Gazelle Stabilizer/Autopilot information?

[Jenrick]

I apologize if this has already been discussed, but the DCS forums don't make it easy to find things some days.

First off can any provide just a general overview of the autopilot/stabilization system for the Gas?  I'm assuming hydro-mechanical, goal of keeping the help level in roll, yaw, and pitch by default?  What controls does it actually effect?  I'm assuming it has a max input level and some kind of break through from the controls?

Next, what is the intended behavior?  I had been using the magnetic trim a decent bit, and just so happened one time to not use it (don't remember why).  Gradually the helo ends up in stable, relatively yaw free flight, with no trim on it at all.  Is this supposed to happen, is that the stabilizer at work?  Am I fighting against the stabilizer when I am using the magnetic trim above 120 kph?

Compared to the info and articles about the autopilot system in the Blackshark there is almost nothing I can find about the system in the Gazelle and I am just trying to figure out what should be happening.  Thanks!

Edited March 18 by Jenrick

[Ramsay]

14 hours ago, Jenrick said:

First off can any provide just a general overview of the autopilot/stabilization system for the Gas?

AFAIK the pilot's desired SAS attitude and heading is set using the same cyclic button as magnetic brake.

The SA342 SAS receives inputs from 
• Heading - Gyromagnetic compass
• Pitch & Roll - Primary ADI
• Altitude/Speed Hold sub-modes - Barometric Altitude/IAS from the Air Data Module
• Air Speed above/below 90km/h (49 knots) - Badin Switch
• Pilot control input - Pitch, Roll and Yaw linkage micro-switches

Heading is maintained with the SAS Yaw channel below 90 km/h IAS and switches to using the Roll channel when above 90 km/h IAS

A French 1970 SA342 Historic Flight Manual is available from www.alat

https://www.alat.fr/documentation-alat-manuels-instruction-techniques-manuels-manuel-equipage-sa342-m-1970.html

Section 1.7 describes the Autopilot and starts on page 65.

 

 

Edited March 19 by Ramsay

[Jenrick]

So if I'm understanding correctly, the SAS should basically function as an heading and attitude hold? Ironically the old FM did this as soon as the SAS kicked in (the much maligned holding roll angle), though I wonder if it held it too well.