Structures and Design Conceptual Questions (Mock Exams)

Low induced drag can be obtained by using:

a. High wing aspect ratio

b. Low wing aspect ratio

c. Constant wing chord

d. Constant wing area

A

Rate of descent can be minimized when:

a. Parasite drag equals induced drag

b. Parasite drag equals one-third induced drag

c. Parasite drag equals there times the induced drag

d. Parasite drag is greater than the induced drag

B

Which is not one of the characteristics of a high wing arrangement?

a. Has minimum interference drag

b. Allows a continuous structural path for the wing spar box

c. Provides for a good downward visibility

d. Offers highest aerodynamic efficiency

A

If the aircraft is operated in steady flight at maximum lift/drag ratio, the total drag

a. equals three times the induced drag

b. equals four times the parasite drag

c. equal two times the parasite drag

d. equals induced drag

C

The angle of attack of a two dimensional wing section is the angle between:

a. the fuselage core line and the free stream direction

b. the chord line and the camber line of the airfoil

c. the chord line of the airfoil and the free stream direction

d. the chord line of the airfoil and the fuselage center line

C

The power available is obtained by

a. multiplying the drag by the airspeed

b. dividing the drag by the airspeed

c. multiplying the brake horsepower by the propeller efficiency

d. dividing the brake horsepower by the propeller efficiency

C

The speed for best climb angle is called:

a. Vo

b. VY

c. VX

d. V2

C

The major items considered by the designer may be summarized as follows:

1. Load required to be carried

2. Performance and other aerodynamic requirements

3. Type of material, structural and general arrangement

4. Weight

5. Powerplant

For the items enumerated above, which item or items cause the most trouble to designer?

a. 1 and 3

b. 2 and 4

c. 5

d.4

D

What are the four basic forms of deformation of solid bodies?

a. Tension, compression, bending and twisting

b. Tension, compression, elongation and bending

c. Tension, compression, plastic and elastic

d. Tension, compression, elongation and torsion

A

What is the ratio of the transverse strain to the corresponding axial strain in a body subjected to uniaxial stress?

a. Poisson's Ratio

b. Euler's Ratio

c. Refractive Index

d. Dielectric Index

A

What is a structural member supported horizontally and carries transverse loading?

A. Beam

B. Column

c. Arch

d. Shaft

A

Volumetric strain is the:

a. change in volume per unit time

b. square root of the difference of the original volume and change in volume

c. original volume minus change in volume

d. ratio of change in volume to the original volume

D

Within the elastic limit, the shear stress is proportional to shear strain. What is the constant of proportionality of this statement called?

a. Modulus of rigidity

b. Modulus of Elasticity

c. Young's modulus

d. Bulk modulus

A

The ratio of moment of inertia of a circular plate and that of a square plate for equal depth, is

a. equal to 3π/16

b. more than one

c. less than one

d. equal to one

A

An isolated drawing of a particle which shows all forces that act on it

a. Shear and bending moment diagram

b. Free-body diagram

c. Method of section

d. Method of joints

B

Match each force or couple (A-D) with the deformation it would cause when applied to a bar (a-d)

~

A. Normal Force

B. Shear Force

C. Torque

D. Bending Moment

a. Slides one bar segment relative to another

b. bends the bar

c. Elongates or shortens the bar

d. Twist the bar

~

a. A - a; B - d; C - c; D - b

b. A - c; B - d; C - a; D - b

c.A - c; B - a; C - d; D - b

d. A - a; B - c; C - d; D - b

C

What is the maximum moment of a beam supported at both ends and carries a uniform load of w throughout its entire length?

a. wL/2

b. wL/8

c. wL²/8

d. wL²/4

C

The shear stress at any section of a shaft is maximum

a. at the center of the section

b. at the top of the surface

c. at a distance r/2 from the center

d. at a distance 3/4 r from the center

B

The ratio of strengths of solid to hollow shafts, both having outside diameter D and hollow having inside diameter D/2, in torsion is

a. 1/4

b. 1/2

c. 1/16

d. 15/16

D

Is the stress beyond which the material will not return to its original shape when unloaded but will retain a permanent deformation

a. Elastic limit

b. Proportional Limit

c. Yield Limit

d. Yield Strength

D

A common wing design structure especially for large commercial aircraft that uses the wing as fuel storage.

(a) dry wing design

(b) fuel wing design

(c) wet wing design

(d) central fuel storage

C

Are kinds of designs that incorporate various techniques to mitigate losses due to system or component failures which includes redundancy and multiple load paths?

(a) fail safe design

(b) fail proof design

(c) safe life

(d) reliable design

A

Which of the following is not a primary control surface?

(a) Aileron

(b) Elevators

(c) Flaps

(d) Rudder

C

In aircraft zoning, zone 400 is?

(a) Left wing

(b) Right wing

(c) Engine

(d) Doors

C

Which of the following statement is true

(a) during straight level unaccelerated flight lift = drag.

(b) during straight level unaccelerated flight lift = thrust.

(c) during straight level unaccelerated flight lift = weight.

(d) all forces are equal.

C

It is the ability of an aircraft to maintain its flight path without the help or being controlled by the pilot.

(a) stability

(b) maneuverability

(c) controllability

(d) operability

A

It is type of deformation in which the material does not anymore return to its original shape.

(a) plastic deformation

(b) yield deformation

(c) elastic deformation

(d) fracture

B

In the stress strain diagram, the constant of proportionality E stands for?

(a) Hooke's Law

(b) Modulus of Rigidity

(c) Modulus of Turbidity

(d) Young's Modulus

D

Which of the following category is not covered by FAR Part 23?

(a) Normal

(b) Utility

(c) Commuter

(d) Transport

D

It is a rotational force produced on an axis by a linear force applied at a distance away from the axis.

(a) Inertia

(b) Equilibrium

(c) Moment

(d) Couples

C

Which of the following is not an advantage of conventional landing gear arrangement?

(a) good pilot field of view

(b) lighter than modern design

(c) better propeller clearance

(d) automatic positive angle of attack

A

It reduces the force required to move the primary control surfaces.

(a) Servo Tab

(b) Trim Tab

(c) Anti-servo tab

d) FBW

B

States that the moment of the resultant is equivalent to the moment sum of its components

(a) State postulate

(b) Pascal's principle

(c) Varignon's Theorem

(d) Hooke's Law

C

The CG of a helicopter is ideally located at?

(a) Aft location of its Main rotor hub

(b) Directly in the line of axis of the hub

(c) forward the hub

(d) near the tail

B

A given truss structure had been found to have three unknowns, which of the following best describes the solution.

(a) the problem is unsolvable

(b) we must make 3 independent equations

(c) use method of joint

(d) It is a type of indeterminate structure

B

It is the measure of the intensity of an internal load acting on a cross section of an object.

(a) force

(b) stress

(c) strain

(d) pressure

B

It is the ratio of the lateral to the longitudinal deformation.

(a) Euler's ratio

(b) stress to strain ratio

(c) Poisson's ratio

(d) fines ratio

C

A design having their elevators in ahead of the wings and at the same time contributes to lift.

(a) Sweptback design

(b) swept front design

(c) Control Canard

(d) lifting canard

D

A type of design that uses skin as the primary source of structural strength.

(a) monocoque

(b) semi-monocoque

(c) cantilever

(d) semi-cantilever

A

The primary purpose of wing dihedral is to improve?

(a) longitudinal stability

(b) lateral stability

(c) vertical stability

(d) overall stability

B

During take-off roll V1 stands for?

(a) initial speed

(b) take off speed

(c) decision speed

(d) cruise speed

C

In biplane wing design, stagger means?

(a) longitudinal offset of the two wings relative to each other

(b) lateral offset of the two wings relative to each other

(c) vertical offset of the two wings relative to each other

(d) angle between two wings relative to each other

A

In biplane wing design, decalage means.

(a) longitudinal offset of the two wings relative to each other

(b) lateral offset of the two wings relative to each other

(c) vertical offset of the two wings relative to each other

(d) angle between two wings relative to each other

D

Which of the following wing geometry and/or design is best to reduce the adverse effect of supersonic and transonic flow.

(a) wing dihedral

(b) swept back

(c) anhedral

(d) taper

B

Under FAR part 23, the Gust velocity at 50,000 ft is?

(a) 20 fps

(b) 25 fps

(c) 15 fps

(d) 30 fps

B

One way of reducing radar detection in most military aircraft is?

(a) reducing RCS

(b) Flying at higher altitudes

(c) using composite materials

(d) using enamel paints

A

The CG of an aircraft must be located at?

(a) Aft of its Center of pressure

(b) forward of its center of pressure

(c) aft of the aerodynamic center

(d) forward the aerodynamic center

D

It is the engine whose failure would most adversely affect the performance or handling abilities of an aircraft.

(a) engine inoperative

(b) left engine

(c) critical engine

(d) ETOPs

C

It is also known as asymmetric blade effect.

(a) critical mass effect

(b) P-factor

(c) C-Factor

(d) engine inoperative

B

A wing design of monoplane where it is raised clear above the top of the fuselage.

(a) mid wing

(b) sesquiplane

(c) parasol

(d) inverted parasol

C

Vmu stands for?

(a) maximum unstick speed

(b) minimum unstick speed

(c) maximum upturn speed

(d) minimum upturn speed

B

The most efficient way to create lift on a fixed wing is to use?

(a) wing taper

(b) wing tip

(c) elliptical wing

(d) vortex generator

C

To counter torque of the helicopter main rotors, the following design can be used except?

(a) tail rotor

(b) tandem rotor

(c) coaxial rotor

(d) meshing rotor

D

VS0 stands for

(a) stalling speed clean configuration

(b) stalling speed landing configuration

(c) stalling speed specific configuration

(d) minimum landing speed

B

VY stands for?

(a) best rate of climb speed

(b) best angle of attack speed

(c) best angle of climb speed

(d) best landing speed

A

ATA 28 is?

(a) Hydraulic Power

(b) Fuel

(c) Flight Controls

(d) Landing gears

B

The Federal Aviation Regulations are under what CFR?

(a) 12 CFR

(b) 14 CFR

(c) 15 CFR

(d) 13 CFR

B

One way of reducing radius of turn is to?

(a) increase airspeed

(b) increase bank angle

(c) decrease bank angle

(d) increase thrust

B

The maximum take-off weight of commuter category under FAR 23 is?

(a) 12,500 lbs

(b) 19,000 lbs

(c) 22,000 lbs

(d) 17,500 lbs

B

One hand fire extinguisher must be located on the following except?

(a) pilot compartment

(b) galley

(c) lavatory

(d) baggage compartment

D

The following are phases of design except?

(a) conceptual

(b) preliminary

(c) detailed

(d) specific

D

It is an axis in the cross section of a beam (a member resisting bending) or shaft along which there are no longitudinal stresses or strains.

(a) axial axis

(b) neutral axis

(c) lateral axis

(d) vertical axis

B

Structural members designed to support loadings applied perpendicular to their axes. They are long, straight bars having a constant cross-sectional area.

a. Shafts

b. Plates

c. Beams

d. Bulkhead

C

The test pilot of a design airplane observed that if the airplane is acted upon by a strong updraft, the

airplane oscillates vertically. The airplane is:

a. Dynamically stable

b. Statically stable

c. Statically and dynamically unstable

d. Statically and dynamically stable

B

For a given aircraft at a given condition, the limit load is constant. The ultimate load is dictated by the factor of safety. Choose which of the following statements are CORRECT in relation to the factor of safety and ultimate load.

a. As the factor of safety increases, the ultimate load decreases.

b. As the ultimate load increases, the factor of safety decreases.

c. As the factor of safety increases, the ultimate load increases.

d. The factor of safety is constant at 1.5 therefore, ultimate load is also constant.

C

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

a. Fixed support

b. Hinge support

c. Roller support

d. Wedge support

A

It is a structure composed of slender members joined together at their end points, in which the members are subjected to only axial loads.

a. Beam structure

b. Monocoque structure

c. Semi-monocoque structure

d. Truss structure

D

It is a measure of the intensity of load acting on a definite plane passing through a given point in the

material.

a. Shear

b. Torque

c. Stress

d. Strain

C

The axial strain in a member is always accompanied by a lateral strain of opposite sign. Thus, if a member stretches under load, its cross-sectional area becomes smaller at the same time. The relationship of the lateral strain to axial strain is expressed by:

a. Modulus ratio

b. Stress-strain relationship

c. Hooke's Law

d. Poisson's Ratio

D

A transverse load on a member tends to make the member rotate about an axis at a section away from that where the load is applied and normal to the axis of the member. If the member is restrained from rotating at any section other than that at which the load is applied, internal tension stresses are set up at one side of the member and compression at the other. At any section where such stresses are present the member is said to be subjected to:

a. Torsion

b. Shear

c. Bending

d. Compression

C

If loads are applied to a member so that it tends to twist about an axis, internal shear stresses are set up in the member at any section between the application of load and the reaction to resist the twisting force. In such a case the member is said to be subjected to:

a. Torsion

b. Shear

c. Bending

d. Compression

A

The ratio of shear stress to strain below the proportional limit is called shear modulus of elasticity or:

a. Poisson's Ratio

b. Stress-strain relationship

c. Modulus ratio

d. Modulus of rigidity

D

The total moment due to internal stresses of a shaft or tube is equal in magnitude to the external torque, and is given by the equation,

T = (GΘ/L)∫r²dA

The quantity ∫r²dA is known as the:

a. Polar moment of inertia

b. Radius of gravitation

c. Moment of inertia about a base

d. Product of inertia about inclined axis through a centroid

A

The maximum anticipated loads in the entire service life-span of a flight vehicle is called:

a. Ultimate loads

b. Limit loads

c. Design loads

d. Imposed loads

B

This condition is obtained in a pullout at the highest possible angle of attack of the wing. The lift and drag forces are perpendicular and parallel respectively to the relative wind.

a. Positive low angle of attack

b. Positive high angle of attack

c. Negative low angle of attack

d. Negative high angle of attack

B

This condition occurs at the diving speed limit of the airplane, it may occur in an intentional maneuver producing negative load factor or negative gust condition.

a. Negative low angle of attack

b. Negative high angle of attack

c. Positive low angle of attack

d. Positive high angle of attack

A

When a load is applied to a member normal to its axis and the member is held fixed at another section, at any section between the load and reaction the particles on one side of the section tend to move in a transverse direction with respect to the other side; that is, they tend to slide by each other. This set up internal stresses in the member called:

a. Shear stress

b. Bending stress

c. Torsional stress

d. Tensile stress

A

The swept back wing design is primarily intended to increase the critical Mach number of a supersonic

aircraft but also useful in:

a. Reducing induced drag

b. Increasing directional stability

c. Improving L/D ratio

d. Reduce parasite drag

B

Where is the buttock line or buttline of an aircraft?

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

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

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

d. none of the choice

A

Where is fuselage station No. 137 located?

a. 137 centimeters aft of the nose or fixed reference line

b. aft of engine

c. 137 inches aft of the zero or fixed reference line

d. 137 inches aft of the engine firewall

C

Which statement is true regarding a cantilever wing?

a. No external bracing is needed.

b. It has nonadjustable lift struts.

c. It requires only one lift strut on each side.

d. all of the choices

A

Buffeting is the intermittent application of forces to a part of an airplane. It is caused by_______.

a. incorrect rigging of flaps

b. incorrect rigging of ailerons

c. an unsteady flow from turbulence

d. all of the choices

C

Longitudinal (fore and aft) structural members of a semi-monocoque fuselage are called___.

a. spars and ribs

b. spars and stringers

c. longerons and stringers

d. bulkhead and formers

C

What of type loads causes the most rivet failures?

a. bearing

b. shearing

c. head

d. strain

B

What physical factors are involved in the aspect ratio of airplane wings?

a. thickness and chord

b. dihedral angle and angle of attack

c. span and chord

d. area and thickness

C

An airplane's center of lift is usually located aft of its center of gravity _______.

a. so that the airplane will have a tail-heavy tendency

b. to improve stability about the longitudinal axis

c. so that the airplane will have a nose-heavy tendency

d. to induce poor static stability

B

A well-designed rivet joint will subject the rivets to______.

a. compressive loads

b. tension loads

c. shear loads

d. bearing loads

C

What one major consideration in selecting an airfoil to be used for the tailplane design of an aircraft?

a. lift curve slope

b. zero-lift angle of attack

c. maximum lift coefficient

d. minimum drag coefficient

A

As a rule of thumb in designing an aircraft, the designer must not allow ___________.

a. the left wing to stall first

b. the canard wing to stall late

c. the rear wing or tail to stall first

d. the vertical stabilizer to stall only

C

The monocoque fuselage relies largely on the strength of

a. longerons and formers

b. bulkheads and longerons

c. skin or covering

d. all of the choices

C

FAR part 23 is the airworthiness standards for __________.

a. normal, utility, commuter & acrobatic category airplanes

b. normal & sport category airplanes

c. commuter, transport & special category airplanes

d. acrobatic category airplanes

A

The velocity-load factor diagram is also known as the ________.

a. flight limits

b. flight envelope

c. flight operations minimums

d. aircraft diagram

B

This type of emergency exit has the following characteristics: a rectangular opening not less than 24 in wide by 48 in high with corner radii not greater than one third the width of the exit. This type of exit is located on each side of the fuselage at the aft portion of passenger compartment unless configuration of the airplane is such that some other location would afford a more effective means of evacuation. This type of exit is at floor-level.

a. Type III

b. Type II

c. Type IV

d. Type I

D

When an airplane is designed to carry 140 to 179 passengers, it must be equipped with ___________ of emergency exits.

a. 1 Type IV and 1 Type III

b. 2 Type I and 2 Type III

c. 2 Type I and 1 Type III

d. 2 Type II and 1 Type IV

B

A piece of formed sheet metal or extrusion riveted to a larger piece of thin sheet metal to give it rigidity

and stiffness.

a. spar

b. strut

c. stiffener

d. bulkhead

C

Structural members designed to support loadings applied perpendicular to their axes. They are long, straight bars having a constant cross-sectional area.

a. Shafts

b. Plates

c. Beams

d. Bulkhead

C

Members which are loaded so that they are compressed axially and therefore have developed within them compressive resistances or stresses.

a. Beams

b. Columns

c. Shafts

d. Trusses

A

What physical factors are involved in the aspect ratio of airplane wings?

a. thickness and chord

b. span and chord

c. dihedral angle and angle of attack

d. area and thickness

B

Which of the following are the phases of aircraft design in the right order?

a. initial, secondary, final

b. conceptual, preliminary, detail

c. conceptual, preliminary, final

d. preliminary, conceptual, detail

B

Which of the following is a performance requirement?

a. ceiling

b. maximum take-off weight

c. cost of material

d. wing span

A