The Geiger HDP 13.5 is a German electric motor for powering electric aircraft, designed and produced by Geiger Engineering of Seigendorf, Hirschaid, Oberfranken.^[1]

Design and development

The HDP 13.5 is a brushless 58 volt design producing 13.5 kW (18 hp), with an outrunner coil. It has a 93% efficiency. The low working rpm of the engine means that it can turn a propeller at efficient speeds without the need for a reduction drive.^[1]

Specifications (HDP 13.5)

Data from Tacke^[1]

General characteristics

• Type: Brushless electric aircraft engine
• Length: 181 mm (7.1 in)
• Diameter: 215 mm (8.5 in)
• Dry weight: 4.70 kg (10.4 lb)

Components

• Coil type: outrunner
• Cooling system: air
• Reduction gear: none

Performance

• Power output: 13.5 kW (18 hp)
• Voltage: 58V nominal
• Power-to-weight ratio: 2.9 kW/kg