Questions and Answers of Elasticity Theory Applications

If the 8000 lb airplane lands with a 10 kts. tailwind, calculate the stopping distance.Aircraft data:Landing speed = 100 kts.Gross weight = 8000 lb Average retarding force = 2000 lb (brakes + thrust
If the aircraft is operating from an airfield where the density ratio is 0.8, calculate the no‐wind stopping distance.Aircraft data:Landing speed = 100 kts.Gross weight = 8000 lb Average retarding
The main difference between the CL–α curves for straight‐wing aircraft is thata. the swept‐wing aircraft has a lower value of CL(max).b. the straight‐wing aircraft does not fly at as high an
Low‐speed stall will start at the wing’s trailing edgea. where C1/CL is a minimum.b. Where C1/CL is a maximum.c. at the root for a swept wing.d. at the wingtip for a straight rectangular wing.
The region of reversed command for a jet aircraft is also correctly known asa. the backside of the thrust‐required curve.b. The backside of the power curve.c. the backside of the drag curve.d. Both
An aircraft should never be flown in the region of reversed command.a. Trueb. False
Pulling back on the control stick (or yoke) will cause the airplane to climb if the plane is flying ata. low speed.b. High speed.c. any speed.
A method of climbing which will work at any speed is to control the airspeed with the stick and add throttle to climb.a. Trueb. False
An airplane is making a final approach for a landing and encounters a horizontal wind shear. Which of the types of bursts below is the most dangerous?a. Headwind burst.b. Crosswind burst.c. Tailwind
An aircraft in which of the following situations is most likely to create the most intense wake turbulence?a. Heavy, dirty, and slow.b. Heavy, clean, and slow.c. Light, clean, and slow.d. Light,
Wake turbulence can cause an airplane to be turned completely upside down. To escape wake turbulence, a pilot should avoida. flying behind and below a large airplane.b. taking off or landing behind a
Spin recovery consists ofa. stopping spin rotation with rudder.b. reducing the critical AOA.c. applying ailerons into the spin direction (swept‐wing airplanes).d. All of the above.
An aircraft loaded within weight and balance limits, but with a CG at the forward limit, will experience a higher stall airspeed.a. Trueb. False
To avoid an accidental spin, a pilot should avoid which phase of a spin:a. Entryb. Incipientc. Developedd. Recovery
A cross‐control stall setup is most likely to occura. during departure while clearing an obstacle.b. In the traffic pattern.c. on a straight‐in final approach in IMC.d. When experiencing wake
Which wing planform is considered to be the most aerodynamically efficient?a. Ellipticalb. Rectangularc. Swept‐wingd. Tapered
According to Figure 10.11, regardless of the angle of bank, anytime 0° flaps are used instead of a 40° flap setting, the accelerated stall speed will always be higher for a given weight.a. Trueb.
Using Figure 10.11, calculate the IAS accelerated stall speed given the following information:Gross weight: 2000 lb Angle of bank: 40°Flap position: 40°a. 52 kts.b. 55 kts.c. 47 kts.d. 40 kts.
If a microburst is encountered on takeoff, what change in performance should be expected when going from a tailwind to a headwind?a. No change in performance.b. Decrease in performance.c. Increase in
A 10 000 lb airplane has the Tr curve shown in Figure 10.3. The Ta is 3000 lb and it is the same for all airspeeds. The airplane is flying at 210 kts. and the pilot decides to climb and pulls back on
Consider the same situation as in Problem 18, except the airspeed at the start of the maneuver is 135 kts. and after the pilot pulls back on the stick, the speed is 130 kts. Find the ROC.
A 14 000 lb airplane has the Tr curve shown in Figure 10.3. The Ta is 3000 lb and it is the same for all airspeeds. The airplane is flying at 200 kts. when the pilot pulls back on the stick,
In a constant altitude, constant airspeed turn, an aircraft is in a state of equilibrium.a. Trueb. False
The G forces on an airplane in a level turn depend ona. airspeed.b. type of airplane (jet or prop).c. bank angle.d. All of the above.
An airplane performing an 8‐point roll can stop in the 90º position becausea. the wings are not supporting the weight.b. the fuselage and vertical tail are supporting much of the weight.c. the
When an airplane is in a constant altitude bank, the stall speeda. remains the same as in level flight.b. increases as the square root of the Gs.c. increases as the square root of 1/cos ϕ.d. Both
What can we find from the aerodynamic limit line on a V−G diagram?a. It shows the maximum Gs that can be pulled at any airspeed below the maneuver speed.b. It shows the stall speed when Gs are
The limit load factor (LLF) is also called maximum design G.a. Trueb. False
If the weight of an airplane, W2, is increased above the design gross weight, W1, the limit load factora. remains the same.b. increases by the weight ratio, W1/W2.c. decreases by the weight ratio,
If an airplane is flying in symmetrical flight at its maneuver speeda. it cannot be overstressed.b. it can make the smallest turn radius.c. it can make the highest rate of turn.d. All of the above.
The constant altitude turn performance chart (Figure 11.14)a. can be used for only one particular model of airplane.b. does not show if the airplane is overstressed.c. is good for any model
When an airplane makes a level banked turn, the airspeed will decrease (unless throttle is added) becausea. parasite drag is increased the most.b. induced drag is increased the most.c. profile drag
Calculate the new stall speed ( ) of an airplane when the is 60 kts., and the airplane is experiencing a load factor of 4.4G during a level altitude, banked turn.a. 78.1 kts.b. 116.9 kts.c. 125.9
For the airplane in Problem 11, calculate the new stall speed ( )of an airplane when the airplane is experiencing a bank angle of 60° during a level altitude, banked turn.a. 84.9 kts.b. 131.6 kts.c.
Calculate the maneuvering speed (VA) if the Vs of the aircraft is 78 kts., and the aircraft is at the positive LLF for a utility category aircraft.a. 163.6 kts.b. 152.1 kts.c. 104.9 kts.d. 191.1 kts.
Calculate the radius of a turn of an airplane with a TAS of 162 kt, and a bank angle of 45° while maintaining a constant altitude.a. 1956 ftb. 2331 ftc. 3553 ftd. 2778 ft
Calculate the rate of turn of an airplane with a TAS of 90 kt, and a bank angle of 30° while maintaining a constant altitude.a. 3.1 deg/sb. 12.1 deg/sc. 14.5 deg/sd. 7.0 deg/s
A twin‐engine airplane has an engine failure shortly after takeoff.The pilot tries to turn back toward the field by making a left turn but crashes after making a 180° turn. The wreckage diagram
Using Figure 11.14, verify the answer to Problem 16. 7 128965 1 9 8 7 6 5 4 9 19 8 7 6 5 4 3 2 19 8 7 6 5 4 3 2 1 90000 90 9 8 7 6 5 4 80000 80 8 70000 70 7 80 60000 60 6 BANK 50000 50 5 ANGLE FOR
Assuming a level turn, find the Gs on the airplane in Problem 16 during the turn.
For the airplane in Problem 16, calculate the rate of turn and time to make the 180° turn.
Using Figure 11.14, verify the ROT you calculated in Problem 19. 7 128965 1 9 8 7 6 5 4 9 19 8 7 6 5 4 3 2 19 8 7 6 5 4 3 2 1 90000 90 9 8 7 6 5 4 80000 80 8 70000 70 7 80 60000 60 6 BANK 50000 50 5
The more stability an airplane has, the easier it is to control.a. Trueb. False
Static stability of an airplane is:a. the ability to return to its equilibrium position once it has been disturbed.b. the long time reaction to a disturbance.c. the initial tendency to move toward
Dynamic stability of an airplane is _____ to a disturbance.a. the immediate reactionb. the long time reactionc. oscillatory in nature.d. Both (b) and (c).
A damped oscillation is one that:a. shows positive static stability.b. shows positive dynamic stability.c. Both (a) and (b).d. Neither (a) nor (b).
Most light, single‐engine training airplanes are designed with the following stability characteristics:a. Positive static, positive dynamic.b. Positive static, negative dynamic.c. Negative static,
Weight and balance of airplanes is important because:a. the CG affects the stability and control.b. if the CG is moved forward, the static pitch stability is increased.c. if the CG is too far
Which of the following conditions is not associated with an aft CG:a. Higher cruise speed.b. Nose‐heavy tendency in the landing flare.c. Lower stall speed.d. Lighter flight control forces.
Longitudinal stability refers to the behavior of an airplane in pitch, which involves rotation around the ___________ axis.a. verticalb. longitudinalc. lateral
The farther back the wings are located, the more static pitch stability an airplane has.a. Trueb. False
Placing the jet engines at the rear of an airplane:a. Contributes to a stabilizing moment for pitch stability.b. Contributes to a destabilizing moment for pitch stability.c. Does not create a
The phugoid oscillation can best be described as an example of static stability.a. Trueb. False
Phugoid oscillation is dangerous because pilot reaction can lead to PIO.a. Trueb. False
In a phugoid oscillation:a. oscillations are damped in 1–3 seconds.b. the aircraft is considered unstable.c. damping is weak.d. All of the above.
The greater the static margin of an airplane, the greater the impact on longitudinal stability.a. Trueb. False
The most critical condition for pitch control is that the elevators must be able toa. rotate the airplane for takeoff.b. flare the airplane for landing.c. overcome a forward CG location.d. All of the
Consider a small, single‐engine general aviation airplane with two rows of seating and an aft baggage compartment. If a 50 lb bag were moved from the aft baggage compartment to the front seat, what
Calculate the moment of a rear seat passenger in an aircraft with the following given information:Passenger weight = 182 lb Arm (rear seat) = 121.0″
Calculate the CG of an aircraft with the following given information:Total weight (including aircraft) = 3270 lb Total moment = 277 680 lb‐in.
Calculate the total moment of an aircraft with the following given information:Aircraft basic empty weight (Arm 78.0) = 2125 lb Front seat occupant weight (Arm 83.0) = 320 lb Rear seat occupant
Calculate the total CG for the aircraft in Problem 19.
For static directional stability, if an airplane sideslips to the left, the plane musta. keep its old headingb. yaw to the leftc. yaw to the right
Directional stability and yaw refers to the behavior of the longitudinal axis to rotate around the ____________ axis.a. verticalb. lateralc. longitudinal
The wings of an airplane contribute to static directional stabilitya. if they are forward of the CGb. if they are behind the CGc. either of the above
The fuselage is unstable in both static pitch and static yaw stability.a. Trueb. False
Engine nacelles with propellers or jet inlets behind the airplane’s CG are stable in both static pitch and static yaw stability.a. Trueb. False
Which of the following aircraft components is a destabilizing component in regards to directional stability?a. Strakeb. Ventral finc. Tail‐mounted engined. Fuselage
Pilots can increase the stability of airplanes without powered controls bya. resting their feet on the rudders, even though the plane is trimmedb. holding the stick (or yoke) in the neutral
Operating an airplane at a high AOA will result in a loss of yaw stability.a. Trueb. False
A yaw damper is a destabilizing component regarding directional stability, though it is still utilized in air transport category aircraft because it aids in mitigating the effects of turbulence.a.
The effects of P‐factor are most pronounced in which one of the following situations?a. High angles of attack and high power settingsb. Low angles of attack and high power settingsc. Low angles of
For a twin‐engine airplane without counter‐rotating propellers, which of the following is true regarding the critical engine?a. The right engine would be considered the critical engineb. The left
During a sideslip to landing, the longitudinal axis of the airplane will be aligned with the ground track of the airplane.a. Trueb. False
For a twin‐engine propeller airplane, a loss of one engine results in a reduction of 50% performance available for maneuvering flight.a. Trueb. False
After an engine failure in a light twin‐engine, propeller‐driven airplane, what is the maximum recommended bank angle into the working engine to maintain during coordinated flight with proper
Which of the following is not stated in the chapter as a certifying condition for the calculation of an airplane’s VMC?a. Flaps in takeoff positionb. Landing gear extendedc. Maximum available
Which of these vertical wing locations will require the most wing dihedral for static roll stability?a. High wingb. Mid‐wingc. Low wing
Swept wings affect static roll stability more than straight wings bya. increasing the stabilityb. decreasing the stabilityc. they do not change the stability at all
Which term best characterizes the yaw of an airplane in the opposite direction of roll without coordinated rudder input?a. Adverse yawb. Proverse yawc. Spiral instabilityd. Dutch roll
If the pilot of a stable airplane applies right rudder, the airplane willa. roll to the left and yaw to the leftb. roll to the right and yaw to the rightc. roll to the left and yaw to the rightd.
Of the three types of coupled effects discussed, which of the following has the potential to be the most dangerous?a. Spiral divergenceb. Directional divergencec. Dutch roll
The yaw damper assists in the mitigation of which coupled effect of roll and yaw?a. Spiral divergenceb. Directional divergencec. Dutch roll
Which of the following airplane design situations may result in spiral divergence?a. Weak lateral stability, strong directional stabilityb. Strong lateral stability, weak directional stabilityc.
The speed of sound is an important factor in high‐speed flight becausea. Mcrit occurs at M = 1.b. the pressure waves generated by the plane move at sonic speed.c. shock waves form when local air
The speed of sound depends on the air density, pressure, and temperature.a. Trueb. False
Critical Mach number, Mcrit, is the aircraft’s speed whena. it goes supersonic.b. the airflow first reaches sonic speed.c. shock waves form.d. Both (b) and (c).e. None of the above.
After passing through a normal shock wave, airflow isa. Subsonic.b. not changed in direction.c. heated up.d. increased in pressure and density.e. All of the above.
Airflow passing through an oblique shock wave remains supersonic but changes in direction.a. Trueb. False
Transonic flight problems may includea. force divergence.b. increase in CD.c. decrease in CL.d. tuck under.e. buffet.f. control surface buzz.g. loss of control effectiveness.h. All of the above.i.
Above about Mach 2, the straight‐wing aircraft has a lower drag than a 60° swept‐wing aircraft.a. Trueb. False
Mach wave angle changes with airspeed as follows:a. It decreases as airspeed increases.b. It increases as airspeed increases.c. It remains the same with airspeed changes.
All supersonic aircraft have circular arc or biconvex supersonic airfoils.a. Trueb. False
Airflow passing through an expansion wavea. speeds up.b. increases the energy of the airstream.c. decreases the temperature of the air.d. Both (a) and (c).
Critical Mach number, Mcrit, of an airplane is increased by incorporating all of the following design features except:a. thin airfoil sections.b. swept wings.c. winglets.d. supercritical airfoil
Incorporating the area rule to airplane design decreases:a. wave drag.b. form drag.c. induced drag.d. oblique shock waves.
When air is passing through a compression wave the static pressure will:a. increase.b. decrease.c. experience the same change as in an expansion wave.d. remain constant.
When an aircraft has both outboard and inboard ailerons installed, which of the following statements is true?a. Inboard ailerons are activated at higher speeds when the outboard ailerons may be
The coffin corner, or “Q corner,” is defined by:a. the apex of the triangle formed by VMO and MMO.b. the apex of the triangle formed by the stall speed and ~5% > Mcrit.c. the apex of the triangle
Calculate the speed of sound at a pressure altitude of 20 000 ft with an outside air temperature of −25 °C.

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