319 (City of Salford) Squadron Principles of Flight Leading
Cadet Training Resources Slide 2 319 (City of Salford) Squadron
Principles of Flight Learning Outcome 4: Be able to apply the
principles of flight and control to gliders Slide 3 319 (City of
Salford) Squadron REVISION Slide 4 319 (City of Salford) Squadron
Questions What happens to Lift when a Wing is Stalled? a.Lift
Increases as Angle of Attack Decreases. b.Lift Decreases as Angle
of Attack Increases. c.Lift is Greatly Reduced. d.Lift Remains
unchanged. Slide 5 319 (City of Salford) Squadron Questions The
Critical Angle of Attack is Generally about? a. 5 o. b.15 o. c.25
o. d.35 o. Slide 6 319 (City of Salford) Squadron Questions Which
of the following will NOT REDUCE the Stalling Speed? a.Extra
Weight. b.Larger Wing Area. c.Flaps Lowered. d.Flaps Raised. Slide
7 319 (City of Salford) Squadron GLIDING Slide 8 Gliding
Objectives: 1.List and describe the Forces acting on Glider during
balanced flight. 2.State the effect of Wind on the distance
travelled over the ground. 3.Explain the effects of Airbrakes on
Glide Performance. 4.Understand the Gliding Angle (Angle of
Attack). Slide 9 319 (City of Salford) Squadron The Glider
Previously we looked at the balance of forces acting on a powered
aircraft (Chapter 1 & 2) Now we will be looking at a glider,
which only has three forces acting, LIFT, WEIGHT and DRAG. The only
way to maintain airspeed in a glider is to remain slightly
nose-down. This uses the pull of gravity to drag the glider
forwards. The forces on a glider can be balanced also, just like in
a powered aircraft, and the glider can maintain its straight and
level flight this way. Slide 10 319 (City of Salford) Squadron The
Balance of Forces As has been mentioned, the glider has only three
forces acting: LIFT, WEIGHT & DRAG They balance as shown: As
you can see, the glide is slightly nose down to maintain airspeed.
The speed is generated by the pull of gravity downwards on the
weight of the aircraft Slide 11 319 (City of Salford) Squadron
Speed Just as a bike can coast down a hill without being peddled, a
glider can glide forwards without an engine. In order to keep going
(and avoid the stall) the pilot puts the nose of the glider
slightly down. To increase speed, the nose is reduced further, and
vice versa for decreasing the speed. Since there is no engine, and
the glider is always nose down, it is continually descending, hence
most gliders cannot stay airborne all day. Slide 12 319 (City of
Salford) Squadron How Far Can It Go? The distance a glider can
travel is related to its height and gliding angle. The higher the
glider is, and the shallower the angle, the longer it can stay
aloft for. A high glider with a deep angle may not be able to glide
as far as a low glider with a very shallow angle. The Lift/Drag
ratio also affects the distance a glider can travel. This will be
optimum at a particular angle, which will differ from glider to
glider by design differences. This information will be available in
the Pilots Notes. Slide 13 319 (City of Salford) Squadron How Far
Can It Go? Most modern gliders are quite efficient, and hence have
a very good Lift:Drag ratio and optimum gliding angle. The ATCs
Gliders, the Viking has a gliding angle of 1 in 35, so for every
1metre up, it can glide 35 metres in still air. Example: if the
glider was 1km (1000metres) up, it could glide for 35km before
landing. Slide 14 319 (City of Salford) Squadron Gliding Angle
Slide 15 319 (City of Salford) Squadron Effect of the Wind The wind
direction relative to the glider flight path will have an effect.
If travelling downwind (i.e. in the same direction as the wind) the
glider will travel further than id it is travelling upwind (towards
the wind). The wind slows down the aircraft going upwind, hence
more nose down angle is required to maintain airspeed, hence the
glide angle is increased, and the glider will be able to cover less
ground before it touches down. Slide 16 319 (City of Salford)
Squadron Effect of the Wind Example: A glider travelling at 35kts
into a head wind also of 35kts will appear not to move forwards,
but instead stay in one place and descend. Slide 17 319 (City of
Salford) Squadron Air Brakes Gliders do not have flaps as powered
aircraft do. Instead they make use of air brakes to have the same
effect. These are deployed from the upper and lower of the wings to
interrupt the airflow over the wing surfaces. The airbrakes are
deployed by the pilot on landing, and cause a huge increase in the
drag on the glider. Slide 18 319 (City of Salford) Squadron Air
Brakes This means a deeper angle is needed to being the glider in,
hence it looses more height faster. This allows the glider to land
in a much smaller space, as we have said, a Viking at 1m would
require 35m of runway in order to land, and thats without the
distance to slow down! Slide 19 319 (City of Salford) Squadron Any
Questions? Slide 20 Gliding Objectives: 1.List and describe the
Forces acting on Glider during balanced flight. 2.State the effect
of Wind on the distance travelled over the ground. 3.Explain the
effects of Airbrakes on Glide Performance. 4.Understand the Gliding
Angle (Angle of Attack). Slide 21 319 (City of Salford) Squadron
Questions Name the Forces Acting on a Glider in Normal Flight. a.
Force, Weight and Lift. b. Drag, Weight and Thrust. c.Drag, Weight
and Lift. d.Drag, Thrust and Lift. Slide 22 319 (City of Salford)
Squadron Questions How does a Glider Pilot Increase the Airspeed?
a. Operate the Airbrakes. b. Lower the Nose by pushing the Stick
Forward. c.Raise the Nose by pulling the Stick Back. d.Lower the
Nose by pulling the Stick Back. Slide 23 319 (City of Salford)
Squadron Questions A Viking Glider with a glide ratio of 1:35
descends from 1640 ft (0.5 km). How far over the ground does it
Travel (in still air)? a. 17.5 kms. b. 35 kms. c.70 kms. d.8.75
kms. Slide 24 319 (City of Salford) Squadron Questions When flying
into a Headwind, the distance covered over the ground will: a. Be
the same. b. Decrease. c. Increase. d. Take you to Burger King.
Slide 25 319 (City of Salford) Squadron
