CNS Aantekeningen
CNS AANTEKENINGEN WEEK 1
Wind triangle
Reader Wind Triangle
The motion of an aircraft relative to the surface of the Earth is made up of two velocities. These are the
aircraft moving relative to the air mass, and the air mass moving relative to the surface of the Earth. Adding
• Triangle
these twoifvectors
velocities:
together gives us the aircrafts motion over the ground. Together, they form the “triangle of
o Velocity of aircraft relative to air mass
velocities”.
o Velocity of air mass relative to ground
A wind
o that is blowing
Velocity from the
of aircraft left willto
relative carry an aircraft onto a track that is to the right of the heading. In order
ground
to achieve a particular track from A to B the aircraft must be turned into-wind by an amount that corrects for
o De heading van het vliegtuig is anders dan de richting waarin het vliegtuig
the drift.
vliegt door de wind (track).
• Magnitudes and vectors
Each of the three velocities:
in the triangle of velocities has two properties – magnitude and direction. This
means that there are a total
o Aircraft: True Airspeed of six (TAS)
components. These (HDG)
and Heading are the True Air Speed (TAS) and heading (HDG) of
the aircraft, the speed and direction of the wind (W/V), and the Ground Speed (GS) and track (TR) of the
o Wind: speed and direction (W/V)
path over the ground. This is shown in Figure 1 – The Triangle of Velocities.
o Ground: Ground Speed (GS) and Track (TR)
•
• (Source: Reader)
• figure 1
FMC:
o Flight Management Computer
Typical navigation problems involve finding two of these properties when given the other four. For example,
mostoof Mechanical Flightwhat
the time we know Computer
track and air speed we would like and we also have the forecast wind
o Electronic
velocity. Flight
What heading do Computer
we need to steer to follow that track, and what ground speed will we achieve?
o Berekend de benodigde Heading en TAS om een bepaalde ground track te
The usual method of solving this problem is with a “Mechanical Flight Computer” or “Electronic Flight
volgen.
Computer” in present aircraft called the Flight Management Computer” (FMC). The wind side of the flight
• Berekenen:
computer consists of a circular rotating compass rose which is marked with an index at the top, and has a
o In weather
transparent screen inreports wordt
the middle de wind
to allow gegeven
viewing als richting
of the slide waarvanuit
plate underneath. hetslide
The blaast.
plate is marked
Dit dient
with concentric dus arcs
speed met and
180radial
graden driftgecorrigeerd te worden.
lines. The computer allows you to physically visualise the triangle
of velocities, and read off the answer you require. Figure 2
But what calculations is the flight computer performing? How do you solve the problem mathematically?
CNS AANTEKENINGEN WEEK 1
Wind triangle
Reader Wind Triangle
The motion of an aircraft relative to the surface of the Earth is made up of two velocities. These are the
aircraft moving relative to the air mass, and the air mass moving relative to the surface of the Earth. Adding
• Triangle
these twoifvectors
velocities:
together gives us the aircrafts motion over the ground. Together, they form the “triangle of
o Velocity of aircraft relative to air mass
velocities”.
o Velocity of air mass relative to ground
A wind
o that is blowing
Velocity from the
of aircraft left willto
relative carry an aircraft onto a track that is to the right of the heading. In order
ground
to achieve a particular track from A to B the aircraft must be turned into-wind by an amount that corrects for
o De heading van het vliegtuig is anders dan de richting waarin het vliegtuig
the drift.
vliegt door de wind (track).
• Magnitudes and vectors
Each of the three velocities:
in the triangle of velocities has two properties – magnitude and direction. This
means that there are a total
o Aircraft: True Airspeed of six (TAS)
components. These (HDG)
and Heading are the True Air Speed (TAS) and heading (HDG) of
the aircraft, the speed and direction of the wind (W/V), and the Ground Speed (GS) and track (TR) of the
o Wind: speed and direction (W/V)
path over the ground. This is shown in Figure 1 – The Triangle of Velocities.
o Ground: Ground Speed (GS) and Track (TR)
•
• (Source: Reader)
• figure 1
FMC:
o Flight Management Computer
Typical navigation problems involve finding two of these properties when given the other four. For example,
mostoof Mechanical Flightwhat
the time we know Computer
track and air speed we would like and we also have the forecast wind
o Electronic
velocity. Flight
What heading do Computer
we need to steer to follow that track, and what ground speed will we achieve?
o Berekend de benodigde Heading en TAS om een bepaalde ground track te
The usual method of solving this problem is with a “Mechanical Flight Computer” or “Electronic Flight
volgen.
Computer” in present aircraft called the Flight Management Computer” (FMC). The wind side of the flight
• Berekenen:
computer consists of a circular rotating compass rose which is marked with an index at the top, and has a
o In weather
transparent screen inreports wordt
the middle de wind
to allow gegeven
viewing als richting
of the slide waarvanuit
plate underneath. hetslide
The blaast.
plate is marked
Dit dient
with concentric dus arcs
speed met and
180radial
graden driftgecorrigeerd te worden.
lines. The computer allows you to physically visualise the triangle
of velocities, and read off the answer you require. Figure 2
But what calculations is the flight computer performing? How do you solve the problem mathematically?
