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15 - Range Endurance

The document discusses the concepts of range and endurance for both propeller-driven and jet-powered aircraft, highlighting the differences in parameters that maximize each. It defines range as the total distance an airplane can fly on a single tank of fuel and endurance as the total time it can stay in the air. Additionally, it introduces specific fuel consumption (SFC) for propeller-powered aircraft and thrust specific fuel consumption (TSFC) for jet-powered aircraft, along with formulas for maximizing range and endurance in both types of aircraft.

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hayder hhrg
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12 views19 pages

15 - Range Endurance

The document discusses the concepts of range and endurance for both propeller-driven and jet-powered aircraft, highlighting the differences in parameters that maximize each. It defines range as the total distance an airplane can fly on a single tank of fuel and endurance as the total time it can stay in the air. Additionally, it introduces specific fuel consumption (SFC) for propeller-powered aircraft and thrust specific fuel consumption (TSFC) for jet-powered aircraft, along with formulas for maximizing range and endurance in both types of aircraft.

Uploaded by

hayder hhrg
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
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Download as PDF, TXT or read online on Scribd
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RANGE AND ENDURANCE

• So far we have focused on characterizing propulsion system

• Also must look at behavior of entire airplane


– How fast can airplane fly?
– How far can airplane fly on a single tank of fuel?
– How long can airplane stay in air on a single tank of fuel?
– How fast and how high can it climb?
– How does it perform?
RANGE AND ENDURANCE
• Range: Total distance (measured with respect to the ground) traversed by airplane
on a single tank of fuel
• Endurance: Total time that airplane stays in air on a single tank of fuel

• Parameters that maximize range are different from those that maximize endurance
• Parameters are different for propeller-powered and jet-powered aircraft

• Fuel Consumption Definitions


– Propeller-Powered:
• Specific Fuel Consumption (SFC)
• Definition: Weight of fuel consumed per unit power per unit time

– Jet-Powered:
• Thrust Specific Fuel Consumption (TSFC)
• Definition: Weight of fuel consumed per unit thrust per unit time
PROPELLER-DRIVEN: RANGE AND ENDURANCE
• SFC: Weight of fuel consumed per unit power per unit time

lb of fuel
SFC 
HP hour 
• ENDURANCE: To stay in air for longest amount of time, use minimum
number of pounds of fuel per hour

 SFC HP 
lb of fuel
hour 
• Minimum lb of fuel per hour obtained with minimum HP
• Maximum endurance for a propeller-driven airplane occurs when
airplane is flying at minimum power required
• Maximum endurance for a propeller-driven airplane occurs when
airplane is flying at a velocity such that CL3/2/CD is a maximum
PROPELLER-DRIVEN: RANGE AND ENDURANCE
• SFC: Weight of fuel consumed per unit power per unit time

lb of fuel
SFC 
HP hour 
• RANGE: To cover longest distance use minimum pounds of fuel per mile

lb of fuel SFCHP 

mile V
• Minimum lb of fuel per hour obtained with minimum HP/V∞
• Maximum range for a propeller-driven airplane occurs when airplane
is flying at a velocity such that CL/CD is a maximum
PROPELLER-DRIVEN: RANGE BREGUET FORMULA

 Winitial 
h CL
R ln 
SFC CD  W final 

• To maximize range:
– Largest propeller efficiency, h
– Lowest possible SFC
– Highest ratio of Winitial to Wfinal, which is obtained with the largest fuel weight
– Fly at maximum L/D
PROPELLER-DRIVEN: RANGE BREGUET FORMULA

h CL  Winitial 
R ln 
SFC CD  W final 

Propulsion Structures and Materials


Aerodynamics
PROPELLER-DRIVEN: ENDURACE BREGUET FORMULA

3
h CL 2
2  S  2 W final2  Winitial2 
1 1 1
E
SFC CD  

• To maximize endurance:
– Largest propeller efficiency, h
– Lowest possible SFC
– Largest fuel weight
– Fly at maximum CL3/2/CD
– Flight at sea level
JET-POWERED: RANGE AND ENDURANCE
• TSFC: Weight of fuel consumed per thrust per unit time

lb of fuel
TSFC 
lb of thrust hour 

• ENDURANCE: To stay in air for longest amount of time, use minimum


number of pounds of fuel per hour

 TSFC Thrust 
lb of fuel
hour 
• Minimum lb of fuel per hour obtained with minimum thrust
• Maximum endurance for a jet-powered airplane occurs when
airplane is flying at minimum thrust required
• Maximum endurance for a jet-powered airplane occurs when
airplane is flying at a velocity such that CL/CD is a maximum
JET-POWERED: RANGE AND ENDURANCE
• TSFC: Weight of fuel consumed per unit power per unit time

lb of fuel
TSFC 
lb of thrust hour 

• RANGE: To cover longest distance use minimum pounds of fuel per mile
lb of fuel SFCThrust 

mile V
• Minimum lb of fuel per hour obtained with minimum Thrust/V∞

TR 1 2W 1
  S CD  1
V 2   SCL CL 2
CD
• Maximum range for a jet-powered airplane occurs when airplane is
flying at a velocity such that CL1/2/CD is a maximum
JET-POWERED: RANGE BREGUET FORMULA

R2
2 1 CL 2 W 12  W 12 
  S TSFC CD  initial final

• To maximize range:
– Minimum TSFC
– Maximum fuel weight
– Flight at maximum CL1/2/CD
– Fly at high altitudes
JET-POWERED: ENDURACE BREGUET FORMULA

1 C L  Winitial 
E ln
TSFC C D  W final 

• To maximize endurance:
– Minimum TSFC
– Maximum fuel weight
– Flight at maximum L/D

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