Powerplant Flashcards
1
Q
Another name for hydraulic lifters is?
A
Tappet
2
Q
What type of valve uses metallic sodium?
A
Exhaust Valve
3
Q
What are the 4 valve types?
A
Flathead, Semi Tulip, Tulip, and Mushroom
4
Q
What’s the purpose of valves?
A
Open and closes ports to allow gases to flow into and out of the combustion chamber.
5
Q
What material are cylinder head made of?
A
Cast aluminum alloy 4220
6
Q
What cylinder port has more cooling fine area?
A
Exhaust port due to high temp gases.
7
Q
What material are cylinder barrels made of?
A
Chrome-molybdenum steel (4130)
8
Q
What’s the fit and material of the valve seats?
A
Shrink fit, and are either aluminum bronze, tin-bronze or steel
9
Q
What is the angle for an intake valve?
A
30 degree
10
Q
What is the angle for an exhaust valve?
A
45 degree
11
Q
How are valve springs held in place?
A
By valve spring retainers (washers and keys)
12
Q
Why piston rings has an end gap?
A
To allow for expansion at operating temperatures
13
Q
What are compression rings used for?
A
To prevent gases escaping from the chamber.
14
Q
What does the oil control rings?
A
Regulate the thickness of the oil film on the cylinder wall.
15
Q
What regulates the amount of oil on the cylinder wall?
A
Oil scraper rings.
16
Q
Camshafts are made of?
A
Steel
17
Q
The camshaft on an opposed engine rotates at…
A
1/2 the speed of the crankshaft
18
Q
What are the two types of lifters/tappet?
A
Hydraulic and solid.
19
Q
The lifter transmit force from______ and to______…
A
From the camshaft to the push rod
20
Q
When the valves would open late and close early?
A
When the valves clearances were set in operating temperatures
21
Q
What type of valve clearance is used hot or cold?
A
Cold clearance is used because the valves expands when in operating temperatures
22
Q
When the intake and exhaust valves are open at the same time this is known as?
A
Valve Overlap
23
Q
Another name for crankcase is?
A
Power Section
24
Q
Name the 4 parts of a crankshaft
A
Main journal, Crankpin, Crank cheek (arm), Counterweights.
25
Crankshaft is made of?
Forged steel (SAE 4340)
26
Is the main journal nitrided if so how much inches deep?
Yes it is nitrided from 0.015 to 0.025 inch deep.
27
How many main journals are in an engine?
Two Journals minimum.
28
What bearing has the least amount of friction?
Ball Bearing.
29
Name the 3 styles of bearings
Plain bearings, Roller bearings and Ball bearings.
30
Which bearing style is the most common?
Plain bearing.
31
Where are plain bearings mostly used?
Crankshaft, camshaft, master rod
32
What is a bearing?
Cylindrical surface that support another for freedom of rotation along an axis.
33
How many stroke and event has the Otto cycle?
4 stroke and 5 event.
34
What are the 4 stroke?
Intake, Compression, Power, and Exhaust.
35
What are the 5 event?
Intake, Compression, Ignition, Power, and Exhaust.
36
What the Boyle’s Law states?
If the volume of a chamber containing a gas is decreased without changing the absolute temperature of the gas, then the pressure of the gas will increase.
37
What Charle’s Law states?
The pressure of a confined gas is directly proportional to its absolute temperature.
38
At what event is the volumetric efficiency increased?
Intake event.
39
When the intake event begins?
Begins during exhaust stroke and ends on the compression stroke.
40
Name 2 disadvantages of valve overlap
Runs rough at low power settings and possible exhaust reversal at high power settings.
41
Name the 3 types of horsepower
Indicated horsepower, Brake horsepower, Friction horsepower.
42
What is Brake horsepower?
The ACTUAL amount of power delivered to the propeller shaft
43
What is indicated horsepower?
Total power developed in the cylinders.
44
What is friction horsepower?
Horsepower used by the engine to overcome the friction of moving parts.
45
What is detonation?
Uncontrolled, explosive combustion.
46
Engine letter prefix O stand for…
Opposed
47
Engine letter prefix G stand for…
Geared
48
Engine letter prefix S stand for…
Supercharged
49
Engine letter prefix T stand for…
Turbocharged
50
Engine letter prefix I stand for
Fuel injected
51
Engine letter prefix A stand for…
Aerobatic
52
Engine letter prefix H stand for…
Horizontal
53
Engine letter prefix V stand for…
Vertical
54
Engine letter prefix L stand for…
Left rotation
55
Engine letter prefix “L” stand for…
Liquid cooled
56
Engine letter prefix R stand for…
Radial
57
What is one of the biggest disadvantages of radial engines?
Large frontal area creates drag.
58
Why do we use metallic sodium in exhaust valves stem in high powered engines?
To dissipate the high heat/temperature of the exhaust gases.
59
What is the purpose of the crankshaft?
It’s purpose is to transform the rotary motion from the pistons and connecting rod to the propeller shaft.
60
What are the three main parts of a crankshaft?
The journal, crankpin and crank cheeks. (Other parts includes counterweights and dampers).
61
What is the purpose of crankshaft counterweights?
They are used for the static balance of the crankshaft and reduce torsional forces.
62
What is used during crankshaft operation to reduce vibrations to a minimum?
Dynamic Dampers
63
What are the 3 types of propeller mounting shafts?
Tapered, Splined and Flanged.
64
What transmit forces between the piston and the crankshaft?
The Connecting Rod
65
What are the two type of pistons?
Slipper type and Trunk type
66
What are the types of trunk pistons?
Recessed head, Concave head and Dome head.
67
What is the only type of a slipper type piston?
Flat head is the only type for slipper pistons type.
68
What is a cam ground piston?
It’s a piston that expand making it completely round when the engine warms up, in order to avoid the tendency of the piston to cock or slap in during warm up. When at low temperatures the piston is oval shaped.
69
Can chromium-plated piston rings be used in a chromium-plated cylinder?
NO, never use chromium-plated piston rings in a chromium-plated cylinder
70
What are the two ways cylinder barrel may be hardened?
By exposing the metal to ammonia or cyanide gas creating a nitrided surface.
71
What is a full-floating piston pin?
It’s a piston pin that freely rotates in between the piston and the connecting rod.
72
Why you should never cut a sodium valve?
Metallic sodium is very reactive with oxygen and becomes explosive.
73
Two materials used to increase hardness on valve faces and valve tips are…
Stellite and nichrome.
74
How many revolution of the crankshaft are required to complete the 4 strokes?
2 revolutions of the crankshaft (720 degree)
75
What is The British thermal unit (BTU)?
The quantity of heat required to raise the temperature of 1 pound of water by 1 degree Fahrenheit.
76
1 BTU is equivalent to how many foot-pounds (ft-lb) of mechanical work?
778 ft-lb of mechanical work.
77
6 factors that decrease volumetric efficiency are…
1. Part-throttle operation
2. Long intake pipes with small diameter.
3. Sharp bends in the induction system.
4. Carburetor air temperature too high.
5. Cylinder head temperature too high.
6. Incomplete scavenging.
78
What is the best indication of worn valve guides?
Oil consumption.
79
What can cause pre-ignition?
- Carbon deposits or other deposits that create local hot spots
- Detonation and high power operation on excessively lean mixtures.
80
What is percentage of fuel flow for gravity fuel system during take off?
150%
81
125% of fuel flow is required during take off for a fuel system requiring a…?
Fuel pump
82
What’s the heat absorption percentages for useful power, exhaust, oil and cooling fins?
Useful power= 25%-30%
Exhaust= 40%-45%
Oil= 5%-10%
Cooling fins= 15%-20%
83
If an engine becomes excessively hot during taxiing or improper run up how do you cool the engine?
Idle the engine to allow the cylinders to cool
84
How much is the energy loss or efficiency in a reciprocating engine?
60% to 70%
85
3 reason why excessive heat is undesirable in a reciprocating engine?
It affects the behavior of the combustion of the air/fuel charge.
Weakens and shorten engine parts.
Impair lubrication.
86
Liquid cooling uses a mixture of_______________ and _________
Ethylene glycol and water
87
What is a float type carburetor?
A float-type carburetor has a float chamber that fills with fuel that the carburetor can draw from. The float inside is connected to a needle-and-seat valve, so that as the bowl (or chamber ) fills, the float rises and closes the valve, cutting off fuel so that it doesn’t flood the carburetor.
88
What are the two types of carburetor?
Float type and pressure type.
89
What are the 3 classification of carburetor icing?
- Fuel evaporation
- Throttle ice
- Impact ice
90
Fuel pumps are divided into 2 system categories:
- Constant displacement
- Nonconstant displacement
91
The fuel storage must provide fuel for at least…
One-half hour (30 minutes)
92
What are the 3 types of fuel tank?
- Rigid removable
- Bladder
- Integral
93
How do we prevent foreign matter from entering the fuel metering unit?
The use of a main strainer (This usually a Gascolator).
94
Where is the main strainer (Gascolator) located in the fuel system?
At lowest point of the fuel system to trap water.
95
Where must be the fuel strainer (Fuel Filter) located in the fuel system?
Between the fuel tank outlet and the fuel metering device.
96
Where is the shut off valve located?
Aft the firewall (out of the engine compartment)
97
Most large aircraft reciprocating engines are equipped with which of the following types of engine-driven fuel pumps?
Rotary vane type fuel pump
98
What is the function of a waste gate on a turbocharger?
Controls the amount of exhaust gases that passes through turbine.
99
3 types of oil filter are?
Spin-on, Cunno and Screen
