BLOCK 9 OVERVIEW
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BLOCK 9 OVERVIEW
is defined as force per unit area. measured in PSI(Pound per Square Inch)
What is the unit of measurement for measuring force per unit area ?
PSI(Pound per Square Inch)
is used to measure Atmospheric and Applied pressure.
Define PSIG ?
Pound per Square Inch Gage
is used to measure applied pressure only. Gage is fixed(calibrated) to 0 PSI at normal atmospheric pressure.
Pound per Square Inch Differential. Is used to measure Differential pressure only.
What is the Atmospheric pressure in sea level?
What is the unit of measurement for Atmospheric and Applied pressure ?
PSIA (Pound per Square Inch Absolute)
is defined as anything that occupies space and has mass. Matter consists of atoms and molecules.
What are the three states of Matter ?
(1) Solid(Definite volume and shape)
(2) Liquid(Definite volume and no shape)
(3) Gas(no definite volume or shape)
What is fluids ?
Gas and Liquids are considered as Fluids. They assume the shape of their container.
Which state of matter exerts pressure in all directions?
Solid objects applies pressure to what direction ?
Which state of matter exerts pressure in Down and out?
Pounds per Square Inch Gage(PSIG) is used to indicate ______ only.
A manometer utilizes inches of water to indicate ______ pressure readings.
What is vacuum?
Area containing less pressure than atmospheric pressure. Referred to as Negative pressure.
A manometer utilizes inches of water to indicate ____ pressure readings.
Inches of Mercury is used to measure _______ pressure.
One inch of Mercury(HG) is equals _____ PSI
What are the three scales used for measuring temperature?
(1) Centigrade or Celsius
(3) Absolute or Kelvin
is defined as the intensity of applied heat expressed in degrees.
What are the degrees of freezing and boiling point of water in Centigrade, Fahrenheit and Absolute(Kelvin)?
Fahrenheit ---------32°F------------ 212°F-------------
Absolute ------------273°K -----------373°K-------------
What is Absolute Zero ?
Temperature at which all molecular activity ceases
0°K(Absolute 0) is equals to -273°C or 459°F
What are the measurement of Heat ?
Joules, Calories and BTU(British Thermal Unit)
What are the three methods of heat transfer?
(1) Conduction(Heat transfer by means of solid)
(2) Convection(Heat transfer by means of fluids)
(3) Radiation(Heat transfer by means of waves)
the amount of heat required to raise the temperature of one pound of water to one degree fahrenheit.
Vacuum is used to prevent heat loss through ______.
Brightly colored paint or foil could be used to prevent heat loss through ______.
Which type of heat transfer does not need a medium?
_______ color paint can used to maximise radiation ?
What are the natural ingredients in our atmosphere ?
Nitrogen, Oxygen, helium, Hydrogen, Argon and Carbon dioxide.
What are the Man-made pollutants in the atmosphere?
Auto exhaust, Factory waste, Dust, Bacteria etc.
With an increase in altitude the density of the air _______ .
At 6 miles in the atmosphere, the density of the air is too thin to support _______.
At 12 miles in the atmosphere, the density of the air is too thin to support _______.
________ filters out ultraviolet rays from the sun.
is the weight of 1 square inch of air at a given altitude.
What is the atmospheric pressure at sea level ?
14.69 PSI or Measured in inches of mercury 29.92Hg
What is the correlation between inches of mercury and PSI ?
The correlation between inches of mercury and PSI is that one cubic inch of mercury is the same as 0.491 pounds per square inch(1 in. Hg = 0.491 PSI)
The first layer of the atmosphere. Extends from sea level and extends to approximately 6 miles. Contains 3/4 of total weight of the atmosphere.
The second layer of the atmosphere. Extends from 6 miles to 60 miles. Ozone layer is found in 12 to 30 miles of Stratosphere.
Found at 12 to 30 miles in the atmosphere made of poisonous gas. Ozone layer filters the ultraviolet rays from sun.
How is moisture in the atmosphere expressed?
the ratio of moisture in the air at a given temperature and pressure as opposed to the total amount of moisture the air could hold at that same temperature and pressure.
Which layer of the atmosphere makes ups 3/4 of the total weight ?
The Ozone is located in which layer of the atmosphere?
What is Ozone layer comprised of ?
Most moister is found in which layer of the atmosphere?
The force that pushes air through tubing or ducking.
The rate at which a substance moves.
The amount or volume of air that moves past a fixed pint in a given period of time.
What are the measurement for Airflow?
Pound Per Minute(PPM)
Cubic Feet per Minute(CFM)
A venturi consists of three sections which are they?
(1) Intel(High pressure and low velocity)
(2) Throat(Low pressure and High velocity)
(3) Outlet(High pressure and low velocity)
Which is the narrow part of a Venturi?
Smooth, thin and parallel layers of airflow.
Venturi creates a
Non-smooth, whirling airflow which creates resistance, loss of energy and increase heat.
a turbulent airflow
What are the two types of airflow limiting devices ?
(1) Venturi(Smooth airflow)
(2) Orifice(Turbulent airflow)
Flow and pressure are __________ proportional.
A _______ prevents starvation of an air source.
A _______ protects components downstream.
Which flow limiting device creates a loss of energy ?Orifice
Which strut is the normal source of bleed air for B-52?
Strut number 2(Engine 3 and 4)
Which strut is the emergency source of bleed air for B-52 ?
Strut number 3(Engine 5 and 6)
Prevents reverse air flow. Allows air to flow in one direction only.
Engine Bleed Air Check Valves
Which switch is used to control Cabin Air Conditioning Shut off Valve ?
Cabin Pressure Master Switch.
When did all four bleed air valves open?
During engine start.
Prevents damage to bleed air ducts due to airframe movement by allowing ducts to pivot.
the purpose of Swinging Gate
Compensate for thermal expansion of bleed air ducts.
Used to connect cold air ducts
Channel Band Coupling
Gasket used to prevent bleed air leaks. Used on hot air ducts only.
Used on hot or cold air. Used when frequent removal is required.
Which strut is the normal source of bleed air?
Which strut provides an emergency source of bleed air?
What is the purpose of Pre-cooler in bomber Air Distribution System ?
Reduces the temperature of the engine bleed air.
Which switch controls all four bleed air valves during engine start ?
Manifold Valve Switch
Which switch controls the Body Crossover Manifold Valve during normal system operation?
Cabin Pressure Master Switch.
When did Strut #1 and #4 bleed valve opens?
Opens only during engine start and operational checks of the valves.
Which valve controls flow of bleed air from Strut #2?
Body Crossover Manifold Valve.
Which switch provides a means for the pilot to chose the source of bleed air?
Bleed Selector Switch. Two positions; Normal(Strut #2) and Emergency(Strut #3).
Which struts are Solenoid controlled and Air Actuated to open?
Struts #1 and #4.
Which component maintains a constant air flow of 140PPM in bomber Air Distribution System?
Pack Pressure Limiter
What is the purpose of Condenser(Coalescer)?
Condenses the water vapor into water droplets.
What is the purpose of Louvered Grid in bomber Air Distribution System ?
Creates a whirlwind effect separating moisture from the air passing through the water separator.
Which component in the Water Separator, allows air to bypass the condenser (coalescer) when the coalescer become frozen or clogged?
Water Separator Bypass Valve
Which component senses air temperature at the water separator outlet ?
Anti-ice Sensing Element.
Prevents rapid depressurization of the aircraft cabin in case of duct or coupling failure.
the purpose of Hot and Cold Air Check Valves
Which component reduces valve noise in bomber Air Distribution System?
Hot Air Muffler
Which sensor senses temperature of both hot and cold air ducts in bomber Air Distribution System?
What are the five components that make up the cabin temperature control system for automatic operation?
(1) Temperature Control Selector
(2) Duck Sensor
(3) Cabin Sensor
(4) Cabin Temperature Regulator
(5) Air Conditioning Modulating Valve
Vertical elevation of an object above a given point.
The actual height of an aircraft above sea level.
The pressure in the aircraft cabin regadless of the aircraft altitude - expressed in feet.
What are the three range of pressurization schedules?(1) Unpressurized (0 to 8,000 feet)
(2) Isobaric (8,000 to 35,000 feet)
(3) Differential(35,000 to Max operating altitude)
What is the Repressurization rate?
Cabin does not pressurize faster than 1 PSI per minute.
What is the purpose of Isobaric section in Bomber Pressurization System?
Maintains a constant cabin pressure at varying altitudes.
What are the four methods of dump cabin pressure?
(1) Cabin Pressure Master Switch to RAM position
(2) Squat switch on Ground
(3) Pressure Release Switch
(4) Emergency Dump Handle
What are the four functions of cabin pressure Outflow Valve ?
(1) Normal control by Pressure Regulator
(2) Over pressure relief (Opens at 8.1 PSID)
(3) Under Pressure(Negative pressure) relief
What is the cabin pressure in 8,000 feet?
What are the electrical methods of operating Pressure Dump Control Valve?
(1) Cabin Pressure Master Switch to RAM
(2) Pressure Release Switch to DUMP
(3) Landing Gear Squat Switch to GROUND
Pressure Dump Control Valve can be operated electrically or _______ .
What is the use of Ground test valve in Cabin Pressurization System?
Used to check operation of the cabin pressure regulator.