Acedemics test - theory of rotary wing Flashcards
Define Ceiling
the lowest layer aloft reported as broken or overcast or the vertical visibility into an indefinite ceiling - if the sky is totally obscured, the vertical visibility will be the ceiling
LGTICCCCG is translated to:
Lightning - in clouds - clouds to clouds - clouds to ground
TSB40 is translated to:
Thunderstorm BEGAN at 40th minute of the hour
TSE23 is translated to:
Thunderstorm ENDED at 23th minute of the hour
PRESSRR / PRESSFR is translated to:
Pressure raising/decreasing rapidly
BKN 000
clouds <50ft
proximity (in RMK) - 3 afstande fra lufthavnen
On station - 0-5 statute miles
Vicinity (VS) - 5-10 stature miles
Distant (DSNT) - + 10 statuteMiles
Pk wind
In RMK if instant speed is >25 kts
Variable wind Direction
Velocity = +6kt
Direction = + 60*
ao2 is defined as
automated weather report from weather station with Precipitation discriminator
Two winds to define gust spread:
PK wind & minimum sustained
When will gust appear in the Metar
If gust spread is above 10kts
3 Types of Metar
METAR
SPECE
CORRECTED
RVR composition
RVR - Runway - Range in Ft
eks: RVR27G6000
4 sky coverages
FEW
BRK
SCT
OVC
Constitutes weather
Vertical precipitation (nedbør)
Horizontal obscuration (eks mist)
Temp / dew point - M23/M25 means
Temp = Minus 23
Dew = Minus 25
Where on the altimeter do you read your altitude
Kollsman window
Std lapsrate - Pressure & temp
Pressure - 1mm hg/1000ft
Temp - 2’C/1000ft
Std pressures & temp
Pressure: 29,92 Hg - 1013.2 mb/hPa
Temp: 15’C - 59’F
Which instruments uses only STATIC pressure
VSI
Altimeter
Which instruments uses both STATIC and PITOT pressure
Airspeed indicator
Define Indicated altitude
Read with the current (correct) altimeter setting and of the altimeter arrow
Define Absolute altitude
AGL altitude
Define True altitude
MSL altitude
Define Pressure altitude
altitude above SDP = standard datum plane
Define Density altitude
Density altitude is a function of PA and temp variation
Max altimeter error check
Field elv - Current altimeter setting = Max 75’ difference
You fly from a place with HIGHER pressure to a place with lower pressure, what is your TRUE altitude
Lower than indicated
Flying into an area of LOWER pressure without resetting the altimeter. would your TRUE altitude be higher or lower than your INDICATED?
Lower than indicated
Flying into an area of HIGHER pressure without resetting the altimeter, would your ALTIMETER indicate higher or lower than TRUE altitude.
Lower than true
Names of the pressure instruments
Altimeter
Vertical speed indicator
Airspeed indicator
2 pressures to determine atmospheric density
Dynamic , static
4 names of dynamic pressure that go into the pitot tube
Ram, total, pitot static, impact
what happens to IAS if static pressure decreases and the pitot pressure increases
IAS increases
Define IAS
Speed read on the Airspeed indicator
Define TAS
EAS calibrated for non std temp and pressure (DA)
Define CAS
IAS calibrated for installation and instrument error
That type of pressure is vented to the case of the VSI
Vented from the calibrated leak
Lag delay in std VSI
few sec
Pressure vented to the VSI diaphragm
Direct static pressure
Difference between VSI and IVSI
Accelerometer
Pito static system failure will affect which instrument
airspeed indicator
Define inertia
Newtons 1. law - A body at rest will stay at rest & a body in motion will stay in motion until an outside force affects it
Define newtons 3. law
For every action there is a reaction…..
occurs from hover to T/o
What happens if there is an increase ind the airspeed over an airfoil?
Dynamic pressure increases
Static pressure decreases
Define airfoil
Its a structure designed to produce lift
Types of airfoil
Symmetric and unsymmetric / nonsymmetrical
Definition of rotational relative wind
Parallel and opposite of the direction of the airfoil
Relative wind velocity on the advancing blade equals rotor tip velocity _____ airspeed
Plus
Relative wind velocity on the retreating blade equals rotor tip velocity _____ airspeed
Minus
Definition of induced flow
Downward velocity of airflow
Definition of resultant relative wind
Airflow that is modified by induced flow
Is the angel of incidence (AOI) an aerodynamic or mechanical angel
Mechanical
Where is the angel of incidence measured from and to
Chord line to tip pan plane ( plane of rotation)
Where is the angel of attack measured from and to
Chord line to resultant relative wind
Is the AOA an aerodynamic or a mechanical angel
Aerodynamic
2 components of total force
Lift and Thrust
2 components of Total aerodynamic force (TAF)
Lift and drag
Lifts relationship to resultant relative wind
Perpendicular
What is drags relationship to resultant relative wind
Parallel but in the same direction
Names of the 4 types of drag
Parasitic, Profile, Induced, total
Which drag increases proportional with airspeed
Parasitic drag
Which is the most critical drag in high power helicopter operations (Hover)
Induced
As we increase induced drag or induced flow, what happens to AOA
Decreases
Definition of dissymmetry of lift
Unequal lift on the advancing and retreading sides of the rotor disk
Definition of Blowback
When blade flapping has compensated for dissymmertry of lift, the rotor disk is tilted to the rear
What does the helicopter do to compensate for dissymmetry of lift
Flapping
What does a pilot do to control dissymmetry of lift
Cyclic feathering
What are the two conditions of flight which of Newtons laws do they apply to
Balanced - 1. Law (Inertia)
Unbalanced - 2. Law (acceleration)
The 3 types of rotor systems
- Fully articulated
- Semi-rigit
- Rigit
Rotor blade coning is a compromise between what two forces
Centrifugal force and Lift
Definition of Centrifugal force
An outward force produced whenever a body moves in a curved path
Definition of rotor blade coning
Upward flexing of the rotor blades
Describe the twist of the rotor blade on standard american helicopters
Higher pitch angel at the root of the rotor blades and lower pitch angel at the tip of the rotor blades, to distribute the lifting force more evenly along the blade
Define torque effect on a single rotor helicopter system
Counter-rotative blades, nose yaw opposite direction, use anti-torque pedals to correct it.
What is the relationship of total force to the tip path plane
Perpendicular
The 4 causes of excessive coning
- High Gross weight
- Low RPM
- High G manuvers
- Turbulent air
Rotation of the main rotor blades produces
Relative wind
The difference between an IGE and an OGE is what in hover operations
Hard surfface
Definition of Effective Transational Lift (ETL)
The rotor completely outruns the recirculation of old vortices and begins to work in relatively undisturbed air
Speed parameters for ETL
16 - 24 kts
What occurs during Transvers flow effect (TFE)
Forward part of the rotor: Going from vertical flow to horizontal flow
Rear part of the rotor: Still effected by induced flow
Speed parameters Transvers flow effect (TFE)
10 - 20 kts.
3 faktors for a dynamic rollover
- Pivot point
- Roling motion
- Exceeding critical angel
3 conditions for setteling the power
- Vertical or near-vertical descent 300 F/PM
- Airspeed less than ETL
- 20 - 100 % power
2 faktors that condribute to a dynamic rollover
Human and physical
The Helicopter has entered a retreating blade stall. What should you expect the helicopter to do
Pitch up and roll left
What would be the primary factor for entering a retreating blade stall
Excessive airspeed
If you depart a base with an altimeter setting of 29.82 and hour later receive a new altimeter setting of 30.22, how much higher or lower than true altitude would the altimeter indicate prior to adjusting the altimeter to the new setting
400’ Lower
At the last reporting point, you corrected the altimeter by setting the Kollsman scale on 29.92 Hg. Prior to landing, you received a new setting of 29.80. What is your True altitude in relation to indicated altitude (Before you reset the altimeter)
120’ Lower
When flying into an area of colder than standard temperature, would the indicated altitude be more or less than true altitude
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