Reset trims

[peirof]

Hi,

 

is there any way to reset the trim on the plane?

 

This has happened to me at some time, during the flight, I have had to trim the plane, since I have used weapons or after take off or before landing... for example ... I have thrown a bomb on the right wing, then I have trimmed the plane ... and later, to launch its sister pump on the left wing, at that moment, instead of trimming again ... There is no assignment to "reset" the trim of the plane?

[HammerUK9]

Hit the T/O Trim button on the left console.

[Frederf]

T/O trim button does nothing in flight (unless you're in mechanical backup). No, there is no reset trim. You drop a bomb you use the trim switch on the stick.

[HammerUK9]

2 hours ago, Frederf said:

T/O trim button does nothing in flight (unless you're in mechanical backup). No, there is no reset trim. You drop a bomb you use the trim switch on the stick.

 

Cheers, wasn't 100% sure on that but thought it worth a go

[Bunny Clark]

Don't think of trim as having a neutral "zero" point to return to. That's not the point. There is Takeoff Trim, which sets the jet up for a take off configuration, but that's not the same as a neutral configuration either. It's just meant for takeoff. 

 

Trim is a pilot relief function, it's only purpose is to help you fly the plane. Fly the plane first, then use trim as necessary. If you drop a bomb and the plane is rolling, trim it out. Don't look for a magic fix-it button, it doesn't exist. Just fly the plane. 

Edited June 23, 2021 by Bunny Clark
spelling

[TimRobertsen]

On 6/21/2021 at 6:00 PM, peirof said:

Hi,

 

is there any way to reset the trim on the plane?

 

This has happened to me at some time, during the flight, I have had to trim the plane, since I have used weapons or after take off or before landing... for example ... I have thrown a bomb on the right wing, then I have trimmed the plane ... and later, to launch its sister pump on the left wing, at that moment, instead of trimming again ... There is no assignment to "reset" the trim of the plane?

 

There is a trim reset, but, you have to have weight-on-wheels.

 

With weight-on-wheels: press and hold the Take-off Trim button for a couple of seconds. That will reset all the axis.

 

Unfortunatly, there is no in-flight trim reset.

 

You might be able to do trim reset during a touch-and-go on a runway  I haven't tried it  

[Svend_Dellepude]

1 hour ago, TimRobertsen said:

 

There is a trim reset, but, you have to have weight-on-wheels.

 

With weight-on-wheels: press and hold the Take-off Trim button for a couple of seconds. That will reset all the axis.

 

Unfortunatly, there is no in-flight trim reset.

 

You might be able to do trim reset during a touch-and-go on a runway  I haven't tried it  

 

As @Bunny Clark wrote above, this will configure the A/C for takeoff, not reset the trim. 

[Foka]

If you open a FCS page, you'll notice that T/O Trim sets steering planes to +12. It's not a reset.

[peirof]

Ok, thanks all... 

 

 

[TimRobertsen]

22 hours ago, Svend_Dellepude said:

 

As @Bunny Clark wrote above, this will configure the A/C for takeoff, not reset the trim. 

 

22 hours ago, Foka said:

If you open a FCS page, you'll notice that T/O Trim sets steering planes to +12. It's not a reset.

 

That's if you press it. 

 

If you press and hold it, you'll see that the aileron-trim slow works itself towards the center: reset  

Yaw trim will also re-center, but that happens regarless of whether you press or hold it.

 

I was a little unclear when I wrote "rest all the axis", I was thinking of the unsymetrical trims: aileron (which is the one in question by OP) and Yaw.

Elevator- and Yaw-trim will, of course, as you guys mention, go to the TO-position, but it nulls out once you have weight off wheels (if you push/hold the TO-trim button with flaps in auto; if you push/hold with flaps in half/full it will only reset when you are airborne and the flaps are set to auto). 

 

Regardless, it is, of course, not particularly practical to have to land after you have dropped some bombs so that you can reset your trims. But it is an option

To avoid all of this, it's best to just drop bombs symmetrically  

 

 

Where @Bunny Clark is a little bit wrong is that the TO-T-button does have a dual function: TO-trim and aileron-trim reset. There is a zero position  

Pushing and holding the TO-T-button on ground (with flaps in auto) does neutralize the aileron and yaw trim axis. It is, almost, a magic button 

 

Try it out: Do a shore landing, with flaps in auto, and aileron and yaw trimmed in any direction. Push and hold the TO-T-button, and then take-off, with flaps in auto. Once you're airborne you'll see that the axis trims are nulled out, and the hornet is perfectly balanced, as all things should be  

 

The weird thing is, if you do land with flaps in auto and pitch trimmed, and then push/hold the TO-T-button once on ground, aileron and yaw will be neutral and elevator will go to 12, then when you take off (with flaps in auto), once you're airborne the "12" will be nulled out but the pitch-trim will revert back to the pitch-trim-setting you had when before push/holding the TO-T-button. The pitch trim will only reset with cycling the flaps.

 

So, all in all, it is a bit odd that the Hornet doesn't have a full-trim-reset-button, since all the trim-axis can be neutralized, just in 3 very different ways.

 

On 6/21/2021 at 7:20 PM, Frederf said:

T/O trim button does nothing in flight (unless you're in mechanical backup). No, there is no reset trim. You drop a bomb you use the trim switch on the stick.

Pushing the TO-T-button in flight does actually reset the the yaw-trim.

[Svend_Dellepude]

43 minutes ago, TimRobertsen said:

If you press and hold it, you'll see that the aileron-trim slow works itself towards the center: reset  

Yaw trim will also re-center, but that happens regarless of whether you press or hold it.

 

Yaw and aileron trim to center is part of takeoff trim, since you don't want to takeoff with an A/C that will rolls inverted as soon as you lift off. With asym loadouts you dial in lateral trim after pressing T/O trim. 

 

The yaw dial will be mechanically centered when you press the T/O trim.

 

I think I read somewhere (might be on these forums) that the FCS reset should reset any trim in flight, but it's not implemented.

[Frederf]

5 hours ago, Svend_Dellepude said:

 

The yaw dial will be mechanically centered when you press the T/O trim.

Only with WOW. In flight it should not. This is a bug.

[Bunny Clark]

7 hours ago, TimRobertsen said:

Where @Bunny Clark is a little bit wrong is that the TO-T-button does have a dual function: TO-trim and aileron-trim reset. There is a zero position  

Pushing and holding the TO-T-button on ground (with flaps in auto) does neutralize the aileron and yaw trim axis. It is, almost, a magic button 

 

There are two things going on here that are important. You are correct mechanically, but going in the wrong direction with your thinking. 

 

The first point is a pedantic one, and that is there is a difference between mechanical neutral and aerodynamic neutral. Just because all the symmetrical trims have been reset to their baseline "0" values does not ensure that the aircraft will fly straight and level. The purpose of the T/O Trim button is to configure the jet to a known baseline trim setting while on the ground. Those baseline settings are then modified based on aircraft gross weight and any asymmetrical stores to ensure that an aircraft makes as stable a transition as possible from a non-aerodynamic state (resting on the ground) to an aerodynamic state (flying). Once the aircraft is flying, there is no point in resetting those trim values because you no longer have to make that transition, you're already flying. 

 

Which brings me to the main point: fly the damned plane. The primary problem with wanting some kind of trim reset in flight is one of mindset. If you drop a bomb and the plane is now rolling left you should not be considering what the specific aileron roll values are nor hunting for a way to reset them to some mathematical mechanical neutral. Just trim the plane until it stops rolling. The T/O Trim button is useful because when on the ground you don't know the aerodynamic state of the aircraft so you have to guess. When you're flying you do know the aerodynamic state of the aircraft so you don't have to guess. Trim the plane until it flies the way you want it to, that's your neutral position, it doesn't matter what the FCS Page says. Wanting some kind of trim reset button is looking backwards to try to solve a current problem when you should just be flying the plane. 

[GrEaSeLiTeNiN]

Is the T/O trim button really necessary to use or good to have? I've never used it and am able to take off just fine.

[Svend_Dellepude]

18 hours ago, GrEaSeLiTeNiN said:

Is the T/O trim button really necessary to use or good to have? I've never used it and am able to take off just fine.

 

Using the T/O trim should remove any guess work and set the A/C to takeoff when it's ready. You still get sucked to the ground under certain circumstances with the current FM, but hopefully that will be fixed with the revision.

[GrEaSeLiTeNiN]

 
Using the T/O trim should remove any guess work and set the A/C to takeoff when it's ready. You still get sucked to the ground under certain circumstances with the current FM, but hopefully that will be fixed with the revision.

Could I not just pull back on the stick? Or is there a difference? Thanks

[Svend_Dellepude]

Natops says that you should or you might not have full stab movement available. Dunno if that is the case in DCS currently.

 

On a turnaround though, pressing T/O trim centers yaw and roll trim, if any present.

 

 

 

 

[Hulkbust44]

Could I not just pull back on the stick? Or is there a difference? Thanks

Just always use T/O trim. It's required for the jet to not yell at you :)
On the carrier you must have a min stab position of 16.

There is potential that you will not have proper pitch authority if you don't.

When you do have proper T/O trim set, you shouldn't need to touch the stick at all for takeoff. Unless it's a section takeoff, I don't.


Mobius708