1. Ex. 11 – Slow Flight
What’s this plane’s AoA? Can’t tell untill you know which way it is going! This plane is actually on a “high alpha” pass – flight at high angle of attack and low airspeed. This is what we’ll explore today (though not quite to the same angle).
Ex Slow Flight

2. OBJECTIVE
What you will learn:
To recognize the signs of slow flight (flight at airspeeds between maximum endurance and stall)
To safely maintain control of the aircraft in slow flight, in a variety of configurations
To recover to normal airspeeds with minimal loss of altitude.
Ex Slow Flight

3. What’s so bad about that?
MOTIVATION
Why learn this:
To know what entry into slow flight feels like, to avoid accidentally entering it
If slow flight is inadvertently entered, to be able to recover safely
To become a better and more confident pilot.
What’s so bad about that?
Ex Slow Flight

4. LINKS
Links:
Climbs, descents and flight at best endurance speed provided you with a chance to fly at reduced airspeeds
You learned how changes in power and flap settings affect the flight
You have been practicing good habits
lookout
carb heat check
controlling yaw.
Ex Slow Flight

5. Let’s see how much you already know:
BACKGROUND KNOWLEDGE - TKT
Let’s see how much you already know:
What are the two types of drag, and how do they vary with airspeed and angle of attack?
What effect do flaps have on lift, drag and visibility?
How responsive are the control surfaces when the airplane is slowed down to best endurance airspeed?
Sketch the power curve (power required to maintain level flight vs. airspeed) and mark best endurance airspeed on it.
Ex Slow Flight

6. Theories and Definitions:
THEORIES & DEFINITIONS
Theories and Definitions:
The Power Curve
Yaw in Slow Flight
Flaps in Slow Flight.
Ex Slow Flight

7. The Power Curve SLOW FLIGHT
THEORIES & DEFINITIONS
The Power Curve
Minimum power is required for level flight at airspeed for best
__________________________________
Slowing down further while maintaining altitude will require an increase in ______________________
Slow flight is flight between the airspeed for best endurance and stall speed.
“Back side” of power curve
Lower airspeeds require more power
“Front side” of power curve
Lower airspeeds require less power
endurance
Power
available
power
SLOW FLIGHT
Ex Slow Flight

8. Yaw in Slow Flight ASYMMETRIC THRUST SLIPSTREAM TORQUE
THEORIES & DEFINITIONS
Yaw in Slow Flight
SLIPSTREAM
ASYMMETRIC THRUST
Which rudder will you need in slow flight?
slipstream pushes tail to the right
plane wants to yaw to the left
at high angles of attack, down-going blade has more “bite” and creates more thrust
left-yawing tendency
TORQUE
GYROSCOPIC PRECESSION
SLOW
FLIGHT
reaction to prop rotation causes roll to the left
pilot corrects with right aileron, causes adverse yaw to the left
spinning propeller acts as a gyroscope
raising nose causes right-yawing tendency
Ex Slow Flight

9. Flaps in Slow Flight ADVANTAGES OF FLAPS More lift
THEORIES & DEFINITIONS
Flaps in Slow Flight
What effect do flaps have on lift? Drag? Visibility?
ADVANTAGES OF FLAPS
More lift
stall speed reduced
More nose-down attitude
better forward visibility
better engine cooling
Ex Slow Flight

10. Procedures HASEL Check Slow Flight Entry During Recovery. PROCEDURES
Ex Slow Flight

11. Height Area Security Engine Lookout HASEL Check 2000’ AGL
PROCEDURES
HASEL Check
Height
Area
Security
Engine
Lookout
2000’ AGL
In your practice area, what is this ASL?
not over built-up area
harnesses, doors and windows secure
baggage strapped down/stowed away
“Downwind” Check
oil temperature and pressure in the green
primer in and locked, master on, mags on both
circuit breakers in, ammeter needle right, light off
carb heat hot, mixture rich
fuel on, gauges show fuel
flaps up
brake pressure
- This is a good time to look at a map, talk with your instructor about how to determine ground elevation, read symbols (towers etc.), MEF…
- Consider different scenarios (you turned and are now over a town, etc.)
- Keep turns gentle-medium/rate one
two 90o turns or one 180o turn - MINIMUM.
Ex Slow Flight

12. How will this affect airspeed and altitude?
PROCEDURES
Slow Flight: Entry
HASEL check
Reduce power to ~1600 rpm
Maintain altitude with elevators
Control yaw with rudder
Flaps to 20o once airspeed in the white arc
Once flight at best endurance airspeed is established, raise the nose
Add power to maintain altitude
Retrim for new airspeed.
How will this affect airspeed and altitude?
Ex Slow Flight

13. Slow Flight: During Keep good look-out
PROCEDURES
Slow Flight: During
Keep good look-out
Maintain altitude with ___________________
Maintain airspeed with ___________________
Maintain heading with _______________________________________
Control yaw with ___________________
How does slow flight affect your visibility?
power
elevators
How will control responsiveness be affected by slow flight?
ailerons + rudder
rudder.
Ex Slow Flight

14. Slow Flight: Recovery Keep good look-out Full power Carb heat cold
PROCEDURES
Slow Flight: Recovery
Keep good look-out
Full power
Carb heat cold
Maintain altitude with elevators (forward pressure)
Control yaw with rudder
Flaps up in stages
Once back to normal cruise airspeed, reduce power back to cruise
Retrim.
Ex Slow Flight

15. Considerations Control Responses Stall
controls are “sluggish” and “mushy” (one of slow flight signs)
ailerons are affected the most
elevator and rudder remain relatively effective due to propeller slipstream
be prepared for a lot of adverse yaw due to propeller effects and aileron drag
Stall
at a certain airspeed the airplane will reach a critical angle of attack at which it will no longer be controllable and will start descending rapidly
stall entry and recovery will be practiced in the next lesson.
Ex Slow Flight

16. SAFETY Good look-out is crucial – visibility is reduced in slow flight
Avoid practicing slow flight for prolonged periods of time – engine may overheat
Max bank in slow flight = 30o
Careful control of airspeed: you’re on the edge of stall!
Yaw control is critical: what can stalling uncoordinated lead to?
Why?
Ex Slow Flight

17. CONCLUSION
Conclusion
Practicing slow flight will improve your confidence and piloting skills, and help prepare you for mastering take-offs and landings
Next lesson: we will slow the plane down even more – to the point of the stall!
Read for next lesson: Ex. 12, Stalls
QUESTIONS?
Ex Slow Flight