Type IV fluids have a shear point that remains in place until speeds of how many knots?

Type IV fluids have a shear point that remains in place until speeds of how many knots?

• A. 50 knots
• B. 150 knots
• C. 100 knots
• D. 200 knots

Answer: (C)

Type IV fluids are designed to stay in place on aircraft surfaces as airspeed increases, resisting aerodynamic shear up to a certain wind speed. The term “shear point” refers to the speed at which the fluid film begins to be displaced by the airflow. For Type IV fluids, this threshold is about 100 knots, meaning the film remains adherent up to roughly 100 knots of relative wind. Beyond that speed, aerodynamic forces can start to shear the film off. This property helps explain why these fluids are chosen for longer protection during taxi and the early phases of takeoff, though actual hold times and coverage still depend on the specific fluid formulation and conditions. The other speeds don’t align with how these fluids behave under aerodynamic shear: they’re too low or too high to represent the typical stability range.

Type IV fluids are designed to stay in place on aircraft surfaces as airspeed increases, resisting aerodynamic shear up to a certain wind speed. The term “shear point” refers to the speed at which the fluid film begins to be displaced by the airflow. For Type IV fluids, this threshold is about 100 knots, meaning the film remains adherent up to roughly 100 knots of relative wind. Beyond that speed, aerodynamic forces can start to shear the film off. This property helps explain why these fluids are chosen for longer protection during taxi and the early phases of takeoff, though actual hold times and coverage still depend on the specific fluid formulation and conditions. The other speeds don’t align with how these fluids behave under aerodynamic shear: they’re too low or too high to represent the typical stability range.