Briefing: Sailplane Familiarisation

Introduction

Aim: To introduce you to the terminology and basics of flight, before going to look at a glider for the first time.

What do we know?

  • Who has experience of flying?
  • What would you like to know about gliders before getting into one?
Parts of a Glider

The Cockpit, Instruments and Controls

What effect do the controls have?
Principles of Flight – the Basics
How a wing works

Gliders are (almost) always descending through the air, but do so very efficiently. A little descent allows a lot of forward movement. This is often illustrated as airflow over and under the wing.

The result of this ‘airflow’ around the wing’s aerofoil is:

  • Low pressure above the wing
  • High pressure below the wing
  • A deflection of the air downwards

The net result is a force upwards: Lift

Some Terminology
Altering Lift

The amount of lift generated varies by changing

  • The angle of attack
  • The speed of the airflow

How the controls work (Pitch, Roll, Yaw)

  • The Wings, Tailplane, and Fin all have an aerofoil.
  • The aerofoil of the Tailplane and the Fin are symmetrical, so when in a neutral setting, they act only to stabilise the glider, and do not generate ‘lift’.
Illustration
  • The Control Surfaces are moved by the stick and rudder pedals to change these aerofoils, creating:
    • a vertical force at the ailerons
    • a vertical force at the elevator
    • a sideways force at the rudder.

Elevator – Pitch

  • Stick forward…
  • Elevator goes down,
  • generating an upward force.
  • The nose of the glider goes down.
  • And vice versa.

Ailerons – Roll

  • Stick moved to the left…
  • Left aileron goes up and right aileron goes down.
  • The right wing generates more lift and the left wing generates less lift.
  • The glider rolls to the left.
  • And vice versa.

Rudder – Yaw

  • Left pedal forward…
  • Rudder moves left,
  • generating a sideways force to the right.
  • The nose of the glider yaws left.
  • And vice versa.

The Centre of Gravity… and why weight matters!

  • The Centre of Gravity is the point on which the glider would balance (fore and aft)

The CoG must be within a pre-defined range for the elevator to be effective.

The CoG position is affected by the weight of the pilots. Add ballast weights if necessary.

CoG affects Pitch Stability

  • Heavy Pilots move the CoG forwards: the glider may be unrecoverable from a dive.
  • Light Pilots move CoG backwards: the glider will be prone to spinning.
Canopy Handling

  • Fragile and Expensive
  • Cleaning and Touching
  • Handling Points
  • Opening & Closing
  • Always have someone responsible for it: “My canopy”
  • Comply with local procedures for leaving a glider unattended: e.g. right wing down
Glider Handling

  • Wooden gliders have Strong Points
  • Holding a Wing
Let’s look at a Glider (Walk-round)

  • Construction (GRP vs “Wood”)
  • Handling Points
  • Parts & Control Surfaces
  • Canopy
  • Ingress & Egress
  • Harness: Fit & Adjustment
  • Instruments
  • FLARM
The Parachute

  • Inspection
  • Handling
  • Donning & Doffing
  • Bailing Out
  • Operating & Landing
Recap
  • How does a glider fly?
  • Why does the weight of the pilot(s) matter?
  • Which part(s) of a glider should you use to move it?
  • Which parts should never be touched?
  • Must you always wear a parachute?
TEM
  • Lack of familiarity may cause incidents: if in doubt, ask.
  • Ergonomics: take time to adjust the pedals, cushions, harness and straps so you are comfortable, and can reach everything.