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Beginner's
Guide to Propulsion
Maximum Flight Time
Activity
If so instructed by your teacher, print out a workskheet page for these
problems.
Complete the following
activities that relate to the Maximum Flight Time of an aircraft. You may
want to read additional slides from the
Beginner's Guide to Propulsion. It will be helpful to
use the links on the Maximum
Flight Time slide.
- The Maximum Flight
Time for an aircraft depends on the specific fuel consumption,
net thrust, and the mass of the fuel load. If all
other factors for the following aircrafts remain the same, which of
the 2 aircraft has the longer maximum flight time? Place an "X"
on the correct line.
A.
AIRCRAFT
A - The throttle setting is 58% ___________
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AIRCRAFT
B - The throttle setting is 75% ___________
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B.
AIRCRAFT
A - The engine is producing 1500 pounds of thrust _______
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AIRCRAFT
B - The engine is producing 2000 pounds of thrust ________
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C.
AIRCRAFT
A - has a turbojet engine with an afterburner ________
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AIRCRAFT
B - has a plain turbojet engine __________
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D.
AIRCRAFT
A - has a turboprop engine ____________
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AIRCRAFT
B - has a rocket engine ___________
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E.
AIRCRAFT
A - has a L/D (lift to drag ratio) of .5 __________
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AIRCRAFT
B - has a L/D (lift to drag ratio) of .8 __________
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F.
AIRCRAFT
A - has a fuel mass flow rate of 2500 lbm/hr_________
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AIRCRAFT
B - has a fuel mass flow rate of 3500 lbm/hr__________
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Before you complete
Step 2, make sure you are comfortable with the Maximum Flight Time
Equation as well as the Range Equation.
- For a given mission,
the required flight time could replace the maximum flight time in the
required equation. This idea may be needed to solve the following:
A. For mission I, we need 4500 pounds of thrust for 3 hours.
If the Thrust Specific Fuel Consumption is .8, how much fuel
is needed for this mission?
B. For the second mission, the engines are being fed from a fuel
tank that delivers 3200 pounds mass per hour. If the aircraft is producing
2500 pounds of thrust, what is the TSFC?
C. If the aircraft can carry 20,000 pounds mass of fuel plus
the amount needed for takeoff and landing, what is the limit for the
time the mission can take?
D. The aircraft plans to maintain a cruise speed of 120 mph.
What is the aircraft's maximum range?
E. The aircraft was forced to land unexpectedly. At that time, there
were only 15,000 pounds mass of fuel in excess of that needed for takeoff
and landing. All other conditions remain the same. If the final destination
of the mission is 630 miles away, what cruise speed should be
maintained?
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Related Pages:
Standards
Worksheet
Propulsion Activity Index
Propulsion Index
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