Benz Bz.IV

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

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 IVsü) was produced from 1917 onwards. In February 1918, pistons from a Bz.IV were the first captured aluminium pistons to be examined by the British Ministry of Munitions.

Variants

IV: (1916) Main production variant produced by Benz & Cie.

IVmarta: (1916) Licensed production of the Benz Bz.IV in Austria-Hungary by Magyar Automobil Részvény Társaság Arad (MARTA). The Marta produced version was heavier and had a lower compression ratio than the German original.

IVsü: (1917) Overcompressed version producing 205 kW (275 hp) at altitudes above 2,000 m (6,562 ft). Also known as the IVs, IVü or IVaü. The "ü" in the model description stands for überverdichtet (German: "overcompressed”) while the "s" denotes the use of steel cylinder liners.

Specifications

Data from

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

1 2 Düsing, Michael (2022). German & Austro-Hungarian Aero Engines of WW1. Vol. 1. Aeronaut Books. pp. 197–205. ISBN 9781953201515.
↑ "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.

Bibliography

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.

External links

[:0-1] 1 2 Düsing, Michael (2022). German & Austro-Hungarian Aero Engines of WW1. Vol. 1. Aeronaut Books. pp. 197–205. ISBN 9781953201515.

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

[JAWA1919-3] 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.