1. THDC Institute of Hydropower Engineering AND
TECHNOLOGY
GYROSCOPE
Submitted By:
Poonam Bhandari
M.E. 3rd year
140970104035
2. GYROSCOPE :
• What is gyroscope
• Vectorial representation of angular motion,
• Gyroscopic couple
• Effect of gyroscopic couple on aero plane
• Effect of gyroscopic couple on ship
• stability of two wheelers and four wheelers
3. WHAT IS GYROSCOPE
• A gyroscope is a device for
measuring or maintaining
orientation, based on the principles
of angular momentum.
• A mechanical gyroscope is
essentially a spinning wheel or
disk whose axle is free to take any
orientation. This orientation
changes much less in response to
a given external torque than it
would without the large angular
momentum associated with the
gyroscope's high rate of spin.
4. We know that the angular acceleration is the rate of change of angular
velocity with respect to time.
It is a vector quantity and may be represented by drawing a vector
diagram with the help of right hand screw rule.
PRECESSIONAL ANGULAR MOTION
(Vectorial representation of angular motion)
8. Case (i): PROPELLER rotates in CLOCKWISE direction when seen
from rear end and Aeroplane turns towards LEFT
9. • According to the analysis, the reactive
gyroscopic couple tends to dip the tail
and raise the nose of aeroplane.
10. Case (ii): PROPELLER rotates in CLOCKWISE direction when seen
from rear end and Aeroplane turns towards RIGHT
11. • According to the analysis, the reactive gyroscopic couple tends to raise the
tail and dip the nose of aeroplane.
12. Case (iii): PROPELLER rotates in ANTICLOCKWISE direction when seen
from rear end and Aeroplane turns towards LEFT
13. • According to the analysis, the reactive gyroscopic couple tends to raise the tail and
dip the nose of aeroplane
14. Case (iv): PROPELLER rotates in ANTICLOCKWISE direction when
seen from rear end and Aeroplane turns towards RIGHT
15. • The analysis shows, the reactive gyroscopic couple tends to raise the tail
and dip the
nose of aeroplane
16. Gyroscope is used for stabilization and directional control of
a ship sailing in the
rough sea. A ship, while navigating in the rough sea, may
experience the following three
different types of motion:
(i) Steering—The turning of ship in a curve while moving
forward
(ii) Pitching—The movement of the ship up and down from
horizontal position in a
vertical plane about transverse axis
(iii)Rolling—Sideway motion of the ship about longitudinal
axis.
17. Ship Terminology
• (i) Bow – It is the fore end of ship
• (ii) Stern – It is the rear end of ship
• (iii) Starboard – It is the right hand side of the ship looking in the direction of
motion
• (iv) Port – It is the left hand side of the ship looking in the direction of motion
18. Gyroscopic effect on Steering of ship
(i) Left turn with clockwise rotor
When ship takes a left turn and the rotor rotates in clockwise direction
viewed from
stern, the gyroscopic couple act on the ship is analyzed in the following way.
19. • From the above analysis, the couple acts over the ship between stern and
bow. This reaction couple tends to raise the front end (bow) and lower the
rear end (stern) of the ship
20. (ii) Right turn with clockwise rotor
• When ship takes a right turn and the rotor rotates in clockwise direction viewed
• from stern
21. • the couple acts in vertical plane, means between stern and
bow. Now the reaction couple tends to lower the bow of the
ship and raise the stern.
22. (iii) Left turn with anticlockwise rotor
• When ship takes a left turn and the rotor rotates in anticlockwise
direction viewed
from stern
23. The couple acts over the ship is between stern and bow. This reaction
couple tends to press or dip the front end (bow) and raise the rear end
(stern) of the ship.
24. (iv) Right turn with anticlockwise rotor
• When ship takes a right turn and the rotor rotates in anticlockwise
direction viewed from stern
25. the gyroscopic couple act on the ship is according to Fig 20. Now, the
reaction couple tends to raise the bow of the ship and dip the stern.
26. GYROSCOPIC EFFECT ON PITCHING OF SHIP
• The pitching motion of a ship generally occurs due to waves which can be
approximated as sine wave. During pitching, the ship moves up and down
from
horizontal position in vertical plane
27. Gyroscopic effect on Rolling of ship.
The axis of the rotor of a ship is mounted along the longitudinal axis of ship
and
therefore, there is no precession of this axis. Thus, no effect of gyroscopic
couple on the ship
frame is formed when the ship rolls
28. Stability of Four Wheeled Vehicle negotiating a turn.
Stable condition Unstable Condition
29. Stability of a Four Wheel Drive Moving in a Curved
Path• Consider the four wheels A, B, C and D of an
automobile locomotive taking a turn towards
left as shown in Fig.
• The wheels A and C are inner wheels, whereas B
and D are outer wheels. The centre of gravity
(C.G.) of the vehicle lies vertically above the road
surface.
30. • A little consideration will show, that the
weight of the vehicle (W) will be
equally distributed over the four wheels
which will act downwards.
• The reaction between each wheel and the
road surface of the same magnitude will act
upwards.
• Therefore Road reaction over each wheel, =
W/4 = m.g /4 newtons
31. Let us now consider the effect of the gyroscopic couple and centrifugal couple on the
vehicle.
The positive sign is used when the wheels and rotating parts of the engine rotate in the
same direction. If the rotating parts of the engine revolves in opposite direction, then
negative sign is used.
32. Fig. shows a two wheeler
vehicle taking left turn over a
curved path. The vehicle is
inclined to the vertical for
equilibrium by an angle θ
known as angle of heel.
Let
m = Mass of the vehicle and its rider in kg,
W = Weight of the vehicle and its rider in
newtons = m.g,
h = Height of the centre of gravity of the
vehicle and rider,
rW = Radius of the wheels,
R = Radius of track or curvature,
IW = Mass moment of inertia of each
wheel,
IE = Mass moment of inertia of the rotating
parts of the engine,
ωW = Angular velocity of the wheels,
ωE = Angular velocity of the engine
rotating parts,
G = Gear ratio = ωE / ωW,
v = Linear velocity of the vehicle = ωW ×
rW,
θ = Angle of heel. It is inclination of the
vehicle to the vertical for equilibrium
33.
34. It is observed that, when the wheels move over the curved path, the vehicle is
always inclined at an angle θ with the vertical plane as shown in Fig. This
angle is known as ‘angle of heel’.
Gyroscopic Couple,
Note: When the engine is rotating in the same direction as that of wheels,
then the positive
sign is used in the above equation. However, if the engine rotates in
opposite direction to
wheels, then negative sign is used.
