AvSport of Lock Haven What’s the Spin on Stalls? Presentation Copyright © 2015 Mastering the most...

Presentation Copyright © 2015

AvSport of Lock Haven

What’s the Spin on Stalls?

Mastering the most dreaded maneuver in flight training

Prof. H. Paul Shuch, Ph.D., CFII LSRM-A/GL/WSC/PPC, iRMT Heavy

Chief Flight Instructor, Director of Maintenance,AvSport of Lock Haven

FAA Safety Team Lead Representative, Piper Memorial Airport, Lock Haven PA




A FAASTeam Wings Award Safety Webinar




• Experimental Aircraft Association• AvSport of Lock Haven• Aircraft Spruce and Specialty Company• Your FAA Safety Team

Brought to you by:




Stalls are undoubtedly the most feared maneuver in the flight training curriculum. They are also an essential element of every single flight, in that an aircraft cannot land if its wing is still developing lift. In this FAA Safety Team Wings webinar, you'll learn how to love stalling the airplane just inches above the runway, while avoiding that dreaded stall/spin accident.

RATIONALE:




OBJECTIVES

Upon successful completion of this webinar, you will:• Understand and master critical angle of attack• Explain how wings stall at any speed, in any attitude• Practice approach-to-landing stalls to master the flare• Practice power-on stalls to avoid inadvertent spins• Convert a power-on to a power-off stall to aid recovery• Avoid spins by ensuring that both wings stall equally• Demonstrate safe stall and spin recovery procedures




Caveat:• The procedures shown here are used successfully by one

particular instructor, in one particular aircraft. They may not apply in your situation.

Disclaimer:• Nothing in this presentation should be considered a substitute for

adequate dual training, conducted by an appropriately rated flight instructor familiar with your particular aircraft.

Waiver:• By viewing this presentation, you understand and agree that:

– Flying is a sport– There is risk associated with all sports– You accept that risk




Aerodynamics - How the wing lifts

Bernoulli’s Principle:

As the velocity of a fluid increases, its pressure decreases. The accelerated air above the wing exerts less pressure on the wing than the un-accelerated air below it.




Aerodynamics - How the wing lifts

Air flow over the wing creates downwash, the pushing of air down creates a lifting force.

The direct deflection of air downwards off of the lower surface of the wing also creates a resulting lifting force upward.




Stall: automotive definition

• The engine quits under load




Stall: aerodyamic definition

• The wing stops developing lift




Common Stall Myths

• You can’t stall without pulling the nose up

• You only stall when you go too slow

• Stall speed is a constant number

• You won’t stall if you stay above stall speed

• To recover from a stall, you must add power

• Failure to recover from a stall leads to a spin




Anatomy of a Stall

• Cord Line

• Relative Wind

• Angle of Attack

• Airflow Separation

• Recovery




Anatomy of a Stall




Critical Angle of Attack Can Be Exceeded In Any Flight Attitude!




Doh!




A stall occurs when:

• The engine quits under load• The airspeed gets too low• Critical Angle of Attack is exceeded• The nose gets too high• A spin develops




“OK, now we’re going to do stalls!”




Three Types of Stall:

• Approach-to-landing stall– often called a Power-Off Stall

• Takeoff and departure stall– often called a Power-On Stall

• Accelerated Stall




The Approach-to-Landing Stall




The Approach-to-Landing Stall

• Power reduction

• Glide established

• Stretching the glide

• Stall recognition

• Stall recovery




Glider and Stall Practice

• Power off stall practice simulates an approach to landing, followed by a flare

• So, the purpose of power off stalls is to learn how to flare properly

• If you don’t stall, you can’t land!• Some pilots believe they can stay safe by never stalling• They’re still up there!




Quiz time!




Power-off stalls are used to simulate

• takeoff rotation• landing flare• slow flight• go-around• touch-and-go




Takeoff and Departure Stall




Takeoff and Departure Stall

• Establishing a climbout

• Over-rotation

• Obstacle clearance

• Stall recognition

• Stall recovery




To go up, pull stick back.

To go down, pull stick way back.




Departure Stall Recovery

• Reduce power

• Reduce angle of attack

• Rudder to keep wings level

• Add climb-out power

• Establish best climb speed




Another Question!




The first step in recovery from a power-on stall should be to

• Level the wings• Lower the nose• Add full power• Convert it to a power-off stall• Pull back on the stick




Accelerated stall




Accelerated stall

• Load factor

• Bank angle

• Abrupt control changes

• Secondary stalls




Accelerated stall




Secondary stall




I know this one!




An accelerated stall

• Happens at lower than normal airspeed• Occurs only during a steep turn• Is another name for a secondary stall• Can occur with little warning• Results in little altitude loss




Spin Avoidance and Recovery




Spin Avoidance and Recovery

• Torque affects

• Power reduction

• Breaking the stall

• Stopping the rotation

• Flying out of the dive




To go up, pull stick back.

To go down, pull stick way back.




Necessary Conditions for a Spin

• Critical angle of attack exceeded

• One wing stalls first

• Asymmetrical lift

• Aggravated by torque




Overshooting turn to final




Spin Recovery Technique

• Remove excess torque

• Break the stall

• Stop the rotation

• Level the wings

• Recover from power off stall




Final Question!




A spin can occur when

• You overshoot the turn to final• One wing stalls before the other• The aircraft is cross-controlled• You initiate a go-around without rudder• Any of the above




Final Safety Thoughts

• Practice at an adequate altitude• Ailerons lose effectiveness• Steer with your feet• If all else fails, let go• Don’t spin unless approved in aircraft




Respect All Placards!




Caveat:• The procedures shown here are used successfully by one

particular instructor, in one particular aircraft. They may not apply in your situation.

Disclaimer:• Nothing in this presentation should be considered a substitute for

adequate dual training, conducted by an appropriately rated flight instructor familiar with your particular aircraft.

Waiver:• By viewing this presentation, you understand and agree that:

– Flying is a sport– There is risk associated with all sports– You accept that risk

AvSport of Lock Haven What’s the Spin on Stalls? Presentation Copyright © 2015 Mastering the most...

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