The Development and Evolution of the DB605 Engine

The development of the DB605 engine was a significant milestone in aviation history, marking a major breakthrough in fuel injection technology. The engine's design was crucial to its success, featuring 12 in-line pistons that raised the fuel pressure to 90 bar before injecting it directly into the combustion chamber. This innovative approach allowed for more efficient combustion and improved performance.

However, the spray injection method presented several challenges. A large amount of fuel hitting the cylinder liner would take out oil, causing problems with the piston's movement. Later, a special nozzle was developed to widen the spray, which also helped alleviate issues with oil consumption due to the engine running inverted. The use of direct injection proved to be particularly beneficial, as it allowed for the evaporation of fuel, absorbing a large amount of heat and lowering the temperature of the cylinder. This enabled the aircraft to fly in any conditions, perform various maneuvers, such as prolonged vertical climbs or inverted flight, which would have been impossible with carburetor-based engines.

Another significant innovation was the incorporation of a hydraulically operated supercharger. The crankshaft drove a gear that fed the torque converter, allowing an automatic system to manage the amount of oil inside the converter according to altitude. As the plane climbed, the air became thinner and lost power, but by adjusting the compressor speed, this problem was resolved. With a compressor pressure of around 20 psi, the engine generated an impressive 1300 horsepower at 2600 rpm.

The DB605 engine's capabilities extended beyond its performance characteristics, as it was also suitable for short-term operation with nitrous oxide or water-methanol injection. This feature made it ideal for escaping from pursuit by another fighter aircraft. The power could be increased to 2300 HP, allowing the aircraft to achieve remarkable speeds and agility.

Manufacturers such as Fiat or Kawasaki received blueprints of the DB605 engine to build and equip their fighters in their respective countries. The resulting engines were slightly larger, at 35.7 liters, generating 1475 HP at takeoff. With high-octane fuel, power could increase to 1800 HP, with a compression ratio of 7.3 to 1 on the right bank and 7.5 to 1 on the left bank. The left bank's lower compression ratio was attributed to knocking occurring only in that side, which was solved by lowering its compression. Additionally, plain bearings were installed instead of roller bearings.

Later, an innovative approach to increasing power involved joining two engines together in parallel, connected by gears. These twin engines, known as the DB610, packed them so tightly that changing an inner cylinder spark plug became impossible without disassembling the exhaust manifolds. The compression ratio of the internal cylinders was lower due to working hotter and more oil falling on them because they were almost vertical.

The DB610 engine was used in the Heinkel He 177 bomber, producing a remarkable 2900 HP. Despite being two inverted V12 engines, they were considered a 71-liter W24 configuration. The concept of using an inverted engine may have seemed unusual, but it had existed in radial engines before. The success of the DB605 engine and its variations paved the way for future innovations in aircraft propulsion systems.

In conclusion, the development of the DB605 engine marked a significant milestone in aviation history, showcasing innovative solutions to pressing problems in fuel injection technology. Its performance characteristics, capabilities, and adaptability set it apart from previous engines, making it an ideal choice for various applications, including fighter aircraft.

"WEBVTTKind: captionsLanguage: enThis V12 engine manufactured by Daimler Benz was completely inverted. With the crankshaft on  top and the pistons below! Being one of the most important engines of the German manufacturer. But,  why would someone make an inverted engine?What would be its advantages? And, why would  someone join 2 engines to reach incredible power values that exceed 3000 horses. Let's start. In 1930, Germany needed engines with more than 800 horsepower for its air force. They must also have an ultra-compact cooling system that does not produce aerodynamic losses, Run on low quality fuels,Be easy to repair, Allow the placement of machine guns in the front for better aiming,  aligned with the pilot's vision,And allow excellent downward visibility, Be totally inverted,Among many other almost impossible things. The response from Daimler-Benz, was the DB-600 engine. The first thing they did was building the block using Duralumin , an advanced alloy of aluminum,  magnesium and copper, which allowed for rapid heat conduction and thus ensured that it was  uniform throughout the engine. In addition, this alloy is very light and, above all, resistant. The cylinder liners contained silicon making them wear-resistant. When inverted, the oil fell and remained on the underside of the pistons, which were removed  when they moved back. This ensured that a large amount of oil touched the pistons cooling them. This is the equivalent of using oil injectors under the pistons as used in cars today. The pistons are made of light alloy. Since they were upside down and had  a diameter of 150 and a stroke of 160 mm, they had to use a larger number of rings. Totally 5. 3 of which were for compression and 2 oil scrapers. This was the only way to prevent oil from passing through the rings into  the combustion chamber and burning. In fact, if the engine was stopped for a long time,  the cylinders could become flooded with oil and the spark plugs had to be removed and cleaned. The lower ring also helped to center the piston in the cylinder. Otherwise,  while being so long, it would produce a pitching effect, which makes noise and accelerates wear. Although the engine had a displacement of 33.9 liters or 2070 cubic inches, giving each cylinder  2.8 liters, the engine was also fitted with a supercharger that was initially driven by a  shaft connected to the crankshaft. This compressor increased power at takeoff and then maintained it  when it rose and encountered less dense air.With its supercharger and 33.9 litres  of displacement, it produced up to 1000 horsepower at just 2800 rpm and  weighed less than 700 kilos or 1500 pounds.Fork and blade connecting rods are used on  the same crankpin. That is, one goes inside and the other outside. This makes the cylinders be  perfectly aligned and not staggered as in engines where the connecting rods are next to each other. In addition, needle roller bearings were used to allow the aircraft to operate for a short  period without oil and let the pilot to return to base. Thanks to being inverted, the pistons  would remain lubricated with the remaining oil.The initial compression ratio was 6.9 to 1. In the aircraft world, engines usually have redundant systems, meaning that if one fails,  the engine continues running by the second. For this reason, the engine had 2 spark plugs  per cylinder. Each one powered by 1 independent magneto. Also, since the cylinder was so large,  using 2 spark plugs is the only way to fully fire the cylinder in time. If a magneto failed and a  spark plug stopped working, the engine would continue to run but with a small loss of power. However, the ideal would have been for the spark plugs to be placed  opposite each other rather than next to each other. This would have achieved better fuel  burning. But due to space and because of the injector, they were placed on the same side. Valve covers also serve as oil pans. In each of these there are oil pumps that raise the fluid to  the tank where the pressure pump is located. This system is also known as a dry sump. This allows  the engine to operate in any position since as long as there is oil in the pressure tank,  the engine will maintain lubrication.The camshaft was also in this area,  and was driven by gears. In fact, the end of the road are the oil pumps, then we go to the  camshaft, and from here a shaft then goes up to these gears, here is the one that feeds the  compressor and is connected to the crankshaft. In transparent you can see the gear that runs  on the first one and feeds the camshafts.There is one camshaft on each side and rotates  at half of the speed of the crankshaft. The same cam drives both the exhaust and intake valves. Each cylinder has 2 intake valves and 2 exhaust valves. Another detail is that the gears of the camshafts are inverted. This one has it  like this, and the other backwards. This is to maintain the direction of rotation.Since it was inverted, The exhaust pipes were in the lower part, ensuring that any oil in  the exhaust would not dirty the windshield.Also during night flight, the short exhaust  manifold flares would not interfere with the view.One thing I want to show you is how to  solve meals simply with Factor.Factor makes meeting your nutrition  goals easier than ever by delivering fresh, never frozen, dietitian-approved meals right  to your doorstep. A team of gourmet chefs create each meal using only ingredients with integrity  to help you feel your best, all day long.• Get chef-prepared meals on the table in  2 minutes with Factor's ready-to-eat meals, so you can get back to soaking in the summer sun. • Factor meals eliminate the hassle of prepping, cooking, or cleaning  up. Simply heat and savor the good stuff.• Factor is so flexible that I can easily  adjust my order size, enjoy with loved ones, or even skip a week when I have a special event. • Factor is a go-to lunch solution when I’m doing home office. Enjoying a delicious menu  is the best way to raise your spirits and then get back to work. Check out  this one called Protein Plus. My favorite!Head to FACTOR75 dot com or click the link below  and use code REPAIRMAN50 to get 50% off your first Factor box and 20% off your next month of orders! That’s code REPAIRMAN50 at FACTOR75 dot com to get 50% off your first box plus 20% off your next month of orders!50% off first box, 20% off next four boxes. Additionally, the inverted engine with the crankshaft output at the top allows for the  installation of a reduction gear and the reduction of the propeller speed. The engine rotated at  a maximum of 2800 RPM and the propeller at 1700. This is to avoid the tip of the  propeller exceeding the speed of sound.The spark plugs and maintenance was  within the reach of the mechanic.This also left more room for machine  guns to be mounted in the pilot's line of sight, which improved aim. It could also fire through the center of the propeller. Thanks to the space between the V,  a duct was left to fire a 30mm MK 108 cannon that was at the rear. If you looked at the engine from the front you could see the other side. Other smaller 20mm cannons were also fitted.The idea of having the gun centered on the plane  means that when firing, the recoil of the weapon is absorbed in the center of the plane,  avoiding vibrations or decreased aim.While the weapons that were on the wing  tended to vibrate and decrease their accuracy.When chasing and doing high G maneuvers,  the wings bends and the cannons loose aim.The two smaller machine guns on top were  synchronized with the propeller so as not to hit the blades. The inverted position of the engine also helps to keep the aircraft's centre of  gravity, making it more maneuverable.The third thing that was sought was that  the engine, instead of working with coolant at 195 °F or 90°C as we have today in our cars,  was increased to 250°F or 120°C.With an extra 55°, the difference  between the air and the radiator increases, which makes the same radiator perform better. This would allow the radiator to be shrunk to almost half the size of the original. This  would give smaller air intakes and better aerodynamics. Also, with smaller radiators  and less water, the weight is also reduced.But how do you prevent steam from forming? Initially, water boils and turns into steam at 212°F or 100°C as long as we are at atmospheric  pressure. But if the radiator and its entire circuit are closed and the pressure is increased,  the boiling point rises progressively. But as a downside, as there is more pressure,  the system must be stronger. A slight weakness under high pressure would be unforgivable. In the event of a system failure or a bullet hitting these components, the closed circuit  would break and the pressure would drop rapidly. Since the water is at 250°F, the result would be  an immediate evaporation of all the coolant, with subsequent total breakdown of the engine. However, this was not achieved satisfactorily and the operating temperature remained around 212°F. Since the engine was operating at high temperature, another problem appeared. The first DB600s were fueled by carburetors. Reliable and well-known. But Germany did not  have the capacity to produce high quality and octane fuels, in fact, it could barely produce  fuel at all. Heat promotes knocking and, as a result of this uncontrolled effect, instant  detonations can destroy the engine. The only way was to reduce the engine's compression ratio,  which reduces power and worsens fuel consumption.The result was the DB 601 launched by 1935. Instead of losing power, the German manufacturer Bosch came up with a solution. The birth of mechanical gasoline direct injection.Although diesel injection already existed,  gasoline is much more aggressive and attacks the seals and o-rings of the pump. It is also  not a lubricant like diesel, which causes the pump pistons to wear out quickly. Overcoming  these challenges meant that Bosch's invention should be kept as a complete state secret. France, the Soviet Union, and other countries wanted to buy the engine but the government did  not allow export to its future enemies.The pump consisted of 12 in-line pistons  that raised the fuel pressure to 90 bar and then injected it directly into the combustion chamber. The spray injection method was difficult to solve, as a large amount of fuel hit the cylinder  liner and took out the oil. That then when the piston passed, it would rub and break. Later,  the spray could be made wider with a special nozzle, and partly because the engine was  running inverted, the extra oil helped.Direct injection, when entering directly  into the cylinder, evaporates. By simply changing from a liquid to a gaseous state,  it absorbs a large amount of heat and lowers the temperature of the cylinder. By lowering the temperature, knocking is avoided, allowing the use of low-octane  fuels such as those available in Germany.Thanks to direct injection, the aircraft  could fly in any conditions, and perform all kinds of manoeuvres, such as prolonged  vertical climbs or inverted flight, whereas a carburetor float bowl would simply ran dry. Another technology incorporated into this new version was the  hydraulically operated supercharger.The crankshaft drives the gear that  feeds the torque converter.The amount of oil inside  the torque converter managed by an automatic system according to altitude  allows to control the speed of the compressor.As the plane climbed, the air became thinner and  lost power, but by adjusting the compressor speed, this problem simply disappeared. By this time the compressor pressure was around 20 psi. With this it now generates 1300 horsepower at 2600 rpm. The engine was also suitable for short-term operation with nitrous  oxide or water-methanol injection. Ideal for escaping when being pursued by another  fighter. Power could be increased to 2300 HP.Manufacturers such as Fiat or Kawasaki received  the blueprints of these engines to build and equip their fighters in their respective countries. The DB605 would now be slightly larger, at 35.7 liters and would generate 1475  HP at takeoff. If high-octane fuel was used, power could increase to 1800 HP. Now, the compression ratio of the right bank would be 7.3 to 1 while the left bank,  where the compressor is, would be 7.5 to 1. The reason was that knocking only occurred  on this side and therefore, it was solved by lowering the compression on that bank. The reason was that supposedly, due to the direction of rotation of the crankshaft,  more oil fell into this bank which then passed to the combustion chamber and caused knocking. The roller bearing was also removed and plain bearings were installed. Later, in search of more power, 2 engines were joined in parallel  and connected by gears. They were called DB610.These engines were so tightly packed that changing  an inner cylinder spark plug was impossible without disassembling the exhaust manifolds,  which required removing at least one engine.The compression ratio of the internal cylinders  was lower because they worked hotter and more oil fell on them because they were  almost vertical and there was at least 0.2 points less in compression ratio vs. the external ones. These twin engines were used in the Heinkel He 177 bomber producing 2900 HP. Although they were two inverted V12 engines, they were considered to be a 71 litre W24. Was the idea of using an inverted engine really crazy? No. In fact,  in radial engines, the lower cylinders are inverted and they existed before. My name is Francis and if you liked the video, don't forget to subscribe and leave  a like. Also check out the comments section which is very important. There are always  interesting things to read.See you next time!\n"