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1. AERODYNAMICS REVIEW This is a basic review of aerodynamic factors listed in the Primary Instructor Pilot MOI.
2. DYNAMIC ROLLOVER Dynamic rollover is the occurrence of a rolling motion; while any part of the landing gear is acting as a pivot, which causes the aircraft to exceed a critical angle, roll over, and recovery is impossible.
3. DYNAMIC ROLLOVER
4. DYNAMIC ROLLOVER
5. DYNAMIC ROLLOVER
6. SETTLING WITH POWER Settling with power is a condition of powered flight in which the helicopter settles in its own downwash.
Conditions conducive to settling with power are a vertical or near-vertical descent of at least 300 feet per minute, low forward speed and using some of the available engine power (20-100 percent )with insufficient power to retard the sink rate.
Normally, increasing airspeed is the preferred method of recovery. Usually less altitude is lost by this method than by the method of lowering collective. The two methods may be combined if altitude permits.
7. SETTLING WITH POWER
8. SETTLING WITH POWER
9. SETTLING WITH POWER
10. DISSYMMETRY OF LIFT In forward flight, the combined effects of the differential airflow across the advancing and retreating blades and the three no-lift areas on the retreating blade result in a dissymmetry of lift potential between the advancing and retreating halves of the rotor disk.
Blade flapping alone or in conjunction with cyclic feathering can eliminate dissymmetry of lift and allow the pilot to maneuver the helicopter.
11. DISSYMMETRY OF LIFT
12. DISSYMMETRY OF LIFT
13. TRANSLATING TENDENCY The tendency of the single-rotor helicopter to move laterally during hovering flight.
It is compensated for by one or more of
the following:
Flight-control rigging.
Transmission tilted slightly to the left.
Collective pitch control system.
Pilot inputs to control drift.
14. TRANSLATING TENDENCY
15. AIRFLOW DURING A HOVER
16. AIRFLOW DURING A HOVER
17. AIRFLOW DURING A HOVER
18. TRANSVERSE FLOW EFFECT
Because of coning and the forward tilt of the rotor system, there is a differential airflow across the front and rear halves of the rotor disk.
19. TRANSVERSE FLOW EFFECT
20. RETREATING BLADE STALL A stall of the retreating blade that begins at or near the tip because of high angles of attack required to compensate for dissymmetry of lift and the three no-lift areas.
Conditions most likely to produce blade stall are:
High blade loading (high gross weight).
Low rotor RPM.
High density altitude.
Steep or abrupt turns.
Turbulent air.
Recover from blade stall
Reduce power.
Reduce airspeed.
Reduce the severity of the maneuver.
Increase RPM.
Check pedal trim.
21. RETREATING BLADE STALL
22. RETREATING BLADE STALL
23. TOTAL AERODYNAMIC FORCE As airflow flows around an airfoil, a pressure differential develops between the upper and lower surfaces. The differential, combined with the resistance of the air to the passage of the airfoil, creates a force on the airfoil. This force, is known as total aerodynamic force, is represented by a vector. Total aerodynamic force acts at the center of pressure on the airfoil and is normally inclined up and to the rear.
24. TOTAL AERODYNAMIC FORCE Total aerodynamic force may be divided into two components called lift and drag.
Lift acts on the airfoil in a direction perpendicular to the relative wind.
Drag acts on the airfoil in a direction parallel to the relative wind and is the force that opposes the motion of the airfoil through the air.
25. TOTAL AERODYNAMIC FORCE
26. TOTAL AERODYNAMIC FORCE
27. AIRFLOW IN FORWARD FLIGHT
