FH.II.D.K10

From the FAA library

• Helicopter Flying Handbookp. 2-21
  Chapter 2: Aerodynamics of Flight › Forward Flight › Effective Translational Lift (ETL)

  Translational Lift Improved rotor efficiency resulting from directional flight is called translational lift. The efficiency of the hovering rotor disk is greatly improved with each knot of incoming wind gained by horizontal movement of the aircraft or surface wind ... efficiency of the tail rotor. Figure 2-38. To compensate for blowback, you must move the cyclic forward. Effective Translational Lift (ETL) While transitioning to forward flight at about 16 to 24 knots, the helicopter goes through effective translational lift…

• Helicopter Flying Handbookp. 2-24
  Chapter 2: Aerodynamics of Flight › Turning Flight

  Turning Flight In forward flight, the rotor disk is tilted forward, which also tilts the total lift-thrust force of the rotor disk forward. When resulting in lift being separated into two components. Lift acting upward and opposing weight ... called the vertical component of lift. Lift acting horizontally and opposing inertia (centrifugal force) is the horizontal component of lift (centripetal force). [Figure 2-45] Figure 2-44. Forces acting on the helicopter during rearward flight. As the angle…

• Helicopter Flying Handbookp. 2-22
  Chapter 2: Aerodynamics of Flight › Forward Flight › Translational Thrust

  additional lift available at this speed is referred to as the ETL, which makes the rotor disk operate more efficiently. This increased efficiency continues with increased airspeed until the best climb airspeed is reached, and total drag ... lowest point. As speed increases, translational lift becomes more effective, nose rises or pitches up, and aircraft rolls to the right. The combined effects of dissymmetry of lift, gyroscopic precession, and transverse flow effect cause this tendency. It is important…

• Helicopter Flying Handbookp. 2-23
  Chapter 2: Aerodynamics of Flight › Translational Thrust › Transverse Flow Effect

  Transverse Flow Effect As the helicopter accelerates in forward flight, induced flow drops to near zero at the forward disk area and increases at the aft disk area. These differences in lift between the fore and aft portions ... rotor disk are called transverse flow effect. [Figure 2-41] This increases the AOA at the front disk area causing the rotor blade to flap up and reduces AOA at the aft disk area causing the rotor blade to flap…

• Helicopter Flying Handbookp. 2-20
  Chapter 2: Aerodynamics of Flight › Forward Flight › Dissymmetry of Lift

  from a hover or taking off from the ground, pilots must be aware that as the helicopter speed increases, translational lift becomes more effective and causes the nose to rise or pitch up (sometimes referred to as blowback). This tendency ... caused by the combined effects of dissymmetry of lift and transverse flow. Pilots must correct for this tendency by maintaining a constant rotor disk attitude that will move the helicopter through the speed range in which blowback occurs…

• Aviation Maintenance Technician Handbook - Airframep. 2-18
  Chapter 2: Aerodynamics, Aircraft Assembly, & Rigging › Forces Acting on the Helicopter

  When lift and thrust equal weight and drag, the helicopter hovers; if lift and thrust are less than weight and drag, the helicopter descends vertically; if lift and thrust are greater than weight and drag, the helicopter rises vertically ... forward flight, the tip-path plane is tilted forward, thus tilting the total lift-thrust force forward from the vertical. This resultant lift-thrust force can be resolved into two components: lift acting vertically upward and thrust acting horizontally…