pp241 intro to turbines test 1

standard day

Altimeter: 29.92 Hg

Temperture: 59 degrees F

Sanford Moss

concept of turbines 1900

Frank Whittle

patented first turbojet engine

Hans von Ohain

(1911-1998): This German engineer built the first operating model of the turbo jet engine in 1936.

Ram Jet

no compressor air in venturi to produce thrust

pulse jet

flapper valves control combustion and intake, cannot take off under own power

turbojet

intake, compressor, combustion, turbine, exhaust, accessory

Engine Pressure Ratio (EPR)

The ratio of turbine discharge pressure divided by compressor inlet pressure, used as thrust indication

Turbofan

A turbojet engine that has a large ducted fan mounted on the shaft ahead of the compressor.

divergant

velocity down pressure up temp up

convergent

velocity up pressure down temp down

Bypass ratio

The ratio of the mass of air moved by the fan to the mass of air moved by the core engine.

Fan Pressure Ratio

the ratio of air pressure leaving the fan to the air pressure entering the fan

2 basic sections of turbojet

hot and cold

2nd law of motion

Force = mass x acceleration

3rd law of motion

For every action there is an equal and opposite reaction

four stroke engines use the _________ cycle

otto cycle

jets use the constant pressure cycle or ____________

brayton cycle

ram air

air entering intake by force or moving forward

RAM recovery

The increase in thrust as a result of ram air pressures being normal 14.7 then low 9 then back due to convergent nose cowl on turbo fan engine

compressor stator

increase air pressure

compressor rotor

keeps air moving

The diffuser

straightns airflow also increases pressure very slightly right after compressor before combustion chamber

where is the highest temp of a jet

in the first stage turbine

compressor taper

keeps air velocity high enough so it doesnt become stagnate in compressor section

factors impacting thrust

temperature, airspeed, altitude, inlet air density

cold air is more

​

dense

thrust decreases with increase in temperature

true

the limitiglng factor of a jet engine is

temperature

humidity has no effect on jets

true

bleed air _______ thrust

decreases

gross thrust

no outside factors limiting thrust

net thrust

actual thrust in real world

primary airflow

goes into core of engine

secondary air

bypasses core and is used for cooling and thrust

compressor stall

caused by poor AOA

compressor stall fixed by

bleed valves in compressor, variable exhaust, multi spool turbine

the fan is part of the

low pressure compressor

safety wire

​

most commonly .032

thin copper wire is what size

.020

AN

airforce or army navy

A

no hole in shank

H

hole in head

most commone bolt class is

3 or medium

how to indentify AN hardware

length diameter and thread count/pitch

Bernoulli's Principle is __________ at super sonic

opposite

at 36000 feet temperature

remains the same

advantages of jets

reliable, faster, increased power to weight