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• Effect of Airspeed
Principles
• Effect of Rotational Velocity
Principles
• The combination of the forward velocity
and rotational velocity creates a helical
motion of the propeller through the air.
Principles
Principles
• Geometric Pitch is the theoretical forward
distance
• Effective Pitch is the ACTUAL distance
travelled
Principles
Fixed Pitch Propellers
• For a given rotational Velocity there is only
one forward velocity in which the propeller
operates most efficiently
Considerations
• Propeller Damage
• Propeller Fatigue
• Efficiency
Airmanship
• Always perform thorough pre-flight
inspections on the propeller.
• Handle the engine smoothly.
• Low power settings on ground to avoid
damage.
Review
• Which side of the propeller do we see from
the cockpit?
• What happens to the angle of attack when
we increase RPM?
• Why do we have “Blade Twist”?
Range and Endurance
Mass Brief
Aim
• To Learn the principles of range and
endurance of an aircraft in flight, and the
factors that effect these conditions
Application
• In long distance flying the maximum
Range is important
• When holding the maximum Endurance or
time in the air is important
Overview
• Revision
– Thrust and Power
• Definitions
• Principles
– Range and Endurance
• Considerations
• Airmanship
Revision
• Thrust
• Power
IAS
Thrust
Power
IAS
Definitions
• Range
– Air distance travelled for a given fuel burn-off
(distance)
• Endurance
– Time in flight for a given amount of fuel (time)
• Best Range Speed
– A certain speed that will allow the aircraft to fly the
furthest distance.
• Best Endurance Speed
– A certain speed that will allow the aircraft to stay in
the air for the longest time
Principles
• Maximum Range
– Range is a certain distance,
usually measured in nautical
miles
– Range is dependent on drag
– Maximum range occurs when
total drag is at a minimum
Principles
• Maximum Endurance
– Is a certain amount of time an
aircraft can spend in the air.
– Endurance is dependant on the
power setting of the aircraft
– Power setting determines the
burn-off (usually in Litres per
hour)
– Minimum power means minimal
fuel flow
– Maximum Endurance occurs at
minimum power
Considerations
• Effect of Airspeed
– Increased airspeed means
a decreased Range and
decreased Endurance
– Decreased airspeed means
a decreased Range and
decreased Endurance
Considerations
• Effect of Weight
– Increased weight, fly at a faster
speed, however range will not
change as you are always flying
at best L/D ratio.
– Increased weight, requires more
power to fly level, so there will be
a decrease in Endurance
– Decreased weight, fly at a slower
speed, however range will not
change as you are always flying
at the best L/D ratio
– Decreased weight, requires less
power to fly level, so there will be
an increase in Endurance
Considerations
• Effect of Wind
– A headwind will decrease the
range, but have no effect on
Endurance
– A tailwind will increased Range,
but have no effect on Endurance
• Power
– An increase in power will reduce
both Range and Endurance
– A decrease in power will reduce
both range and endurance
Considerations
• Effect of Altitude
– An increase in altitude will not
change range as the L/D ratio is
the same, however speed and
power will need to be increased
– An increase in altitude will
decrease the endurance since a
greater power setting is
required
– A decrease in altitude will not
change range (Same L/D ratio)
– A decrease in altitude will
increase Endurance as a lower
power setting is required
– In reality range is affected by
propeller efficiency which
decreases with altitude, which
would decrease the range.
Airmanship
• Set power according to cruise tables in
POH
• Lean the mixture in the cruise
　
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