Exam 1 Graded Questions

Groundspeed equals ______ when there is zero wind at altitude.

True airspeed

An aerodynamic force results from differences in static pressure and ambient pressure acting on an airfoil. (T/F)

False (it is the resultant of pressure forces and shear forces)

Practical pilot application of the continuity equation

Air speeds up over the curved upper surface of a wing because the effective flow area is reduced

Chord line

A straight line connecting the leading edge and the trailing edge of the airfoil

NACA 0012: which statement is true?

The airfoil has a thickness of 12%

Air (atmosphere) can be treated as incompressible flow when M < 0.3. (T/F)

True

Pressure forces vs. shear forces on an airfoil

Pressure forces act perpendicular to the surface; shear forces act tangentially

How the pitot-static system measures airspeed

The pitot tube measures total (stagnation) pressure and the static port measures static pressure; their difference is dynamic pressure, which gives airspeed

Aerodynamic force (AF) can be resolved into

Lift and drag

Figure 3.19: relationship of V2 to V3

V2 is greater than V3

Maximum thickness (airfoil)

The maximum distance between the upper and lower surfaces

Towing an airplane 200 ft with a tow bar accomplishes

Work

NACA 2412: what do the 3rd and 4th digits mean?

Maximum thickness is 12% of chord length

If AOA of an airfoil increases, the center of pressure (CP) will

Move forward

Continuity equation (A1V1 = A2V2) physical meaning

As cross-sectional area decreases, airspeed increases to conserve mass flow

The ISA troposphere extends up to approximately

36,000 ft

Component of aerodynamic force perpendicular to the relative wind

Lift (L)

Air (atmosphere) is

A compressible gas

As altitude increases while maintaining the same IAS in level flight, TAS

Increases

NACA 0013: which statement is true?

It is a symmetrical airfoil

As you go up in altitude, the composition of the atmosphere does not change. (T/F)

True

An airplane parked on the ramp is experiencing which Newton's Law?

First

The stagnation point is where

D: Both B and C (velocity is zero and static pressure equals total pressure)

IAS vs CAS difference is typically smallest

At cruise airspeeds with flaps up in straight-and-level flight

Taxiing an airplane 100 ft in 30 seconds accomplishes

Power

On a standard day, pressure at 18,000 ft is approximately

One-half of sea level pressure (~500 hPa)

Density ratio if temperature ratio = 0.9656 and pressure ratio = 0.8962

0.9281 (sigma = delta/theta)

Density ratio sigma at FL180 (18,000 ft MSL)

0.5699

Density rho at FL180 (18,000 ft MSL)

0.0013546 slugs/ft^3

NACA 4412: 1st digit means

Maximum camber is 4% of chord length

Total lift needed for straight-and-level, unaccelerated flight at 2300 lb weight

2300 lb

Mean camber line

A line drawn equidistant between the upper and lower surfaces

NACA 4412: 3rd and 4th digits mean

Maximum thickness is 12% of chord length

NACA 2412: 1st digit means

Maximum camber is 2% of chord length

Temperature increases with altitude in the troposphere. (T/F)

False

An airspeed indicator measures

The difference between total pressure and static pressure at the pitot tube

Why pilots should understand their aircraft's NACA airfoil

It helps predict lift, stall behavior, and performance characteristics

Cambered airfoil

A non-symmetrical airfoil

Correction from EAS to TAS depends on

Density ratio alone

Figure 3.19: relationship of V1 to V3

V1 is greater than V3

Mass of an airplane that weighs 12,000 lb

373 slugs

If the four forces of flight are imbalanced, the airplane will

Accelerate or decelerate

"Mass entering the pipe is greater than mass leaving, so mass flow must change." (T/F)

False (mass flow is conserved)

Component of aerodynamic force parallel to the relative wind

Drag (D)

NACA 4412: 2nd digit means

Location of maximum camber is at 4/10th (40%) of the chord line from the leading edge

One slug weighs

32.2 lb

Static pressure on the top surface of a wing as airflow speeds up (Bernoulli)

Decreases

An aerodynamic force is the resultant of which two forces?

Pressure force and shear force

NACA 2412: 2nd digit means

Location of maximum camber is at 4/10th (40%) of the chord line from the leading edge

Figure 3.19: relationship of V1 to V2

V1 is less than V2