Inability to Trim Jet with TGP Loaded

[Mirage2425]

I was talking with BIGNEWY on Discord and he suggested I upload a track file for you to review. I know this has been brought up before and I think it was determined to not be a bug. That being said I was wondering if you guys would be willing to take another look and maybe run it past your SME's. When loaded with the TGP it's nearly impossible to completely trim the aircraft out. This makes tanking and formation flying difficult. I've attached a track for your review. In it I take off from Ramat David, bank to the right and then level off. I then wait about ten seconds to show the jet slowly rolls to the right. I then put in one click of trim and the jet starts slowly rolling to the left. If this is the way it is IRL then I definitely want to keep it that way. I just can't believe that the Air Force would allow something to be loaded onto the jet that compromises it's ability to fly straight and level. A lot of the work a pilot needs to do is heads down, whether it be working the radar or lining up for a LGB attack. If the jet is slowly rolling to the right or the left it makes it difficult. Please take another look at this and let me know.

 

Thanks,

 

Mirage

TGP Trim Test.trk

[Mikaa]

F16FLCS-SME also has reported that the pitch and roll trim rates seem to be much faster in DCS as compared to the real jet. Not sure if they have any documentation to prove so, but I'd be inclined to believe someone who specifically worked on those systems. Maybe this has to do more with the granularity of each "click" of trim, or overall speeds, or both.

 

https://forums.eagle.ru/forum/englis...es#post7131511

Edited November 28, 2020 by Mikaa
words are hard

[randomTOTEN]

You're constantly accelerating throughout your track as well. You will give yourself major difficulties if you try and trim with constantly variable aerodynamic forces. Hold a constant airspeed and then trim to relieve pressure. A lot of people don't like it when I say this, but you can also give a click or 2 of rudder trim to center the ball and counteract the asymmetric drag from the pod too.

A lot of the work a pilot needs to do is heads down,

Pilots aren't robots. They are taught airmanship. They know not to stay heads down for long periods, and to divide their attention between outside and inside. You also shouldn't be heads down at all during close formation or AAR.

In your track their isn't a major amount of roll anyways... better than the A-10C most days. Video games teach you that the airplane should fly perfectly level for very long periods when trimmed for straight and level. This just isn't true.

 

Cue the angry replies...

 

EDIT: Using roll trim only (no yaw), it took 1m43 seconds after releasing my joystick for the jet to roll just 10° of bank in your track....:music_whistling:

[Mirage2425]

No angry reply from me actually. I want the jet to be as realistic as possible and I want to learn how to fly it that way. I've found that using the TGP or the Maverick difficult as it takes me a long time to find and get a firing solution on a target. This will get better with time as I practice. If this is really the way the jet is I want it to stay that way and learn to compensate. I've already learned to compensate some during refueling and formation flying. It's just the heads down tasks I struggle with. So you are saying if I set a specific fuel flow and allow the speed to stabilize it will be easier to trim the jet? I can try to apply rudder to compensate but I currently have the cheap thrustmaster pedals and it's difficult to apply just a little rudder. I'll continue to practice that. To summarize, if this is the way it is IRL then that's the way it needs to stay. I just need to continue to get better and learn to go heads up from time to time to make sure the roll doesn't get out of control. Thank-you for the response.

[Mirage2425]

On another note, how do you take control of a track?

[Mirage2425]

I've been thinking about this more and if you set trim it will only be effective at that altitude and speed. I've noticed at higher altitudes the jet doesn't roll as much. This must be due to thinner air. So trim must be there to assist the pilot in dealing with asymmetric loadouts, not to eliminate it entirely. I doubt a combat pilot is constantly trimming the aircraft as they change speed and altitude.

[randomTOTEN]

It's just the heads down tasks I struggle with.

Sounds like you need to work on what is called "division of attention." Interrupt your heads down work with moments of looking outside to see what the airplane is doing and where it is going. Have a look at the flight instruments either in the panel or the HUD indications. Once satisfied go back to heads down. I suggest timing this with accomplishing steps of a procedure. Do a step, look up, do a step, look up....

To take control of a track press escape while it is running.

Jet (in this case) does not care how thick or thin the air is. It is just one of many factors which determine the rate at which air molecules strike the aircraft (aerodynamic force).

All pilots are always trimming. Your F16 teaches you bad habits but that is the price you pay for Fly-By-Wire.

Vary fuel flow to maintain desired speed. That is what speed control is. To set a random fuel flow and let speed wander randomly is not how you maintain speed.

[Mirage2425]

Got it, thanks randomTOTEN. We'll see if the drag on the TGP is accurate. Either way it's not going to take away the pilot's responsibility to control the aircraft.

[Dee-Jay]

Hi!

I doubt a combat pilot is constantly trimming the aircraft as they change speed and altitude.

 

Sure he does.

 

F16FLCS-SME also has reported that the pitch and roll trim rates seem to be much faster in DCS as compared to the real jet.

 

This issue in DCS is not about the rates (witch looks okay, I didn't measured them) but the implementation of the trim input/pulse itself. It is all or nothing (1/0) with no progressiveness/trim acceleration. That makes trimming "difficult" (quite often too much or not enough) and rather unrealistic on DCS F-16.

 

Regards.

[Mikaa]

 

This issue in DCS is not about the rates (witch looks okay, I didn't measured them) but the implementation of the trim input/pulse itself. It is all or nothing (1/0) with no progressiveness/trim acceleration. That makes trimming "difficult" (quite often too much or not enough) and rather unrealistic on DCS F-16.

 

Regards.

 

Yep, that's what I meant about the granularity of the trim clicks. I probably could've explained myself better. Now I've never flown an F-16, but every auto-trim system I've used has been incredibly easy to counter roll for asymmetric loading throughout the entire flight envelope - none of this clicking back and forth because it overtrims too much each way. Regardless, I'm sure it'll get sorted in due time.

[Furiz]

Same goes when you try to reset your trim back to 0, when you remove your TGP and try to trim the aircraft back to 0 it will always roll to a side.

[Glide]

On another note, how do you take control of a track?

Press ESC and take control.

[Falconeer]

You can perfectly trim the Viper using the trim wheels on the rear left console.

 

It should work the same, when using the trim hat on the sidestick.

[Paladin1cd]

So the F-16 doesn't automatically trim for asymmetric loads like the hornet? IRL?

 

Trim in general is to granular in DCS. It has been a problem for the years I've been flying, regardless of airframe. No matter how I flick the trim I never can get it lined out. 

[Crptalk]

2 hours ago, Paladin1cd said:

So the F-16 doesn't automatically trim for asymmetric loads like the hornet? IRL?

 

The hornet does not.

[=52d= Skip]

Well, it was worse in the early days, so ED is working on it
With any luck it´ll even out once we also have the HTS Pod installed.

[Nikolas_A]

13 hours ago, Desert Fox said:

 

A gut feeling, an opinion or verifiable?

You mean IRL or DCS?

[Nikolas_A]

Well, IRL the trim switch on the stick turns the trim wheels on the panel, according to the -1, as @Falconeer said

[Dee-Jay]

20 hours ago, Paladin1cd said:

So the F-16 doesn't automatically trim for asymmetric loads like the hornet? IRL?

 

Correct. No automatically trim for asymmetric loads. (Nor on M2000 nor on Rafale (out of any AP mode)).

[Falconeer]

On 12/1/2020 at 12:03 AM, Desert Fox said:

 

A gut feeling, an opinion or verifiable?

The latter one

Edited December 2, 2020 by Falconeer

[SpaceMonkey037]

Upon testing of the trim system i have noticed and reported the issue. DCS has the trim switch modelled with "clicks" meaning that you either miss your perfect trim by half a click in one direction or the other. It's impossible to hit the perfect trim as with the TGP the perfect trim is in-between two clicks. With "perfect" trim I mean a pretty good trim. Nothing is perfect here. The way the trim switch out work IRL is that you would hold down the trim switch for x amount of time and get the exact trim you held the switch for. As it's almost impossible to hold a switch down for the perfect amount of time the "perfect" trim shouldn't be possible to reach, neither should it be possible to get the exact same trim twice in a row as the chances for this happening are very low. So, IRL it is a smooth trim effect, while in-game it's in clicks which is totally unrealistic. I asked Bignewy about this and he quoted an SME saying "stick trim is course, fine trim is on the left panel". What I think has happened is that they have misunderstood how the stick trim works. Stick trim is equally fine as the trim wheels on the manual trim panel, however it's hard to be very precise with the switch due to the high trim speed, especially in the roll axis. The trim switch should be any less fine than the trim wheels. Hoping that this will get fixed in the future as it is super annoying.

[Dee-Jay]

7 hours ago, SpaceMonkey037 said:

What I think has happened is that they have misunderstood how the stick trim works.

Same here (and I do not think. I am sure), especially because of:

 

Quote

quoted an SME saying "stick trim is course, fine trim is on the left panel"

 

(... !? I wonder what kind of "SME"?)

Left panel is not "fine" trims. It is backup trim (called "Manual Trims" but both stick and wheel trims are manuals) in case of stick trim inpo or "sucked contact" (is also the reason for the Trim/Ap Disc switch).

 

Regards.

Edited December 3, 2020 by Dee-Jay

[SpaceMonkey037]

6 hours ago, Dee-Jay said:

Same here (and I do not think. I am sure), especially because of:

 

 

(... !? I wonder what kind of "SME"?)

Left panel is not "fine" trims. It is backup trim (called "Manual Trims" but both stick and wheel trims are manuals) in case of stick trim inpo or "sucked contact" (is also the reason for the Trim/Ap Disc switch).

 

Regards.

Not correct. The trim panel is considered as finer triming option over the switch, as precice trim is very difficult to do with the switch as the trim input is very large. Therfor the trim panel is often used for more precise trimming. Additionally yaw trim is only available through the manual trim panel. It is true what you say about the trim/ap disc switch, however the panel isn't considered a backup panel.

[Dee-Jay]

1 hour ago, SpaceMonkey037 said:

Not correct. The trim panel is considered as finer triming option over the switch, as precice trim is very difficult to do with the switch as the trim input is very large.

 

Hi!

 

If you say it, I believe you (so it may depends an counties/pilots habits then).

Because wheels are "analog" (no switch pulses) so it is "easier" to get intermediate positions ... but stick trims are not supposed to have such an "all or nothing" effect. (On the jets I have flown I never had wheel trims, only stick trims, it wasn't a problem to perfectly trim the stuff).

 

However, a better answer/recommendation that shroud have been provided by "SMEs" about the stick trim issue should be : as long as DCS will simulate the trims that way (1) instead of something like (2) or even better, something like (3) it won't match a correct stick trim.

 

Regards.

Edited December 3, 2020 by Dee-Jay
Image attachement

[SpaceMonkey037]

32 minutes ago, Dee-Jay said:

 

Hi!

 

If you say it, I believe you (so it may depends an counties/pilots habits then).

Because wheels are "analog" (no switch pulses) so it is "easier" to get intermediate positions ... but stick trims are not supposed to have such an "all or nothing" effect. (On the jets I have flown I never had wheel trims, only stick trims, it wasn't a problem to perfectly trim the stuff).

 

However, a better answer/recommendation that shroud have been provided by "SMEs" about the stick trim issue should be : as long as DCS will simulate the trims that way (1) instead of something like (2) or even better, something like (3) it won't match a correct stick trim.

 

Regards.

The F-16s roll trim has very agressive input and therfor it's hard to get correct trim when using the switch, this is why a lot of the pilots use the wheels instead. Pitch trim inputs via the switch is much slower, and therefor a lot easier to get the correct trim. I have no idea why the F-16s roll trim works like this, and it seems silly to have a system like this, but that is what general dynamics went with and we have to deal with it.