F-5 Pitch trim question.

Great module! but one thing is bugging me. Aircraft setup with no stores or gun ammo, fully fueled.

I set the trim roughly according to the table, maby a little less nose up trim. I find that i have to trim it nose down forever to get it even close to straight and level flight, even dialing back the throttle to maby 70-80% it still likes to jump up. For me trimming nose up at all seems useless before takeoff? Only other module that i have experienced this slow trim response is the F-86, i accept that because of it's old age. I would like your input on this.

Thanks.

Yes that's correct, after the 'rotate' you'll need to trim it down until the aircraft stablizes, once you get used to it, it'll not bug you anymore :)

In my opinion, using the trim (6 degrees of nose up) during the take off helps me a lot (that's why it is recommended to use it during the take off).

Yeah i guess it is a getting used to thing like you say. Would be interesting to know if the trim is so "slow" in real life though, well i guess i am a little to picky abouth the details :)

Thanks.

Yeah i guess it is a getting used to thing like you say. Would be interesting to know if the trim is so "slow" in real life though, well i guess i am a little to picky abouth the details :)

 

Thanks.

That's interesting because in my opinion the trim response is just fine, even faster than some aircraft, like the Viggen, in the Viggen it takes a while to do something. :)

Trim setting for takeoff or approach speeds has nothing to do with trim setting for level flight.

All planes are like this irl.

Pitch trim is really important when the plane is loaded but also to reduce takeoff speed and distance and landing speeds especially on the f-5,busted tyres are common with improper trim settings.

At what speed do you rotate and how much input does it take?

For the f-5 i think i use a pitch trim of 1 or 2 during flight.

Actually the f-5 is more representative in this matter of real planes than others in dcs

That's interesting because in my opinion the trim response is just fine, even faster than some aircraft, like the Viggen, in the Viggen it takes a while to do something. :)

Strange. I don't own the viggen (yet) because im only on steam. I find the mig-15 to be very responsive and quick to get level and straight, and of course the A-10 as well. But the F-5 is by far the slowest in trim response of my modules. For the F-86 i used curves to get a softer center response to get it to fly almost hands off after some trim adjustment. Using a TM warthog with its hard spring i like to get things nice and trimmed.

Trim setting for takeoff or approach speeds has nothing to do with trim setting for level flight.

All planes are like this irl.

Pitch trim is really important when the plane is loaded but also to reduce takeoff speed and distance and landing speeds especially on the f-5,busted tyres are common with improper trim settings.

At what speed do you rotate and how much input does it take?

For the f-5 i think i use a pitch trim of 1 or 2 during flight.

Actually the f-5 is more representative in this matter of real planes than others in dcs

I get that. Never had a bursted tyre on my F-5. Input wise i pretty much have to center the stick and hold the trim nose down for a long time right after it unsticks. And also dialing back throttles, it really likes to shot straight up. I will try to fly at these setting and se what i find.

Thank you.

Hey guys

The issue of trimming is to set the trim tab in order to have the chosen pitch staying steady. Without any input on stick. If you speed up as fast as the f5 does on take off with ab, then the pilot must trim the tab on the elevator very quickly in order to get rid of the pressure on the stick. Do not steer the plane with your trim nob, the adjustment of the tab will not happen fast enough. Always first input is on stick. You are right, after take off while speeding up, you need to push the stick or you will go into the vertical.

The trim tab does not reduce the take off or landing speed like flabs do, because it does not affect the wing profile. The tab only adjusts the angle of the elevator (or the rudder). Except for take off do not rely on trim indicator, just feel the proper setting. Pitch trim depends on speed, altitude, aoa, weight, balance, flab setting.... We have to work a lot....

I agree with Figaro9. The Trim tab there so that back pressure does not have to be held by the pilot. If you are empty and no ordinance or tanks... you should only trim a little like 4 or 5 and that may be too much. There are recommendations that I have attached from the manual however my trim settings are lower than what this recommends. I like to put a little back pressure on the stick to pull the nose up when I take off.

For landing I always set the trim to 5 and that usually puts me at just the right angle of attack for the approach with just a bit of nose down pressure until the moment of touch down then I flatten the decent and flare. Hope this helps.

I agree that the trim doesn't affect the takeoff and landing speeds, i phrased it poorly, wrong trim however does lead to early or late rotation and too steep or shallow approaches.

The settings in the manual are pretty good, i use 5-6 on approach too and find the f-5 pretty much flies itself down.

When cruising the technique is always the same set pitch, then power and trim last.

Personally, I leave the trim at zero. I pull full back stick at 140 kt on takeoff with a clean airframe. Nose lifts just fine. I have to hold back pressure until I cut the burners at 300-400 knots, but I prefer that over trimming constantly after takeoff.

That's just my way of doing it, it's by no means the "best" or most realistic method.

There seems to be something wrong with the trim settings with the F5. I have the trim setting mapped to my HOTAS stick. I placed the plane on the ground and watched the trim tabs from an outside view, I notice that the trim keeps moving. For example, if I apply pitch up trim, the trim tab does not stop when I stop applying trim, the trim tab continues to move.

In flight, this means I an continually applying opposite trim in one direction; then another. Is there a fix for this. The trim should be momentary and not continuous.

I've never seen anything remotely like this-- granted I haven't played since Friday night but I don't think any updates have dropped since then. It sounds like a binding problem. Did you clear every other binding on every other device except your desired HOTAS buttons for up and down? What happens if you just map it to a pair of keyboard keys and test that way? What does the pitch trim indicator show?

I've never seen anything remotely like this-- granted I haven't played since Friday night but I don't think any updates have dropped since then. It sounds like a binding problem. Did you clear every other binding on every other device except your desired HOTAS buttons for up and down? What happens if you just map it to a pair of keyboard keys and test that way? What does the pitch trim indicator show?

Good question. When I try the actual key mapping the same thing happens. Whichever direction you push the trim, the trim tab just keeps going in that direction until it can go no further. I've only tested this with the F5. Don't know if this happens with other planes in DCS.

I just tested the SU-33, A10-C, F-86, and none of them exhibited the issue with trim. So far, only F5 is doing this.

Sorry man, just to be safe I tested my system again, no issues here. Trim moves up and down through the full range and stops when I let off the HOTAS hat I have it mapped to. I also looked through the bindings under the axis commands just to make sure there isn't the possibility of a "pitch trim" axis, there is not....

This really sounds like a binding problem to me. I don't know what kind of set up you are running and how many controllers you have, but I know sometimes I have to scroll right on the control setup screen to see all my attached controllers.

If its not a binding issue it might be time to try a repair on your installation-- I think if this was a problem more people were having this thread would be packed with responses, runaway trim is a RL emergency, people would be howling about it here if it were widespread.

EDIT: One last question -- you are confirming this trim movement through the indicator, correct? In your first post you mentioned an external view-- I just want to confirm it is actually the trim moving, not a wandering elevator that you are having to chase with trim.

There seems to be something wrong with the trim settings with the F5. I have the trim setting mapped to my HOTAS stick. I placed the plane on the ground and watched the trim tabs from an outside view, I notice that the trim keeps moving. For example, if I apply pitch up trim, the trim tab does not stop when I stop applying trim, the trim tab continues to move.

I had this happen to me in a Viggen flight last week. I was setting takeoff trim, and it just continued to increase until it went max noseup. Trying to adjust it down sent the trim all the way in the other direction, even after I released the hat. There was no way to keep it in the middle.

I've only had it happen once, but it was bloody weird when it did.

Jesus, it's always something with this freaking program. This issue is happening only with the F5E. No other planes are doing this. I've testing with with all the modules I own.

First, I am doing this from the runway or parked. When I control the trim with the trim hat on my HOTAS, I can see the stick continuing to move in relation to the trim tab movement. However, If I control the trim hat with the mouse, the freaking thing functions normally and does not exhibit the crazy traits.

WTF!

Sorry man, just to be safe I tested my system again, no issues here. Trim moves up and down through the full range and stops when I let off the HOTAS hat I have it mapped to. I also looked through the bindings under the axis commands just to make sure there isn't the possibility of a "pitch trim" axis, there is not....

 

This really sounds like a binding problem to me. I don't know what kind of set up you are running and how many controllers you have, but I know sometimes I have to scroll right on the control setup screen to see all my attached controllers.

 

If its not a binding issue it might be time to try a repair on your installation-- I think if this was a problem more people were having this thread would be packed with responses, runaway trim is a RL emergency, people would be howling about it here if it were widespread.

 

EDIT: One last question -- you are confirming this trim movement through the indicator, correct? In your first post you mentioned an external view-- I just want to confirm it is actually the trim moving, not a wandering elevator that you are having to chase with trim.

In the controls setup, there are no additional controllers install. Only running a mouse, keyboard, and X55 HOTAS.

Not sure how to make the indicator display. However, the trim tabs are in fact moving the plane. when flying I must constantly readjust the trim due to the surfaces constantly moving from full stop, to full stop. Secondly, I can see the stick moving as the trim moves through its full range. Also, this is the strangest of them all. If I tap the trim hat using the mouse, the trim performs as expected, moving only for as long as I press the hat in a given direction, and stopping as soon as I release pressure on the hat. But, If I use the keyboard commands for trim, the odd behavior resumes and the trim continues moving until it reaches the stop.

I have never noticed the stick movement before but I started up on the ramp and moved the trim and my stick in fact moves with it. And my trim is working normally, so I believe the stick movement is not relevant.

That mouse/keyboard thing is weird...did you try clearing the keyboard binding and setting it to something else?

You don't have to do anything to make the trim indicator display, it is a small gauge directly above your ADI. It is the gauge you use to set your elevator trim before takeoff. If this gauge is moving back and forth from stop to stop you indeed have a trim problem, I would submit a track file of this. If this gauge isn't moving, I suspect the issue is actually an elevator axis binding problem masquerading as a trim problem.

EDIT: Did some research on the stick movement. USAF TO 1F-5E-1 is very thin on the flight control section, but it describes the horizontal as "an all moveable horizontal tail" and it says the pitch trim indicator "indicates trim position of the horizontal tail." It also says "Artificial "feel" is built into the system, and electrical trim actuators change the relationship of the "feel" springs to the control stick." This is all on page 1-57. The DCS manual says the trim gauge indicates "pitch trim position (control stick position and horizontal tail position accordingly)." That is page 106. This leads me to believe movement of the stick when the trim is moved is a correct feature. Maybe someone with RL F5 time could speak to that though...

I have never noticed the stick movement before but I started up on the ramp and moved the trim and my stick in fact moves with it. And my trim is working normally, so I believe the stick movement is not relevant.

 

That mouse/keyboard thing is weird...did you try clearing the keyboard binding and setting it to something else?

 

You don't have to do anything to make the trim indicator display, it is a small gauge directly above your ADI. It is the gauge you use to set your elevator trim before takeoff. If this gauge is moving back and forth from stop to stop you indeed have a trim problem, I would submit a track file of this. If this gauge isn't moving, I suspect the issue is actually an elevator axis binding problem masquerading as a trim problem.

So, the default key bindings for trim, and the HOTAS bindings for trim are jacked up. If I eliminate the default key bindings for trim for a entirely new set of bindings, can I return to the default bindings for trim?

So, the default key bindings for trim, and the HOTAS bindings for trim are jacked up. If I eliminate the default key bindings for trim for a entirely new set of bindings, can I return to the default bindings for trim?

I would think you would be able to after you figure this out. First and foremost though I think you need to verify it is for sure the trim that is sticking and I think the gauge is the best way to do this. Since the tail is an all moving surface I don't think external views are sufficient to sort trim movement from elevator movement.

I would think you would be able to after you figure this out. First and foremost though I think you need to verify it is for sure the trim that is sticking and I think the gauge is the best way to do this. Since the tail is an all moving surface I don't think external views are sufficient to sort trim movement from elevator movement.

The indicator dial is showing the movement of the trim, as I expected it would.

Well I hate to say it but that empties my barrel of ideas. I have never had to do it but it sounds to me like you are reaching the point of an installation repair or similar tactic. I think if this were a more systemic problem there would be a boatload of people here trying to chase this problem down, runaway trim is something no one will tolerate-- as your frustration indicates. Sorry I wasn't able to help, good luck. Hopefully someone with more knowledge (or just the specific knowledge you need) shows up and reads this thread and will be able to help.

Well I hate to say it but that empties my barrel of ideas. I have never had to do it but it sounds to me like you are reaching the point of an installation repair or similar tactic. I think if this were a more systemic problem there would be a boatload of people here trying to chase this problem down, runaway trim is something no one will tolerate-- as your frustration indicates. Sorry I wasn't able to help, good luck. Hopefully someone with more knowledge (or just the specific knowledge you need) shows up and reads this thread and will be able to help.

Is there a re-installation procedure for DCS modules?