Jet Engine Flashcards
(354 cards)
0
Q
What would happen to a plain cylinder with an open end under the wing of an aircraft flying at high speeds if heat energy was added to the air as a pass-through the duct?
A
The air would expand and increased the jet velocity
1
Q
What is jet propulsion
A
The propelling force generated in the direction opposite to the flow of a mass of gas or liquid under pressure
2
Q
What is accomplished by a divergent entry nozzle in the ramjet
A
Decreases the velocity of the air and increases the pressure
3
Q
What is left at the other end of a rocket with the release of the internal pressure at the nozzle end?
A
And unbalanced pressure (which propels the rocket in the direction opposite of the exhaust gases)
4
Q
What jet is used in remotely piloted vehicles (RPV) and cruise missiles?
A
The “Aero Thermo Dynamic duct” or Ram jet
5
Q
What determines the amount of heat that can be used in a pulsejet engine?
A
The amount of air available
6
Q
What engine proved that the more air in engine could compress the greater the power (thrust) it produced?
A
The pulsejet
7
Q
What increases the compression of the air used for combustion in the gas turbine engine?
A
Each set of blades and vanes
8
Q
What results from increasing the number of stages and a gas turbine engine?
A
A higher compression ratio
9
Q
What governs the action of matter, motion, force, and energy?
A
Physical principles
10
Q
What increases the jet velocity?
A
A convergent exit nozzle.
11
Q
What type of missile uses the Aero thermal dynamic duct or ramjet?
A
Piloted vehicles (RPV) and cruise missiles
12
Q
What does the intermittent impulse Jet engine known as the areopulse or pulsejet, improve?
A
Compression by sacrificing the principle of continuous power generation
13
Q
What is the greatest single reason the gas turbine bronze and produces the rest needed in the modern aircraft?
A
The compressor
14
Q
What is the area for fuel and air are mixed and ignited?
A
The combustion chamber
15
Q
What is force?
A
The action or effect on the body that changes the state of motion of the body
16
Q
What is known as matter?
A
Anything that occupies space and has weight.
17
Q
What is mass?
A
The quantity of matter in a body measured in relations to it inertia
18
Q
What is the common measurement to determine the quantity of matter with pull of gravity on it?
A
Weight
19
Q
What is the mathematical formula for mass?
A
M=W/G….which is mass is equal to the weight of the object divided by the acceleration due to gravity
20
Q
How is slug define?
A
A mass was force and acceleration (due to gravity) taken into consideration.
21
Q
How is energy defined?
A
The capacity of doing work.
22
Q
How is work defined?
A
When a force moves a mess through a distant (work = force x distance)
23
Q
How is power defined?
A
The rate of doing work
24
How is horsepower defined?
English measurement for mechanical power and is 33,000 foot pounds per minute or 550 foot-pounds per second
25
How is speed defined?
The distance a body in motion travels per unit of time
26
How is velocity defined?
Speed in a given direction
27
How is acceleration defined?
The rain velocity change and is gained or lost a velocity with time
28
What is the rate of acceleration due to gravity?
32.2 ft./second
29
How is a standard day defined?
A reference or standard that shows conditions at sea level: biometric pressure = 29.92 inches of mercury temperature = 59.0°F
30
How are all gas turbine engines related?
With air at the standard temperature of 59°F
31
How is pressure effect defined?
An increase in pressure resulting in more molecules per cubic feet which in return increases the weight of a slug of air
32
How is ram effect defined?
Simply as more air arriving at the engine intake than the engine can ingest
33
What is Newton's first law state?
A body at rest tends to remain at rest and a body in motion to move at a constant speed in a straight line unless acted upon by some external force
34
What is Newton's second law State?
an unbalance of force on a body tends to produce an acceleration in the direction of force and that acceleration if any is directly proportional to the force and inversely proportional to the mass of the body. "Force is proportional to the product of the mass and acceleration"
35
What is Newtons third law state?
For every acting force there is an equal or opposite reacting force
36
What are four basic types of classes of jet engines?
Rocket, pulse jet, ram jet, and jet turbine.
37
What are the simplest and oldest kind of general purpose jet engines?
Turbo jets
38
What are the most modern Jets Injun where most of the air entering the intake bypass the combustor?
Mainly turbofans
39
What is the major drawback for Ramjet engines, although they are similar in design since they virtually have no move mean parts?
They are incapable of operating at low flights speed
40
What happens to the compressed air in a turbo jet after leaving the compressor section?
It enters the combustion chamber
41
What is the primary use for the turbojet turbines rotational energy?
Driving the compressor (although some shop power is extracted to drive accessories)
42
Why is the fuel air mixture brought almost to a stop just after the start of the start turbojet combustion chamber?
So that a stable flame can be maintained
43
What is the normal nozzle pressure ratio on a turbojet?
Usually high enough for the expanding gases to reach Mark 1.0 and choke the throat
44
What is the normal nozzle pressure ratio on a turbo jet?
Approximately 2.5 pounds Force per horsepower (15mN/W)
45
What principle do turboshaft engines use?
The free turbine principle
46
What type of engine has a compressor, combustion chamber, turbine, and jet nozzle, all of which operate in the same manner as their counterparts in the turbojet?
turboprops
47
How does the turboprop engine differ from a turbo?
It has an additional fan blade in the turbine stage to recover more power from the engine to turn the propeller
48
What is the simplest composition of a turboprop?
an intake, compressor, combustor, turbine and a propelling nozzle
49
What is the simplest composition of a turboprop?
An intake, compressor, combustor, turbine any propelling nozzle
50
Why are turboprops very efficient modest flight speed (below 450 mph)
Because the jet velocity of the propeller and exhaust is relatively low
51
How is supersonic speed of the propeller to prevent it in a turboprop?
A speed reduction gearbox is inserted between the power turbine and the propeller shafts
52
Why do most turboprop engines only contain one stage of centrifugal compression (while most modern turbojet and Turbofan engine use axial flow compressors)?
Because of their smaller size
53
What type of engine has the same as the turboprop and an duct-enclosed, axial-flow that replaces the gearbox and prop?
Turbofan
54
Essentially, what is the compression of the Turbofan?
Similar to the turbojet and consists of a ducted fan with a smaller diameter turbojet engine mounted behind it that powers the fan
55
How did modern turbofans evolve from the two-spool axial-flow turbojet engine?
Essentially by increasing the relative size of the low pressure compressor to the point where some if not most of the air exiting the unit actually bypass the quarter or gas generators Stream, passing through the main combustor.
56
Besides direct thrust, what the main difference between a turbofan and the propeller?
The intake duct of the former slows the air before it arrives at the fan face
57
What recent developments in Turbofan turbine blades have allowed operation at higher temperatures with less distortion ?
Original polycrystalline (regular metal) blades are now made from lined up metallic crystals and more recently mono-crystalline
58
Which one of the engine designation systems is in use today?
The old system under Air Force-Navy bulletin No. 306
59
What is the second engine designation system that is used today?
The new system under M I L-STD-879 and includes all newly developed gas turbine engine of the Air Force, Navy, and army.
60
What does the first part of the designation system symbol consist of?
A letter (or letters) with a number showing each basic engine type
61
What is the letter X?
A prefix showing experimental and service test of the particular engine. After exhaustive test confirming the ability of an engine to perform under all operating conditions X prefix is removed
62
What does the Y apply to?
An engine or device that has a specific function rather then a general one, or that the engine has only completed a 50 hour qualification test.
63
What happens upon satisfactory completion of the 150-hour qualification testing?
The engine is approved as a J type
64
What is the second part of the designation?
A dash and the manufacture's letter symbol
65
What does the third part of the designation consist of?
A dash and a numeral showing the model number
66
What does the MIL-STD-879 system consist of?
Three parts; a type indicator, manufacturer's symbol, and a model indicator.
67
What does the type indicator, of the MIL-STD-879, the first part of the designation, consist of?
The appropriate type of letter symbol together with the type numeral
68
What does MIL-STD-879 second part of the designation consist of?
A dash and two letter symbol showing the manufacturer
69
What does the MILSTD879 model indicator consist of?
A dash and a model number, or a dash and a model number with a suffix letter you assign, and a model number for each configuration of a given engine.
70
What happens should any service use another's designated engine?
The designation remains of the same unless there is a model change, in which case only the model indicator is changed, showing the engine has been modified.
71
What does a turbojet engine consist of?
Air entrance section; compressor section; combustion section; turbine section; exhaust section; accessory section; and systems necessary for starting, lubrication, fuel supply, and auxiliary purposes, such as anti-icing, cooling, and afterburning
72
What does proper duct design contribute?
Aircraft performance by increasing ram recovery and limiting pressure drops
73
What does divergent inlet designs do?
Change ram air velocity into high static pressure at the compressor inlet
74
What are two methods of classifying inlet ducts?
1. Single entrance and divided entrance
| 2. sub sonic and supersonic ducts
75
Why do modern navy aircraft, that is capable of supersonic flight, pose problems to aircraft designers?
Because the airframe can withstand supersonic velocity air but the engine cannot
76
What are the two methods commonly used to defuse the intake air and slow it's flow to subsonics speeds during supersonic flight?
1. To create shockwave in the intake airstream, which will disrupt the flow and cause a decrease in velocity
2. To vary the area or the geometry of the intake duct
77
What are the two basic types of compressors?
Ratios approaching 15:1 and air flows up to 350 lbs; the addition of a fan raises these values to 25:1 and 1,000 lbs/sec
78
What does the single entry centrifugal-flow compressor consist of?
An impeller (rotor element, a diffuser (stator element), and manifold
79
What are two main elements of an axial-flow compressor?
A rotor and stator
80
What are the stature vanes made of?
Steel with corrosion and erosion resistant qualities
81
What are rotor blades made out of?
Stainless or semistainless steel
82
What is referred to as blade "profiles"?
Compressor blades tips reduced in thickness by cutouts
83
What does the disc type rotor consist of?
Separately machined discs and spacers flanged to fit one against the other in sequence.
84
What does a disc-type rotor consists of?
Separately machined discs and spacers flanged to fit one against the other in a sequence
85
What are two examples of the combination compressor now in use?
The F404-GE-400 and the TF34-GE-400
86
What are the two configurations of the axial compressor now is use?
The single rotor and the dual rotor, sometimes referred to as solid spool and split spool.
87
Which version of solid-spool compressor uses variable inlet guide vanes?
Pratt and whitney's J52 engine
88
What is considered primary air?
About one-fourth of the air entering the combustion chamber area that mixes with the mixed fuel for combustion
89
What are pollution emissions?
Particles of matter such as smoke, carbon monoxide, partially burned hydrocarbons, and nitrics oxides
90
When does exhaust smoke become a problem?
When combustors operate at pressure greater than 10 atmospheres and when the fuel-air ratio in the primary zone of the combustor is rich
91
What are the three basic types of combustion chambers?
1. Can
2. Can-Annular
3. Annular
92
Which combustion chamber is typical of the type used on axial-flow engines?
The can-type
93
How are can-type combustion chambers numbered?
Clockwise direction: as you face the rear of the engine and look forward, the number 1 chamber is at the top.
94
What are two types of nozzles being used in the various types of combustion chambers?
Simplex nozzle and duplex nozzle
95
Which nozzle is limited for use on current models of jet engines?
Simplex nozzle
96
What does the annular combustion chamber, the type usually found in axial- flow engines, consist of?
A housing and a liner, similar to the can type
97
What is the function of the inlet section of the combustion chamber housing?
It receives the air from the axial-flow compressor, which is a diffuser, also slows the velocity of the air by providing a larger area just before the liner area thus rising air pressure
98
What is the function of a coarse wire screen?
To increase turbulence to aid in fuel atomization
99
What is the function of the center section of the chamber housing?
It's surrounding the liner providing an outer wall for the axial path in the air and provides the mounting pads for the installation of fuel drain valves
100
What action prevents after fire or excessive starting temperatures during the next start?
The drain valves drains the residue or accumulated fuel out of the combustion chamber after engine shutdown
101
What is the function of the rear section?
Converges to form a narrow anulus and speeds up airflow before it enters a turbine section
102
What are the two important functions imperative to proper flame propagation performed by swirl vanes?
1. Hi flying speed: better mixing of air and fuel, ensuring spontaneous burning
2. swirling prevents the flame from moving rapidly rearward.
103
What does a turbine transform?
Portion of the kinetic (velocity) energy of the exhaust gases into mechanical energy to drive the compressor and necessary accessories and is the sole purpose of the turbine
104
Where is it's her bank section of the turbojet engine located?
Aft, or downstream, of the combustion chamber section; specifically, it is directly behind the combustion chamber outlet
105
What is the first function of the turbine nozzle?
After the combustion chamber has introduced to heat energy into the mass flow and the delivered evenly to the turbine nozzle, its become the job of the nozzle to prepare the mass flow for harnessing of powers through the turbine rotor
106
What is the second purpose of the turbine?
Deflect the gases to a specific angle in the direction of the turbine wheel rotation
107
What is one method the expansion feature of the turbine nozzle is accomplished?
Have the vanes assembled loosely in the supporting inner and outer shrouds
108
What does the rotor element of the term a section consist of?
A shaft and a wheel
109
What are the two basic types of turbine blades?
Impulse and reaction
110
How may the impulse turbine be defined?
As a turbine the derives it's rotation from the weight and the velocity of the air striking its blades
111
What are the two methods of connecting the shaft to the turbine disc?
Welding and bolting
112
Of the two methods, bolting or welding, which one is more common?
Bolting
113
What is the most satisfactory method of attaching turbine blades or buckets?
The fir-tree design
114
What are the most common method blades are retained in their respective grooves?
Peening
Welding
Locking tabs
Riveting
115
Which method of a blade retention is used quite frequently?
Peening
116
What are the two most common application to peening?
1. A small notch is ground in the edge of the blade fir-tree route before blade installation
2. Construct the blades root in such a way as to contain all the elements necessary for its retention
117
What is the purpose of shrouded turbine?
It forms a band around the outer perimeter of the turbine wheel and improves efficiency and vibration characterize and permits lighter stage weights (on the other hand, it limits turbine speed and requires more blades).
118
When is the occasional use of more than one turbine wheel necessary?
In cases of heavy rotational loads
119
What is the one common function of the exhaust section of the turbojet engine?
It must direct the flow of hot gases rearward in such a manner as to prevent turbulence, while causing a high final or exit velocity to the gases
120
Where is the exhaust section located?
Directly behind the turbo section and ends with the ejection of gas at the rear in the form of a high-velocity jet
121
What do the parts of the exhaust section include?
The exhaust cone, tailpipe, and the exhaust, or jet nozzle
122
What is the purpose of the exhaust cone?
It collects the exhaust gases discharged from the turbine assembly and gradually converts them intoa solid jet
123
What is caused by the diverging passage between the outer duct and the inner cone?
During the exhaust cone operation, the velocity of the gases will decrease slightly and pressure will increase
124
What do the elements of the exhaust cone assembly consist of?
An outer shell or duct, an inner cone and three or four radial hollow struts of fins with tie rods aiding the struts in supporting the inner cone from the outer duct.
125
What is the two fold function of the radial struts?
Support the inner cone in the exhaust duct and also perform the important function of straightening the swirling exhaust gases, which otherwise would leave the turbine at an angle of about 45*
126
Why must the clearance between the turbine disc and the inner cone be checked periodically?
The pressures aft tend to push the inner cone against the turbine wheel
127
What is the terminating part of the basic engine?
The exhaust cone assembly
128
What are the remaining parts, the tailpipe and jet nozzle, considered?
Air-frame parts
129
Where are the tailpipe ends in a jet nozzle located?
Forward of the end of the fuselage
130
What are the two most common methods for protection of the fuselage structure?
Insulation blankets and shrouds
131
What gives to the exhaust gases the all-important final boost in velocity?
The exhaust or jet nozzle
132
What are the two types of jet nozzle designs?
The converging design and the converging-diverging design
133
Why are adjustments in a fixed-area nozzle sometimes necessary?
Because the size of the exit orifice will directly affect the operating temperature of the engine
134
How many inserts of various curvatures are provided with each aircraft?
Usually a set of 10
135
What does the different size inserts allow?
A total change of 10 square inches in the nozzle area in 1-inch increments
136
What has eliminated the need for physically changing the exhaust nozzle area?
All advanced technology engines now used by the navy have a state of the art electronic parts
137
When is it vet important to use the variable-area nozzle?
To increase the exit area during after burning
138
On some engines, what does the inner- and outer- flap variable nozzle assembly have?
An internal primary nozzle with sectional flaps and an external secondary nozzle with sectional flaps
139
How are the flaps controlled?
Four synchronized hydraulic actuators
140
What is the primary function of the accessory section of the turbojet engine?
To provide space for the mounting of accessories necessary for the operation and control of the engine, also includes accessories concerned with the aircraft, such as electric generators and fluid power pumps
141
What is the secondary purpose?
Acting as an oil reservoir, oil sump, and providing for and housing of accessory drive gears and reduction gears
142
What are the two factors of an axial flow engine accessory section?
The accessory gearbox and a power takeoff assembly and these units contain the necessary drive shafts and reduction gears
143
What are the two factors that affect the location of gearbox, in general?
Engine diameter and engine installation
144
What are the non-driven type accessories?
Booster coils or ignition exciters
Fuel and oil filters
Barometric units
Drip vales
145
What is the function of the afterburner duct?
It functions as the engine tailpipe during no afterburning (cold) operation and is also the main working element of the afterburner and is the essential working element of the afterburner
146
What is the design of the afterburner duct?
It's designed so that the normal pressure relationship between the air entering the main engine turbine and the air leaving the turbine is not upset
147
What is the primary purpose of any lubricant?
to reduce friction caused by metal-to-metal contact
148
What may cause the contamination of oil by rust?
water in the oil system
149
What may cause the contamination of oil by engine fuel?
a ruptured fuel-oil cooler
150
What results from using the wrong type of lubricants for internal-combustion engines?
because they form fatty acids, which cause corrosion when exposed to high temperatures
151
How can you ensure you have the right oil for an engine?
Check the applicable technical instructions for the grade number or MILSPEC of the oil recommended
152
How are the different types of lubricants classified?
```
Animal
Vegetable
Petroleum
Mineral
synthetic
```
153
Which lubricant is not suitable for internal-combustion engines?
Animal oils
154
Which lubricant has good lubricating qualities, but breaks down (they change in chemical structure) after long periods of operation in internal-combustion engines?
Vegetable oils
155
What are the 3 groups of mineral-base lubricants?
1. Solids
2. Semisolids
3. liquids
156
What is an example of petroleum-based oils used in early jet engines?
MIL-L-6081 grade
157
What are the 2 grade of petrouleum base oils?
1010, for normal use, and 1005 for extremely low temperatures (MIL-L-6081 grade 1010 is still used as a preservative oil in fuel systems)
158
What was the first synthetic oil developed to meet the demands of higher bearing temperatures?
MIL-L-7808
159
What synthetic oil do most jet engines use today?
MIL-L-23699
160
What is the downgrade when MIL-L-7808 & MIL-L-23699 oils are mixed?
Certain 23699 characteristics are downgraded in proportioning to the quantity of 7808 oil
161
What are synthetic oils based on?
Acids and other chemicals; therefore, they are not compatible with the mineral- or petroleum-based oils
162
Which oils do reciprocating engines use?
MIL-L-22851, W-120, or E-120 oil, which is NOT compatible with the turbojet engine
163
what are the 3 basic functions of the lubricating oil in a jet system?
Lubrication, cooling, and cleaning
164
What is the Saybolt scale for designating the viscosity of oil?
the designation consist of 4 digits; the 1st digit designates the use of the oil, the 1 indicates aviation engine lubrication and the last 3 digits give the viscosity using the Saybolt scale
165
What is the comparison of the , Saybolt scale and the Society of Automotive Engineers (SAE) numbers for grading viscosity?
Take the 3 numbers for the Saybolt system divide by 2 and round to the nearest multiple of 10
166
What is an example of operational contamination?
Carbon, which forms when oil evaporates especially where heat is concentrated
167
What is a secondary source of operational contamination in the lube system>
the presence of sand, dirt, and metallic particles
168
is oil a type of contamination?
Yes, synthetic oil will cloud or form other contaminants if stored too long; NEVER use overaged oil, the shelf life of synthetic oil is usually 6 months
169
What are the important requirements of greases?
Stability, noncorrosiveness, water resistance, and satisfactory performance.
170
What are 2 major disadvantages of a wet-sump system?
the oil supply is limited by the sump capacity and its very difficult to cool the oil
171
What is the function of wet-sump engines?
Stores the lubricating oil in the engine or gearbox
172
What does the gear box provide?
Space for foaming and heat expansion because the oil level only partly fills the casing
173
Why is the dry-sump lubrication system most common?
a tank located in the airframe or mounted on the engine holds the oil and it carries a larger oil supply, and an oil cooler is usually included to control temperature
174
How is the representative oil tank designed?
A welded aluminum tank with an oil capacity of 3.25 gallons and a 0.50 gallon foaming space and furnishes a constant supply of oil to the engine in any attitude and during negative g loading or forces
175
What are the three most common oil pumps?
1. Gear
2. gerotor
3. piston types
176
What are the only 2 elements of the gear type oil pump?
One for pressure oil and one for scavenge
177
What are the elements of the gerotor oil pump?
a single element for oil feed and several elements for scavenging oil
178
What is the pumping capacity of the pressure element in the gerotor oil pump?
the piston lubrication pump
179
What is the function of the oil pressure relief valve?
Limits the maximum pressure within the system and is present to relieve pressure and return the oil to the inlet side of the lube pump
180
What do the check valves installed in the oil supply lines or filter housings prevent?
oil in the reservoir from seeping (by gravity) into the engine after shutdown
181
What do other check valves prevent?
Accumulation of undue of amounts of oil in the accessory gearbox, rear of the compressor housing and combustion chamber
182
What is the pressure required to open most vales to permit oil to flow from the bearings?
2 to 5 psi
183
What is the purpose of the thermostatic bypass valves?
to maintain proper oil temperature by varying the proportion of the total oil flow passing through the oil cooler
184
Which filter consists of a series of spacers and screens?
the disk filter
185
Which filter uses either a paper or metal cartridge type of oil filter and is also used as a main oil filter?
the micronic-type filter
186
What is the magnetic-chip detector?
a metal plug with magnetized contacts, and is placed in the scavenged oil path
187
What is one of the chip detectors functions?
has magnetized contact points to collect metal particles; when enough metal particles collect on the magnetized contacts it completes a circuit between the contacts and gives a warning light in the cockpit, advising the pilot of metal contamination
188
What is the function of the other chip detector?
gives no cockpit indication and is removed and inspected at regular intervals for metal particles
189
How do oil coolers reduce the temperature of the oil?
through either an air oil or a fuel oil type cooler
190
What is the dual function of the fuel-oil cooler or heat exchanger?
Cools the hot oil and preheats the fuel for combustion
191
Where are the oil jets (or nozzles) located?
in the pressure lines next to or within the bearing compartments and rotor shaft couplings
192
How is the air-oil mist produced in some engines?
by tapping high-pressure bleed air from the compressor and mixing it with the oil and is adequate for ball and roller type of bearings; however, the solid oil spray method is better
193
Where is the oil pressure gauge connection always located?
in the pressure line between the pump and the various points of lubrication
194
Where is the temperature gauge connection located?
either in the pressure or the scavenge line; however the scavenge line is preferred, since this location permits a more accurate indication of the actual bearing temperatures, as the tof the oil is shown shortly after it leaves the bearings
195
What are the most common methods of oil temperature indicators?
thermocouple-type fitting or an oil temperature bulb
196
What is the purpose of the vent in an oil tank?
to keep the pressure within the tank from rising above or falling below that of the outside atmosphere
197
Where are the screened breathers usually located?
in the front center of the accessory case to prevent oil leakage through the breather
198
Why can the importance of oil seals not be overemphasized?
Because an improperly installed or leaking seal in the oil system could cause bearing failure, fire, or cockpit fumes
199
What are the 3 common methods of preloading carbon seals?
1. Spring tension
2. Centrifugal force
3. Air pressure
200
What is the capacity of the oil tank and air/oil cooler in the engine oil system?
7.6 U.S quarts
201
When does the ENGINE OIL PRESS caution light, in the cockpit, come on?
if the oil pressure drops below 24 psi
202
When must the oil pump be changed?
When an engine prohibits decreasing oil pressure.
203
What metals are usually found in the oil strainer?
steel, tin, aluminum, silver, copper (bronze), chromium, nickel, and tin cadmium combinations
204
What is the test procedure for iron (Fe) and nickel (Ni)?
use a permanent magnet to isolate these metal particles
205
What is the test procedure for tin (Sn)?
use a clean soldering iron, heated to 500*F (250*C) and tinned with a 50-50 solder (50% tin and 50% lead)
206
What is the test procedure for aluminum (Al)?
Determined by their reaction with hydrochloric aci when dropped into the hydrochloric acid, it will fizz, and the particle will gradually disintegrate; also will dissolve rapidly and form a white cloud in a strong caustic solution (sodium or potassium hydroxid)
207
What is the test procedure for silver (Ag) and copper (Cu)?
bronze
208
What is the test procedure for chromium (Cr)?
it may be determined by their reaction to hydrochloric acid when dropped into concentrated hydrochloric acid the acid will develop a greenish cloud
209
What is the test procedure for cadmium (Cd)?
Particles will dissolve rapily when dropped into a 5% solution of chromic acid which causes a clouding of the solution
210
What does the Navy Oil Analysis Program (NOAP) provide?
A diagnostic technique to monitor and diagnose equipment or oil condition
211
Who must participate in the NOAP?
All activities operating aeronautical equipment and type commanders or the cognizant field activity (CFA) who are the only ones to relieve you from the requirement
212
What does the CFA establish and maintain?
Sampling information for the maintenance requirements cards (MRCs); also maintenance manuals (MIMs) for the respective equipment or weapon systems
213
What is spectrometric oil analysis?
A diagnostic maintenance tool used to determine the type and amount of wear metals in lubricating fluid samples
214
How are wear metals generated?
the motion between metallic parts, parts, even though lubricated
215
What are the 2 methods or spectrometric oil analysis currently used to measure the quantity of various metals?
1. Atomic emission
| 2. Atomic absorption
216
What is atomic emission and the emission spectrometer?
An optical instrument used to determine the concentration of wear metals in the lubricating fluid
217
What is the absorption spectrometer?
An optical instrument used in determining the concentration of wear metals in the lubrication fluid
218
When is the spectrometric fluid analysis method effective?
Only for those failure that are characterized by an abnormal increase in the wear metal content of the lubricating fluid
219
When should sampling intervals be?
As close as possible to specified times without interfering with scheduled operations
220
What is the oil sampling interval variation?
it should not vary more then +/- 10% of the time specified
221
What are the two basic methods of taking a fluid sample?
1. the dip tube technique
| 2. the drain technique
222
Which NOAP form is vital?
The Oil Analysis Request (DD Form 2026)
223
When are logbook entries necessary for oil sampling?
When starting, stopping, or changing the monitoring laboratory for oil analysis
224
What instruction has complete Information concerning the NOAP?
NAVMATINST 4731.1
225
What publication provides instructions for oil sampling and filling out the sample request form (DD Form 2026)?
The Joint Oil Analysis Program Laboratory Manual (NAVAIR 17-15-50)
226
What is the science of liquid pressure and flow?
Hydraulics
227
The word hydraulics is from what Greek word?
the word for water
228
What is any fluid whose particles have freedom of movement among themselves but remain separate?
a liquid
229
What is the color of refined hydraulic fluid?
clear in color
230
What is a catalyst?
A substance that, when added to another substance, speeds up or slows down chemical reaction
231
What is the main source of core sand contamination in a hydraulic system?
Parts designed with hidden passages, beyond the reach of sandblasting
232
Where do particles introduced from outside forces inter hydraulic system?
At points where the liquid or working parts of the system are in temporary contact with the atmosphere
233
What are the 2 general types of hydraulic system contaminants created during system operation?
Mechanical and chemical
234
What is the most common foreign fluid contaminant, especially in petroleum-based hydraulic fluid?
water
235
What hydraulic fluid should NOT be used?
Fluid drained from hydraulic systems or equipment or fluid that has been stored in open containers
236
What was the original definition of hydraulics?
the study of physical behavior of water at rest and in motion and is derived from the Greek word for water
237
What does hydraulics ususlly mean in aviation?
The "red fluid" used to operate landing gear and flight control or propeller systems and applies to fuel and oil systems
238
What does Pascal's law state?
"Any force applied to a confined liquid transmits undiminished in all directions"
239
What publication has detailed information on the principles of hydraulics?
the training manual FLUID POWER, NAVEDTRA 12964
240
What are the most widely used fluids in hydraulic systems?
Petroleum-based liquids
241
What is added to the hydraulic fluid that is clear in color?
Red dyes to find and identify leaks
242
What hydraulic fluid is approved for use in the servicing of Navy aircraft hydraulic systems?
MIL-H-83282B
243
What is the approved hydraulic fluid for the preservation packaging, and is used in hydraulic test benches?
MIL-H-6083C
244
What are the 2 general classes of contaminants?
Abrasive and non-abrasive
245
What are the major sources of tracing contaminants in hydraulic systems?
1. particles originally contained in the system
2. particles introduced from outside forces
3. particles created within the system during operation
4. particles introduced by foreign liquids
246
What is the chief source of chemical contaminants in hydraulic fluids?
Oxidation
247
When does chemical contamination form in hydraulic fluids?
As a result of high pressure and temperature and temperatures actig with the catalytic action of water, air, and copper or iron oxides
248
Why should you NOT use hydraulic fluid stored in open containers?
Because hydraulic fluid absorbs dust and grit from the air, resulting in contamination problems
249
why do you not use your hand to feel for a leak in the hydraulic system?
A pinhole leak in a 3,000 psi system can force fluid through your skin
250
What publication has information on hydraulic maintenance procedures?
AVIATION HYDRAULICS MANUAL, NAVAIR 01-1A-17
251
What is a good example of a system that uses fuel as a hydraulic fluid?
the TF41 engine
252
What engine uses 2 different systems to operate the variable IGVs and variable stators?
the F404-CG-400, installed in the F/A-18 aircraft
253
What are the 2 systems that operate the variable IGVs and variable stators?
the fan variable geometry (FVG) system and the compressor variable geometry (CGV) system.
254
What provides the optimum exhaust throat area?
the convergent-divergent geometry of the variable-area exhaust nozzle
255
How is the action of the variable area nozzle achieved?
By close tolerance overlapping seals, which bridge adjacent leaf segments to provide a relatively smooth surface contour
256
What is installed in the F-15 aircraft that uses the hydraulic action of fuel to position the nozzles?
the TF30-P-414/414A
257
What is elecricity?
a form of energy, the ability of a body to do work, and does not occupy space but can be measured
258
what are the 2 forms of electricity?
Static and dynamic
259
What is static electricity?
Electricity at rest and is produced by friction, which causes one body to give up electrons to another
260
What happens to electrons?
the body that lost the electrons will have a positive charge. The boy that gained the electrons will have a negative charge. As a result, the positively charged body wil tyr to gain electronsnegative neutrally
261
What is dynamic electricity?
Electricity in motion and is the most useful form of electricity, and it is produced, controlled, and measured with relative ease
262
What is a circuit?
Electricity in motion that flows along a definite path
263
What is a circuit?
Electricity in motion that flows along a definite path
264
What are the 3 methods of producing electricity?
1. Heat
2 Chemical
3. Mechanical
265
What are the 3 types of current that mechanical devices produce?
1. Direct
2. Pulsating
3. Alternating current
266
How does direct current always flow?
in the same direction
267
What is pulsating direct current?
Direct current that is interrupted by a set of breaker points and the current will flow in one direction when the circuit does
268
What is alternating current?
Current that changes direction in the circuit, flowing first in one direction and then in the other q
269
What is a cycle?
2 complete alternations within a period of time
270
What does the hertz (Hz) indicate?
1 cycle per second
271
What is the standard unit of electricity used in the United states?
60 Hz ac
272
What is the electromotive force?
The force that causes electrons to flow from atom to atom in a conductor
273
What are the practical electrical units?
Volt, ampere, and ohm
274
What is the volt?
the unit of electromotive force necessary to cause electrons to flow in a circuit
275
What is the ampere?
The rate of flow of these electrons in a conductor
276
What is called the unit of electrical resistance?
the ohm
277
What system is the most widely used ignition system?
the high-energy, capacitor-discharge ignition
278
How are high-energy, capacitor-discharge systems classified?
As ac or dc systems, and they use either a high- or low- voltage capacitor
279
Where does the dc ignition exciter gets its input?
From the low-voltage dc supply of the aircraft electrical system
280
What are the 3 major components of the high-energy, capacitor discharge dc ignition system?
1 ignition exciter and 2 lead assemblies
281
What is the ac ignition system?
An automatic, intermittent duty, ac-powered, electronic capacitor-discharge system
282
What is the primary purpose of the high-energy, capacitor-discharge dc ignition system consist of?
An ignition exciter, a control amplifier, leads and ignition plugs, and an alternator stator
283
What is the engine ignition exciter?
A dual-circuit and dual output unit that supplies a high voltage, high engery electrical current for a ignition
284
What is the function of the engine control amplifier?
It controls the electronic function of the ignition system as well as other engine functions
285
What is an engine alternator stator?
An engine driven, single phase, ac electrical output unit on the engine accessory gear box
286
what are the jet engine electronic ignition operation starting procedures?
Ignition switch ONm the engine cranking for starting and the throttle advanced to the 10 degree power lever angle (PLA) position
287
In the jet engine electronic ignition system, when does the gas generator speed (Ng) logic circuit close the ignition relay to provide ignition?
Whenever the Ng is within the 10%-48% Ng range
288
What does current crossing the gaps in the igniters produce in the jet engine electronic ignition system
A continuous high intensity spark to ignite the fuel mixture in the combustion chamber
289
When is a T5 signal generated in the jet engine electronic ignition system?
When engine speed reaches 8,500 rpm Ng and interturbine temperature (ITT) reaches operating range
290
When is ignition automatically reactivated in the jet engine electronic ignition system?
When T5 temperature drops in excess of 800*F from T5 selected by PLA, a signal transmitted from the T5 detector, which activates ignition system operation
291
What is the only ignition system maintenance performed at the organizational level?
Cleaning and replacement of ignition parts
292
What is a way to remove the spark igniters?
leave them hanging on the high tension leads, and operate the ignition system
293
What does starting a jet engine require?
rotating the compressor fast enough to begin the engine combustion cycle; starting engines must be capable of providing both high starting torqure and high speed
294
what is the air turbine starter?
a lightweight unit for starting engines with compressed air; the starter itself is a turbine air motor equipped with a radial inward-flow turbine wheel assembly, reduction gearing, splined output shaft, and a quick detaching coupling assembly
295
What part of the air turbine starter transforms the high speed and low torque of the turbine wheel to low speed and high torque at the output shaft?
the reduction gear system
296
what is tubine impingement starting?
When some naval aircraft is started by means of low-pressure onto the turbine or compressor blades
297
How is starting air supplied in the turbine impingement starter?
By an external starting unit (and is controlled by an air shutoff valve in the external air supply unit)
298
What are electrical starters?
28 volt dc series wound motors, designed to proved high starting torque and their use is limited to small engines ( they make ideal starters for APUs)
299
What is bleed air be used?
engine starting
seal pressurization
anti-icing
300
Which fleet aircraft employ a cross bleed starting system?
those using 2 or more engines
301
What controls oil leakage on nonrubbing labyrinth or clearance type bearing seals?
air pressure, bled from the compressor
302
When is air coldest and subject to icing?
AT the point where the guide vanes of a turbine powered engine is used to direct the flow of inlet air into the compressor section
303
what is the biggest problem resulting form ice forming?
blockage of inlet air,
304
When does icing not normally occur?
in supersonic flight because heat caused by the friction of the aircraft passing through the air is sufficient to prevent ice from forming
305
What results from using bleed air in aircraft anti-icing systems?
engine power loss
306
What type of ice has a smooth appearance and is hard to detect visually?
Glazed ice
307
What type of ice has a rough appearance and is easily noticeable?
rime ice
308
How can frost form on aircraft surfaces?
it can collect on aircraft parked outside overnight when the temperature drops below freezing and the proper humidity exists and on aircraft surfaces when the aircraft descends rapidly into warm moist air after flying at higher cold altitudes
309
what are the 2 methods for eliminating or preventing ice?
1. deicing employs a mechanical system to break up and remove the ice after it has formed
2. Anti-icing uses heated bleed air to prevent the formation of ice
310
What does the pressurization and vent system provide?
Regulated bleed air pressure to all fuel tanks and prevents fuel boil off at altitude and provides a means to transfer fuel between tanks
311
what are auxiliary power units (APUs)?
Small, self contained jet engines that are started either electrically through on board batteries or hydroaulically through a hydraulic starter motor
312
Which aircraft can use compressed air from an APU to start engines?
those with air turbine starters
313
What APU repairs are authorized at the O level?
minors component replacements and adjustments
314
What is the difference in maintenance on the APU and that on aircraft engines?
other than the size, in that most APUs use centrifugal flow jet engines instead of axial flow
315
What performs major APU inspections and repairs?
The supporting intermediate maintenance activity (IMA) under the APU and Support Equipment Gas Turbine Management Program
316
What engine was developed by General Electric for the F/A-18 Hornet?
the F404
317
What enabled the F404 to have a high resistance to compressor stalls, even at high angles of attack?
because of a fan designed to smooth airflow before it enters the compressor
318
What is the average between "in flight" events for the F404 engine?
6,500 hours
319
What is the high responsiveness to control imputs of the F404 engine?
Spooling from idle to full afterburner in 4 seconds
320
What does the F404 engine contain that monitors for critical malfunctions and keeps track of parts lifetimes?
An in-flight Engine Control Monitoring Systems (IECMS)
321
What type of engine is the GE F404?
An afterburning turbofan
322
What is the length of the GE F404?
154 inches
323
What is the dry weight o the GE F404 engine?
2282 lbs
324
What type of compressor is contained in the GE F404 engine?
Axial compressor with 3 fan and 7 compressor stages
325
What type of turbine is contained in the GE F405 engine?
one low-pressure and ne high-pressure stage
326
What is the maximum thrust of the GE F404 engine?
11,00 lbf (48.9 kN)military thrust and 17,700 lbf (78.7 kN) with afterburner
327
What is the overall pressure ratio of the GE F404 engine?
26.1
328
What is the thrust-to-ratio of the GE F404 engine?
7.8:1
329
Why can an experienced maintenance crew remove and replace F/A18 engine in only a couple of hours?
Because the engine is attached at only three points and can be directly removed without excessive disassembly.
330
what type of air inlets are found on the engines of the Hornet?
Fixed air inlets.
331
What is used on the Hornet engine to slow and reduce the amount of air reaching the engine?
Bleed air vents on the inboard surface of the engine air intake ducts
332
What type of engine is found in the F/A-18E/F super Hornet?
the more powerful GE F414 afterburning turbofan engine
333
What is used by the GE G414 for advanced Tactical Fighter competiotion?
the core of the F4123 and its Full-Authority Digital Engine Control (FADEC), alongside the low-pressure system from the YF120 engine
334
What is the major differences between the GE F404 and the GE F414 engines?
the fan of the F414 is larger than that of the F404, but smaller than the fan for the F12
335
What is used in the GE F414 to reduce weight of the engine by 50 pounds?
The first 3 stages of the high pressure compressor are blisks rather than dovetailed blades
336
What is used by the Full Authority Digital Engine Control (FADEC) of the GE F414 to manipulate the afterburner section?
A fuel actuated system rather than a separate hydraulic system
337
What type of engine is the GE F414 engine?
An afterburning turbofan
338
What is the length of the GE F414 engine?
154 inches
339
What is the diameter of the GE F414 engine?
Axial compressor with 3 fan and 7 compressor stages
340
What type of turbine is used on the GE F414 engine?
1 low-pressure and 1 high-pressure stage
341
What is the maximum thrust of the GE F414 engine?
22,000 lbf (98kN)
342
What is the oerall pressure ratio of the GE F414 engine?
30:1
343
What engine was developed by Pratt&Whitney to power the F-15E strike Eagle?
the afterburning turbofan F100
344
What is the length of the PW F100 engine
191inches (4,851 mm)
345
What is the diaeter of the PW F100 engine?
46.5 inches (1,181 mm)
346
What is the dry weight of the PW F100 engine?
3,740 lbs (1,696 kg)
347
What type of compressor is found in the PW F100 engine?
Axial compressor with 3 fan and 10 compressor stages
348
What is the bypass ratio of the PW F100 engine?
0.36:1
349
What type of compressor is found in the PW F100 engine?
2 low-pressure and 2 high-pressure stages
350
What is the maximum thrust of the PW F100 engine?
17,800 lbf (79.1kN) military thrust and 29,160 lbf (129.6 kN) with afterburner
351
What is the overall pressure ratio of the PW F100 engine?
32:1
352
What is the thrust to weight ration of the PW F100 engine/
7.8:1 (76.0 N/kg)
353
What is the main difference between a helicopter and an airplane?
the source of lift
