General Trim Questions

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General Trim Questions

Postby ditto58 » Tue May 04, 2004 11:06 am

I have found trimming airplanes to fly straight and level to be frustrating in MS flight sims, particularly in CFS1 and 2.  (There the fighter planes all seem to want to climb, climb, climb).

I have FS2002 and there the planes have trim wheels on the panels and it is a little easier, but it still seems difficult.  This doesn't seem to be much of an issue with real planes.  In other words, I get the feeling that it is actually harder to properly trim planes in MS flight sims than in real aviation situations.  

Any advice on how to get better at trimming aircraft?

Thanks,

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Re: General Trim Questions

Postby GeneticA » Wed May 05, 2004 5:06 pm

Hi ditto,

You're right. Trimming a plane in FS is a way different than trimming a real plane (I've never been in a plane but read a lot  ;D ;) ).
The trim in FS is made for non FF joysticks (or for keyboards). It adjusts the position of the elevator relative to your joysticks position such that you'll have your joystick in the center position when you trim the plane.

However in a real plane trim wheel never moves the elevators unless you let the stick free. It just adjusts the force on the elevator (thus the stick). So that you can adjust this forces such that you do not have to hold the stick when you settle to a level flight, climb or descent.

Coming to the solution of the problem, first, of course, you've to have an FF joystick. The point is that FF joysticks do not need to return to center position allways. However FS does not make use of this excellent property.

A few days ago I've come up with an add-on for FS by chance. That is FS Force. With this add-on you can have trim just as I described above for the real planes. I tried this and think it is very good. It also improves the feedback forces (return center forces change with speed, landing impacts, baking forces, etc. all adjustable).

The bad news is, this is an payware. Only 10 runs of FS  :( . I'm now looking for an free alternative. Hope I'll find one.  ::)
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Re: General Trim Questions

Postby Hagar » Wed May 05, 2004 5:18 pm

It might depend on the aircraft. Not all 3rd party aircraft are set up properly which makes me suspect that the person who created the flight dynamics didn't have their joystick correctly calibrated. The trim settings will also vary throughout the flight envelope.

I find it difficult (almost impossible) to trim using the keyboard or a joystick with push button trim controls. It's much easier & more natural if you have a joystick like the Saitek X-45 with rotary trim controls. This is similar to the way it works on a real aircraft. If you don't have something suitable you might prefer to use a panel with mousable trim wheels.

It should be just the same whether the stick is Force Feedback or not.
Last edited by Hagar on Wed May 05, 2004 5:22 pm, edited 1 time in total.
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Re: General Trim Questions

Postby GeneticA » Wed May 05, 2004 6:16 pm

I find it difficult (almost impossible) to trim using the keyboard or a joystick with push button trim controls. It's much easier & more natural if you have a joystick like the Saitek X-45 with rotary trim controls.

Well, the diffuculty here does not arise from the way we trim (either by buttons or a rotary control), it arises from the way FS does it and the way it actually differ from the real thing.

Let me try to explain:
Say, I climbed up to my cruise level and now I want to level off. I push the stick forward and level the plane, very nice up to here. Then what I do is trim the plane so that I will not have to force the stick forward. So I keep the stick in position and apply trim. Guess what happens? The plane starts to descent  :o . Well I was holding the stick in position, never moved, how it managed to start a descent. It did start a descent because FS wants me to bring the sitck back to the center position while I trim (couse it thinks that every stick is non-FF and spring loaded). However as to my knowledge, in a real plane when you trim without moving the stick, the plane does not change attitude. What changes is the force acting on the stick. So after trimming the stick should be positioned a little forward and should stay there with no force.

However, you're right with your observations. Ruling out the real thing, some planes may be easier to trim, and of course having a rotary control would ease it as well. But I think the main problem is the way it is programmed in FS. I tried the FS Force and it is very good in this manner, fixes the problem. You may have a look at it here.

http://www.dirks-software.ca/fs-force/R ... TrimSystem

Read the text below the title "Know Your Systems"

This will clear the things up I guess.
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Re: General Trim Questions

Postby Hagar » Wed May 05, 2004 6:24 pm

I agree with your comments but I still think you would find it so much more realistic using a joystick with those rotary trim controls. My old Saitek X-36 combo is just like the later X-45 although it has no Force Feedback. A decent joystick makes all the difference & you wouldn't need any special software.
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Re: General Trim Questions

Postby GeneticA » Wed May 05, 2004 6:57 pm

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Well, I must accept, this is experience talking  :)

But wouldn't it be nice that MS resolved this issue and we enjoyed it much more with a descent joystick?   ::)
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Re: General Trim Questions

Postby Hagar » Thu May 06, 2004 2:52 am

The number of posts means nothing so don't let that influence you. However, I do have plenty of experience with the sims, R/C models & real aircraft. There is no issue to resolve. The trim function works perfectly well & is only limited by your hardware & the way the flight dynamics of a particular aircraft is set up. It's not possible to get the best out of any version of FS/CFS without a decent joystick (or yoke/pedals) any more than it would be possible to fly a real aircraft using a keyboard or a basic joystick. IMHO

PS. [quote]Let me try to explain:
Say, I climbed up to my cruise level and now I want to level off. I push the stick forward and level the plane, very nice up to here. Then what I do is trim the plane so that I will not have to force the stick forward. So I keep the stick in position and apply trim. Guess what happens? The plane starts to descent
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Re: General Trim Questions

Postby Lux13 » Thu May 06, 2004 6:41 am

Hi!
Just remember that if an aircraft has been trimmed to fly at (for example) 100 kts in straight flight,and you change the speed,you will have to trim it again  ;)
If it's a stable aircraft you will feel just a little difference,but if it's very handling (as fighters aircrsfts),you'll need a lot of trim :P
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Re: General Trim Questions

Postby GeneticA » Thu May 06, 2004 7:12 am

The difference here is that you are putting pressure on the stick against the spring to keep the nose down. With a standard (non-force feedback) joystick you have to allow for this by gradually releasing the pressure as you adjust the trim. This is not difficult once you get used to it.


Yes, that is what I am trying to explain. Of course you have to allow the pilot to return his stick to the center position if it is a non-FF stick (which is the case in FS now, so no problem here. Although it is not completely realistic there is no other way.), and yes again it is not so difficult to get used to.
However, if you are using a FF stick, which does not have to return to the center position to cease the forces (in other words, the center position can shift back and forth), you should not have to return your stick to the center position while trimming. (While saying this, I am assuming that my knowledge on trimming a real plane is true and in a real plane you do not have to return the stick to the center position while trimming. Please correct if not.)

Now I would like to kindly request that you try this add-on and share your experiences, if you have time for. Actually I do not have much problem in trimming and I believe I will get better at it with time, as you mentioned. What I am trying to do is to make it as real as it gets.
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Re: General Trim Questions

Postby Hagar » Thu May 06, 2004 7:28 am

I think it would help if you understand how trim is applied on a real aircraft. There are several methods of doing this depending on the type & age of the design. Early aircraft had no method of adjustable trim at all but as the speeds involved were so slow this would have little effect throughout the speed range - providing the aircraft was rigged to fly straight & level.

As speeds increased various methods were used to adjust trim. These were often simple bias springs attached directly to the joystick & rudder pedals as on the Tiger Moth. The tension on the elevator spring is controlled by a large lever in the cockpit & rudder trim is usually only adjustable on the ground. (This is very similar to the method used on the old analogue gaming joysticks.) If you taxy a Tiger Moth without your feet on the rudder pedals it will go round in a large circle.

All aircraft have different flying characteristics, even 2 examples of the same type straight off the production line. It was common practice to trim an aircraft by doping a short length of cord below the trailing edge of a control surface to make it fly properly hands-off. Some aircraft have small aluminium trim tabs for the same purpose. Again, these can only be adjusted on the ground, usually by being bent in the desired direction.

The modern method usually involves adjustable trim tabs incorporated in the control surfaces. Some aircraft have all-moving tailplanes for pitch trim. These can be operated by mechanical linkages or remotely by hydraulic, pneumatic or electric rams. The pilots controls vary between levers, wheels, handles like the old-fashioned car window winders, & electric toggle, rocker or slider switches. Some high performance jets can be controlled in normal flight by the trim alone. Many aircraft have fixed trim settings on the controls for different flight conditions. It's very difficult to simulate every possible combination of these in a $50 flight simulator. ;)

PS. I don't have time right now to try the software you mention. It hardly seems worth it for a limited trial period. I'm quite happy with things as they are.
Last edited by Hagar on Thu May 06, 2004 8:05 am, edited 1 time in total.
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Re: General Trim Questions

Postby GeneticA » Thu May 06, 2004 8:11 am

Well, I was not aware that there are so many different ways of trimming  :o .
Thank you very much for your help.
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Re: General Trim Questions

Postby ditto58 » Mon May 10, 2004 12:59 pm

Thanks everyone.  I'll have to look into the Saitek joystick.  I have a very basic Saitek now, but it works well.

I've noticed that the FS2002 planes with trim wheels on the panel are easier to trim than using the number pad on fighters in MSFS2.  Perhaps a good idea for an addon would be to provide trimwheels for all aircraft.
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Re: General Trim Questions

Postby bricks4wings » Sat Jun 19, 2004 10:19 pm

Another way to adjust your trim for cruise in the sim if your having trouble. Is to throw on your autopilot and hit the hold altitude button and it will adjust the trim itself. then turn it off and Viola your trim is set.
This however does not work on a real plane. But like a real plane. You use your throttle to induce a sink or climb rate and your speed remains fairly constant and does not usually affect your trim.
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Re: General Trim Questions

Postby Skittles » Tue Jun 22, 2004 10:13 am

...Any advice on how to get better at trimming aircraft?...


I purchased GoFlights GF-LGT (Landing Gear Toggle) module.  It has a trim wheel. It eliminated all my frustration. It's still not perfect (FS9 software issue)  But it's acceptable to me.  After climbing to 5-10K ft I can then trim the aircraft within +/-25 fpm
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Re: General Trim Questions

Postby MattNW » Tue Jul 06, 2004 11:19 pm

[quote]

I purchased GoFlights GF-LGT (Landing Gear Toggle) module.
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