Weight and Aircraft Momentum Flashcards
What limits an aircraft’s structural weight?
Lift
If the cannot equal the aircraft’s weight then the aircraft cannot maintain level flight
What is the effect of increased weight on an aircraft?
Performance is reduced
Stalling speed is increased
Manoeuvrability is reduced
Wear on tires and brakes is increased
Structural safety margins are reduced
What is the centre of gravity?
Point where total weight of the body will act
Describe centre of gravity moment?
Is the turning effect/ force of a weight around the datum. It is a product of weight times by arm
Moment = Weight x Arm
How is the pitching moment of the lift-weight couple balanced?
The horizontal tail plane will have a downwards deflection. Causing a nose down counter pitch.
How can the Centre of Gravity being forward affect the aircraft?
More Stability
More Stick Force required
More Drag (reduced range)
Higher stall speed
It being aft has the opposite affect
How does a forward centre of gravity affect the stall speed, and why?
It causes a higher stall speed.
This is because forward COG will cause a pitch down moment below that which is required for en-route best performance. So downforce is needed by stabilizer to nose up. This downwash however increases the effective weight. Weight is a factor of stall speed.
What causes the centre of gravity movement?
Fuel burn
Passenger Movement
High Speeds
Greater the speed, greater the lift. To maintain straight and level the aircraft adopts a more nose down. This means a reduction in tail plane effective weight. Causing the COG to move
How does weight affect an aircrafts flight profile descent point?
Heavier aircraft required an earlier descent point
Heavier aircraft causes a greater momentum. Aircraft will have to maintain shallower descent rate to control it’s momentum. Shallower the ROD, the aircraft will have a greater Ground Speed as the aircraft will cover greater distance over ground per 100 ft ROD.
