BMW IV
Preserved BMW IVa
Type	Inline engine
Manufacturer	BMW
First run	1919
Developed into	BMW V BMW VI

The BMW IV was a six-cylinder, water-cooled inline aircraft engine built in Germany in the 1920s. Power was in the 180 kW (250 hp) range.

World record

On 17 June 1919 Franz Zeno Diemer flew a DFW F37, powered by a BMW IV engine to an unofficial world record height of 9,760 m (32,021 ft) from Oberwiesenfeld, reaching that altitude in 89 minutes.^[1] Diemer stated at the time, "I could have gone much higher, but I didn't have enough oxygen."^{[citation needed]}

Applications

• Arado SC I
• Albatros L 72
• Albatros L 74
• Caspar C 27
• DFW F37
• Heinkel HD 22
• Heinkel HD 24
• Heinkel HD 39
• Junkers A 35
• Junkers F 13
• LFG V 59
• LFG V 60
• Polikarpov R-1 BMW (Soviet unlicensed copy of Airco DH.9A)
• Rohrbach Ro VII Robbe
• Rohrbach Ro VIII Roland I
• Type 91 Heavy Tank
• Type 95 Heavy Tank

Specifications

Data from BMW Type IV description and user manual.^[2]

General characteristics

• Type: Six-cylinder inline piston engine
• Bore: 160 mm (6.30 in)
• Stroke: 190 mm (7.48 in)
• Displacement: 22.92 L (1,399 cu in)
• Dry weight: 290 kg (640 lb)

Components

• Valvetrain: Overhead camshaft, two valves per cylinder
• Cooling system: Water-cooled

Performance

• Power output: Nominal 230 PS (227 hp; 169 kW) , maximum continuous 250 PS (247 hp; 184 kW)
• Compression ratio: 5.5:1