Erj-145xr

[91100 100 set]

Seriously though, what aerodynamic advantages do the ventral strakes provide? I know in some planes it helps with directional stability (especially in high AOA situations), or it can help the autopilot/yaw damper. Just curious.

 

[LearLove]

In high or "approaching limit" AOA conditions the strakes will cause drag and nose down pitching moment to lower the AOA. I believe Lear was the first to put them on a civil aircraft. The F-8 and A-7 along with the F-16 and some others also had/have them.

The professor I worked for in college did alot of this research, but basically its just a zero camber NACA foil that is set to stick into the airstream at high AOA. Along with pushing the nose down they also act like the tail at high AOA as the "tail on top" may be blanked by the fuselage.

Its either that or the jungle people engineers thought it would look neat so they slaped them on. And don't laugh, it would be the first time in aircraft develpoment that was useless but done because they thought it look cool.

My research and work concerning aerodynamics centered around very low reynolds number conditions - read high camber airfoils but my wind tunnel was next to the guys doing the above mentioned work. My stuff wasn't sexy like the dudes operating the supersonic wind tunnels but it had teeth. These same guys came up with the tail fix for the F-18 back when the vert stabs were flying off due to the "rough" flow off the wing root extensions.

 

[Wasted]

The tail strakes were added to compensate for some directional instability caused by the added winglets.

 

[SLFLYHI]

In high or "approaching limit" AOA conditions the strakes will cause drag and nose down pitching moment to lower the AOA. I believe Lear was the first to put them on a civil aircraft. The F-8 and A-7 along with the F-16 and some others also had/have them.

The professor I worked for in college did alot of this research, but basically its just a zero camber NACA foil that is set to stick into the airstream at high AOA. Along with pushing the nose down they also act like the tail at high AOA as the "tail on top" may be blanked by the fuselage.

Its either that or the jungle people engineers thought it would look neat so they slaped them on. And don't laugh, it would be the first time in aircraft develpoment that was useless but done because they thought it look cool.

My research and work concerning aerodynamics centered around very low reynolds number conditions - read high camber airfoils but my wind tunnel was next to the guys doing the above mentioned work. My stuff wasn't sexy like the dudes operating the supersonic wind tunnels but it had teeth. These same guys came up with the tail fix for the F-18 back when the vert stabs were flying off due to the "rough" flow off the wing root extensions.

You went to Riddle, didn't you?