Slide for student who want to take EASA part66 exam Other note you can get at http://part66.blogspot.com

1. 8.3 THEORY OF FLIGHT
www.part66.blogspot.com

2. FORCES ACTING ON AIRCRAFT IN
THRUST FLIGHT
• The aircraft’s propelling force LIFT
• Arranged symmetrically to the Acts at right angle to the line of
centre line flight & through the Centre of
• Act parallel to the line of flight Pressure of the wings
DRAG
• Opposes the forward motion
WEIGHT@ GRAVITY • Regarded as a rearward acting
Acts vertically downwards through force
the Centre of Gravity
FORCES ACTING ON AIRCRAFT IN FLIGHT

3. FORCES ACTING ON AIRCRAFT IN
FLIGHT
• An aircraft flying at constant height and speed
LIFT = WEIGHT
THRUST = DRAG
• Under these condition
i. Angle of attack altered to adjust the production of lift
exactly equals the weight which it must support
ii. Engine thrust set to exactly equal the aircraft drag
generated at that particular speed
FORCES ACTING ON AIRCRAFT IN FLIGHT

4. Arrangement of forces
• Lift = Weight and Thrust = Drag
 Aircraft tend to rotate nose up or nose down if the forces line
of action not correctly arranged
 Proper arrangement of the forces (depends on aircraft design)
i. Centre of pressure aft of centre of gravity  nose
down
ii. Thrust line below drag line  nose up
FORCES ACTING ON AIRCRAFT IN FLIGHT

5. Arrangement of forces
LIFT
WEIGHT
LIFT and WEIGHT = nose down couple
FORCES ACTING ON AIRCRAFT IN FLIGHT

6. Arrangement of forces
THRUST and DRAG = nose up couple
DRAG THRUST
FORCES ACTING ON AIRCRAFT IN FLIGHT

7. Arrangement of forces
THRUST and DRAG = nose up couple
LIFT
DRAG THRUST
WEIGHT
LIFT and WEIGHT = nose down couple
FORCES ACTING ON AIRCRAFT IN FLIGHT

8. GLIDE
• Condition aircraft with no thrust from engine
• Glide ratio distance covered to hight lost
• Highest Lift/Drag ratio give maximun distance
by flying with minimunm drag

9. FLIGHT ENVELOPE
• Load factor is ratio of aircraft lift to its weight
• Flight envelope discribe aerodynamic and
structural limitation of aircraft
• Pilot fly the aircraft based on the envelope