Benz Bz.IV

Bz.IV
	A Benz Bz.IV at the National Air and Space Museum's Udvar-Hazy Center (2017)
Type	Inline piston engine
National origin	Germany
Manufacturer	Benz
First run	c. 1916
Number built	6,400
Developed from	Benz Bz.III
Developed into	Benz Bz.IVa

The Benz Bz.IV was a German six-cylinder, water-cooled, inline engine developed for aircraft use. Deliveries began in 1916, and some 6,400 were produced.

Design and development

The Bz.IV was a dual-camshaft design, with two intake and two exhaust valves per cylinder. The cylinders were cast iron surrounded by a sheet metal cooling jacket. The crankcase was aluminium and pistons were initially steel but later versions had aluminium pistons. A high compression version of the engine (Bz IVü) was produced from 1917 onwards and can be recognised by the red bands painted on each cylinder. In February 1918, pistons from a Bz.IV were the first captured aluminium pistons to be examined by the British Ministry of Munitions.^[1]

Applications

AEG C.VI
AEG J.I
AGO C.IV
Albatros C.VII
Albatros C.XIV
Albatros J.I
Chitty 2 (racing car)
DFW C.V
Dobi-II
Friedrichshafen FF.49
Friedrichshafen G.II
Halberstadt C.III
Halberstadt C.V
Junkers J.I
LFG Roland C.III
LVG C.VI
NAVO RK-P4/220
Pfalz D.XII
Pfalz D.XIV
Riesenflugzeug, the German giants of WWI

Specifications

Data from ^[2]

General characteristics

Type: 6-cylinder, water-cooled, inline aircraft piston engine
Bore: 145 mm (5.7 in)
Stroke: 190 mm (7.5 in)
Displacement: 18.825 L (1,148.8 cu in)
Length: 1,990 mm (78.3 in)
Width: 530 mm (20.9 in)
Height: 1,150 mm (45.3 in)
Dry weight: 370 kg (815.7 lb)

Components

Valvetrain: Twin inlet and exhaust valves operated by pushrod actuated double rockers
Fuel system: Two Benz 2-jet carburettors feeding three cylinders each
Fuel type: Gasoline specific gravity 0.72
Oil system: Pressure feed at 0.2 MPa (28 psi): 50% Vacuum Heavy, 50% Sternol
Cooling system: Water-cooled

Performance

Power output: 170 kW (228.0 hp) at 1,400 rpm
Specific power: 9.1 kW/L (0.2 hp/cu in)
Compression ratio: 4.91:1
Fuel consumption: 85.2 L (150 imp pt) / hour
Specific fuel consumption: 0.495 L/kW/hr (0.65 pts/hp/hour)
Oil consumption: 2.6 L (4.5 imp pt) / hour
Power-to-weight ratio: 0.3796 kW/kg (0.231 hp/lb)

References

^ "Report on Aluminium Pistons from 230 HP Benz Engines". Flight. 4 July 1918.
^ Grey, C.G. (1969). Jane's All the World's Aircraft 1919 (Facsimile ed.). David & Charles (Publishing) Limited. pp. 1b to 145b. ISBN 978-0-7153-4647-1.

Grey, C.G. (1969). Jane's All the World's Aircraft 1919 (Facsimile ed.). David & Charles (Publishing) Limited. pp. 1b to 145b. ISBN 978-0-7153-4647-1.
Kroschel, Gunter and Helmust Stützer. (1977) Die deutschen Militarflugzeuge 1910-1918 Wilhelmshaven: Lohse-Eissing Mittler.
[1]

[1] "Report on Aluminium Pistons from 230 HP Benz Engines". Flight. 4 July 1918.

[JAWA1919-2] Grey, C.G. (1969). Jane's All the World's Aircraft 1919 (Facsimile ed.). David & Charles (Publishing) Limited. pp. 1b to 145b. ISBN 978-0-7153-4647-1.

[1]

[2]