Flight Instructor for Rotorcraft Category Helicopter Rating › II. Technical Subject Areas › Task D. Principles of Flight

HI.II.D.K11

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Transverse flow effect.

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Get a short, cited explanation of this element written from the FAA handbooks: the core idea, the numbers that matter, common test traps, and a quick self-check.

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Helicopter Flying Handbook p. 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 Handbook p. 2-22
Chapter 2: Aerodynamics of Flight › Forward Flight › Translational Thrust
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 to understand these effects and anticipate correcting for them. Once the helicopter…
Helicopter Flying Handbook p. G-5
Glossary
lift. The additional lift obtained when entering forward flight, due to the increased efficiency of the rotor system. Transverse-flow effect. The condition of increased drag and decreased lift in the aft portion of the rotor disk caused…
Helicopter Flying Handbook p. 2-20
Chapter 2: Aerodynamics of Flight › Forward Flight › Dissymmetry of Lift
rise or pitch up (sometimes referred to as blowback). This tendency is 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…
Aviation Maintenance Technician Handbook - Airframe p. 2-23
Chapter 2: Aerodynamics, Aircraft Assembly, & Rigging › Forward Flight › Effective Translational Lift (ETL)
work in relatively undisturbed air. The flow of air through the rotor system is more horizontal, therefore induced flow and induced drag are reduced. The AOA is subsequently increased, which makes the rotor system operate more efficiently. This increased efficiency ... aircraft rolls to the right. The combined effects of dissymmetry of lift, gyroscopic precession, and transverse flow effect cause this tendency. It is important to understand these effects and anticipate correcting for them. Once the helicopter is transitioning through…