Predator/Reaper, why they went with a V-tail design?

[RandomGuy88]

I have some questions about these two aircraft.

Does anyone know why they went with a V-tail design?

My understanding is that the Reaper is a more advanced version of the Predator. Why is the tail of the Predator point downwards but not the tail of the Reaper? I have heard that the Predator's tail was upside down because of the coupling between yaw and roll that the V-tail creates. If an upside down V-Tail tries to yaw the aircraft to port then the aircraft will roll to port, but if the V-Tail is right side up and it yaws the aircraft to port then it will create a rolling moment to starboard. Was this an actual reason for this tail config, or are the rolling moments from the V-tail to small to worry about? And if so what was the reason? It seems like a downwards pointing V-tail could have ground clearance issues.

The Reaper also has a vertical stabilizer in addition to the V-tail. Why is that?

 

[Cyrus]

I have some questions about these two aircraft.

Does anyone know why they went with a V-tail design?

My understanding is that the Reaper is a more advanced version of the Predator.

The MQ-9 is much larger than the predator, and flies a bit faster. For the MQ-9, its a Y tail, not a V tail.

Why is the tail of the Predator point downwards but not the tail of the Reaper?

It was an issue of ground clearance for the landing gear.

I have heard that the Predator's tail was upside down because of the coupling between yaw and roll that the V-tail creates. If an upside down V-Tail tries to yaw the aircraft to port then the aircraft will roll to port, but if the V-Tail is right side up and it yaws the aircraft to port then it will create a rolling moment to starboard. Was this an actual reason for this tail config, or are the rolling moments from the V-tail to small to worry about? And if so what was the reason? It seems like a downwards pointing V-tail could have ground clearance issues.

Yep.

The Reaper also has a vertical stabilizer in addition to the V-tail. Why is that?

For more weathercock stability.