Daimler-Benz DB 605

The Daimler-Benz DB 605 was a German aircraft engine, built during World War II. Developed from the DB 601, the DB 605 was used from 1942 to 1945 in the Messerschmitt Bf 109 fighter, the Bf 110, Me 210C heavy fighters. The DB 610, a coupled version of the DB 605 was used in Germany's only operational heavy bomber, the Heinkel 177 License-built versions of the DB 605 were used in the MC.205 Veltro, G.55 Centauro, Reggiane 2005 and some other Italian aircraft. It was also initially used in the pusher-design Swedish Saab J21. Approximately 42,400 DB 605s of all kinds were built.

Design and development

The primary differences between the 605 and 601 were the displacement, higher revolutions, higher compression ratio and a more powerful supercharger. Through careful study, the engineers were able to determine that the existing block could be bored out to a larger diameter without seriously affecting the strength of the engine block. The difference was minimal, increasing from the 601's 150 mm to the 605's 154 mm, but this increased the overall displacement from 33.9 liters to 35.7. Altered valve timing increased the inlet period and improved the scavenging to give greater volumetric efficiency at higher speeds, which improved the maximum allowable RPM to 2800 from the 601's 2600. The combination of these changes improved power from 1,350 PS (1,332 hp) to 1,475 PS (1455 hp). The engine was otherwise similar, notably in size, which was identical to the 601. However, weights did increase from 700 to 756 kg.

In other ways the engine was essentially identical to the 601. Both used dual Bosch magnetos firing twin spark plugs for ignition. Fuel injection was powered by a pump supplying up to 90 bar, and the oil system used three pumps with a separate 35 liter oil tank. The supercharger was fairly advanced for the era, it used a barometrically controlled hydraulic clutch (fluid coupling) which allowed the system to automatically compensate for changes in altitude.

Like the 601, the 605 was designed to run on "B4" fuel, at 87 octane. In 1944 a series of newer engines was introduced, allowing the engine to run on the 100 octane "C3" fuel and optionally including fittings for various optional power-boosting agent dispensing systems, such as the MW50 methanol-water injection system, and GM-1 nitrous oxide injection system. The DB 605AM, running initially on C3 and MW-50, saw power improved to 1,800 PS (1775 hp) for takeoff. In mid-1944, the requirement for C3 was dropped and B4 + MW-50 was used. The DB 605AS(M) improved the maximum rated altitude by using a larger supercharger taken from the DB 603 but was otherwise similar to the A(M). The DB 605ASB improved takeoff performance to 1,800 PS (1,775 hp), while maintaining the high-altitude performance of the ASM. The final version of the A-series was the DB 605ASC of 1945, further improving takeoff performance to 2,000 PS (1,973 hp).

Daimler had also be working on an upgraded D-series as early as 1942, capable of running on either C2 or C3 fuel. These engines did not see service until 1944, and were quickly followed by the 1,800 PS (1,775 hp) DB 605DB (running on B4 + MW-50 or C-3 without MW-50) and 2,000 PS (1,973 hp) DB 605DC. These engines saw widespread use on the late-war Bf 109 G-10 and Bf 109 K-4.

Variants

Production versions

• DB 605 A(M) Standard fighter engine, up to 1475 PS, 605 AM with MW-50 system up to 1800 PS
• DB 605 B Same as 605 A but for use in twin-engined aircraft like Messerschmitt Bf 110, Me 210 (different prop/gear ratio)
• DB 605 AS(M) Altitude optimized version of 605 A using the larger DB 603 supercharger, up to 1435 PS, ASM with MW-50 system and up to 1800 PS
• DB 605 ASB(M) Altitude optimized late-war version of 605 AS using B4 fuel, ASBM with MW-50 system and up to 1800 PS
• DB 605 ASC(M) Altitude optimized late-war version of 605 AS using C3 fuel, ASCM with MW-50 system and up to 2000 PS
• DB 605 DM First DB 605 D version, standard MW-50 equipment, up to 1700 PS
• DB 605 DBM Improved 605 DM, standard MW-50 equipment, first version up to 1850 PS, later reduced to 1800 PS, B4 fuel
• DB 605 DCM Improved 605 DM, standard MW-50 equipment, up to 2000 PS, C3 fuel
• DB 610 Two DB 605 "coupled" (geared together) to work on a single propeller shaft for use in Heinkel He 177, up to 2950 PS

Prototype/pre-production versions

• DB 605 BS proposed version for twin-engined aircraft, derived from DB 605 AS
• DB 605 E proposed version for twin-engined aircraft, derived from DB 605 D
• DB 605 L Similar to 605 D but with two-stage supercharger, 2000+ PS

Note: All power ratings in PS (metric horsepower). Unless otherwise noted takeoff/emergency power at sea level.

Specifications (DB 605AM)

(also known as DB 605 G during development)

References

• The Daimler-Benz DB 605

External links

• Aviation History.com, DB 600 series page
• Kurfürst! - Messerschmitt 109 Resource Site - DB 605 pages