Straight-and-level flight lesson
Straight-and-level flight is flight in which a constant heading and altitude are maintained.
Objectives of the lesson
- To flight straight and level (constant heading, selected altitude and airspeed) at various speeds within the full operational speed range of the aircraft.
- The combination of attitude and power to achieve performance.
In the previous lecons
- Cruise attitude: The cruise attitude is attained with level flight attitude, a constant altitude, a constant airspeed and power, and level wings.
- Control yaw with rudder.
- Increase power: yaw to the left: right rudder.
- Decrease power: yaw to the right: left rudder.
- Cause of yaw: Bank attitude, slipstream effect , asymmetric thrust.
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Straight flight
- Straight means: No turn.
- Straight flight is maintained by keeping the wings level with ailerons and applying the necessary pressures on the rudder pedal to prevent yaw.
- If you allow the aircraft to bank it will begin to turn in direction of the lower wing.
Straight flight control of Yaw.
- An increase in power, which increase the rotational force of the propeller slipstream, will cause aircraft with clockwise rotating propeller to yaw to the left.
- A decrease in power will cause the aircraft to yaw to the right.
- Any tendency for the aircraft to yaw with power change should be anticipated and prevented by appropriate use of rudder.
Level Flight
- Level flight means flying at a constant altitude, not going up and down.
- As power is increased or decreased, keep the pitch attitude constant with appropriate elevator control pressure.
- When the aircraft is at the desired airspeed, trim to relieve the control pressure required to maintain straight-and-level flight.
Attitude+power=performance
This formula simply states that for any given attitude (pitch and bank) and power setting, a certain performance will result.
When an aircraft is in straight-and-level flight forward or backward pressure on the control column will affect both speed and height. Likewise , changes in power settings can affect both speed and height.
To increase the airspeed while in straight-and level flight.
- Advance the throttle smoothly to the power setting estimated for the speed desired.
- Anticipate the yaw to the left with the right rudder.
- At the same time apply sufficient forward pressure to the control column to keep the altitude from increasing.
- Keep the wing level.
- When the desired airspeed is reached, readjust the power setting if necessary, then trim the aircraft.
To decrease the airspeed while in straight-and-level flight.
- Throttle back smoothly to the power setting estimated for the speed desired.
- Anticipate the yaw to the right with the left rudder.
- Back pressure to the control column to maintain the desired altitude.
- Keep the wing level.
- When the desired airspeed is reached readjust the power setting if necessary, then trim the aircraft.
Resume
To change airspeed at level flight without changing the altitude.
To increase airspeed :
- Increase power.
- Lower the nose.
To decrease airspeed :
- Decrease power.
- Raise the nose.
This plane has a pitch nose up but it could be in straight-and-level flight at reduced airspeed.
Straight and level flight instruments
The six pack: the six main flight instruments.
No change in theses instruments mean that we are in straight-and-level flight.
- Use ailerons to keep wings level
- Use elevator and power to maintain altitude and airspeed
- Use rudder to control yaw
Trim technique
- As you increase and decrease airspeed, you will feel pressure on the control as you try to maintain level flight.
- Once the new speed and/or pitch attitude is established, eliminate the control pressure by trimming the aircraft.
Review questions
- When reducing power in level flight, what control movement will be necessary to maintain straight and level flight ?
- What Attitude + Power = Performance means?
- When adding power to accelerate what else will you have to do?
- What happened with visual reference if I increase the pitch attitude?
- Why is trimming the aircraft important?
