What is the primary physical reason for the significant drop in the maximum lift-to-drag ratio as an airplane accelerates through Mach 1?
Explanation
This question tests the understanding of the fundamental aerodynamic change—the onset of wave drag—that causes a sharp decrease in aerodynamic efficiency at supersonic speeds.
Other questions
What is the primary characteristic of the drag polar for an actual airplane, such as the Lockheed C-141A, that differs from the simplified approximation where the axis of the parabola is the zero-lift axis?
In level, unaccelerated flight, what condition must be met for the thrust required (TR) to be at its minimum?
For the hypothetical CJ-1 jet aircraft with a weight of 19,815 lb, what is the thrust required to fly at a velocity where its lift-to-drag ratio is 9.55?
How is the maximum velocity (Vmax) of a jet airplane at a given altitude determined graphically?
How does power required (PR) vary with the aerodynamic ratio CL^(3/2)/CD?
What aerodynamic condition holds when an airplane is flying at the velocity for minimum power required?
The hypothetical CP-1 airplane has a power plant rated at 230 hp at sea level and a propeller efficiency of 0.80. What is the power available (PA) in horsepower?
How is the rate of climb (R/C) of an airplane defined in terms of power?
An airplane is in a power-off glide. What determines its equilibrium glide angle, theta?
What is the definition of an airplane's service ceiling?
For a propeller-driven airplane, how is maximum range achieved according to the Breguet range formula?
For a jet airplane, under what condition is maximum endurance achieved?
The hypothetical CP-1 airplane has a wingspan of 35.8 ft and a wing area of 174 ft squared. Its parasite drag coefficient (CD,0) is 0.025 and its Oswald efficiency factor (e) is 0.8. Calculate its maximum lift-to-drag ratio.
During takeoff ground roll, the reduced drag experienced by an airplane flying close to the ground is known as what phenomenon?
What is the load factor, n, for an airplane in a level turn with a bank angle (phi) of 60 degrees?
What does the corner velocity on a V-n diagram represent?
What is the specific energy (or energy height, He) of an aircraft?
What key design improvement, developed by Fred E. Weick at NACA in the late 1920s, dramatically reduced the drag of airplanes with radial engines by about 60 percent?
What design parameter, other than aspect ratio, dictates the induced drag force for an airplane in steady, level flight?
What are the two fundamental sources that produce all aerodynamic forces and moments on a body, as emphasized in Chapter 6?
An airplane has a weight of 5000 lb and is in a power-off glide at its maximum lift-to-drag ratio of 10. What is its equilibrium glide angle?
According to the simplified takeoff distance formula (Eq. 6.104), if the weight of an airplane is doubled, how does the required liftoff distance (sLO) change?
For a jet airplane, how is maximum range achieved, according to the Breguet range formula?
What is the relationship between the rate of change of an airplane's energy height (dHe/dt) and its specific excess power (Ps)?
What is the primary purpose of wing fillets, first used successfully on the Douglas DC-1?
For a jet airplane with a maximum load factor of 5 and a corner velocity (V*) of 43.6 ft/s, what is the minimum turn radius (Rmin) in a level turn at sea level?
How does the liftoff distance (sLO) depend on the ambient air density (rho_infinity), assuming thrust is proportional to density?
Which of the following is NOT one of the three general design parameters identified in the Design Box of Section 6.8 as being critical for increasing maximum velocity (Vmax)?
What is the primary difference in the thrust-available (TA) curve between a reciprocating engine-propeller combination and a turbojet engine?
According to the Oswald efficiency factor definition in Section 6.1, what does the term `CD,0` in the drag polar equation `CD = CD,0 + CL^2 / (pi * e * AR)` represent?
If an airplane is flying at its absolute ceiling, what is its maximum rate of climb?
For the hypothetical CP-1 airplane at sea level, the minimum thrust required is 217 lb. The airplane's weight is 2950 lb. What is the maximum lift-to-drag ratio?
What is the equation for the power required (PR) for an airplane in steady, level flight, expressed in terms of thrust required (TR) and velocity (V_infinity)?
To calculate the time to climb from one altitude to another, what quantity must be graphically integrated with respect to altitude?
An airplane has a maximum lift coefficient (CL,max) of 1.2, a wing area (S) of 100 ft squared, and a weight (W) of 2000 lb. At sea level (rho_infinity = 0.002377 slug/ft^3), what is its stalling velocity (Vstall)?
In a level turn, to achieve the smallest possible turn radius and the largest possible turn rate, what two conditions must be met?
What does the symbol `CD,i` represent in the context of the drag polar?
For the hypothetical CP-1 airplane with a weight of 2950 lb, a wing area of 174 ft squared, and a max L/D of 13.6, what is its maximum glide range from an altitude of 10,000 ft?
How did the Wright brothers' design philosophy regarding stability differ from the prevailing European philosophy of the early 1900s?
What is the consequence of the lift-induced thrust required decreasing with velocity while the zero-lift thrust required increases with velocity?
In the simplified analysis of takeoff, the liftoff velocity (V_LO) is typically taken as what multiple of the stalling velocity (V_stall) to ensure a margin of safety?
An airplane has a maximum L/D of 15. It is in a power-off glide from an altitude of 30,000 feet. What is the maximum ground distance it can cover?
What is the primary effect of increasing altitude on the power-required (PR) curve for a given airplane at a constant lift coefficient?
According to the analysis in Section 6.17, which of the following airplane designs would likely have the smallest turn radius and largest turn rate, assuming all other factors are equal?
What does the term 'specific fuel consumption' (SFC) for a reciprocating engine represent?
Which of the following drag components is described as being due to a redistribution of surface pressure over a finite wing caused by the creation of wing tip vortices?
An airplane in a pull-up maneuver has a load factor `n`. Its velocity is `V_infinity`. What is the equation for its turn radius `R`?
A key finding in the evolution of airplane design is that the zero-lift drag coefficient (CD,0) for modern jet airplanes is in what approximate range?
According to the Design Box in Section 6.24, what is the primary effect of increasing the design aspect ratio (AR) for a subsonic airplane, given specified values of W/S and CD,0?