Description

The WALTER M601 series engines have been designed for commuter, agricultural, and trainer aircraft. The WALTER M601 engine is a free power turbine turboprop engine.

The engine can equipped with a water injection system and thus take-off power can be flat rated up to higher ambient temperatures. This system can be utilized also for compressor recovery wash.

The WALTER M601 engine features two independent parts: the gas generator and power section. The gas generator and free turbine shafts are arranged in a tandem layout.

Air enters the engine in the rear part, flows forward through the compressor, combustion chamber, and turbines and exits through exhaust nozzles near the front of the engine.

Gas Generator

Air enters the compressor in a radial direction via a protecting screen and annular plenum. The air is axially directed in front of the compressor. The compressor consists of two axial stages followed by one centrifugal stage. The combustion chamber is of an annular configuration. Part of the primary air enters the flame tube through the perforations in the walls, the remainder passes through the hollow nozzle guide vanes of the gas generator turbine. The fuel is atomized by a special ring rotating with the gas generator shaft. The one stage gas generator turbine drives the compressor via the compressor shaft. The interturbine temperature is measured by a set of thermocouples installed in the flow path at the gas generator turbine outlet.

Power Section

Tip shrouded one stage axial-flow turbine drives the propeller via two-stage countershaft reduction gearbox. The reduction gearbox embodies an integral torquemeter which also assists for evaluation of engine power. The exhaust gasses from the free turbine pass through the annular plenum to the atmosphere via two opposed exhaust nozzles. Exhaust gases provide for an additional jet thrust.

Fuel System

The fuel system of the engine is a low pressure system with a gear fuel pump and fuel control unit. In case of the fuel control unit failure it is possible to use (by means of switching the electromagnetic valve on) an emergency circuit of the engine control. Fuel is atomized in the combustion chamber with aid of spray ring. The fuel in the combustion chamber is ignited by means of two torch igniters. Gear pump delivers fuel to the torch igniters.

Engine Starting

The engine is started by an electric starter/generator. Fuel in the torch igniters is ignited by means of low voltage plugs.

Oil System

The oil system is a circulatory, pressure fed system with an integral oil tank incorporated in the accessory gearbox. The oil system provides lubrication for all areas of the engine; further, pressure oil for the torquemeter and propeller speed governor.

System of Limiters

The engine is equipped with a limiter system which prevents from permitted interturbine temperature exceeding at start, and propeller speed exceeding in BETA range (at reverse). The limiters indicate exceeding permitted values of torque, propeller and gas generator speeds and interturbine temperature at other operating modes or the system directly intervenes through engine power reduction. Authorities of the limiter system varies with individual engine models.

Engine Controls

Power plant is controlled by three levers. Engine operation mode at forward-thrust powers and at BETA range is selected by means of engine control lever. Shut-off valve is controlled by the shut-off valve actuating lever and when the emergency circuit is switched on the lever controls engine operation. Controlled propeller speed and propeller feathering (in front extreme position) is selected by means of propeller control lever.

Engine Mounting

The engine is mounted to the engine mount bed ring by three elastically supported pins which are located on the centrifugal compressor casing.

Propeller

M601 engines can be fitted with either single or double acting propellers. Basic engine equipment provides for emergency feathering by means of the propeller control lever; an airplane can be fitted with system of manual propeller feathering (for all power levels), actuated by a push button in the cockpit and with autofeathering system which operates in case of engine shutdown at higher power.