# Aircraft Design MCQ – Landing Gear – Shock Absorbers

1 - Question

What is the function of the undercarriage?
a) To absorb the shock during landing
b) To provide lift
c) To increase lift at landing
d) To carry cargo at airport
Explanation: Undercarriage should absorb the shock or impact during landing and make ride smooth during taxiing. Lift is primarily generated by wings. Lift can be increased by high lift devices. Cargo container is used to carry cargo.

2 - Question

A typical glider will solely rely on tires for shock absorption.
a) True
b) False
Explanation: Typically, tires can provide some shock absorbing characteristics by deflection. Gliders or sail planes are built with rigid axles typically. Hence, they solely rely upon the tires for shock absorption. Hence, the correct answer will be true.

3 - Question

Which of the following is an example of a shock absorber?
a) Solid spring shock arrangement
b) Lift curve slope
c) Flap
d) Elevator
Explanation: Solid spring shock arrangement is an example of shock absorber. Lift curve slope is defined as change in lift by change in alpha. Flap is secondary control surface.

4 - Question

Which of the following is correct?
a) Solid spring shock absorber is heavier than the other types
b) Lift to drag ratio is always unity
c) Weight at takeoff is same as weight at landing
d) Thrust is same as drag always
Explanation: Solid spring shock absorber is heavier than the other types Lift to drag is not necessarily be unit always. Typically, a good design will have lift to drag ratio more than 1. During flight weight decreases and as a result takeoff weight and weight during landing will not be same.

5 - Question

Which of the following is correct?
a) The solid spring year deflects with some lateral motion
b) Lift is always same as weight
c) Drag polar shows lift variation with velocity
Explanation: Some lateral motion can be observed when we deflect solid spring. Lift is same as weight during cruise. Drag polar does not show lift variation with velocity. Thrust loading is ratio of Thrust and weight which cannot be same as lift.

6 - Question

Which type of shock absorber is most widely used nowadays?
a) Oleo
b) Signal beam type
c) Aurora beam type
d) Longerons type always
Explanation: Oleo type shock absorber is widely used shock absorber. Longerons are structural elements of the aircraft. They are straight and heavy. They are lesser in number and opposes the bending.

7 - Question

Following diagram represents ____________ a) simple oleo schematic
b) drag polar
c) wheel base distance only
d) wheel track only
Explanation: A typical oleo mechanism is shown in the diagram. Simple oleo system has been illustrated in the figure. Drag polar is graphical representation of drag characteristics. Wheel track and base distance are related to wheel terminology not to shock absorber.

8 - Question

Stroke of a shock absorber is defined as _________
a) required deflection of the shock absorbing system
b) lift required at takeoff
c) length of crank shaft of engine
d) piston distance travelled inside engine
Explanation: Stroke of absorber can be defined as the required deflection of the shock absorbing system. Stroke of the shock absorber depends upon number of factors such as shock absorbing material etc. Lift required at takeoff will be more than its weight.

9 - Question

If an aircraft has sink speed at touchdown as 9 ft/s then, find the stroke in inches approximately.
a) 9 in
b) 19 in
c) 1 in
d) 2 in
Explanation: Given, sink speed = 9 fps. Required stroke in inch = vertical or sink speed = 9 inch.

10 - Question

If a tire has diameter of 18 in and rolling radius of 6 in then, what will be the approximate value of stroke of the tire?
a) 3 in
b) 4 in
c) 5 in
d) 8 in
Explanation: Stroke = (diameter/2) – rolling radius = (18/2) – 6 = 9 – 6 = 3 in.

11 - Question

Determine the gear load factor if landing weight is 250 unit and average total load during deflection is 550 unit.
a) 2.2
b) 4
c) 4.5
d) 8.9
Explanation: Load factor is given by, Load factor N = average load/ weight during landing = 550/250 = 2.2.

12 - Question

An oleo is used as shock absorber in an aircraft. Determine at which external diameter we should design oleo if load on the oleo is 100 pounds.
a) 0.4 unit
b) 0.9 unit
c) 2.9 unit
d) 3.4 unit
Explanation: Diameter of oleo d = 0.04*(length of oleo)0.5 = 0.04*(100)0.5 = 0.4 unit.

13 - Question

If an aircraft has gear load factor of 3 and average total load during deflection is 180 unit then, find how much weight is carried during landing.
a) 60 unit
b) 10 unit
c) 100 unit
d) 283 unit
Explanation: Weight during landing W = load L / gear load factor = 180/3 = 60 unit.

14 - Question

f piston diameter of an oleo system is given by 20 unit then, find the approximate value of typical external diameter of the same oleo system.
a) 26 unit
b) 10 unit
c) 50 unit
d) 200 unit
Explanation: Approximate value of external diameter can be given by, D = piston diameter + 0.3* piston diameter = 20 + 0.3*20 = 26 unit.

15 - Question

Stroke depends on ___________
a) vertical velocity at touchdown
b) vertical velocity at climb
c) rate of climb
d) lift by wing at cruise