Dutch Roll

[Brandon]

I've heard it mentioned from time to time, but I really don't know anything about it other than it is an unfavorable characteristic of swept back wings. Anyone care to elaborate?

[**DONOTDELETE**]

Dutch Roll is a dynamic instability that is encountered with swept wing configurations. Swept wings have strong lateral stability but weak directional stability. Basically, the aircraft begins to roll before yaw can be corrected. The yaw is most likely induced from gusts etc. It is a design problem with swept wings. The yaw dampining is very slow and hard to correct. The problem increases with altitude but is corrected on jet aircraft with yaw dampner. Rudder alignment.

[Wannabe2]

I thought dutch rolls were a manuver to help coordinate alerons and rudder. Perhaps these are called something else, but when I first started flying, my instructor would have me do them. Basically if you do opposite aleron and rudder, you can "roll" the plane back and forth, while trying to keep the nose stationary. Am I way off base?

[MartinFierro]

Dutch roll is simply when the airplane yaws in one direction while rolling in the other, and oscillates back and forth. While your instructor may have done this intentionally to show the effects of super-uncoordinated flight, it is a phenomenom which occurs unintentionally in many aircraft, particularly swept-wing aircraft, airplanes with lots of wing dihedral, or small vertical tails.

According to _The_Illustrated_Guide_to_Aerodynamics_,:

"The motion was once likened to a Dutch boy on skates doing a series of opposite turns. The direction of the turn is always out of phase with the rolling motion of his body (which is how he initiates the turn). This motion in an airplane thus became known as 'Dutch Roll'."