FS9 jet engines "hunting"?

[doylebob]

Hi all,

Definitely not a classic problem, I have a question about jet engine hunting in FS9. I'm trying to correct the problem but am not sure where best to start. (At low speed the oscillation of the engines even causes the aircraft to pitch up and down). Can anyone help me determine what entries in the "aircraft.cfg" file would be the best to attempt alleviate this problem?

Thanks in advance,

Bob.

[sunny9850]

1. Which airplane or is it all of them
2. Does it still happen when you disable all joystick inputs and run throttles only via the standard key commands or dragging the levers with the mouse ??

Stefan

[garryrussell]

Hi Bob

Not good to be thinking of fixing problems by delving straight into the aircfaft CFG ...I doubt if anything in there would fix this.

Stefan raises a couple of good points there and in addition I would ask if you are using AP and AT. Also are you using the correctpanelfor the model.

This sort of problem is usually the users set up, the users hardware or a corruption of FS itself rather than a problem with the aeroplane, in a case like this, which must be assumed is general as you don't specify a particular model.

In short..you need to checkout a whole lot of things first before fiddling with any CFG unless is is a problem with a particular
model.

If that is the case then a visit to the support site of the developer will usually have an answer as the problem will have been experienced by others.

But let's start with the questions already asked and we'll walk you through it bit by bit

Garry

[ashaman]

I remember I had this problem, or one similar enough, with the SGA MD80 and a particular panel made by Aldus Aldus... at low speeds (below 200kias) the autothrottle and the engines seemed to be unable to keep up one with the other, beginning a cycle of accelerations/decelerations with following pitch oscillations that most of the times were lethal in some borderline situations, like an autolanding... but in that particular case and panel the [never resolved] fault was of the autothrottle's gauge, and the plane behaved well, if throttled manually.

In your case, if the problem is related to one plane, then that plane deserves a panel, or at the very least an autothrottle, better suited for its engines, but if the problem is extended to each and every plane in your sim... then I guess it's reinstallation time.

[doylebob]

Hi guys,
Thanks for all your responses. Well, let me try to answer the questions.

1. This is specific to one model only. It is the (fairly recent) B773ER-v2 from a well known excellent freeware developer. I'm currently not experiencing this problem with any other aircraft.

2. The problem only exists when the aircraft is controlled by the AP/AT. When controlling the engines via the joystick there is no problem.

3. I am using a customized (modified by me) version of the supplied panel which is very similar to, but not exactly the same as, the FS9 T7 default.

I have tried reducing the "thrust_scalar" from 1.0 to 0.82 and reducing the "autothrottle_max_rpm" from 110.0 to 90.0 resulting in some improvement but the problem is not completely resolved.

I'm picking up from the responses that this could be a panel related problem. Perhaps I'll try starting from scratch with the un-modified package in case I made a mistake in any of my panel mods. I'll report back my findings.

Thanks for your help guys.

Regards,
Bob

[garryrussell]

Like is a panelprob Bob

Best of luck

Garry

[doylebob]

My PC took a tumble yesterday so I have not been able to try out anything yet.
Working on getting back up. Hopefully will be back to normal before too long.
Bob

[Johan Dees]

The well know freeware developpers make good visuals, but not so good airfiles..
You can look in the .air, table 1199 and tune the ap/throttle there..