11.1 Theory of flight Flashcards
(110 cards)
1
Q
what are the 3 primary axis
A
lateral, longitudinal, vertical
2
Q
what are the 3 movements along the axis’s
A
pitch, roll, yaw
3
Q
at what angle do all the axis intersect
A
90 degrees
4
Q
where is the lateral axis on the aircraft
A
wing tip to wing tip
5
Q
where is the longitudinal axis on the aircraft
A
nose to tail
6
Q
where is the vertical axis on the aircraft
A
runs through aircrafts centre of gravity
7
Q
what are the 3 primary flight controls
A
ailerons, elevators, rudder
8
Q
on larger aircraft what flight controls are added
A
roll spoilers
9
Q
what control an aircrafts roll?
A
ailerons and spoilers
10
Q
if an aircraft is rolled to the right what do the ailerons do
A
right aileron up, left aileron down
11
Q
what ailerons are used during high speed flight
A
inboard
12
Q
if an aileron goes down does it increase or decrease lift?
A
increase
13
Q
what’s the equation to calculate dynamic energy
A
1/2 x density x airspeed(2)
14
Q
at low speed flight what ailerons are used
A
both inboard and outboard
15
Q
what controls an aircrafts pitch
A
elevators, stabilators, variable incidence stabiliser, canards
16
Q
what are the elevators furthest away from the centre of gravity
A
greatest leverage
17
Q
do the ailerons operate in the same direction
A
no
18
Q
do the elevators operate in the same direction
A
yes
19
Q
what is a variable incidence stabiliser used for
A
pitch trimming
20
Q
when the variable incidence stabilisers are used what can the compensate for
A
passenger weight, freight, fuel loads, engine settings
21
Q
where are the wings located on an aircraft when canards are used
A
front of aircraft
22
Q
what controls yaw on an aircraft
A
rudder
23
Q
what is used to prevent the pilot over stressing the rudder during flight
A
rudder limiter
24
Q
A
25
when is the rudder only used independently
correct direction of aircraft in crosswind or when a single engine fails
26
what is used to move the elevators
screwjack
27
what are the names of the two, duel purpose flight controls
elevons, ruddervators
28
what makes up elevons
elevators, ailerons
29
what makes up ruddervators
elevators, rudder
30
where are elevons usually used
high performance, military aircraft
31
what's a common example of an aircraft with ruddervators
v - tail
32
what are the 3 common high lift devices
slots, slats, flaps
33
what do slots allow the aircraft to do in terms of speed
fly at slower speed and high angle of attack
34
whats a disadvantage of slots
produce a lot of drag
35
are flaps secondary or primary flight controls
secondary
36
what does the flap do to the wings shape
increase its camber
37
what are all the types of flap (7)
plain flap, split flap, slotted flap, fowler flap, slotted fowler flap, krueger flaps, flaperons
38
how much lift does a plain flap produce
50-55%
39
how much does a split flap increase lift by?
60-65%
40
how much does a slotted flap increase lift by
65-70%
41
how much does a fowler flap increase lift by
95%
42
whats the difference between a slotted fowler flap and fowler flaps
slotted fowler flaps have a gap between the trailing edge and leading edge of the flap to re-energise the boundary layer
43
what flaps do some heavy aircraft have
leading edge flap
44
what can krueger flaps increase in the aircrafts handling
low speed handling
45
what is a flaperon
an aileron that can also function as a flap
46
what are the 2 main induced drag devices on modern aircraft
spoilers, speed brakes
47
where are spoilers located on the wing
upper surface
48
what can be the 3 distinct spoiler functions
flight spoilers, ground spoilers, roll spoilers
49
what are roll spoilers used in conjunction with
ailerons
50
where are speed breaks positioned on aircraft
on structural areas strong enough to withstand high air loads
51
what do wing fences do
reduce the effect of spanwise flow and reduce wing tip stall
52
what is the direction of the flow in spanwise flow
along the leading edge
53
whats the ideal direction of the wind over wing
right angle to leading edge
54
what is a saw tooth leading edge and what does it prevent
slight extension on the leading edge and reduces wing tip stall
55
what is the purpose of a vortex generator
re-energises the boundary layer
56
what is the purpose of stall wedges
to ensure the wing root will stall before the wing tip
57
whats the shape of the cross section of stall wedges
triangular
58
59
what duct do all high lift devices have and why
convergent duct to accelerate airflow from lower to upper surface
59
are trim tabs a primary or secondary flight control
secondary
60
what is the purpose of trim tabs
compensate for aircrafts imbalances
61
what are the 2 types of trim tab
fixed and moveable
62
whats the difference between fixed and moveable trim tabs
fixed can only be adjusted on the ground, moveable can be adjusted in the air
63
what direction does the trim tab go
opposite to the flight control
64
what is the purpose of a balance tab
to assist the pilot in moving a flight control
65
what direction does a balance tab go in comparison to the flight control
opposite
66
what direction does the anti balance tab go in comparison to the flight control
same direction
67
what aircraft are servo tabs used on
large aircraft
68
what is the purpose of a servo tab
make it easier to move the flight control for the pilot
69
what is linked with mass balancing
aircrafts centre of gravity and centre of pressure
70
what is a balance panel
plate connected to the leading edge of the control surface
71
what do balance panels divide the front of the control surface into
upper chamber, lower chamber
72
what is the speed of sound
mach 1
73
what are the 3 speed regions
subsonic, transonic, supersonic
74
whats the compressible flow speed at subsonic
0.8 mach or less
75
whats the compressible flow speed at transonic
0.8 - 1.2 mach
76
whats the compressible flow at supersonic
1.2 - 5 mach
77
what speed do most modern aircraft operate at
subsonic
78
if an aircraft is traveling at transonic speed what speed is the airflow on the aircraft
subsonic and supersonic
79
when traveling at supersonic what is the speed of all the airflow around the aircraft
all supersonic
80
if an aircraft is flying at the same speed as sound whats its mach number
1
81
if an aircraft is at 0.6 mach what percentage of sound is it flying at
60%
82
what is the critical mach number
lowest mach number at which airflow over some points of the aircraft reaches the speed of sound but not exceed it
83
what mach number is air considered compressible at
0.4 mach
84
what creates a shock wave
air being disturbed due to the aircraft going through it
85
if an aircraft is going faster than the speed of sound where is the shockwave
behind the aircraft
86
are expansion waves shock waves
no
87
when are expansion waves formed
supersonic airflow changes direction over a curve or corner
88
what are the 2 typical supersonic wing profiles
double wedge, circular arc
89
what is wave drag
portion of total drag which is caused from shock waves
90
what 2 ways can help reduce wave drag
vortex generators, applying the area rule
91
whats the slight disadvantage of vortex generators when reducing weave drag
introduces slight parasite drag
92
describe the area rule briefly
changing certain areas on the aircraft where shockwaves are most common
93
what can aerodynamic heating also be known as
friction heating
94
what happens to temperature during supersonic flight
increases alot
95
for a supersonic aircraft what must the airflow be slowed to when entering the compressor
subsonic
96
gas turbines cannot take in airflow speeds above what
0.4 mach
97
how does a normal shock diffuser inlet slow air velocity
using a normal shock wave
98
in a converging duct does velocity increase or decrease
increases
99
in a converging duct does static pressure increase or decrease
decrease
100
what happens to static pressure and velocity in a convergent duct
velocity decrease, static pressure increase
101
how does a single/multiple oblique shock inlet slow air velocity
external oblique shock wave
102
if multiple oblique shock waves are used to slow air velocity what are its advantages
less wasted energy and highest pressure recovery
103
what does a variable supersonic inlet provide
optimum efficiency at all airspeeds and angles
104
at flight speeds below mach 1 is the supersonic inlet open or closed
fully open
105
at flight speeds slightly above mach 1 how do supersonic inlets slow the air
slight panel angle change creating a normal shockwave
106
at flight speed of high mach numbers how does a supersonic inlet slow the airspeed
inlet adjusts to create 3 oblique shock waves and then a normal shockwave
107
how do we reduce the profile thickness of the wing and delay the critical mach number
swept back wings
108
whats the most common swept wing angle on modern jet aircrfat
30 degrees
109
if the centre of pressure is forward of the centre on gravity what risk is increased
stall risk
