PS51L COOLING SYSTEMS Reciprocating Engines

A reciprocating engine converts only about BLANK (what percent) of the heat energy

of the burning fuel into mechanical energy.

30

The radial engine cowling that encloses the engine and provides for pressure cooling is called a/an BLANK cowling

NACA

BLANK (what devices) are used between the cylinders of an air cooled engine to force the cooling air to flow between the cooling fins on the cylinders.

Intercylinder baffles

Cowl flaps on an air-cooled engine are located in such a way that they produce a BLANK pressure area to increase the airflow through the cylinder fin

Low

Cowl flaps on an air-cooled engine should be BLANK during ground runup

Open

The velocity of the exhaust gases creates a BLANK pressure at the inlet of the augmentor tubes.

Low

Accessories and local hot spots are typically cooled with additional air from BLANK tubes directed at them.

Blast

Helicopter engines are typically cooled by a BLANK system that provides cooling airflow.

Fan

The thermocouples used to monitor cylinder heat temperature may be either of these designs:

Bayonet

Gasket

1. If a cylinder head thermocouple lead is too long, you should BLANK the excess.

Coil and tie

Cracks in cylinder head fins can sometimes be BLANK to prevent further cracking.

Stop drilled

Dents or bends in cylinder head fins should be BLANK if there is no danger of cracking.

Left alone

Nearly all of the cooling air for a turbine engine must be passed BLANK the engine.

Through

The 25% of the airflow through a turbine engine that is used to support combustion is called BLANK airflow.

Primary

Cooling airflow is called BLANK airflow.

Secondary

The coolest point within a gas turbine engine is at the BLANK

Compressor inlet

The engine exterior and the engine nacelle may be cooled by passing BLANK between the case and the shell of the nacelle

Air

The thin walls of the combustors of a gas turbine engine are protected from heat by a flow of BLANK

Air

The hottest point within a gas turbine engine is in the BLANK section.

Turbine

1. Cooling hollow vanes and blades with bleed air is known as BLANK cooling or BLANK cooling.

Connection / by a flow

Cooling air passing through porous high temperature material is known as BLANK cooling.

Transpirational

What may be used to reduce the temperature of the structure in the vicinity of the exhaust duct?

Insulation blanket

What is meant by pressure cooling of an air-cooled engine.

Air cooling in which air is forced to flow through baffles and cylinder fins by a pressure differential across the engine.

What must be inspected on the cooling system of an air-cooled engine?

All of the baffles and air seals must be in place and in good condition.

Why should an air-cooled engine not be run up to high power without the cowling installed?

The engine depends on the cowling to force air through the cylinder fins to remove the excess heat.

Why do some air-cooled engine installations have cowl flaps?

Cowl flaps produce a low pressure on one side of the engine to pull air through the cooling fins on the cylinder.

Where can you find what is the maximum amount of cylinder fin area that can be removed in order to clean out a damaged area?

In the engine overhaul manual.

What document describes the proper use of cowl flaps on an air-cooled engine?

The pilot's operating handbook (POH)