1. Chapter 2 – Thrust and Drag
Principles of Flight
Chapter 2 – Thrust and Drag

2. Thrust and Drag To generate lift the wing must travel through the air
So we need thrust.
But the faster you go the more drag is generated which hinders your progress

3. Drag
To reduce drag an aircraft must be streamlined

4. Streamlining + Variation of Drag
Streamlined shapes should have a fineness ratio of 3-4 to 1
The amount of drag varies with the square of the airspeed
2 x Airspeed = 4 x Drag
3x Airspeed = 9 x Drag

5. Thrust and Drag in Balance
If Thrust is greater than drag aircraft speeds up
If Thrust is less than drag aircraft slows down
If thrust and drag are equal aircraft’s speed stays constant

6. Aircraft in Balance
If all the forces (Weight, Lift, Drag and Thrust are equal the aircraft will stay level at a constant speed.