1. #1
    Hi Oleg

    We had few discussions in our squad about how to boost turn rate in a fight. One issue was the elevator trim position while in a turn.

    Question: In the FB flight models, does elevator trim has an influence on turn rate? If I trim the aircraft to fly straight and level at say 500 kph in LA7, does it limt the maximum "pull up" input from the Joystick? Is there a difference between various Joysticks? with or without force feedback?

    What do you guys know about the issue from real WW2 veterans? did they change trim settings in a turning fight?

    My opinion about the subject: What I learned to do in real PPL course is that you dont change trim settings in a temporary manouver. I was told there that the elevator trim is not a control device, it's purpose is to let the pilot to fly comfortly in various flight situations and airspeed without struggeling with the aerodynamic forces that screen back to he's stick. I think it should not have influance on turn rate because:
    in Real World, you never reach maximum elevator deflection, You will stall or exceed stractual limit way before maximum deflection. In addition, in "pull up", you apply pressure, you dont move the stick/column. The resistance of the stick is relative to the airspeed, so when the speed decreases (like in a tight turn) you can pull up further because there is less resistance.

    What is the game makers policy about the subject? how much does it similar to Real World (ofcourse, considering the limitations of PC simulation and game joysticks)??

    Waiting for your reply,
    IDF_Baruchi
    Training guide,
    IDF_Squadron

    [This message was edited by IDF_Baruchi on Thu March 25 2004 at 03:52 AM.]

    [This message was edited by IDF_Baruchi on Thu March 25 2004 at 03:59 AM.]
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  2. #2
    Hi Oleg

    We had few discussions in our squad about how to boost turn rate in a fight. One issue was the elevator trim position while in a turn.

    Question: In the FB flight models, does elevator trim has an influence on turn rate? If I trim the aircraft to fly straight and level at say 500 kph in LA7, does it limt the maximum "pull up" input from the Joystick? Is there a difference between various Joysticks? with or without force feedback?

    What do you guys know about the issue from real WW2 veterans? did they change trim settings in a turning fight?

    My opinion about the subject: What I learned to do in real PPL course is that you dont change trim settings in a temporary manouver. I was told there that the elevator trim is not a control device, it's purpose is to let the pilot to fly comfortly in various flight situations and airspeed without struggeling with the aerodynamic forces that screen back to he's stick. I think it should not have influance on turn rate because:
    in Real World, you never reach maximum elevator deflection, You will stall or exceed stractual limit way before maximum deflection. In addition, in "pull up", you apply pressure, you dont move the stick/column. The resistance of the stick is relative to the airspeed, so when the speed decreases (like in a tight turn) you can pull up further because there is less resistance.

    What is the game makers policy about the subject? how much does it similar to Real World (ofcourse, considering the limitations of PC simulation and game joysticks)??

    Waiting for your reply,
    IDF_Baruchi
    Training guide,
    IDF_Squadron

    [This message was edited by IDF_Baruchi on Thu March 25 2004 at 03:52 AM.]

    [This message was edited by IDF_Baruchi on Thu March 25 2004 at 03:59 AM.]
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  3. #3
    Trim can't be modelled accurately in a sim. In real life you use the control column to fly level and straight and trim away the forces. In the sim you do the exact opposite. You leave the control in centre and start trimming to fly level and straight. Ofcourse, this all implies that trim isn't accurately modelled to begin with in FB. Trim can't be accurately modelled in any sim.

    And sure, you can boost your turn rate with trim in FB, like you can also boost your roll rate with trim in FB.


    (I took some of your words here
    In FB in "pullup", you apply pressure, you actually move the stick/column. The resistance of the stick is relative to the airspeed and the amount of trim applied. So when the speed increases but as long as you have enough elevator trim applied, you can pull up further because there is less resistance.

    Don't know what the game makers policy is about the subject. Seems to me they just wanted to put it in as a gimmick. They coulda just left it out and let all planes fly in trim automatically. Adding unrealistic trim adds nothing to the game but an unnescessary control to fiddle with. It's like adding a disfunctional gauge to an instrument panel. It's nice it's there but it has no realistic value.
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  4. #4
    Hey Dnmy thanks for your reply
    So now I understand that Its a sim problem not a Trim problem.

    Anyway, You convinsed me about use of trim in a turn but I disagree that Trim has no function at all. Try to fly fast and keep your nose inplace relative to the horizon, you will fill that you do need to move stick forward in order to resist the nose tendancy to go up, and vise versia, if you fly slow you need to pull up. in FB I use the trim to kill these up/down tendencies.This is exactly how it is done in real world, you put your nose inplace relative to the horizon and you "lock" it (cancel stick resist forces) using the elevator trim.

    Is there any real fighter pilot (or former fighter pilot) here who can pure some light on this issue? What do they do with the trim in a fight???
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  5. #5
    Well the difference is that in real life you feel the stickforces when your plane has a nose up/down tendency.

    In the sim we don't feel them.

    The only forces we "might" feel are the centering forces, but they can hardly be compared with the real life stickforces. How can they be? But that's how it's done in the sim.

    E.g. i have a joystick with which i can adjust the centering force to my liking, from ultra strong to non existant. I like it a non existant centering force.

    So that means it doesn't cost me any trouble to keep the stick pointed down whatsoever. Hence the need for me to apply trim is absent. (Except for rudder trim and the occaisional recovery at high speed.) But the guy who has a cougar with ultra high centering forces might not agree. He even feels the "stick" (centering) force when he's deflecting his controls waiting on the runway.
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  6. #6
    WWMaxGunz's Avatar Senior Member
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    In the real world your control stays where you had to move it to keep the nose right after you trim. Can you say that about your joystick? No. The reason is simple. Your joystick is not a direct control of the stick in the sim cockpit. Your joystick is only telling the pilot how hard to pull that stick. You control pilot, pilot controls stick as he is best able.

    The unreal part is that you cannot feel the stick force in the plane getting less and less. You cannot make the pilot hold the stick steady as forces on the controls change. You can only say "pull, push or bend this hard" by moving your stick a corresponding distance. It is more like the pilot has a bungee cord to pull the stick with than he is holding it in place because if the force on the stick drops and you who have no feel of this do not loosen up on your joystick then your pilot will still be pulling just as hard and the stick will move further. You get into a situation where the forces are fluctuating and not only have you no feel but the pilot will actually make things worse unless you are trimmed whether for level or any other kind of flight.

    It is this way partly or wholly because our joysticks have very short travel compared to real. I would love for some way for the pilot to hold the stick steady yet since as forces lessen there may be times I want him to be able to get more deflection it becomes impossible to have both ways.

    Just be aware of it. Trim makes it easier to pull more stick. If you are using default stick settings then trim also lets you have finer control over turns in a somewhat realistic manner. Think that through before you say no, it doesn't. Really think.

    Last of all there is the recollections of US Ace Bud Anderson who described using trim in combat as a matter of course and did so in some detail including why. When you're out flying GA around, your butt isn't on the line to be shot off where those guys' were and they used every bit of advantage they could handle.


    Neal
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  7. #7
    Hey Max thanks
    I am giving "orders" to the "pilot" in the sim - thats an interesting way of thinking.

    Despite all what was written here about the disadvantages of game joysticks, I would like to suggest a programmed algorithm that takes into account the speed and strength of the airflow that flows around control surfaces, and change the controlling inputs sensitivity accordingly. This way, in slow speeds, you will need to add more stick deflections than in high speeds. Well, true it will never be the same as in Real world because what we can change here is the amount of travel rather than the amount of pressure, but provided that our joystick has a constant centering spring K coeficiant, bigger travel means also bigger force (or pressure -what ever)so it makes it a bit similar. Maybe this feature already exists???


    Editing: Well, after second thought -this will result exactly the opposit of the desired effect: you will need higher deflections = higher forces in slow speeds. In real world you fill higer resistance in higher speeds. oh boy this is confusing. Maybe I should put a fan in front of my joystick and see what happens in various fan speeds.... end of editing.
    What is mostly missing to me in simulators refering to real world is that when you are on the ground and push the throtlle, the yoke goes back towards your stomach -due to the propeller stream around the elevator control surface. It never happened to me in any simulator...LOL.

    Max, You gave here a name of a real fighter pilot who refered to the subject. Do you have any link to he's articles????

    [This message was edited by IDF_Baruchi on Thu March 25 2004 at 06:29 AM.]
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  8. #8
    WWMaxGunz's Avatar Senior Member
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    <BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by IDF_Baruchi:
    Hey Max thanks
    I am giving "orders" to the "pilot" in the sim - thats an interesting way of thinking.<HR></BLOCKQUOTE>

    Well you can thank Oleg because that is what he posted I guess 2 years ago about how the stick interface works. It may also be in an IL2 readme file.

    <BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Despite all what was written here about the disadvantages of game joysticks, I would like to suggest a programmed algorithm that takes into account the speed and strength of the airflow that flows around control surfaces, and change the controlling inputs sensitivity accordingly. This way, in slow speeds, you will need to add more stick deflections than in high speeds. Well, true it will never be the same as in Real world because what we can change here is the amount of travel rather than the amount of pressure, but provided that our joystick has a constant centering spring K coeficiant, bigger travel means also bigger force (or pressure -what ever)so it makes it a bit similar. Maybe this feature already exists???<HR></BLOCKQUOTE>

    Sort of. With more speed there is in the model more backforce on the virtual stick that you see in the cockpit. When you pull your joystick you are commanding the virtual pilot to pull against the backforce with a certain amount of strength that is 50 lbs force x the % of stick travel x the stick sensitivity value for the range of how far back you have pulled your joystick. I believe that this is in a readme or was in IL2:Sturmovik. There comes speeds in most or all planes where the pilot is unable to pull hard enough to get full deflection.

    Oleg is a pilot and also an Aero Engineer.

    <BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Editing: Well, after second thought -this will result exactly the opposit of the desired effect: you will need higher deflections = higher forces in slow speeds. In real world you fill higer resistance in higher speeds.<HR></BLOCKQUOTE>

    And that is what we have.

    <BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>oh boy this is confusing. Maybe I should put a fan in front of my joystick and see what happens in various fan speeds.... end of editing.
    What is mostly missing to me in simulators refering to real world is that when you are on the ground and push the throtlle, the yoke goes back towards your stomach -due to the propeller stream around the elevator control surface. It never happened to me in any simulator...LOL.<HR></BLOCKQUOTE>

    Well, when the desktop PC's get powerful enough and there's enough time and space to code it in then maybe you get that wish as well!

    <BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Max, You gave here a name of a real fighter pilot who refered to the subject. Do you have any link to he's articles????

    [This message was edited by IDF_Baruchi on Thu March 25 2004 at 06:29 AM.]<HR></BLOCKQUOTE>

    A little Google, matchwords Bud Anderson trim and the top of the list is that interview.

    http://www.elknet.pl/acestory/anderson/anderson.htm

    BTW, this man was Chuck Yeagers wingman and friend from traing, through the war and all afterward. He may still be alive. You can be sure that all those men at least in their wing shared any knowlege or practices that could help so I doubt that this was an isolated case, just one of the few times it was related.


    Neal
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  9. #9
    "What do you guys know about the issue from real WW2 veterans? did they change trim settings in a turning fight?"

    I think it was Yeager who said that he adjusted trim continually and that you could recognize inexperienced LW pilots because their planes were out of trim.

    Also, I can't recall who it was at the moment, but I've read an account where a Me109 pilot was in a high speed dive to escape someone on his six and used his trim to help pull out.

    My impressions of the last two months revolve around dawns. Pink dawns, grey dawns, misty, rainy and windy dawns, but always dawns; first light. Shadowy Spitfires and quietness . . . . Geoffrey Wellum, First Light.
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  10. #10
    CHDT's Avatar Senior Member
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    "I think it was Yeager who said that he adjusted trim continually and that you could recognize inexperienced LW pilots because their planes were out of trim."

    Yes, continuous adjustements, but small ones. At high speeds, hard trimming can result in loss of control or even very rapid changes in flight patch which could give even structural failures.

    "Also, I can't recall who it was at the moment, but I've read an account where a Me109 pilot was in a high speed dive to escape someone on his six and used his trim to help pull out."

    I remember this story. It's a Finnish pilot who said that he would have lose his wings if he used trim to get out of the dive!

    Cheers,
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