FSX Aileron Trim Tab Tags

The aircraft I am currently modelling has two trim tabs on the left aileron & one on the right, I am confused as to what the correct animation tags they should be given, as far as I can see from the SDK "animation tags" HTML document there are two tags that could be used trimtab_l_aileron_key_pct or trimtab_l_aileron_key, I would assume that trimtab_l_aileron_key_pct would be used for the extra trim tab on the left aileron & trimtab_x_aileron_key used for the identical aileron trim tabs on the left & right ailerons.

Any guidance would be most appreciated.


Resource contributor
The modeldef.xml says:

  <Variable>AILERON TRIM PCT</Variable>




As you can see, each and every entry works exactly the same, so pick whichever one you like.

Paul Domingue

Resource contributor
"deprecated" ?? - Johnman
deprecated is an attribute applied to a computer software feature, characteristic, or practice to indicate that it should be avoided (often because it is being superseded). Beyond describing software, the term is also used for a feature, design, or practice that is permitted but no longer recommended in other areas, such as word usage, hardware design, or compliance to building codes.


Resource contributor
Hmmm. Are you sure the two tabs on the left aileron are both trim tabs? I would have thought one would be a trim tab and the other a spring tab, in which case the right aileron has a spring tab only. The DH.103 Hornet had spring and balance tab on the starboard wing and spring tab only on the port wing, for example.

Paul Domingue

Resource contributor
But what's the meaning of deprecated in the context of FSX - which is an obsolesent application in any case?
Generally some of the old code in the model definition file were included from FS9 and superseded with similar new code. That's why you will see key and percent key for the same function.
Just backing up Tom's point.

Are you sure they are both actual trim tabs? It depends on the aircraft but on a small aircraft such as the Cessna 172 there is usually only one elevator trim tab as that is all that is needed for normal operation.

If there are two trim tabs then one may indeed be a servo or balance tab which will function differently to the way the trim tab is defined in the modeldef.

See here for more info:

The aircraft I am working on has a servo trim tab on the left elevator. It pitches up 8-10 degrees when elevator is full down, 2-4 degrees up when elevator is neutral and 14-16 degrees up when elevator is full up.

Thanks' for the replies, the aircraft I am working on is the Gates Learjet 35A, I was going to post a photo but I don't want to infringe any copyrights. I have tried searching online to try & find out what the extra aileron tab is for but without any success.
Have you read this or do you have a copy already. It's for the 30 series? How different is the 35A from the 30 series aircraft in this manual?


Page 240 (section 15.5). It's quite comprehensive.

EDIT: For some reason I thought we were talking about elevator trim but on re reading the OP we are talking about the trim tabs on the ailerons. The outboard ones on both ailerons are balance tabs. The smaller inboard on the left wing is a typical trim tab. It doesn't say much about the balance tab but there is a picture on page 242 which shows the aileron upwards and the trim tab pointing downwards. The balance trim tabs would therefore move based on the aileron position and not have anything to do with the normal trim tab position.
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Thanks' Anthony31 for the link, very useful. It appears that the balance tabs move in opposition to the ailerons, so now I will have to look in the modeldef.xml to see if there is an entry for this & if not I will have to write a partinfo entry for this or I could just animate it to move the opposite to the aileron it's attached too & tag it as an aileron.
As Tom says, just use the same tag as for the ailerons (will save you one or two drawcalls). This is assuming they are mechanically operated by the aileron controls and not electrically operated.
Thanks' all,

Athony31, why would it be problem if they are electrically actuated? do you mean that they would not move in correlation of the ailerons, have the same deflection angles?
If you were parked and had the power off and moved the ailerons then the balance tabs were electrical then the tabs wouldn't move as they wouldn't have any electricity. I think they are most likely mechanical though which I think the ailerons are too so it probably isn't an issue but it's your plane so I guess you would know the systems better than I.
I have found out that the ailerons & balance tabs are both mechanical so will have no problem animating & tagging both as ailerons only animating the balance tab opposite to the respective aileron.

Thanks' for everyone's help.