73G Autotrim?

[sinkingship]

Hi all,

I am wondering if the NG737 have autotrim and how does it work (handling point of view), i presume its 777 way of trim for speed as oppose to Airbus' trim for position.

Any inputs appreciated, Thanks

[CaptainSandL]

No autotrim on the 737, but it does have a limited amount of speed trim and Mach trim at the low & high speed ends. If you change thrust, stick pressure, assym thrust etc you have to manually retrim the aircraft.

If the autopilot is engaged it will trim the aircraft in pitch for you, it cannot trim the rudder or ailerons.

S&L

[alexban]

Indeed ,it's not like the bus:
The spped trim system is designed to improve flight characteristics during operation with a low weight,aft CG and high thrust with A/P off.
Purpose of the STS is to return the airplane to a trimmed speed by commanding the stabilizer in a direction opposite the speed change.
As the speed increases or decreases from the trimmed speed,the stabilizer is commanded in the direction to return to the trimmed speed.
The STS operates most freq during takeoffs,climb and go-arounds.
Conditions are:
speed between 100 KIAS and M 0.5
10 sec after takeoff
5 sec from trim switch release
A/P off
Sensing of trim requirement
(From FCOM2 9.20.8 )
I guess it is a speed trim,like on the 777 ,is it right?