Daimler-Benz DB 604


The Daimler-Benz DB 604 was an experimental German 24-cylinder aircraft engine, which did not progress beyond the initial engine testing phase and was ultimately abandoned in September 1942.


The DB 604 was unique among the DB 600 series of aircraft engines by having its 24 cylinders arranged in an X, with four inline rows of six cylinders. The DB 604 was also unique amongst the X-24 engines, in that it was not conceived as a further development of existing Daimler-Benz aircraft engines such as the DB 601, DB 603 or DB 605, which themselves had been twinned-up as two separate powerplants sharing a new common gear reduction case at their front ends, into the "coupled" DB 606, DB 613 and DB 610 "power systems" respectively, starting before World War II.


The DB 604 was a completely new Daimler-Benz engine design featuring a perfectly square stroke ratio of 135 mm x 135 mm. The square stroke ratio enabled the relatively high engine speed of 3,200 rpm. The first engine tested in 1939 on the engine test stand achieved a power output of 1,725 kW (2,350 hp).
Further development of the first test engines led to the DB 604A/B. The only difference between the DB 604A and the DB 604B - as with the similarly suffixed A and B versions of the DB 606 and 610 "coupled" power system engines - was the direction in which the DB 604's crankshaft turned. The DB 604A/B was equipped with a two-speed supercharger, achieving 1,835 kW (2,500 hp) whilst testing.
Development of this promising engine was canceled by the Reich Air Ministry (RLM - German: Reichsluftfahrtministerium) in September 1942.



DB 604A/B
Type: Water-cooled 24-cylinder X (4 rows of 6-cylinders) piston engine
Bore: 135 mm
Stroke: 135 mm
Displacement: 46.38 L (2,830 cu in)
Dry weight: 1,080 kg (2,379 lb)
Power output: 1,835 kW (2,500 hp) at 3,200 rpm at 5,100 m (16,732 ft)
Specific power: 25.3 kW/L (0.9 hp/cu in)
Compression ratio: 7.0:1
Power-to-weight ratio: 0.59 kW/kg (0.95 hp/lb)