The Engine of the Dark Side? Daimler-Benz DB-600 - DB-605 - Part 1

the daimler ben 600 series engines have always fascinated me i'm not entirely sure why to be honest maybe because of its inverted design maybe because of its characteristic sound or maybe because i think we all have a bit of a fascination with the villains of a story in fact when i watched star wars as a kid i can remember just being in awe anytime i saw a tie fighter on the screen the dark colors the sleek lines and i mean come on if i put these engines in a lineup you can just see which one is the bad guy's engine i mean it's incredible it looks like it's about to rip off its mouths and come at me with a baseball bat i know that the guy that designed the ss uniforms went for this type of look intentionally but i find it hard to believe that the chief designers at daimler benz didn't know how evil their engine looked i think there must have been something in the water in germany so i guess with a healthy fascination for the dark side and because the db600 series is one of our favorite engines here at flight dojo we'll be taking a very long look at the development history and evolution of the engine through the pre-war 1930s until the end of the war before we get too far into this series however we want to take a second to give a shout out to the book the secret horsepower race by callum e douglas if you guys enjoy this video and are interested in content like this this is the book for you the painstaking research mr douglas put into this work is simply astounding and we cannot recommend it enough so with that out of the way let's get to it the story of the db 600 series is one of technological advancements being continually sought and achieved despite the severe resource limitations germany faced during the conflict more specifically limitations in their supply of precious metals fuel quality issues and mismanagement by the rlm created a situation that forced germany's engineers to attempt the impossible win and design race with inferior materials in an inferior environment all while dealing with a logistical nightmare surrounding a two-front total war now the origin of these issues were due to war planning being flawed from the outset every supply issue germany faced whether it be precious metals or crude oil was to be resolved by conquering neighboring territories and taking their supplies say this was a plan that lacked any sort of failsafe would be a gross understatement if one vital territory failed to be captured the ensuing shortage would collapse the entire war machine to overcome this issue the plan was to stockpile fuel and invest in tech hopefully with war machines that outmatch their opponents they would fall quickly giving germany access to the much needed resources they possessed and that policy superior technology as a method for increasing the speed with which war can be waged is where daimler benz enters the scene knowing a war was on the horizon shortly after hitler became chancellor on march 24 1933 the nazi party ushered in a forced age of rampant technological advancement after passing the enabling act giving the party virtually unlimited authority any design firm willing to research technologies that might help advance the cause of the german ground or air forces would be state funded the reason for this was simple at the time germany lacked behind america and the rest of europe in scientific and military achievement to win a war they needed to catch up unsurprisingly this unlimited budget was like christmas morning to germany's curious engineers because any design that had even the slightest potential contribution to the war effort was given merit time attention and funding firms like daimler bins while not only working to develop more practical engines such as the db600 series also split their resources spending time on more avant-garde projects such as x-engines disc valve engines and even sleeve valve designs as we'll see in a moment had daimler bins focused their efforts on small incremental improvements to the 600 series rather than becoming distracted by experimental research britt may have found herself in an entirely different war in the early 1940s in the mid 1930s a man named wolf from eisenlure sent a list of design requirements to bmw argus daimler bins and junkers detailing what the rlm which was germany's air ministry equivalent desired from the next generation of military aero engines these specifications included an inverted layout lower mounted exhaust systems reduction gearings for the propeller which would allow for higher engine speeds a hollow propeller axis for essentially mounted cannon a high altitude supercharger which was single stage direct fuel injection and a hot high pressure cooling system capable of operating within 115 to 120 degrees celsius that last requirement was important because it would allow aircraft designers to greatly reduce the size of a radiator reducing overall drag essentially this document would prescribe what would eventually become the db-600 series of engines causing daimler-benz to redesign their f-series engines into their famous inverted layout while their original f-series engines began in 1926 with a three-cylinder water-cooled engine eventually advancing into a 12-cylinder design intended for airships the latest iteration resulted in the world's first inverted liquid-cooled v12 engine displacing 33.9 liters and weighting 565 kilograms carefully drafted by designers arthur berger and fritz nallinger the f4a as it became known would serve as the common ancestor through which all subsequent permutations of the 600 series would evolve in terms of its design the f4a was not too dissimilar to the eventual 605 variant but at this stage it still used a carburetor and natural aspiration the engine also suffered from a lack of structural integrity caused by the use of separate cylinders to solve this daimler-benz developed the f4b which employed a single monoblock construction which in my opinion is largely responsible for the bad guy aesthetic with the monoblock completed they would rename the f4b the db600 the first official engine of the series while work on adding fuel injection was nowhere near completion this iteration at least used a supercharger specifically this supercharger was mounted on the pilot's left side but an alternate area for mounting another supercharger to the right side was preserved a decision that would prove useful in future years during these early design years at daimler bins research was being conducted into more advanced liquid cooling methods as one of the primary issues with liquid cooling engines is their large radiators and subsequent aerodynamic drag reducing the size of the radiator can create large speed improvements to realize gains such as those being displayed in britain with similar research research into high temperature high pressure cooling systems began early tests showed that using such a system could reduce the radiator's size by as much as 70 percent and 32 kilograms but the lack of system durability was clear namely a single point of failure in the system would cause the coolant to rapidly evaporate shortly resulting in an engine failure later engineers at heinkel no doubt taking inspiration from several earlier schneider trophy planes experimented with developing a cooling system that entirely removed the radiator all together instead it used a complex set of evaporative surfaces on the wings by piping coolant to these ducts rather than a radiator the coolant would become steam and then be condensed back into liquid by cold airflow where it would then be transported back to the engine the problem however was that the system had issues with steam forming in the engine itself rather than only in the wing ducting when this system was tested with the db600 engine these pockets of steam led to thermal runaway and engine destruction the other issue with this system was that by enlarging the overall surface area of the cooling system to include ducting throughout the entire wing any stray bullets even those striking the outer areas of the wing would end up indirectly destroying the engine fortunately for the bf-109 an evaporative cooling system was not implemented but whether a high temperature high pressure system capable of reducing the radiator size could be designed in time remained a question as many of you are probably aware one of the biggest obstacles germany was forced to overcome throughout the war were issues surrounding their inferior fuels and the logistics that they required to procure it because these issues had a direct tangible impact on the design of the 600 series this context is important in the early 30s when another war was being first envisioned germany still struggled with regulations placed on it that were designed to prevent any sort of rearmament however as we know germany had no intention of keeping quiet knowing they would need fast stockpiles of fuels to wage another war an organization named the institute for economic research founded by both the nazi party and ig farben began construction of a set of massive underground concrete fuel storage bunkers the organization would place this network of bunkers in key strategic locations throughout the country storing invaluable aviation fuel ready to be used at a moment's notice however once construction was finished on these tanks another problem emerged how would they fill them because germany lacked the natural oil resources to refine the fuel in the traditional way refineries were built in close proximity to coal mines and plans were made to produce fuel from the coal through a process called hydrogenation while hydrogenation is an inefficient process it proved to be the only method germany had to gather fuel without relying on any outside nations additionally while fuel infrastructure plans were being drafted academic consultants warned the organization against relying on only a few large refineries instead suggesting they use a series of small refineries scattered throughout the country this way the strategic bombing of only a few key refineries wouldn't interrupt fuel generation as a whole unfortunately for germany the institute for economic research insisted on building large refineries which would later turn out to be a grave mistake fortunately the organization did take some safety precautions specifically refined fuel could not be stored on site at the refinery but was instead transported to the underground storage bunkers then mixed with additives creating the final product at an alternative location after storing it in the final storage silo the fuel would be transported via roadway or railway to various airfields the important bit here is that the logistical decision to perform fuel blending away from refineries at remote locations effectively creating a middle step between fuel refinement and final transportation would also prove to be an eventual nightmare for the luftwaffe also if strange methods of refinement weren't enough of a problem for germany the resulting fuel product was proving to be inferior to allied fuels despite their synthetic fuel having a similar octane rating it was later discovered that the octane testing procedure itself was flawed because the octane test didn't account for changes in air ratio or temperature it couldn't be used as an accurate predictor for when knock would occur in an arrow engine by performing new tests researchers discovered that the performance differences between the fuels were due to the high iso-octane additives in american fuel which performed better at variable fuel mixtures and temperatures unfortunately for the germans the hydrogenation process proved inadequate at generating sufficient quantities of iso octanes because their fuel performed worse than american fuel and buying large amounts of foreign fuel seemed an unlikely solution the rlm decided to rush the development of a fuel injection system if such a system could be designed it was thought the fine control over the fuel mixture would overcome their fuel limitations while many designers of the era were aware of fuel injection technology carburation was still very much the status quo for fuel delivery systems throughout world war ii had it not been for germany's fuel issues as well as a desire to fully automate engine management fuel injection probably wouldn't have arrived for several more years the system used in the db601 engine was developed by the bosch company and its development had proven to be a hard-won victory as it turned out perfecting the nozzle spray pattern had been more difficult than anticipated the issue was that a nozzle that mixed fuel into the air stream improperly had a tendency to wash the oil off the face of the cylinder liner causing engine damage however by 1936 a publication entitled a flawless system for mixture control of direct injected spark ignition for petrol engines was released indicating that the issue was remedied in fact the fuel injection victory appeared to be so hard one that it was being guarded as a state secret we know this because when daimler bins began receiving orders from france and russia prior to the war the rlm outright denied that the engine be given to the russians and insisted that only a carbureted version be exported to france both the french and russians were eventually denied rights to produce the engine but a sale of these rights was eventually made with the fuel injection system to japan interestingly the development of electronically controlled direct fuel injection had numerous unintended benefits beyond the hopes of the original designers namely the system allowed aircraft to perform inverted flight maneuvers without risking engine shutdowns and perhaps even more importantly it was quickly discovered that precise fuel metering can have big effects on the efficiency of the supercharging process [Music] early in the development cycle of the 600 series engines designers were still trying to decide between a single stage or two-stage supercharger in 1934 researchers performed testing on a db 600 series using a two-stage layout attempting to increase climb performance even at sea level as much as possible however pushback on the added hassle of adding a second stage to the force induction system prevented its final adoption because at the time the rlm still believed the luftwaffe would act only as a ground support force and high altitude operations were not considered this would prove to be another serious error in the rlm's thinking as at the time two german spies had recently been willingly let into the pratt whitney company's headquarters in america after studying the entire production the spies reported heavy research on turbocharging technology discussing the apparent advantages of the technology over engine powered superchargers from their reports on the presence of high-altitude testing chambers as well as the obvious focus on turbocharger development it should have been clear that if america was involved in an air war her strategy would involve high altitude operations surprisingly though this information was ignored in other parts of germany research was being conducted on recently obtained rolls-royce buzzard superchargers written by one of germany's top supercharging scientists werner von der knoll the final report noted that the construction of the buzzard supercharger was superb but it lacked efficiency in obtaining adequate boost pressure he claimed that this was largely because rolls-royce selected to use straight rather than curved impeller veins and while the straight vanes were easier to manufacture they left substantial performance capability untapped ultimately he did not recommend german firms copy the design continuing his research vandernil found himself interested in continuing to study the benefits of two-stage supercharging applications to learn more he began studying the recently produced thomas supercharger's two-stage design to his surprise he later noted that a two-stage supercharger application does not necessarily result in better engine performance instead extensive developments and design iterations were necessary to reap the benefits of adding a second stage to a forced induction system as it turns out these improvements take time and intensive effort and so because war was on the immediate horizon german firms adopted the idea that their time would be better spent focusing on making efficient single-stage systems which were deemed to be adequate to sufficient altitudes and not require after cooling the results of the german scientific community's research into forced induction first saw practical use after the unveiling of the db601 most notably the supercharging system employed on the db601 used a fluid coupling rather than a direct drive gearbox this ingenious system helped solve the problem of the steep sawtooth performance curves seen from designs using a fixed gear ratio instead the variable speed fluid coupling created a smoother curve and a more consistent power at altitude even the americans agreed that this design was superior to most others noting in post-war studies that the bins fluid drive coupling was lighter and smaller than any british gearbox however despite it being previously decided that german firms would focus their efforts on single-stage superchargers as employed in the db-601 superfluous research was still being conducted on potential turbocharger applications further highlighting the lack of focus present in the academic community despite knowing that it was nothing more than an academic exercise the rlm ordered von dernold to create a mock-up of the db601 featuring a turbo capable of allowing the engine to achieve full power up to thirty thousand feet they ordered this despite knowing that none of their fighter aircraft were large enough to even house the resulting turbocharged design furthermore metallurgic limitations namely the inability to source metals to create a heat resistant alloy called mnemonic 80 made it impossible for germany to create exhaust manifolds that could endure the heat output of a turbocharged system during the research engineers were forced to water cool the exhaust manifolds to even perform the tests knowing that this wouldn't be possible in the field these sorts of purely academic tests would prove to be an unfortunate pattern in germany's pre-war years with even more wild design ideas soon ordered by the rlm only proving to waste their engineers valuable time the primary additions to the 601 over its predecessors were the fluid drive coupling and the direct fuel injection system however the engine also featured a larger supercharger impeller with more vanes which resulted in cam timing with a high valve overlap that substantially improved performance the collection of these advancements directly led to the creation of a highly modified db db601a which would later be renamed the 601r boosted to an incredible 2.2 atmospheres at 33 liters these engines produced 2500 brake horsepower and would eventually propel a special made messerschmitt bf-209 to 469 miles per hour on april 26 1939 shattering the previous world air speed record you see even at a time as critical as this the rlm and the propaganda machine concern themselves with feats of strength intended to show or perhaps warn the world of germany's rapidly improving engineering capabilities initial reports of the new air speed record included details that reported that the engine used was a relatively standard engine and that the airframe of the 109 had only been slightly improved in reality however this couldn't have been farther from the truth in fact the aircraft's fuel was a highly modified cocktail using about 40 methanol 20 gasoline 10 benzene and 10 toluene even more the engine's speed had been increased greatly reducing its lifespan and it was also completely handcrafted meaning it wasn't reproducible in mass quantities nevertheless it was still an impressive achievement and test stand models of the db-601r reportedly achieved upwards of 2800 brake horsepower while daimler benz could definitely achieve impressive power figures even if only for a short time further research was being conducted into novel ways to improve power more reliably one of these tests no doubt inspired by the work of harry ricardo and roy fredden included a db-601 with sleeve valves however it was soon determined that the sleeve valve did not improve the overall power output of the engine so the idea was abandoned as it turned out german engine makers preferred to find novel ways to increase boost pressure in a poppet valve engine overcoming the inherent volumetric inefficiency through brute force rather than go through the arduous process of prototyping a sleep valve design while it's now evident that much of the research into advanced guard engine layouts and valve types was a waste of precious time one bit of research conducted by dr otto cuno would prove to be invaluable what kino had discovered was that an engine injected with nitrous oxide during the combustion process created a more balanced combustion temperature in layman's terms kuno had found a way to delay knock a loophole that could be exploited for more power shortly after this discovery a bf-109 fitted with nitrous oxide tanks showed speed improvements of 40 kilometers an hour at eight kilometers altitude and a hundred kilometers an hour at 10 kilometers altitude the results were staggering by the end of the 1930s just before the onset of the war the quest to not only catch up to the rest of the world in terms of engine development but surpassed them was well underway before the battle of britain the db601 had a more advanced fuel delivery system than any other production aircraft engine in addition the engine's supercharger design was much more efficient with increasing altitude than any of its competitors however what would follow would be more challenges the 600 series would have to overcome before it won its reputation as one of the most fearsome capable power plants of the war if you've made it this far we thank you the next episode of this series will cover the developments made to the 600 series during the battle of britain and the first few years of world war ii if you liked this video don't forget to like and subscribe so we can continue to provide new content and once again thanks for tuning in to flight dojo we'll see you guys next time

Channel: Flight Dojo

Views: 1,290,686

Keywords: Engines, WWII History, WWII Aviation, Horsepower, Evolution of Engine Development, Engine Devleopment, Historical Engineering, daimler benz, db 600, db 605

Id: mVsdWyYXdoQ

Length: 21min 34sec (1294 seconds)

Published: Tue May 31 2022