Can "Trim" actually be simulated in a Desktop Sim

[-sam-]

Hi there,

I wonder if the trim funktions (especially elevator) actually work in a desktop Sim
like FS as they do in Realworld. Maybe I just confuse something.
From a realworld flying lessons I know that trim should work like this.

When you need to pull the stick back to fly straight and
level.. you

[garymbuska]

About the only way I can think of that might trim correctly would be a yoke. I do not own one but I am reasonably certain that it would behave just like the real thing as far as no center posistion like a joystick. But as for actually feeling the force what do you expect from a less than a $100 flight simulator. The only way to make it lifelike would be to invest in a full motion simulator, and most of us just do not have that kind of money to toss around.

[jimm57]

I adjust my trim with keys 7 for down, and 1 for up on the number keys, not the top row keys above the letter keys. Make sure num lock is off. It works.  8)

[-sam-]

I adjust my trim with keys 7 for down, and 1 for up on the number keys, not the top row keys above the letter keys. Make sure num lock is off. It works.  8)

No doubt that I can adjust trim in FS. But as I said.. in realworld it is used to reduce the force on the flightstick.
And this doesn

[Brett_Henderson]

I think it's pretty realistic, even with a non-force-feedback stick. If you have to hold the stick/yoke against it's tendency to "spring" back to center.. that's very similar to having to hold back-pressure to keep from descending in a real plane. And you can use the trim so that a centered yoke/stick holds level flight.

Same for climbing and descending. For extended climb in a real plane.. once you're established (power and pitch), you just trim until the plane will hold that pitch and airspeed when you let go of the yoke/stick. Same thing in the sim.

[Hagar]

This is an example where the old analogue joysticks were actually more realistic than digital ones. The rotary trim wheels move the neutral position of the joystick itself.
http://www.aerotraining.com/html_gif/1800.htm

[wji]

"I wonder if the trim funktions (especially elevator) actually work in a desktop Sim like FS as they do in Realworld."

Affirmative.

Test: (with Auto Rudder deselected)
Load FS9's B744 from the Default Flight and place the cursor over the console's (SHFT-4) trim-wheel

Move the mouse to get plus sign + Using the center, mouse wheel rotate trim until is DWN-6
(the plus and minus appear to be reversed)
Apply power and try to take-off

[vololiberista]

Trim does work but not in the analogue sense as in real flying. ie one trims until the load is taken off the control column. In the sim  eg on take-off I pull back hold the correct attitude and trim and at the same slwoly easing the control column forward until it's neutral possition. If one coupld find an analogue control column then it would be much closer to reality.
Vololiberista

[Gypsy_Baron]

Trim does work but not in the analogue sense as in real flying. ie one trims until the load is taken off the control column. -SNIP-
Vololiberista

I beg to differ...I have elevator trim programmed to the Hat# 2
on my Saitek X-45 stick...during climbout, I adjust trim until the
aircraft is holding the desired climb rate when my stick is centered,
i.e. hands off.

At cruise altitude I adjust trim to hold the desired altitude when
I have hands off the stick.

    Paul

[RollerBall]

I agree with Paul. I have allocated 2 buttons on the base of my Logitech Wingman Force 3D and I get a perfect simulation of trim.

But you need to take the time to adjust the stick and centring forces in the set up of your stick - you can't expect it to work right if you just accept any old force feedback settings.

However, not all designers appreciate the importance of applying correct MOI and pitch/roll/yaw stability figures to their aircraft. These have to be 'right' and you may therefore have to adjust the cfg and/or air files of an aircraft to get real 'hands-off' pitch trim stability.

[Brett_Henderson]

I think what the trim purist would want...  Is not only for the pitch to be held with hands off the yoke/stick.. I think they mean that it would be more realistic if you could trim to where you're not only NOT having to hold the yoke/stick, but that it would stay in that held position (not spring back to center), once trimmed.

That would be nice.. But you know ?  I've never really noticed it enough to think about, until this thread. I go about flying and trimming a plane in the sim, exactly like I do in a real plane..

[beaky]

I'm not sure what the problem is... I can easily trim for "hands off" flight at any attitude or airspeed (well, "easily" is relative, depending on the model). My joystick of course returns to center, but honestly, in RL I never really notice much change in the "throw" of the yoke or stick, so that doesn't bother me.

The only obvious difference, as sam points out, is that you can't "trim off the pressure" in the sim; it takes getting used to if you have any RL hours logged.
but in FS9 as in RL, you trim for results. You set the stick or yoke where you want the eleveator to stay, then you trim until you can release the controls and the airplane still does what you want. That's the more important thing in RL (that you're getting the airspeed and/or climb/descent rate you want), not the feel of pressure or no pressure... the "feel" factor is just a little extra feedback that helps, but is not essential.

[vololiberista]

I trim so that I can release the pressure on the control column and the a/c stays at the attitude set.  In real life flying the trim takes the load force out of the control column but it stays at that setting in relation to the control surfaces.
The more I pull on my CH yoke in the sim the more resistance I get from the springs thus simulating the force of the airflow over the control surfaces trying to put everything back to neutral. The only way to reduce this "force" on the sim yoke is to return it to it's neutral position. So as I trim the a/c I release the load on the sim control column. If one knows one's a/c then one can set the trim before hand for take-off,  approach, landing etc as one does in reality. Now, if the trim in FS9 electronically moved the springs inside the CH yoke, thus altering the load force, then that would certainly be closer to the real thing.
Vololiberista

[Ivan]

[quote]Hi there,

I wonder if the trim funktions (especially elevator) actually work in a desktop Sim
like FS as they do in Realworld. Maybe I just confuse something.
From a realworld flying lessons I know that trim should work like this.

When you need to pull the stick back to fly straight and
level.. you

[Lysander77]

Certain models of payware add-on aircraft actually have trim gauges that show the degree of trim (positive or negative), which can be controlled by the 7 or 1 in the keyboard number pad or linked to the buttons on a Wingman joystick.  Thanks to some helpful instruction from various Simviation regulars, I was able to copy the trim gauge from one of these aircraft to my favorite plane, so that the degree of trim now shows up numericaly on the instrument panel.