Rivets ,on the C130 ,it has increased hydraulic pressure to the rudder when you select flaps (below limit speed) .it is a well known `cheat` if you need to `vigorously manoeuvre` the aircraft above f/limit(speed or `g`) by popping a couple of c/bs,and then put the flap selector to 20*,and obtain full hyd. pressure to the rudder...so I was told...!