Pre-Solo Training Program Flight Briefing: Lesson 2 Airspeed Control In cooperation with Mid Island Air Service, Inc. Brookhaven, NY (Michael Bellenir, CFI)

Lesson 2 Objectives During this briefing, we will review the fundamentals of basic flight, and basic flight maneuvers. You will learn how airspeed changes affect aircraft performance and handling characteristics, how to change airspeeds during flight, and constant airspeed climbs and descents. The effect of flaps and slow flight will also be introduced. Upon completion of this briefing, you will practice slow flight and constant airspeed climbs and descents, study the effect of flaps, and demonstrate proper use of flaps in takeoff and landing.

Effect of airspeed on handling Airspeed has a great effect on aircraft handling characteristics. At high airspeeds, flight controls will be more effective. At low airspeeds, flight controls will be less effective, more control deflection is required for aircraft response. Aircraft will handle differently in cruising flight than on approach to landing. LSAs can typically operate as speeds low enough that the controls essentially lose effectiveness

Effect of airspeed on performance The amount of lift and drag on an aircraft vary exponentially with airspeed. Doubling airspeed will quadruple amount of lift.

Relationship between speed and drag. There are two main types of drag: Induced drag: The drag created as a by-product of lift. Induced drag is highest at low speed, and decreases as airspeed increases Parasitic drag: The drag produced by turbulent airflow around aircraft structures. Parasitic drag is lowest at low speed, and increases as airspeed increases.

Relationship between speed and drag. There is one airspeed at which the total drag on the airplane will be minimal. This speed is typically used to climb the fastest or glide the farthest.

Relationship between power and drag. At different speeds, there are different amounts of drag on the airplane, therefore different airspeeds require different power settings to overcome drag and maintain airspeed and/or altitude.

Relationship between power and drag.

Airspeed and “Regions of Command” The Power/Airspeed relationship is an important concept. One power setting can yield two different airspeeds depending on which side of the power/drag curve you are on. In the “Region of Normal Command” (ahead of the power curve), to fly faster more power is required to overcome increasing parasite drag. In the “Region of Reversed Command” (behind the power curve), to fly any slower requires more power to overcome increasing induced drag.

Airspeed and “Regions of Command” Power must be increased to increase speed to overcome increased parasite drag. Power must be increased to maintain a slower airspeed to overcome increased induced drag One power setting can yield two speeds

Airspeed Stability in Region of Normal Command (Ahead of power curve) The natural relationship between airspeed and drag gives the airplane a natural tendency to maintain an airspeed specific to its power setting; the airplane will attempt to maintain a constant speed. If the airplane gets faster than the airspeed that the power is set for, then the increasing drag will cause it to slow down; if the airplane slows down below the airspeed the power is set for, the reducing drag will cause it to speed up. When flying ahead of the power curve, the airplane will be more naturally stable.

Airspeed Stability in Region of Reversed Command (Behind power curve) The airplane will not be as naturally stable when in the Region of Reversed Command (behind the power curve). If the airspeed increases above the airspeed for which the power is set, induced drag will decrease and cause the airplane to continue to increase its speed. If the airspeed decreases below the airspeed for which the power is set, induced drag will increase and cause the airplane to slow down further

Airspeed Stability If airspeed changes without power change, it will tend to return to the initial speed to balance power and drag. Keeping the aircraft in trim enhances this natural tendency! (Static longitudinal stability enhanced, aircraft returns to trimmed condition)

Relationship Between Pitch and Airspeed Just like power changes affect airspeed, changing the airplane’s pitch attitude will also have an effect on its airspeed. Bringing the nose up will cause a decrease in airspeed. Lowering the nose will cause an increase in airspeed. These changes in speed are the simply caused by gravity acting on the aircraft.

Pitch and Power Increasing the pitch will also increase the amount of lift created by the wing (to a point). This will cause the airplane to climb and result in decreasing speed. Lowering the pitch will decrease the lift created by the wing and cause the airplane to descend and possibly increase speed

Pitch and Power To control an airplane precisely and maintain both a specific airspeed and a specific altitude, a pilot needs to coordinate the airplane’s pitch and power settings together to get the desired results. To maintain constant lift, as airspeed is reduced, pitch must be increased. The most precise method of controlling flight path is to use pitch control while simultaneously using power to control airspeed. A change in pitch will require a change in power, and vice versa.

Constant Airspeed Climbs The ability of an airplane to climb is dependent on how much power it has. If an airplane has more power than it needs to hold its altitude, it will be able to climb. The more excess power an airplane has the faster it will be able to climb. An important skill a pilot must develop is the ability to climb at a specific airspeed.

Constant Airspeed Climbs To climb at a specific airspeed, increase power to a level above that required for level flight, then use the pitch control to maintain the desired airspeed. If the airplane is too fast, increase the pitch. If the airplane is too slow, reduce the pitch. To increase the climb rate, increase power. To reduce the climb rate, decrease power.

Constant Airspeed Descents If the power is reduced below the level required to maintain altitude, the airplane will descend. To descend at a specific airspeed, reduce the power below the power setting required for level flight. To reduce airspeed, increase the pitch; to increase airspeed reduce the pitch. To increase the descent rate, reduce the power To decrease the descent rate, add power.

Flap Aerodynamics Flaps alter the performance of the wing by physically changing its shape. There are different types of flaps, each with its own set of aerodynamic principles. Generally speaking, flaps increase both lift and drag. Flaps also typically reduce the stalling speed of an airplane, allowing it to fly slower.

Types of Flaps Piper Cub Evektor Sport Star Tecnam Sierra/Eaglet Most Airliners

Using the Flaps Flaps can be used by an airplane to descend at a steeper angle or increase the descent rate without increasing speed. (Used on approach to landing) Flaps can also be used to generate extra lift to help the airplane get off the ground sooner (Used on takeoff) Prior to extending flaps, ensure the airplane is at a safe speed for flap extension (white arc on airspeed indicator) The maximum speed that the flaps can be extended at is referred to as VFE (top of white arc) At speeds above VFE, aerodynamic pressure could cause damage to the flaps.

Review Questions Which kind of drag increases with airspeed? Decreases? What is another term for “region of reversed command?” At what airspeeds are controls least effective? Which kind of flaps does the SportStar have? Which do flaps increase: lift or drag? How is airspeed controlled in a constant airspeed climb or descent? How is maximum flap speed indicated? Write down your answers before continuing to next slide

Review Answers Which kind of drag increases with airspeed? Decreases? Parasitic / Induced What is another term for “region of reversed command?” behind the power curve At what airspeeds are controls least effective? at low airspeeds Which kind of flaps does the SportStar have? split flaps Which do flaps increase: lift or drag? Both! How is airspeed controlled in a constant airspeed climb or descent? with pitch (elevator control) How is maximum flap speed indicated? Top of white arc Review any missed questions before continuing to today’s flight.

On Today’s Flight We will practice holding headings and altitudes and making turns. We will study the effect of airspeed on performance and handling. We will practice flying the airplane at different speeds, including slow flight (behind the power curve). We will study the effects of flaps

Today in the Traffic Pattern Try to climb out a specific climb speed after takeoff (constant airspeed climb). Try to descend at a specific speed on approach to landing (constant airspeed descent). Extend the flaps properly for takeoff and landing Thanks to Mid Island Air Service, Inc. Brookhaven, NY (Michael Bellenir, CFI)