Internal combustion engine - ppt download

Internal combustion engine - ppt download

Hydromatic Propellers

The Aircraft Propeller Basic Principles

Hydromatic Propellers

Basic Operation Principles : The pitch changing mechanism of hydromatic propeller is a mechanical-hydraulic system in which hydraulic forces acting upon a piston are transformed into mechanical forces acting upon the blades.

Piston movement causes rotation of cam which incorporates a bevel gear (Hamilton Standard Propeller) . The oil forces which act upon the piston are controled by the governor

Single Acting Propeller: The governor directs its pump output against the inboard side of piston only, A single acting propeller uses a single acting governor. This type of propeller makes use of three forces during constant speed operation , the blades centrifugal twisting moment and this force tends at all times to move the blades toward low pitch , oil at engine pressure applied against the outboard side of the propeller piston and this force to supplement the centrifugal twisting moment toward the low pitch during constant speed operation., and oil from governor pressure applied against the inboard side of the piston . The oil pressure from governor was boosted from the engine oil supply by governor pump and the force is controlled by metering the high pressure oil to or draining it from the inboard side of the propeller piston which balances centrifugal twisting moment and oil at the engine pressure.

Double Acting Propeller: The governor directs its output either side of the piston as the operating condition required. Double acting propeller uses double acting governor. This type of propeller , the governor pump output oil is directed by the governor to either side of the propeller piston.