3 versus 4 fins on maneuvering rockets / missiles.

Patrick, Mon Oct 07 2019, 10:02PM

Is there a reason 4 fins seem to be more common than 3 fins on missiles and controlled rockets ?

Obviously there's the surface area restoring force difference in surface area (3 vs 4) in just a ballistic non-maneuvering child's rocket.
But is there a stability advantage or is it just a stowage-volume issue before its thrown at the enemy.

The NASA X-31 test program included the conclusions that 3 vs 4 thrust paddles seem to make little difference.


Thrust vectored aided Rockwell-MBB X-31 Link2
Re: 3 versus 4 fins on maneuvering rockets / missiles.
2Spoons, Tue Oct 08 2019, 12:33AM

Probably just easier to control - 2 fins for pitch and 2 for yaw
Re: 3 versus 4 fins on maneuvering rockets / missiles.
Plasma, Tue Oct 08 2019, 07:08AM

Center of pressure, its for stable flight, will add more later