Forum: Technology

Just wondering, why are the alierons and or elevators on some jets positioned upwards or downwards when the jet shuts down? If you look at the Eagles, their alierons are not neutral, and the Bone's elevator seems to be pointed downward a bit. I've also seen this on the viper...

Thanks!

F-16.net Sponsor

When you shut down the plane there's no hydraulic pressure, so the ailerons and elevators are free to move as much as they want.

As deepspace stated, the surfaces are free to "relax". The hydraulic pressure used to keep them centered, or moving as needed is no longer there. When there is no pressure on the actuator, the mere weight of the surface will press against one direction of the actuator, slowly forcing fluid from the actuator back into the system. If you were to recenter the surface, then try and pull down or push up on the surface to re-accomplish this state, the actuator and system would prevent it. Only over an extended period of time (usually just a couple hours) will the surface move to this state.

On the vipers, whenever the motor is spooling down you still have some hydraulic pressure and if you cut power during that process, the will snap up. Watch your fingers! Laughing

Forum: Technology

Question about this picture - Alierons and elevators