Accession Number:

AD0729231

Title:

Grundlagen des Motorseglers (The Rudiments of Powered Gliders),

Descriptive Note:

Corporate Author:

DEUTSCHE FORSCHUNGSANSTALT FUER LUFT- UND RAUMFAHRT E V BRUNSWICK (WEST GERMANY)

Personal Author(s):

• Lohner,Kurt

Report Date:

1960-09-22

Pagination or Media Count:

10.0

Abstract:

From investigations of thermal upcurrents it becomes clear that the rate of vertical descent of powered gliders has to be less than 1 msec. Further requirements take-off distance of 600 m over a 15 m high obstacle, climbing ability 1,25msec are contained in the German regulations for powered gliders. Calculations on the air resistance of the propeller have demonstrated that a propeller in feathered position or with hinged blades represents the best condition. For cooling piston engines of tractor propellers the air flow produced by the propeller will generally be sufficient. For pusher propellers a cooling blower will be required. In case of a constant air speed, the jet efficiency of the propeller only depends on the propeller performance and on the diameter it will increase with increasing diameter. In case of tractor propellers essential components of the fuselage are in the propeller slip stream a fact which reduces the jet efficiency of the propeller according to the proportion of the propeller plane to the blown fuselage section. With drive by air-jet blowers the efficiency together with the diameter will increase in a similar way as in case of the propeller. This drive can only be applied to single-seaters with assisted take-off and take-off with own power. In case of a turbojet engine the jet efficiency is low due to the high jet-stream velocity, a fact by which the fuel consumption is increased. Author

Descriptors:

• *PROPULSION SYSTEMS
• *AIRCRAFT ENGINES
• GLIDERS
• DESCENT
• AERIAL PROPELLERS
• CLIMBING
• WEST GERMANY

Subject Categories:

• Gliders and Parachutes

Distribution Statement:

APPROVED FOR PUBLIC RELEASE