deltatech....your info on mach tuck and dutch roll are accurate but needs some refined explanations....Mach tuck is compensated by trimming the horizontal stab/elevator with the A/P engaged....on older Boeings its done by a Mach Trim actuator trimming the elevator slightly up with the NSS(Neutral shift sensor ) retrimming the stabilizer to keep the plane flying @ the same altitude(using Alt Hold)....on newer Boeings its done thru the FCC,s and a Mach Trim actuator or thru the FCC,s/IRU accelerometers and retrim of the horizontal stab thru the A/P (Alt Hold or VNAV with FMC flying the airplane)....Dutch Roll on the older Boeings is compensated for by a Yaw Damper coupler using inputs from the VG,s to drive yaw damper actuator.....newer Boeings use a Yaw Damper computer using inputs from IRU accelerometers to drive the yaw damper actuator ...these IRU accelerometers are so precise they can measure the rotation of the earth around its axis.....Some aircraft incorporate the use of fuel in the horzontal stab to help with Mach Trim...a dedicated microprocesssor moves fuel from the wing tanks to the Hor stab fuel tanks to accomplish this(A330-A340)....the Concorde moves fuel inside the fuselage thru several fuel tanks to compensate for mach trim also done by a dedicated computer.....Good Luck with your B2...let us know how it does....Bill....