What is the meaning of the yellow arc on the airspeed indicator?

Question

Quiz SPL - Sailplane Pilot License - Aircraft General Knowledge - What is the meaning of the yellow arc on the airspeed indicator?

QuizVDS · Accepted Answer

Flight only in calm weather with no gusts to avoid overload.

QuizVDS · Answer

Cautious use of flaps or brakes to avoid overload.

QuizVDS · Answer

Speed for best glide can be found in this area.

QuizVDS · Answer

Optimum speed while being towed behind aircraft.

SPL: What is the meaning of the yellow arc on the airspeed indicator?