Aircraft Structures and Design - Set 2 (Q&A)

a

Buffeting, an intermittent application of forces to a part of an airplane, is caused by _____.

a. an unsteady flow from turbulence

b. the incorrect rigging of elevator

c. the incorrect rigging of ailerons

d. incorrect combination of controls by the pilot

d

The point at which there is an appreciable elongation of the material without any corresponding increase of load.

a. Elastic point

b. Proportional limit

c. Rupture point

d. Yield point

c

Flutter can be prevented by ___________ to alter the moment of inertia of the surface and therefore the period of vibration (move the control surface CG closer to the hinge) such as placing the engines on pylons forward of the wing leading edge.

a. weight reduction

b. pulling back on the control

c. mass balancing control surfaces

d. fuel jettisoning

a

The maximum positive maneuvering load factors for a commuter and normal airplane are _____, respectively.

a. 3.8 and 3.8

b. 3.8 and 4.4

c. 1.2 and 3.8

d. 3.8 and 6.0

a

It is the combination of compressive and tensile loads.

a. Bending

b. Gust

c. Shear

d. Torsion

b

It is the ratio of ultimate stress to the allowable stress.

a. Critical Ratio

b. Factor of Safety

c. Marginal Allowance

d. Proportional Limit

c

Calculate the minimum wall thickness for a cylindrical vessel that is to carry a gas at a pressure of 1,400 psi. The diameter of the vessel is 2 feet and the stress is limited to 12 ksi.

a. 0.7 inches

b. 1.0 inch

c. 1.4 inches

d. 1.5 inches

c

Friction always acts _____ to the contact surface.

a. diagonally at 45 degrees

b. normal

c. parallel

d. the same angle of static friction

a

The 16-ft wing of an airplane is subjected to a lift which varies from zero at the tip to 360 lb/ft at the fuselage according to w=90x0.5 lb/ft where x is measured from the tip. Compute the resultant and its location from the wing tip.

a. R=3,844 lbs; x=9.60 ft

b. R=3,840 lbs; x=8.60 ft

c. R=3,480 lbs; x=9.06 ft

d. R=3,804 lbs; x=9.60 ft

c

It is defined as the measure of the structure's resistance to change in shape when subjected to force.

a. Ductility

b. Resilience

c. Stiffness

d. Toughness

c

Large transport airplane hydraulic systems usually operate with a system pressure of approximately _____.

a. 1,000 psi

b. 2,000 psi

c. 3,000 psi

d. 4,000 psi

d

Referring to a rotorcraft, it is an anti-torque system which has no visible rotor mounted on the tail boom.

a. Conventional

b. Ducted Fan

c. Fenestron

d. NOTAR

d

It is known as the measurement of height in inches. It is perpendicular from a horizontal plane located at a ground, cabin floor, or some other easily referenced location.

a. Aileron Station

b. Butt Line

c. Wing Station

d. Water Line

d

An airplane weighing 11,500 lbs has a positive maneuvering load factor of _____.

a. 2.78

b. 2.99

c. 2.21

d. 3.22

a

In reference to a V-n diagram, it is the slowest speed at which the maximum load factor can be reached without stalling.

a. VA

b. VB

c. VSX

d. VS1

a

It is the ratio of modulus of elasticity and material density.

a. Specific strength

b. Specific stiffness

c. Specific volume equivalence

d. Specific toughness

c

Given the difference of the angle setting and angle at zero lift to be 14 degrees, what is the slope of lift curve (in per rad) if your coefficient of lift is 1.35?

a. 0.0964

b. 0.00168

c. 5.525

d. 10.370

b

This speed is vital in protecting the aircraft from inadvertent stall and from overstressing.

a. VPRO

b. VRA

c. VD

d. VH

b

What is the gust velocity for diving at 20,000 feet and below?

a. 12.5 ft/s

b. 25.0 ft/s

c. 30.0 ft/s

d. 50.0 ft/s

b

For a conventional, single-engine airplane of 6,000 pounds or less, the minimum design maneuvering speed is given by _____.

a. 12.5 (n₁w/s)^0.5

b. 17.0 (n₁w/s)^0.5

c. 19.5 (n₁w/s)^0.5

d. 27.3 (n₁w/s)^0.5

c

This V-speed means 'design speed for maximum gust intensity.'

a. VG

b. VNO

c. VB

d. VGE

b

What parameter is at its maximum when shear is equal to zero?

a. Bending

b. Moment

c. Force

d. Stability

d

It is a flat sheet triangular shape used to reinforce the corners of structure.

a. Webs

b. Fittings

c. Caps

d. Gussets

b

Frames which serve merely to maintain the shape of the fuselage is called _____.

a. Intermediate frames

b. Simple frames

c. Main frames

d. Transverse frames

b

The tangent of this angle where the opposite side is the frictional force and the adjacent side is the normal force is called _____.

a. bank

b. friction

c. incidence

d. attack

a

The buttocks line, or butt line, is _____.

a. the width measurement left or right of, and parallel to, the vertical centerline

b. the height measurement left or right of, perpendicular to the horizontal centerline

c. the width measurement left of, and perpendicular to, the vertical centerline

d. the length measurement from the datum line

b

Which among the following statements best describes a cantilever wing?

a. Externally braced with either struts and /or bracing wires

b. Supported at one end only with no external bracing

c. Braced at both the upper and lower section of the airfoil

d. Able to be folded at the root section to ease storage in confined spaces

a

A single bolt is used to lap joint two steel bars together. Tensile force on the bar is 20,000 Newtons. Determine the diameter of the bolt required if the allowable shearing stress on it is 70 MPa.

a. 19 mm

b. 16 mm

c. 13 mm

d. 9 mm

a

A simply supported beam is five meters in length. It carries a uniformly distributed load including its own weight of 300 Newtons per meter and a concentrated load of 100 Newtons, 2 meters from the left end. Find the reactions if reaction A is at the left end and reaction B is at the right end.

a. RA=810N ; RB=700N (790N)

b. RA=700N ; RB=810N

c. RA=710N ; RB=800N

d. RA=800N ; RB=710N

c

For any category airplane having a gross weight of 6,000 pounds or greater, the constant k value in determining the landing reaction is _____.

a. 0.23

b. 0.25

c. 0.33

d. 0.35

a

Normally designed to provide restraints against rotation and all translations; therefore, reactive forces and moments (reactions) are developed along the directions where movements are not permitted.

a. Fixed support

b. Hinge-roller support

c. Wedge support

d. Hinge support

b

The maximum anticipated load in the entire service life-span of a flight vehicle is called _____.

a. ultimate loads

b. limit loads

c. design loads

d. imposed loads

c

For the design maneuvering wing loading for aileron, the average surface loading is given by _____.

a. 0.566 (n₁w/s)

b. 0.534 (n₁w/s)

c. 0.466 (n₁w/s)

d. 0.366 (n₁w/s)

c

Without added oxygen, the time of useful consciousness at 25,000 feet is approximately _____.

a. twenty seconds

b. eighty seconds

c. three minutes

d. six minutes

d

Airspeed limitations are shown on the airspeed indicator (ASI) by color coding. Operation of an airplane in the yellow airspeed arc is for _____.

a. speed range between maximum structural cruising speed and VNE

b. smooth air only

c. only with caution

d. speed range between maximum structural cruising speed and VNE, smooth air and only with caution.

b

The calibrated power-off stalling speed or the minimum steady flight speed at which the aircraft is controllable in a specified configuration is designated by _____.

a. VS0

b. VS1

c. VFE

d. VNO

b

This type of wing vertical location is known to be the most aerodynamically streamlined.

a. High

b. Mid

c. Low

d. Parasol

a

It is a soft metal or plastic used to protect the airframe from damage caused by the cable system.

a. Fairlead

b. Gusset plates

c. Phenolic tape

d. Plastic lugs

d

The shear diagram on a certain portion of the beam intensifies from 0 N to 2,000 N. What is the bending moment experienced by this 3-feet portion?

a. 3,000 N-m

b. 6,000 N-m

c. 1,830 N-m

d. 915 N-m

d

Any deformable solid body which is capable of carrying loads and transmitting these loads to other parts of the body is referred to as ______.

a. bar elements

b. fuselage elements

c. shear panels

d. structural systems

a

The positive limit maneuvering load factor (+n) for utility category airplane shall not be less than ____.

a. 2.5

b. 3.8

c. 4.4

d. 6.0

d

Doors shall be designed to withstand an equivalent horizontal steady state wind of _____ knots while opening or closing.

a. 25

b. 30

c. 35

d. 40

a

The service ceiling of a Cessna 172 Skyhawk is 13,500 feet or _____ nautical miles.

a. 2.22

b. 2.56

c. 4.11

d. 5.76

d

A force of 525 N lies 105 degrees from the positive x-axis. What is the horizontal component of this force?

a. 507.111 N

b. 135.880 N

c. -135.88 lbf

d. -30.547 lbf

d

In the rectangular coordinate system, in what quadrant will you find the center of the circle with the equation x² + y² - 5x + (7y/3) = (511/18)?

a. First

b. Second

c. Third

d. Fourth

b

This tail design is sometimes referred to as "butterfly" tail.

a. Triple-tail

b. V-tail

c. Inverted-Y

d. Boom-tail

b

What is the length of the moment arm of a 40 Newton force producing a moment of 40 foot-pounds?

a. 1.00 feet

b. 1.36 meter

c. 1.00 meter

d. 4.45 meter

d

It is the maximum speed for structural design.

a. VA

b. VB

c. VC

d. VD

d

The stick force required by the elevator is _____.

a. 100 lbs

b. 150 lbs

c. 200 lbs

d. 250 lbs

c

This type of door closes from the inside to provide safety advantages for pressurized aircraft. The passenger entrance and service doors are examples of this type.

a. Stressed

b. Non-stressed

c. Plugged

d. Non-plugged