split rudder

[SoundBarrier]

I fly small hairyplanes and dart around the sky somewhat. I was sitting at the terminal the other day and noticed that the rudder of the likes of the B744 and A380 were split, I thought they were cut in half by a pi$$ed maintennance man, but alas they look engineered.

So, why would the rudder of these big jets be split. Do they turn at varying rates for varying speeds, i.e. only the lower at high speeds and both at lower speeds?

I could of course be talking rubbish - in fact often guaranteed, but can someone please let me in as to what the deal is with the split rudders?

THANKS

SB

[galaxy flyer]

Mostly, provides redundancy-each rudder panel has several different hydraulic power sources. Pretty standard on bigger planes.

GF

[MarkerInbound]

And the 727 has a rudder load limiter on the lower rudder. The top rudder always works with lower hydraulic pressure, the lower rudder shifts to a higher pressure when the flaps are extended.

The 744 has rudder ratio changers on both the upper and lower rudders to reduce the rudder's response to pedal input as the speed increases.

[matkat]

Being a type rated engineer on B747s I can concur with soundbarrier defiantely for redundancy.