View Single Post
Old 10th Aug 2010, 21:09
  #1856 (permalink)  
Join Date: Jun 2009
Location: NNW of Antipodes
Age: 77
Posts: 1,330
bearfoil - in reply to Post # 1847

The acute angle between a water or airborne craft's fore-and-aft line and the current longitudinal center-line of the rudder.
The Graph likewise shows a ~4degree angle consistent with RTLU default after Law Change for the assumed speed, 272 knots.
Wrong! The graphic shows 7.9 of rudder angle at 272KCAS - the value that is "locked in" (when the flight law changed to Alternate) until slats extension, when it reverts to that available in Normal Law.

The 4.0 angle is that available at 350KCAS and beyond when in Normal Law, and would be the value "locked in" if an overspeed event had resulted in a change to Alternate or Direct Law. The 4.7 angle was included as a reference as to the angle at FL350 and M0.86 / 330KCAS.

Maximum rudder travel is therefore automatically limited as a function of aircraft KCAS to prevent structural overloading. In this respect, the "travel" is the angular deflection from the fore-and-aft line as described above. I haven't seen a schematic for the RTLU, but I suspect that a worm screw driven device creates a "feedback" position that inhibits hydraulic pressure to the operating rams beyond the set point. In this respect, the RTLU position is utilized by both port & starboard rams.

mm43 is offline