Heads-Up Display Modes 35 - Metaboli

108 Ground School
GROUND SCHOOL
Air combat is a complicated task; military pilots receive years of training and
practice before being turned loose to fight for their country. Simulated air combat
isn’t as complicated, but a thorough understanding of basic flight and combat
principals is required to ensure victory.
8.001 Indicated Airspeed and True Airspeed
All airspeeds are not created equal. Dense air at lower altitudes both increases the
lift generated by the wings, and resists the aircraft’s movement. Thinner air at
higher altitudes reduces the amount of lift the wings can produce, but lets the
aircraft move more easily. As a result, an aircraft moving at a constant 350 knots
has different performance and flight characteristics at sea level than at 40,000 ft.
This is called the aircraft’s True Airspeed (TAS).
Most modern aircraft adjust the airspeed display to account for altitude. This
Indicated Airspeed (IAS) displays the airspeed that would provide equivalent
performance at sea level. For example, an aircraft flying at 350 knots IAS at 5,000
ft has the same performance as flying 350 knots IAS at 45,000 feet; however, its
TAS is actually significantly faster at the higher altitude. Displaying IAS reduces the
pilot’s workload, minimizing the amount of flight performance data that must be
memorized.
hSome airspeed indicators show TAS; others show IAS. Always confirm
the operation of each air speed indicator prior to takeoff.
8.002 Velocity Vector
The velocity vector is an extremely important indicator displayed on most fighter
jets’ HUDs. The velocity vector shows where the aircraft’s momentum is actually
taking it. For example, any time you change course, the aircraft’s momentum
keeps it moving in the original direction until the thrust of the engines overcomes
the momentum and establishes a new heading. Aircraft like the MiG-29 and Su-27
are famous for high AOA flight, in which case the aircraft’s nose is pointing one
direction, but the plane is actually moving a different direction. In this case, the
velocity vector indicates where the aircraft is actually heading.
hThe velocity vector is useful during landings. If the velocity vector
appears short of the runway, you’re going to crash short of the runway!
8.003 Angle Of Attack Indicator
Whenever the velocity vector is not aligned with the aircraft’s heading, the pitch
angle between the airflow and where the aircraft is pointing is called the Angle Of
Attack (AOA). Anytime the pilot pitches the aircraft (whether in a steep turn, or just
initiating a climb), the AOA increases. In level flight, reducing thrust generally
increases AOA because the reduced thrust results in reduced lift. The aircraft
begins to sink while holding a nose-level attitude.
AOA and airspeed impact the amount of lift (G-load) generated by the wings.
Generally, if the wing isn’t stalled, then increasing AOA will increase the amount
of lift being generated. Likewise, increasing speed with a constant AOA also
increases lift. Unfortunately, this also increases the drag generated by the wing,