an 11-50 model from 1937. I note that DomiRacer has a similar DKW for sale, and am tempted, but I rarely go backwards...

Some notes about the DKW story; at one time (1936?) they were the largest motorcycle factory in the world, and were amalgamated into the Auto-Union umbrella, which we know now as Audi. Their RT125cc two-stroke single was a huge seller, and immediately after WW2, both the Yanks and Brits 'appropriated' the blueprints and production facilities of the DKW factory - hence we had the Harley Hummer and BSA Bantam, both of which were faithful copies of the little pre-war DKW. After the war the factory in Zschopau ended up in East Germany, and the company became MZ (Motorrad Zschopau). MZ continued to develop motorcycles for road and race through the communist era (I rode a 250cc MZ across the Eastern Bloc in '88).

Their race chief, Walter Kaaden, used mathematical formulae to perfect harmonic resonance in two-stroke exhaust systems ('expansion chambers'), and the little made-on-a-shoestring racers became world beaters. Kaaden's protege, Ernst Degner, defected to Japan and sold Kaaden's secrets to Suzuki, who then went on to world championship status . Degner later committed suicide .... Who says there isn't drama and intrigue in old motorcycle history?