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View Full Version : Hardware trim vs software trim



na85
08-30-2009, 04:02 PM
Okay boys, here's a question for you:

For staying "in trim" and getting max level speed etc, would using a hardware trim device (i.e. something that displaces the joystick by a small amount) have the same effect *IN GAME* as using the regular trim controls?

Waldo.Pepper
08-30-2009, 05:59 PM
No I think that drag would be increased.

julian265
08-31-2009, 12:33 AM
I've been wanting to test this for a long time, but just never got around to it (it's an easy test so I'm just lazy)

There wouldn't be a difference in the real world, and I doubt there would in-game. Remember - either the pilot exerts the force which holds the control surface in position, or the trim tab does. Either way the surface is in the same position (or very, very close, since a trim tab is pretty small).

Phant0m_99th
08-31-2009, 02:09 AM
Yes the trim tab is small, but therfore - shouldn't you have to move it more to create the same effect? Therefore they should be the same.

but I have heard that using the hardware tim can screw up the joystick calibration - whether or not it is by a noticable amount I cannot say, but it is certianly somthing to consider.

Im not sure what setup you have nate but I have a fighterstick and I can say that messing around with the tim while having a hand on the keyboard, the throtle and the stick has proved too much for me http://forums.ubi.com/images/smilies/winky.gif When I do use it, I find that it is more effective than when I use the software trim (probably because I have it set to the numpad and it takes forever to get a good amount.)


Edit: Also I thought I read here recently (probs on a 51 discussion thread) that olegg said that applying trim has the same effect as moving your stick (or somthing like that) and has no futhur advantages (thinking about it I cant think of any anyway - execpt being able to take your hands off of the stick. Or maybe it gives you more lift than before (which I would expect you would only see when you pull the stick all the way back (which I couldn't imagine would be a very good idea most of the time.))). I think that is enough brackets

AndyJWest
08-31-2009, 06:30 AM
I'd be very surprised if the drag effects of trim tabs were modelled in IL-2. Visually, moving trim in software just moves the whole control surface, and I don't think it alters the limits to which the surface can go to. If this is the same in the FM, then adjusting trim, whether by hardware or software, is not going to change maximum control surface deflection - but does the FM actually work that way? Probably the only people who know are at 1C:Maddox or amongst the 'modders', and we'd better not go there...

Using hardware trim may have slightly different effects than software, depending on how linear your response curve is, though I think you'd be unlikely to notice the difference unless you have an extreme setup.

One thing to remember though, is if you are using hardware trim, you should not use any 'dead zone' in the setup, as this will be offset as the trim is moved.

RPMcMurphy
09-01-2009, 03:06 PM
Originally posted by na85:
Okay boys, here's a question for you:

For staying "in trim" and getting max level speed etc, would using a hardware trim device (i.e. something that displaces the joystick by a small amount) have the same effect *IN GAME* as using the regular trim controls?
Thats a good idea. If the trim tab never moves and it stays neutral then the pressure distibution over the control surface would be less so therefore induced drag would be minimized. I wonder if that is accuratley modeled in this game however.

na85
09-01-2009, 05:08 PM
Originally posted by julian265:
I've been wanting to test this for a long time, but just never got around to it (it's an easy test so I'm just lazy)

There wouldn't be a difference in the real world, and I doubt there would in-game. Remember - either the pilot exerts the force which holds the control surface in position, or the trim tab does. Either way the surface is in the same position (or very, very close, since a trim tab is pretty small).

I understand the principles involved and how it works IRL, but I'm curious if the game behaves correctly

julian265
09-03-2009, 01:16 AM
Enough thinking and talking! I'm testing this tonight.

BillSwagger
09-03-2009, 01:26 AM
The game responds differently to software trim than it does hardware trim.

The end effect is the same, however when you are exerting your pilot and black out, the hardware trim input is no longer received.
The software trim in game will continue to work even when the pilot is under.

That is the main difference that i can see.
As for drag, this is something that would require a test.


Bill

julian265
09-03-2009, 03:39 AM
I did some testing...
Flown in 4.08 standard, P51D-20, crimea, 1000m starting alt, 25% fuel, unlimited fuel, no overheat. After launch, I attempted to maintain 3000ft, and centered the slip ball with rudder. Rads closed, 100% pitch and throttle. All tracks taken from the same flight.

I didn't know that disabling no-cockpit view in the difficulty section would also prevent tracks from being played back with it, so to accurately look at speed, I played the tracks back in 4.09 modded with the speed bar set to 1km/h increments.

Part 1 - pitch trim fully downward, maintained level with back-stick. Top speed ~545 km/h.
Part 2 - approximately middle pitch trim, top speed ~545 km/h
Part 3 - pitch trim fully upward, maintained level with forward-stick. Top speed ~545 km/h.
Part 4 - set stick to neutral position, maintained level with pitch trim. Top speed ~545 km/h.

So there ya go, it's proven. You don't have to trim elevator (and rudder and ailerons, by deduction) to get the least drag. I'm not denying that the slip ball needs to be centered, but it doesn't matter whether you do it with pedals or trim.

Tracks:
Part 1
http://www.jpfiles.com/misc/trim_test_down.ntrk

Part 2
http://www.jpfiles.com/misc/trim_test_mid.ntrk

Part 3
http://www.jpfiles.com/misc/trim_test_up.ntrk

Part 4
http://www.jpfiles.com/misc/tr...t_stick_neutral.ntrk (http://www.jpfiles.com/misc/trim_test_stick_neutral.ntrk)

julian265
09-03-2009, 03:41 AM
BillSwagger is right, with one clarification - stick inputs are ignored after a blackout, any trim inputs (from hardware or keyboard) are still accepted.