LESSON 8 Chapter 7 Applied Jet Performance ANA Chapter 2

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Flight Theory

Chapter 7

Jet Aircraft Applied Performance

Variations in the thrust required curve

The importance, Nea the necessity, of analyzing thrust required curves under certain conditions are the basis of all phases of performance.

These curves define the requirements of the airplane and must be considered when deciding which power plant to hang on the plane.

Weight pg 99 navweps

Changing the weight influences the parasite drag only a minimal amount because of changes in surface area of engine nacelles fuel pods ect. Graph

Induced drag changes significantly because of the higher AOA needed to generate the extra lift required.

This causes the thrust required curve to move greatest in the lower region.

Effect of a Weight Change on the Tr Curve

Configuration Changes pg 101 navweps

The change in configuration causes a change in the L/Dmax curve as well as forcing the thrust required curve up and to the left.

This could be thought of as being the opposite to the effect of weight because the increase in parasite drag will effect the curve most in the higher region.

Tr and Ta for Configuration

Configuration Change (Overall)

Altitude Changes pg101 navweps

This is useful for understanding how range and endurance is effected by changes in altitude.

Lets say we have an airplane with a min drag of 1250lbs at 160kts

If operated at the same q or 160kts at 22,000 ft, you would have a true airspeed of 227kts.

This would then cause the thrust required curve to flatten out and move to the direction of higher velocity.

Tr and Ta for Altitude

Altitude Effect on the Thrust Curve

Go Over page 102-103 Dole

Read over these items

Specific Range

Remember SR is nm/lbs of fuel

As fuel is burned the weight becomes less

To maintain the correct amount of thrust as weight is reduced, reduce throttle settings to lower thrust and a lower airspeed.

Speed and thrust decrease as weight decreases to get max range

Weight effects on SR

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