Alfa Romeo RA-1050

Daimler-Benz DB 605
Company type	Aircraft piston engine
Industry	Aerospace
Founded	1942
Headquarters	Germany
Products	Aircraft engines (DB 605, DB 610)

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The Daimler-Benz DB 605 was a German aircraft powerplant produced during the Second World War. It evolved from the earlier DB 601 and powered various aircraft between 1942 and 1945, including the Messerschmitt Bf 109 fighter series, as well as the heavy fighters Bf 110G and Me 210C.

The DB 610, which combined two DB 605 engines geared to a single output shaft as a replacement for the similar DB 606, was installed in the A-3 and all A-5 versions of Germany’s sole operational heavy bomber, the Heinkel He 177A.

Several Italian aircraft, such as the Macchi C.205, Fiat G.55, and Reggiane 2005, utilized licensed versions of the DB 605. Additionally, it powered Swedish models like the SAAB B 18B and initially the pusher-type SAAB J 21. In total, around 42,400 units of all DB 605 variants were manufactured.

Design and development

The key enhancements distinguishing the DB 605 from its predecessor, the DB 601, included increased displacement, elevated maximum RPM, a higher compression ratio, and an upgraded supercharger. Engineers found it feasible to enlarge the cylinder bore without compromising block integrity; this bore was increased from the DB 601’s 150 mm to 154 mm in the DB 605. This modification boosted displacement from 33.9 liters to 35.7 liters. Adjustments to valve timing extended the intake duration and enhanced scavenging efficiency, which improved volumetric efficiency at higher engine speeds. Consequently, maximum permissible RPM rose from 2,600 in the DB 601 to 2,800 in the DB 605. These refinements elevated power output from approximately 1,350 PS (1,332 hp) to about 1,475 PS (1,455 hp). The engine’s weight also increased slightly from roughly 700 kg to approximately 756 kg.

File:Daimler Benz DB 605.jpg

The DB 605 is an inverted V-12. Shown here is a DB 605A model.

In most other respects, the design mirrored that of the DB 601. It remained an inverted V-12, featuring a crankshaft positioned above the cylinders. Both engines employed dual Bosch magnetos firing twin spark plugs per cylinder for reliable ignition. Bosch direct fuel injection was maintained via a pump delivering pressures up to around 90 bar. The lubrication system incorporated three pumps feeding oil from a dedicated reservoir holding about 35 liters. The supercharger was notably advanced for its time due to its barometrically controlled hydraulic clutch (fluid coupling), enabling automatic adjustment for altitude variations.

File:DB605.jpg

The supercharged design of the DB 605 is illustrated here with a DB 605A.

A significant design change involved replacing ball bearings with plain bearings; this alteration, combined with deteriorating lubricant quality during wartime, caused severe operational issues including engine fires. Initially, emergency power usage was prohibited due to these problems. Although Daimler-Benz modified bearing designs and introduced oil slingers with associated cooling systems, the Reich Air Ministry regarded the DB 605 as problematic throughout much of its service life.

In addition to bearing complications, material shortages during wartime Germany severely affected the engine’s reliability. Starting early in the conflict, critical elements like nickel and cobalt became scarce. This forced reductions in nickel content within exhaust valves—from roughly 13.5% down to about 8%—which diminished their corrosion resistance and led to scaling during operation. The buildup of scale triggered pre-ignition events causing destructive detonation and eventual engine failure. This issue primarily limited use of full manifold pressure at around 1.42 ata for extended periods despite occurring well before official restrictions were imposed—a problem also experienced by contemporaneous Jumo and BMW engines. The solution involved applying heavy chrome plating to exhaust valves; this coating improved resistance to scaling while reducing reliance on scarce nickel alloys. BMW pioneered this plating technology first on their BMW 801 radial engine used in Fw 190 fighters that suffered similar detonation failures.

Like its predecessor, the DB 605 was initially designed for "B4" aviation gasoline with an octane rating near 87. In late-war developments beginning in 1944, newer variants were introduced capable of running on higher-octane "C3" fuel (100 octane), along with optional equipment for power-enhancing systems such as methanol-water injection (MW50) and nitrous oxide injection (GM-1). The DB 605AM version initially operated on C3 fuel combined with MW-50 injection and delivered takeoff power up to approximately 1,800 PS (1,775 hp). By mid-1944, requirements shifted back to standard B4 fuel supplemented with MW-50 injection instead of C3 fuel alone. The high-altitude performance was further improved by the DB 605AS(M), which incorporated a larger supercharger borrowed from the Daimler-Benz DB 603 but otherwise resembled previous models. The DB 605ASB maintained takeoff power ratings near those of earlier models while preserving enhanced altitude capabilities similar to those of the ASM variant. The final A-series iteration—the DB 605ASC introduced in early 1945—raised takeoff output further to around 2,000 PS (1,973 hp).

Work on an advanced D-series variant capable of operating on either C2 or C3 grade fuels began as early as 1942 at Daimler-Benz. Late in 1944, a limited batch of DB 605DM engines appeared followed by main production runs designated as DB 605DB and DC models. These featured an adjustable screw stop permitting flexible fuel usage: either B4 fuel with MW-50 (DB designation), C3 fuel without MW-50 (also DB), or C3 fuel combined with MW-50 injection (DC suffix). Output for the DB variant reached about 1,800 PS (1,775 hp) at takeoff under approximately 1.8 ata manifold pressure; whereas DC versions achieved roughly two thousand PS (1,973 hp) at nearly two ata manifold pressure. When MW-50 was unavailable alongside B4 fuel usage throttle settings were limited to about1.45 ata throughout flight duration. This adaptability suited wartime Germany’s increasingly erratic fuel supplies during late conflict stages. These D-series engines primarily powered later Messerschmitt Bf 109 models such as G-10 and K-4 variants.

An unusual case involved fitting a captured British Supermarine Spitfire with a DB 605 engine. In November 1942, Spitfire VB EN830 NX-X from No. 131 Squadron RAF made an emergency landing in German-occupied Jersey farmland. German forces repaired this aircraft and replaced its original powerplant with a DB 605A among other modifications before operating it under Luftwaffe control until it was destroyed during an Allied bombing raid on August 14, 1944.

Variants

Production Models

File:Db610a.jpg

DB 610 gearbox end, displaying side-by-side DB 605 V12 engines

File:Daimler-Benz DB 605 showing crankshaft for motorkanone.jpg

Front perspective of Daimler-Benz DB 605, highlighting the hollow propeller shaft for 20mm and 30mm motorkanone

DB 605A

Standard fighter powerplant delivering up to 1475 PS, operating on B4 fuel

DB 605AM

Enhanced 605A equipped with the MW-50 system, capable of up to 1800 PS, using C3 fuel

DB 605AS

Altitude-optimized variant of the 605A utilizing the larger DB 603 supercharger, producing up to 1435 PS on B4 fuel

DB 605ASM

605 AS model fitted with MW-50, reaching up to 1800 PS on C3 fuel

DB 605ASB/605AB

Late-war iterations, initially rated at 1850 PS then reduced to 1800 PS, operating on B4 fuel with MW-50 or on C3 fuel without MW-50

DB 605ASC

Late-war model delivering up to 2000 PS when using MW-50 and C3 fuel

DB 605B

Identical to the 605 A but adapted for twin-engine aircraft such as the Messerschmitt Bf 110 and Me 210 with altered propeller and gear ratios

DB 605BS

Proposed twin-engine variant derived from the DB 605 AS

DB 605DB

Upgraded version of the 605 DM featuring standard MW-50 equipment, initially producing up to 1850 PS then lowered to 1800 PS, fueled by B4 with MW-50 or C3 without MW-50

DB 605DC

Further improved version of the 605 DM with standard MW-50 gear, capable of up to 2000 PS running on C3 fuel

DB 605DM

The initial DB 605 D variant equipped with standard MW-50 gear, outputting up to 1700 PS

DB 605E

Proposed twin-engine configuration based on the DB 605 D model

DB 605T

Developed specifically to power the HZ Anlage supercharger installed on the Henschel Hs 130

DB 605 L

Similar to the DB 605 D but featuring a two-stage supercharger delivering around 1700 PS; development ceased in December 1944

Fiat RA.1050 R.C.58 Tifone

Italian license-built and modified DB 605A-1 engines manufactured by Fiat

DB 610

Consists of two DB 605 engines mechanically coupled (geared together) into a single power unit (71.53L / 4364.8in³) driving one propeller shaft, employed in the Heinkel He 177A. The starboard engine component has a mirror-imaged supercharger.

DB 610A - Right-hand (clockwise) propeller rotation - Reduction ratio of 0.413:1.

Takeoff and emergency power rated at 2,950 hp (2,200 kW) at 2,800 rpm with a boost pressure of 1.2 atmospheres at sea level.

At 18,700 ft (5,700 m), delivers 2,700 hp (2,000 kW) at the same rpm with a boost of 1.42 atmospheres.

Climbing power output is 2,620 hp (1,950 kW) at sea level running at 2,600 rpm with a boost of 1.3 atmospheres.

At 19,000 ft (5,800 m), it produces 2,500 hp (1,900 kW) under similar rpm and boost conditions.

Maximum cruise power reaches 2,160 hp (1,610 kW) at sea level at an engine speed of 2,300 rpm and a boost of 1.15 atmospheres.

At 18,000 ft (5,500 m), maintains 2,160 hp (1,610 kW) under identical rpm and boost levels.

Fuel consumption during maximum cruise at sea level is approximately 0.474 lb/(hp⋅h) (0.288 kg/kWh) (or kg/kWh).

Overall dimensions are length 2.13 m (7 ft 0 in), width 1.62 m (5 ft 4 in), height 1.04 m (3 ft 5 in), with a weight of 1,580 kg (3,480 lb).

DB 610B - Left-hand (counterclockwise) propeller rotation - Weight is 1,580 kg (3,480 lb).

DB 610C - Right-hand propeller rotation variant.

Takeoff and emergency power rated at 2,870 hp (2,140 kW) at sea level running at 2,800 rpm.

At an altitude of 25,000 ft (7,600 m), it provides 2,560 hp (1,910 kW) at the same rpm setting.

Climbing power stands at 2,550 hp (1,900 kW) at sea level at an engine speed of 2,600 rpm.

At 24,300 ft (7,400 m), it produces 2,400 hp (1,800 kW) under similar conditions.

Maximum cruise power is 2,100 hp (1,600 kW) at sea level running at an engine speed of 2,300 rpm.

At an altitude of 23,000 ft (7,000 m), delivers around 2,040 hp (1,520 kW) under identical rpm parameters.

DB 610D - Left-hand propeller rotation configuration.

DB 616: A further advancement based on the DB 605 platform.

DB 620: A unit combining two DB628 engines.

DB 621: A conceptual two-stage supercharged version of the DB605.

DB625: A turbocharged iteration derived from the DB605.

DB628: The DB605 equipped with a two-stage supercharger program discontinued in March 1944.

IAR DB605: Produced under license in Romania by Industria Aeronautică Română (IAR).

Note: All power outputs are expressed in metric horsepower (PS). Unless specified otherwise, takeoff or emergency power ratings apply at sea level conditions.

Survivors

A Hispano Aviación HA-1112, which is a licensed-produced version of the Messerschmitt Bf 109 G-2, has been restored by the EADS/Messerschmitt Foundation in Germany and fitted with a Daimler-Benz DB 605 engine.

Applications

DB 605

DB 610

Engines on display

Exhibited DB 605 engines can be found at the Royal Air Force Museum in London as well as at the National Air and Space Museum located in Washington, D.C..

Specifications (DB 605AM)

File:Daimler DB 605 cutaway.jpg

Partially sectioned DB 605

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External links

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