F-15 trim - is it correct or too coarse?

[Crescendo]

I have noticed that when flying the F-15 it is difficult to trim for level flight for more than a few seconds at a time.

 

Whenever I trim the aircraft left or right with one 'click' of input it begins to roll noticably in that direction almost immediately, to the point where it is difficult, if not impossible, to find a 'sweet spot' where some semblance of level flight can be achieved for more than 10s. I don't trim an aircraft for level flight and then expect it maintain that attitude indefinitely, but there should be some ability to fly 'hands off' for a minute or so without significant flight path deviations. Otherwise, what's the point of having trim at all?

 

To me, the current trim is too coarse, or to put it another way, the resolution is too low. I think one 'click' of trim input should result in less control surface movement, which would make it easier to find that sweet spot. As it stands now, it bears no relation to my real life experience with trimming an aircraft. I'm not saying that this makes me an expert or that my limited civil experience bears any relation to a modern fighter — it doesn't — but it does make me pity F-15 pilots if they have to struggle as much as I do.

 

(And yes smart alecs, I could use autopilot, but that is beside the point.)

[fitness88]

I have noticed that when flying the F-15 it is difficult to trim for level flight for more than a few seconds at a time.

 

Whenever I trim the aircraft left or right with one 'click' of input it begins to roll noticably in that direction almost immediately, to the point where it is difficult, if not impossible, to find a 'sweet spot' where some semblance of level flight can be achieved for more than 10s. I don't trim an aircraft for level flight and then expect it maintain that attitude indefinitely, but there should be some ability to fly 'hands off' for a minute or so without significant flight path deviations. Otherwise, what's the point of having trim at all?

 

To me, the current trim is too coarse, or to put it another way, the resolution is too low. I think one 'click' of trim input should result in less control surface movement, which would make it easier to find that sweet spot. As it stands now, it bears no relation to my real life experience with trimming an aircraft. I'm not saying that this makes me an expert or that my limited civil experience bears any relation to a modern fighter — it doesn't — but it does make me pity F-15 pilots if they have to struggle as much as I do.

 

(And yes smart alecs, I could use autopilot, but that is beside the point.)

 

 

Flying Migs makes you very familiar with trimming, I did make adjustments in the axis controls of the options menu. However I've never needed to trim the F15.

[Crescendo]

The F-15 does have an autotrim function, so yes, I don't trim as often as in a Russian aircraft or a propellor-driven aircraft etc. However, there have been situations where manually trimming the F-15 would be useful, but I haven't really been able to do it my satisfaction for the above reasons.

[fitness88]

The F-15 does have an autotrim function, so yes, I don't trim as often as in a Russian aircraft or a propellor-driven aircraft etc. However, there have been situations where manually trimming the F-15 would be useful, but I haven't really been able to do it my satisfaction for the above reasons.

 

 

Go to the axis controls in the options menu and change the settings for the trim.

[HiJack]

Crescendo, I don't know what stick you got but I wrote this post to make better trim with the X52Pro. You may get some ideas on how to make your own "half click" at least.

http://forums.eagle.ru/showthread.php?t=82773&highlight=trim

[Crescendo]

Go to the axis controls in the options menu and change the settings for the trim.

 

I must be missing something because there is no setting for trim controls in the "Axis Commands" menu for the F-15.

 

As I understand it, all trim commands for the F-15 are just a one button press (or POV hat press) to one 'click' of trim.

 

Crescendo, I don't know what stick you got but I wrote this post to make better trim with the X52Pro. You may get some ideas on how to make your own "half click" at least.

http://forums.eagle.ru/showthread.php?t=82773&highlight=trim

 

I use the HOTAS Warthog. I'll definitely check out your link.

[fitness88]

Refer to page 25 of 'DCS User Manual' titled 'Axis Tune Panel' This will desensitise your trim.

OR as I do: I too use Saitek x52pro and find using the mini mouse control works well for me.

[Crescendo]

Refer to page 25 of 'DCS User Manual' titled 'Axis Tune Panel' This will desensitise your trim.

OR as I do: I too use Saitek x52pro and find using the mini mouse control works well for me.

 

I read that page. I do understand what curves are and how to use them, but I still don't see how this relates to trim. There is no ability to apply a curve to the trim controls because trim is not an axis in FC3.

 

Either I'm missing something very obvious, or we're talking about very different things.

[fitness88]

I read that page. I do understand what curves are and how to use them, but I still don't see how this relates to trim. There is no ability to apply a curve to the trim controls because trim is not an axis in FC3.

 

Either I'm missing something very obvious, or we're talking about very different things.

 

That's interesting because the choices of controls given when selecting trim happen to be axis controls. I use X rotation [rotary control] and Y rotation on my Saitek X52 Pro and it works incrementally.

In FC3 axis controls:

trim pitch=Joy RX

trim roll=Joy RY

These 2 have axis tuning.

Edited February 17, 2013 by fitness88

[Crescendo]

That's interesting because the choices of controls given when selecting trim happen to be axis controls. I use X rotation [rotary control] and Y rotation on my Saitek X52 Pro and it works incrementally.

In FC3 axis controls:

trim pitch=Joy RX

trim roll=Joy RY

These 2 have axis tuning.

 

OK, I definitely don't have the "trim pitch" and "trim roll" axes in my F-15 controls.

 

It seems that this is due to you using the Saitek X52 Pro and myself using the HOTAS Warthog. I suppose that the X52 Pro has extra axes which prompts FC3 to enable trim axes in the control menu.

[fitness88]

OK, I definitely don't have the "trim pitch" and "trim roll" axes in my F-15 controls.

 

It seems that this is due to you using the Saitek X52 Pro and myself using the HOTAS Warthog. I suppose that the X52 Pro has extra axes which prompts FC3 to enable trim axes in the control menu.

 

 

You must be using the All Commands list which offers trim rudder left, trim up, etc.

You are quite correct, because you don't have the available controls on your HOTAS, you won't have the bind options available in the axis commands list.

I see slider is available as well in Axis Commands...I would guess you don't have a slider on your HOTAS?

Edited February 18, 2013 by fitness88

[Crescendo]

You must be using the All Commands list which offers trim rudder left, trim up, etc.

You are quite correct, because you don't have the available controls on your HOTAS, you won't have the bind options available in the axis commands list.

I see slider is available as well in Axis Commands...I would guess you don't have a slider on your HOTAS?

 

To be clear, I have been checking both "All Controls" and "Axis Commands" as I mentioned in an earlier post. There is no "trim pitch" and "trim roll" for me anywhere.

 

There is a single axis slider on the HOTAS Warthog called "JOY_SLIDER1". I presently have it assigned to "Zoom View" as there isn't much else it's useful for.

[fitness88]

To be clear, I have been checking both "All Controls" and "Axis Commands" as I mentioned in an earlier post. There is no "trim pitch" and "trim roll" for me anywhere.

 

There is a single axis slider on the HOTAS Warthog called "JOY_SLIDER1". I presently have it assigned to "Zoom View" as there isn't much else it's useful for.

 

Yes I do understand...this being the limitation of your joystick. I too use the slider for zoom.

Also the trim characteristics on the Mig or SU gives less input to your controls than the F15, but in my case it doesn't make contolling the F15 more difficult.

Edited February 19, 2013 by fitness88