View Full Version : Aircraft Trim

11-01-2004, 10:05 PM
~S~ Airmen,
New to the series, have PF installed as a standalone, tweaked and worked, and finally got 'er to run smooth, but at 800x600 which ain't too durn bad.
Aircraft trim really bad. Programmed controls to the Saitek X-45 in game setup. Slight touch does nothing, little heavier touch does nothing, push and hold for a second and it PLOWS one way or another.....really hard to set level flight at 70%.
Anyone else with this issue?


11-01-2004, 10:21 PM
Program trim to one of the rotators in the HOTAS axis section. Much better than using a button.

11-01-2004, 11:00 PM
Welcome NSFO

There is a bit of lag between when you apply the trim adjustment and it taking effect on the aircraft. You'll get used to it, but it can be a tad irritating - and certainly makes trimming the plane for hands off a bit tricky.

It wasn't always this way - the change was made in response to complaints about trim exploits during combat.

I have elevator trim set to one of my x45's throttle rotaries (the one under your thumb).

Rudder and aileron trim are not always available - depends on the aircraft type - and aren't generally adjusted as much as the elevator; so I tend to leave them as keyboard commands.



11-01-2004, 11:21 PM
To set trim to the X45 rotaries, scroll all the way to the bottom of the controls screen where the axis assignments are list under the "HOTAS CONTROL" heading. There you'll find axis based trim assignments.

Trim will still lag behind control input if you move the rotary quickly through a large range of motion, but it doesn't overshoot like the keyboard control does.

11-02-2004, 12:03 AM
Doesn't really matter if you use a rotor command, or a button. They actually work the same. The trim wheel moves the same speed either way, and the trim reaction lags behind. So, if you stay with the button, use a series of bumps and waite for the plane to respond. You'll get use to it.
Thank-the-maker the trim isn't instantanious via rotor/slider commands. That's the biggest reason PC Pilots - not gamers left CFS2.


11-02-2004, 02:10 AM
But there is heaps of lag for even small trim changes. when the aircraft is nearly in trim, in level flight for example, the change should be pretty much instantaneous.

11-02-2004, 07:56 AM
Thanks to all.....

I am at work now, but will attempt the rotary programming when I get home tonight, after voting.
I know that in R/L there is a slight lag in the trim, and result, but what I have experienced does not seem to be accurate.
Thanks for the help and suggestions, this forum is a great place to hang out, get the gouge, (for all you non US Naval types that means knowledge).

~S~ !

11-02-2004, 10:11 AM
you can either hit ctrl+ up arrow 20 times to go levelled or

in planes like the bf at high speed the elevator wont respond so you have to trim

in real life you would use the trim when losing elevator autority because of the speed

in il2 life you have to trim up in advance and push the joystick to keep it levelled then release joystick presure and youll pitch up

this is totally unreallistic because you wouldnt have the strengt to push the stick hard enough to keep it levelled at that speed

in the p40 you can see an elevator trim tell me it takes so long to operate a stick

so i recomend putting the trim on a slider

although the way trim handles sucks in this game anyway

11-02-2004, 11:39 PM
I donn'a disagree with Vidar much (experienced and good hand), but most planes that I have flown, trim feedback is pretty instantaneous, so the trim here is a real pain in 'D-Az'. I am, aware with his CFS2 issue, na-da real life like deal either.

learning to live with it!

11-03-2004, 04:29 AM
I have a problem with the trim too, I tried this onQmission with about 6 ot 7 planes.

I set my Throttle to 65% power and before I pick a plane I pulled back on the stick and let go to flick it and let it rest in its own position. After that I never touched the stick again.

First up was the A20 , when the cockpit loaded I F2'd outside and brought the camera around to side on, I did the same with the other planes I tried. (Auto-Pilot OFF)

A20 , starts off in a very low angle of decent and after a few moments levelled out, only to go into a climb then level again and then back to a decent then back finally to a climb. All of this with the right wing tipped slighly down to the right and turning a dergee every 2 or 3 seconds..

The B25 was the same as the A20

On all the fighters I tried, all of them went into a climb again with right wing tipped down and turning anywhere from a degree every 2 or 3 seconds to 2 to 3 degrees a second.

If I am in level flight and set the Elevator Trim to neutral I should stay in level fight??

I don't know to much about flying, but given that I am right about what I said about setting trim to neutral and level fight.

How long would the trim stay in a neutral position, and if it did move what would make it move? down in one plane and up in another ?

I find that even pressing the neutral Elevator trim button after a few moments of level flight I have to push forward on the stick to bring the nose of my plane back down again into a level flight!

Are there any setting I can used to stop the trim moving so fast and making some of my planes decend and other rise? but with both types decending and climbing while there right wings a tippped down to the right making these plane turn to the right. Some a degree every 2 or 3 seconds to others that go into this turn at 2 or 3 degrees a second!

11-03-2004, 08:26 AM
Life gets complicated! Trim requirements in real planes change with speed and power settings! How this is modeled in the 'sim' I cannot say at present, but your observations were quite inteesting!

Generally trim is a bit more important for good 'feel' in a sim as you have little leverage on a short joystick and no direct feedback from the aircraft control surfaces. In a real aircraft controlled by a stick, it sits between your knees and you can rest your forearm on your leg, making small adjustments with your wrist. larger aileron forces can be generated with the help of your leg, which can also be used to set against an anoying but temporary out of trim aileron condition.

In sim's we cann'a generally do this, though I have heard of folks mounting their joystick on the floor with a 30" or so extension! I am sure it would work well!

At any rate, in either a real plane or in a sim one can fly much more precisely if the thing is in trim and it's not continously trying to do something besides what you want. So far the trim system doesn' seem optimal, but I am sure the experienced sim souls here will work it out just fine!

The basic rule for power and trim settings, use what you need!

11-03-2004, 08:29 AM
Elevator trim (pitch/airspeed) and aileron trim (roll) are not connected.

Setting the trim is essentially selecting an airspeed. The aircraft will then try to maintain this airspeed. If this will mean a climb or a descent will depend on the trim setting and the power setting.

The trim setting won€t change unless you change it yourself.

Trim is pretty much transparent in Il-2. I use it the same way as I do when flying for real. The only times I even think about it is on the pre-takeoff checklist and before starting an approach to a carrier.


11-03-2004, 08:33 AM
Walsh2509 - Elevator trim is not the limit of trimming. You also have aileron and rudder trim.
The tip to the right is due to propeller torque and can be countered with aileron trim. Rudder trim is required to counter gyroscopic effects of the slip stream.
Not all aircraft have adjustable rudder/aileron trim (per historical config) - though most do have elevator.

Most 109s for instance have fixed trim tabs on the ailerons and rudder (adjusted by the ground crew) that allow the craft to fly true at ~400kmh. At other speeds the pilot has to apply control inputs to counter various forces.

Maintaining proper trim is a dynamic exercise - the settings required for hands off level flight will vary depending on altitude, airspeed etc.

The main use of elevator trim in the IL2 series is to counter the upward/downward movement of the nose - making accurate shooting a lot easier.



Gotta be quick here http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif

11-03-2004, 12:08 PM
" posted Wed November 03 2004 07:33
Walsh2509 - Elevator trim is not the limit of trimming. You also have aileron and rudder trim.
The tip to the right is due to propeller torque and can be countered with aileron trim. Rudder trim is required to counter gyroscopic effects of the slip stream."

I am sorry there is one thing I forgot to mention in my post these little tests were done in "Easy Setting" so wind torque and flutter? were all switched off.. So my roll to the right could not have been torque!

And as for speed affecting the evelvators I never adjusted the speed of each plane each one had 63% of power through out the tests and each time I did applied "Neutral Elevator Trim" and this was in a re run with each plane, I would first get the plane level and hold it there "hands-on".

I would then apply the Neutral Elevator Trim and loose my grip on the stick but keep pressing N-E-T moments after I had loosed my grip on the stick the planes would start to climb and dip to the right. As I said this was on Easy Flight settings, and not realistic!

I read about having to keep applying the N-E-T by several pushes of the button and not just one, but it didn't matter the climb and the slight roll would still kick in!

Now I realise that if flying in realistic flight mode you would have to keep adjusting the trim rudder and ailerons but in Esay?

Saying that these 3 things apply to Easy just as they do in Realistic mode, and the advice that it takes a while and several pushes of the buttons be it Elevator up or down Rudder yaw left or right and alierons roll left or right.

In what I have found with this is that I would be constantly applying Elevator and Aileron trim, surely in level flight and not changing your speed you should only need to do this once in a while and not all the time? Especially in Easy Flight Mode with no torque wind or flutter overheating all turned off?

If you tell me that is the way it is then I have to work at it and learn to fly these kites, but I can't believe that even realistic level flight mode (never mimd easy) with no change to airspeed that I would have to be constantly pressing buttons to stop the plane going into a climb or in some cases go into to a decent. I would see that I would have to adjust these things if I pushed my throttle forward and increased my speed, but not at a constant speed.

Thanks guys for all of your replies , I hope with the other info about the easy mode I forgot to mention you might be able to shed some new light on my problem and maybe give different views on it!

Any Thanks again for you help!


11-03-2004, 01:06 PM
you appear to want a deeper understanding. It's not a difficult issue, but you will have to do some reading (http://www.av8n.com/how/htm/aoa.html). Trying to figure it out from the simulator and your current level of understanding (where we all were once!) will be a rather enourmous waste of time. http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif


11-03-2004, 02:33 PM
Trim in the game works fine. It's only issue is it "Lags" behind the control input. In real aircraft, trim reacts instantanious to the pilots "small" inputs because the tab movements is a mechanical linkage. - Electrical motor driven in moden high-performance aircraft.

The issue in CFS2's trim wasn't that it was some much instantanious to input - it should be, and was modeled correctly in that light. However, "instantanious" full throw of the tab was available in CFS2 via slider/axis input which made it rediculously wrong when utilized that way. Some actualy assigned another joystick to the trim! When they needed it, they just yanked back on the other joystick and had instant full trim deflection and was able to return it to neutral by simply releasing the spare joystick. Trim inputs do NOT move that fast from one extreme to the next. CFS2'ers took too much advantage of that, and serious PC pilots got fed up with it. The trim commands in CFS2 were way to pronounced as well. They practicaly elliminated "criticle angle-of-attack, and could even aide a Corsair in recovering from a 400mph G-lock dive!

IL-2's trim is good to go folks.They just need to get the lag input taken out, and don't allow instantanious full throw via axis and sliders. A button command is all you need either via keyboard or joystick just like a real aircraft.


11-03-2004, 02:49 PM
BSS~Vidar:: <BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>IL-2's trim is good to go folks. They just need to get the lag input taken out, and don't allow instantanious full throw via axis and sliders. <HR></BLOCKQUOTE>
Thanks Vidar. They never could do both it seems--lagg free trim but not on a slider. Hence the trim lagg as the only solution to onwhine Cheat. Not sure if it worked though, and it hurt offline simming for the other 95% of simmers.

11-03-2004, 03:59 PM
Strangely, I never notice any lag on small trim changes.

Must be a bug in my install or something. http://forums.ubi.com/groupee_common/emoticons/icon_rolleyes.gif

11-03-2004, 05:20 PM
It seems that so many that ask for this really dont have an idea of the history or development of the IL2 series. It was per the communities request to add a delay in the trim adjustments to prevent instant full deflection use. Much like what I am hearing from people who have flown the cfs series. I dont think we would see a return to a no delay on the trim. I beleive the only way to not have it assigned to an axis or slider would be to assign a fixed non adjustable key. Also keep in mind, if it was returned to a no delay in the trim, even it its only with fixed keys, then those of us with nicely programmable joysticks could set a key to run a macro command and we would have full trim available within a matter of a few short seconds. Again I wouldnt want to see this return and its another reason why I doubt we will see a return to a non delayed trim.

11-03-2004, 06:05 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by walsh2509:
snip - I would then apply the Neutral Elevator Trim and loose my grip on the stick but keep pressing N-E-T moments after I had loosed my grip on the stick the planes would start to climb and dip to the right. As I said this was on Easy Flight settings, and not realistic! - snip <HR></BLOCKQUOTE>

Hi Walsh2509 - I must admit I'm not familiar with IL2's easy settings as I've only played it with all the effects on.
One thing I can point out here though is that the neutral elevator trim key doesn't actually set any trim - it just returns the trim tab to a neutral position - i.e flush with the main control surface.
One way to see trim at work in the IL2 series is to get your aircraft flying level at constant speed - change you view to watch instruments only and, with your hand off the joystick, adjust the trim axiis as needed to keep your artificial horizon and yaw indicators level. It is possible to get the plane to fly hands off for some time with fine tuning.



Ps - please note that the above is only applicable for types with all axis trim (eg P51 - the trim controls move in the pit too - very neat) - some other types are beasts that require constant hands on control to fly anything like level.

11-03-2004, 06:21 PM
We would ~love~ a return to correct trim for the 95% offline simmers. http://forums.ubi.com/images/smilies/11.gif

11-03-2004, 07:19 PM
Well Guys, seems to have opened quite a good discussion here....
Lots of good answers, and some history of the Maddox series as well.
I flew the CFS 2 and 3 series, and it just don't hold a candle to PF in my humble opinion.
Lots of good advice from experienced pilots in this sim, and I thank you for the input and experience.
I had add-on aircraft from the AvHistory website that were within 1% of the flight model of the original aircraft, which flew pretty good trimmed out, and adjusted trim as you burned off fuel, and expended stores and ammo. I am just looking to get as realistic a flight model as possible.
If you look at the films over on Zeno's Warbird Drive-In, (the original training films on the aircraft, made by the Department of the Navy, or Army) there were trim settings before takeoff, (like rudder set 6 degrees to the right to counteract the torque) aileron trim at 15 degrees down rudder, etc...etc...etc....
Still a great sim, and I hope to get more acquainted with it as time goes on.


11-04-2004, 10:44 PM
I'm familiar with the function of control trimming systems (aircraft mech by trade) and altho not a qualified pilot I've not only the theoretical and mechanical knowledge but have used elevator, aileron and rudder trimming in flight.

I haven't played FB etc. beyond quick goes at the demos because I have NO interest in European theatre of combat - but anyhting in the Pacific and I'M THERE!! - so of course I now have PF.

The trimming system in PF drives me nuts in dogfights - as someone has absolutely correctly observed, the trim required varies with speed (as well as CG and thrust etc.) - and in a dogfight this is varying quite wildly at times. In PF it isn't too much of a problem while trying to set up a shot, but my joystick has quite a stiff centering spring so when it comes time to try and steady the reticle and let loose I have dreadful problems fighting the inevitable out-of-trim stick forces.

I'd guess those with adjustable stick tension (like sidewinders etc.) or sticks with no centering force don't have too much hassle but those of us with sticks sprung to centre quite heavily could use something like an auto trim.

11-04-2004, 10:58 PM
What sort of stick are you using killer2359?
I use the x45 stick/throttle combo and have the elevator trim on a rotary axis I can adjust with my thumb.
The x45 also has a rather irritating stick centering mechanism - which can at least by worked around with an assortment of lubricants.

IIRC it is also recommended to trim nose down (or was that nose up? http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif) when entering combat as this can help make gunfire solutions a little easier.



11-05-2004, 02:49 AM
keep at it. It will become second nature. TM Cougar here, which is about as stiff as they come (flew with an F22 Pro before which is stiffer and that worked too) and no problems at all. You do have trim on a rotary, don€t you?

In real life, I´m an aero engineer and fly gliders. For those not familiar with glider flying, it is a lot more active than most of the other civvie stuff. Apart from towing out in turbulent weather (turbulence is good!), you are always manoeuvring while spam can folks do spend a lot of time flying in straight lines. In gliders, you find a thermal while crusing along at high speed, zoom climb up into it and immediately bank hard over. Sometimes, this means going straight into a 60-degree 2G turn which you then maintain, constantly adjusting and working hard to center the thermal, often with other gliders doing the same thing both right across the thermal, above and below you. Yes, it can give you a sore neck...

The key point here is that you vary your speed and load factor a lot, all the time having to manoeuvre and do it with some precision. This also means constant trim changes.

I find that I use trim in Il-2 as in real life. Just as with the primary controls, it is just something I do to get the results I want, without even thinking about it. If I have to adjust trim when I am about to have a good guns solution, it is never by a large enough amount for the change rate cap of the trim to be a problem.

You have to learn to anticipate what is going to happen next and trim accordingly for it to work. But then again, this is what you have to do in real life as well. This is part of the realism you are buying for yourself when you invest in a high-end stick with a stronger centering force. Yes, it is probably easier to cope with out-of-trim situations holding something more reminiscent of a dead fish €" but the feel of flight will not be there.

Personally, I fly Il-2 to recreate aerial combat of WWII. If being competitive online was my main focus, I would probably fly other simulators.

The trim change rate cap is a good thing and should be kept.

Sometimes, I suspect there to be a slight delay as well, or a ramping up of the rate of change on adjusting. If this is the case, this should be dropped, even if I personally don€t have a problem with it.


11-05-2004, 04:15 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by killer2359:
I'd guess those with adjustable stick tension (like sidewinders etc.) or sticks with no centering force don't have too much hassle but those of us with sticks sprung to centre quite heavily could use something like an auto trim. <HR></BLOCKQUOTE>

Real life pilots didn't use trim much in combat and (if they're doing it by the book) don't use it much in dynamic flight conditions now. By dynamic flight conditions I mean aerobatics or manouvering with lots of speed and pitch changes.

Similarly, I find I'm not using trim much in combat unless I get in a long stern chase. When flying against a good pilot it's rare to have oppurtunities to hold the sights on target for any length of time anyway, so it's rarely an issue.

Trim is (in real life) only intended to ease stick force required to hold a steady climb, level cruise or steady descent. It is not intended as a primary control during manouvering.

Edit: you should also temper what I've said here with Effte's post just above me http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif.

11-05-2004, 08:54 AM
To clarify, I completely agree with Tully. By "constant trim changes" I do not mean that you use the trim to fly the aircraft. You constantly trim as flight conditions change. Steepen the turn, trim back a bit to reduce the elevator force required. Retrim for thermalling during the zoom climb into a thermal. Prepare for exiting a thermal by trimming nose heavy... and so on. Not "trim as soon as you correct for a gust of wind". That is what the stick is for. http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif

11-05-2004, 12:34 PM
why should you not assign the trim to a slider


11-05-2004, 04:00 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by raaaid:
why should you not assign the trim to a slider

Er... it was stated a post or two above that it should be on a rotary.

Whatever he is smoking, I'll have the same! http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif

11-05-2004, 04:29 PM
read the entire thread and you will understand why they suggested not allowing it on a slider or rotary.

11-07-2004, 12:55 AM
I've got a Logitech Extreme 3D Pro and don't have rotary or slider controls I can map trim functions to so have at the moment got pitch and yaw trims mapped to Q/A and Z/X respectively.

The way the trim control function operates I think is fine - I have no problem with either the stepping or the rate (ie. how quickly trim is wound on with the key held).

I take everyone's points - but I need to reiterate that I believe it's my joystick that's the problem inasmuch as it's got a very stiff centering force - and all I'm saying is that an optional auto trim would help me and others in a similar situation a great deal.

Such an option could even be incorporated with full manual trim control still available - ie. simply assign a control function that provides current correct trim setting when you press that button - so when trying to line a shot one can just tap the "Auto Trim Set" key (assigned to a handgrip button would be ideal) and be immediately free to make the shot without wrestling against the stick for atleast a second or two.

I understand perfectly how REAL WORLD trim control works both in theory and practice - ie. strictly speaking, in a real situation the actual stick position changes with trim.

On the line of "it's realistic" - apart from my observation above about the real stick changing position with trim (which the game CANNOT faithfully reproduce - tho maybe force feedback sticks can do it?) the zero requires it's pilot to deselect gear up when the gear is indicated up else blow the hydraulics (ie. there's no automatic cutout) - but they don't have that modelled - so they could surely live with letting us have an auto trim option.

11-07-2004, 10:28 AM
Ehm... in real life, with most flight control systems, the stick position does not vary as you apply trim. The force required to hold the stick in that position varies. http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif

Many aircraft require the pilot to select gear off on positive indication of retraction, but usually not since they'd blow the hydraulics otherwise. The hydraulic system should be able to withstand the maximum pressure exerted by the hyd pumps. The reason is that having the system pressurized will cause more wear, and will also empty the system should a leak develop. Much better to depressurize the system when no pressure is needed then. Do you have a specific reference for the Zero? I'd be very interested in reading a bit about the systems in that bird.


11-08-2004, 04:10 AM
:-) Ahhh, but think about this for a second - what is "that position"? - it will be the stick / pedal position required to make the plane fly in the desired direction - ie. if you want to descend you push the stick forward - aerodynamic forces oppose that so it's fairly quickly quite hard work - so you wind in trim to "unload" the control - so it's then unloaded and in a different position! (ie. relative to centred/neutral I mean). Likewise situation exists if the trim of the aircraft alters due to speed variation or load shifting - the controls need to be pushed in a given direction to achieve the desired direction/attitude or maintenance of direction/attitude - and to "unload" the control the trim is used - final result is that the stick pedals is/are made much easier to keep in the required position.

So... - the stick most certainly DOES change position with trim application in aircraft such as the fighters in PF - the flight control surfaces have small tabs which are moved by the trim control - these tabs effectively "fly" the whole surface to the desired position (or to put it another way: provide aerodynamic forces which reduce the effort required to hold the control surface in the given position) - you can see this by operating the trim control on any of the aircraft in PF whilst in external view - you'll see the whole surface move - which means the stick / pedals attached to the other end of the control system must also be moving - I work on such systems every day (it's a bit of a flaw that you can in fact see the whole surface move when aircraft are stationary on the ground in PF - in which case the tab only should move with no resulting effect on the whole surface - but asking the team to provide such detail as the trim tabs IS probably going overboard!..... - isn't it?... Oleg?).

Other trimming systems are related to powered flight controls and "all flying" surfaces and in certain of those cases I suspect the actual controls might stay centered - I'd have to do some research/revision to confirm that or otherwise - I personally haven't worked on such systems and any book learning was a long time ago.

I've worked on undercarriage systems that stay pressurised in the selected direction (Aerocommander for example) and those that engage mechanical uplock systems then automatically unload the hydraulics so the system is under no pressure - and same for down position - I've no doubt that there are also systems that mechanically uplock/downlock and then require manual selection to an unloaded/recirculating (neutral) state - the Zero is evidently one of the latter - the point being that IRL it DOES require manual selection not only to go up or down respectively but also to "neutral" - and in the context of denying an auto trim system on the basis of simulated fidelity I think my point is clear. The Zero also has a little bar that's attached via cable to the RH landing gear scissor links such that with weight on the wheels the bar extends and physically stops the undercarriage lever being selected up.

All this is said in the spirit of good natured academic banter BTW - no offense is either taken or intended (a little cheekiness maybe - but no hostility) :-)

I do gather that some sort of damage can result eventually in the Zero's hydraulics or undercarriage if it's not manually neutralised - check out http://rwebs.net/avhistory/history/zeke32.htm

Some excellent info on other aircraft and topics at that site - enjoy!

11-08-2004, 06:24 AM
good to see that there are still people here capable of academically disagreeing. Sometimes, I get the feeling that the adults are few and far between, as any disagreement seems to be taken as a personal insult. http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

As for the position of the controls during trim application, the position relative to a fixed point (such as measured from the dash) will (largely) remain fixed as you trim out the rudder forces.

If you do the proposed experiment in Il-2 in external view, the surfaces will probably move as you are holding the stick steady rather than maintaining constant attitude. This is the equivalent of holding a constant control pressure while trimming in real life, which would also move the controls and the rudders.

However, when trimming, you maintain attitude through the normal feedback loop, using whatever stick force is required, while reducing the stick force through trimming in another feedback loop. The controls don€t move (as measured from e g the dash). What you are really doing is moving the neutral position of the controls to wherever it needs to be to maintain the desired flight condition with the stick at the neutral position, i e without applying control pressure.

As for the trimmable main planes of the Bf109 et al, I am a bit more out in the blue as to the exact effect as I have no personal experience to build on. The rudder surfaces should, however, align with the local airflow which is in turn directed by the trimmable fixed part of the elevator. I e, the effect should be similar but not identical. What I do know is that the way you experience it in the cockpit would be identical. Fly for attitude, trim to relieve control forces.

Thanks for the A6M link! Very interesting reading there! By the sound of it, the concern isn€t blowing the hydraulic system but rather burning out the hydraulic pump. On most systems with a neutral selection, you are maintaining main system pressure but depressurizing the landing gear part of the hydraulics. One example off the top of my head, to show that it isn€t only small and/or old aircraft is the venerable Boeing 747-400. I€d venture a guess and say that a majority of aircraft (but not all, as you say) have a system which operates in a similar manner, whether automatic or manually selected. Remind me and I€ll have a dive in the type manuals I have available to give some more statistical backing on this.

Fred (and yes, also working with aircraft for a living http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif)

11-08-2004, 07:35 AM
I have my trim on the thumb slider of my X45 as well along with aileron trim on the index slider and rudder trim on the twist handle of my MSFFB2. I find that the rim in turns does help a tad at times. It helps to get those extra few degrees sometimes like when climbing up to a target. I mainly use aileron trim when I am damaged. I read a few accounts oif some WW2 pilots and I know of a few who used trim in combat..... think about it.. they had thier lives on the line so they probably used whatever the plane had to get that edge and stay alive. Even if it wasnt in the books so to speak..... Oh and Walsh... do yourself a huge favor and dump the easy settings immediately. You develope bad habits and wind up having to re learn some basics. Always try to keep your flight settings as fully realistic as possible as far as the way the plane behaves... (stalls,spins,headshake etc..). Views and icons are more of a personal thing but I am sure that 98% of the people here would agree that the full FMs are the only way to fly..... especially if you want to do any online flying.

11-09-2004, 02:57 AM
effte - nope - sorry, I can't agree with what you're saying about the trim only affecting the effort required to hold the control - the whole reason that effort has come into being in the first place is that the CONTROL has been MOVED by the CONTROL STICK or PEDALS to a position against which there is opposing (aerodynamic) force! - tab type trim systems as used in the fighters (and I think the bombers) in PF most certainly do result in changed stick and (in the case of rudder trim - pedal) positions.

Picture this - you're flying along at a given speed which has the aircraft flying straight and level with controls centred - then something changes - for argument sake we'll say you have a centreline bomb and you drop it. This changes C of G which results in the plane now wanting to nose up, so to return it to and hold it at level flight again you need to fly with some down elevator (and to do this you need to push the stick forward some amount) - but as you move that stick forward (thus deflecting the elevator downward) an opposing force builds up as it's trying to push itself back to centre (because the elevator wants to aerodynamically return to the same plane as the tailplane) - so you use the trim tab to "fly" the elevator into the downward angle you need - so the stick also is then in that forward position.

The trim systems in these fighers didn't simply lengthen or shorten the cables or push-pull rods between the control stick (or pedals) and the control surfaces - this would not work, because the aerodynamic forces opposing the desired control deflection would still exist.

In PF the FM of necessity does away with this control repositioning because you simply can't replicate it with computer joysticks that are springloaded to a fixed centre. The result is that in PF as you wind in trim, the joystick returns to centre thus imitating the unloading EFFECT of trim but NOT the true FUNCTION of it - thus once again I've held this as an example of something that falls short of true fidelity and which can be held up as yet another precedent in favour of allowing another non authentic feature such as the auto trim I've asked for.

You can see the evidence of the simulated and therefor not realistic method with which trim controls are implemented in PF by going to external view with an aircraft that is stationary on the ground and then operating the trims - you'll see the actual control surfaces moving and this is NOT HOW IT REALLY WORKS! On the ground when you operate tab type trim controls you will see the trim tabs deflecting but with no aerodynamic forces there is no effect on the control surfaces or indeed the controls themselves.

Also - I do gather that IRL fighter pilots did indeed use particularly the elevator trim A LOT! - it's no accident the elevator trim controls in many if not pretty much all fighters were not far from the throttle control and often quite large and easy to use in configuration (ie. almost wheelchair style wheels or crank handle style affairs such as ME109 and Zero - or nice large easy to operate rotary knobs such as the P51)

HMMMM ..... - you know what's just occurred to me as I write this? - my big problem with the FM is that when in a trimmed configuration I find the controls very "twitchy" - which makes accurate gunnery a bit tricky (I've seen another thread complaining of twitchy controls making gunnery difficult). It occurs to me that the twitchyness is because the FM is calculating the control surface loadings in relation to their deflections from original "zero" rather than resetting the aerodynamic loadings to neutral (and control maps to original zero) in any given trimmed/balanced position. This means that any subsequent movement of the stick results in excessive input. In other terms, imagine the controller maps suspended in space around the top of your joystick handle - ie. in X and Y axes for example. Now you push the stick forward to make nose down - you're fighting the centering spring so you "unload" it by winding on trim which in reality enables you to slowly return your computer joystick to centre with no spring opposition - but what's happened in the simulated world of your virtual fighter?? What's happened I would suggest is that the aforementioned controller Y axis map has been repositioned in relation to your joystick so that the centre/origin point is no longer X(0)/Y(0) - now it is X(0)/Y(0 but in the previous 10 position in relation to original zero) - so any more movement toward nose down of the stick suddenly sees you effectively making an input value of 17 (I'm using the suggested controller maps shown on page 27 of the PF manual - Pitch is my Y axis and Roll is my X axis).

What I'm getting at is that the initial mapping for the joystick allows us initially fine adjustment because the values immediately off centre are small - you get larger deflections/responses by moving the stick further which coincides with larger deflection values - but once trim is applied I'm thinking that perhaps we're left with small deflections resulting in inordinately large input values - nett result being really "twitchy" controls!

11-09-2004, 03:26 AM
With that reference to the Zero hydraulics, I used the term "blow the system" to mean a general failure - I didn't necessarily mean a physical blowout of fluid. I wondered at that report's reference to burning out the hydraulic pump - the thoughts that come to mind are that either the hydraulic pump is electric and only operates when the gear is selected either way and switches off in "neutral" selection so that tho the system can run at a continuous pressure the pump motor might not cope with the load for long - or alternatively the hydraulic system if engine driven utilises a pump that heats up excessively if operated under load for anything more than brief intervals. Maybe it's just a small pump - for weight saving - and/or the system doesn't operate on bypass style pressure relief (excepting the manual selection to neutral) - so the pump just "churns" once the devices being operated reach maximum travel therefor in addition to a heap of load and subsequent heat there's no cooling via operational or bypass circulation - ie. lots of pressure + heat and no flow.

11-09-2004, 09:12 AM
I€m sorry to say this, but this discussion is the worst argument I€ve had here in a long time. Why? Since we are both saying the same thing! http://forums.ubi.com/groupee_common/emoticons/icon_biggrin.gif

There is a difference though. You are describing what happens to the stick with no force applied when trimming, and it does move. I e, the neutral point of the controls change when trimming. I€m describing what happens if you maintain the desired attitude while trimming, in which case the stick doesn€t move but the forces required to hold it in position diminish.

The only thing which can ruin a good discussion more than someone who actually knows the facts is finding that both sides agree. http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif

And yeah, the entire control surface moving while stationary on the ground with no airflow over the surface is a bug. It was pointed out in the very first versions of Il-2 but still remains. I could of sworn that it was not present in one release of the simulator... either I€m wrong there, or it was reinstated in a later relase.

I once, after the initial first version release, wrote an applet which showed how it should work, based on actual physics. I really should find that and put it back online... it seems the confusion remains. It does seem to work as it should in flight though, so whatever the visual representation does is of lesser importance IMO.

Regarding the in-game control mappings, I€m so incredibly happy that I have sensitivity adjustment in my joystick. I just set the in-game sliders to 100 and leave them there. Smooth sailing, as soon as I remembered to apply the log scaling to the rudder axis as well anyway....http://forums.ubi.com/groupee_common/emoticons/icon_biggrin.gif

As was stated earlier in this discussions, trim is and with all certainty was used liberally during what would in the motorbike scene be described as €œinspired handling of the vehicle€, but not as a primary means of control.

As for the hydraulics of the Zero, it looks like we have some ideas but no solid knowledge until more detail on the design of the system are acquired. One source on the net, without any references, is hardly enough to be considered conclusive.


11-09-2004, 10:29 AM
The trim works OK once you get it 'on'. It reminds me of guys I see that haven't flown the full motion boeing sims before (or the real planes). Because of the delay and lack of good control force feedback here, it's hard to havea good feel from the stick as to the aerodynamic forces that are suposedly acting on the aircraft. Perhaps a way to do this, without much lag, but with a 'trim change limit' would be to have to trim in increments, much as the use of the F4F gear is implimented. Small increments of 'trim' with each stroke or button application, without much lag.

Note that all three trim axes are related, as is triming requirements for power and airspeed changes. For example, add some power and the effectiveness of the rudder and elevator increases, but torque, thrust line and p factor effects all make whatever you had now wrong. Perhaps now you need a little right rudder (less as speed increases) a little right aileron and a little down elevator for example, depending on what you are trying to do. As your airspeed cahnges, so does the trim requirments.

Trim is usefull once you achieve a fairly steady state, which could also include definition as a constant rate of change!

Small, responsive units of trim? Any thoughts?

11-09-2004, 07:45 PM
effte - I see your point and you're quite right that it does look like we're basically on the same freq, tho do be clear that where you say: "I€m describing what happens if you maintain the desired attitude while trimming, in which case the stick doesn€t move but the forces required to hold it in position diminish." - what I'm in turn trying to point out is that to get the aircraft to that "desired" attitude you would have moved the controls away from original neutral and be holding them in that new position - and then yes, you apply trim with the nett result that the controls then effectively want to stay in their new position without much/any physical effort any more to keep them there (they "unload").

From my point of view it sounds like you come awfully close to saying that: "from a starting point of fat dumb and happy at straight and level, if I want to enter a climb using trim only then I wind on some nose up trim to which the aircraft responds and shifts to a nose up attitude (as desired) but the stick does not physically move at all from where it started out because we are only using the trim." - and that is most certainly NOT right. You will indeed experience the plane pitching up to the newly trimmed nose up attitude - but as this was happeneing you would have seen/felt a ghost slowly moving the stick back to an elevator up position (as required to mantain the new attitude).

Fliger747 - I've deliberately kept it simple by speaking in terms of simplified physics and environment and as much as possible only in terms of pitch trim - you can imagine where we'd be if all this was discussed in terms of all the real world influences that can come into play and in their varying effects on all three axes of flight!! Also, I'm fairly sure the trim control implementation is in the form of stepping (like the F4F gear) - ie. each tap of the relevant key makes a small finite adjusment - and if you hold the key down it simply "repeats" after a brief initial pause (this might simply be the std keyboard repeat function?) - tho whether this continuous repeat accelerates with time or is constant I'm not sure. I do think it could be beneficial if the continuous rate was made much slower - but then again maybe any of us can acheive this thru the keystroke repeat settings from the desktop (I'll try that next time I fly).

In general terms I still have concerns about exactly how the FM implements trim control - especially as it has to compromise for our desktop joysticks not being able to physically reposition to new "neutral" positions and therefor we might be ending up in a position with trim applied where the next mapping position out of the new neutral is not the same as the proper first off centre value it should be mapping to - but I also think my joystick might not be real friendly to PF so a new one might be in order.

11-09-2004, 08:11 PM
A good discussion!

Some large aircraft have flight controls which are 'flown' into position by a tab, will indeed not move without airflow. However the WWII fighters that I am familiar with will deflect the controls on the ground as they are directly conected for positive motion, with the tab setup to move in the opposite direction to reduce forces.

I have sat in the cockpits of both a P47 and F4U and verfied this.

The trim in the game is not optimal, but we can get used to it. My only 'beef' with the FM probably is that power and speed trim changes are not as much as I might expect foma lot of experience in planes of similar size but lower power loadings.

In some aircraft such as the F6F, trim in certain phases of flight such as approach (right rudder) was necessary as the physical strength limits of the pilot could be exceeded.

11-09-2004, 08:18 PM
For what it is worth, I have programmed my X45 primary top-hat (#1 on the joystick) for aileron and elevator trim (like the old F-86). Adjustments are very quick and instinctive - the old thumb almost has a mind of its own. I know it is not "real-life", but it is effective in achieving level flight with miscellaneous power settings, etc. I use the mouse-cursor on the throttle for up, down, left and right views.

11-09-2004, 08:52 PM
Fliger747 - you've seen control surfaces deflect with trim on the ground in P47 and F4U (aircraft stationary)? - Well there you go, I must stand corrected with my specific statement in regard to that physical arrangement of those systems (humblest opology to the PF dev team for calling that physical movement on ground unrealistic!).

Do understand tho that the attention I've placed on that particular situation has been in the context of trying to demonstrate that the trim system affects the actual flying control surface - which in turn affects the physical position of the control stick in the cockpit (or pedals if it's rudder trim in question) - as opposed to the notion that the trim control system operates in parallel with the primary control and is designed to be transparent to the primary control (ie. no resultant stick/pedal movement with trim movement of the flying surface).

Did the stick also move to reflect the movement of the control surface as well (ie. using elevator as example)? If so then that's the main significance of what I've been getting at - if the stick does not move then it means the trim system in those aircraft is indeed effectively directly altering the interconnection between cockpit control stick and control surface (ie. as opposed to just independently driving the control surface).

This bears significance with regard to what I've postulated regarding the FM's implementaion of trim control (as it relates to altering joystick mapping) - ie. if the stick moves as trim is applied then I stand by my proposition that the mapping is (incorrectly) not actually being shifted - only the stick centre is being moved along the map, but if the stick does not move as the trim control deflects the surface+tab then it will make me rethink my position.

11-10-2004, 01:26 AM
as I'm constantly referring to trimming out the control forces, it surprises me a bit that you could read trimming from a controls centered situation into my words. Very peculiar control forces which don't displace the controls from the neutral position, I'd say! http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif

I do believe that the control input scaling is around the joystick center. It just would not make sense to have it any other way, as it would not only be useless but also harder to implement. Also, that€s not my subjective experience of the system. It should be easy to try out though, just have a very steep scaling at the top end and flat scaling at the bottom and see what the difference is between neutral trim and trim for slow flight, compared with the normal change in control response associated with the respective region of flight.

11-10-2004, 01:28 AM
the controls should and do indeed move with control input when stationary. The issue is that they move as you change the trim, even without an airstream over the surface.

11-10-2004, 01:30 AM
There are two tabs on the elevator of the F4U, one is a ballance tab, which is connected by a bell crank and tube to the horizontal stabilizer. The ballance tab moves in the opposite direction of the elevator because of the attachment geometry, reducing aerodynamic control force. The other tab is connected to the elevator trim control wheel to the left of the pilot. If you move the trim wheel, the tab changes position, but has no effect on the stick if there is no airflow. With airspeed, the tabs position will fly the elevator to a given position and will be felt in the stick and tend to move it to a position for which the trim is set. I'd have to dig it out, but I recall HH Hurd, "Aerodynamics for Naval Aviators" as having a discussion on this type of trim setup.

Pretty simple cables and pushrods here, but setting up the ballance tabs so they worked just right took over 100 test flights for the F4U!

11-10-2004, 03:19 AM
effte - well it looks like we've indeed been saying the same thing - or more precisely you've not been saying differently to myself and I've misunderstood - my apologies - altho the reason we've got into this is because you seemed to disagree with what I was trying to say about the controls moving in response to control surface movement from trim adjustment (in flight).

The idea of lowering the mapped values for a range that should cover any reasonable trim range to see if that makes a difference is something I've considered trying.

Fliger747 - I'm a bit lost - you've just described exactly what I've been saying all along (you've described it very well actually) - BUT you said earlier that the P47 and F4U control surfaces do move directly in response to the adjustment of trim even in the static situation???

Not important tho - as I think everyone's near enough on the same wavelength at last.

I'm familiar with balance tabs - again I wasn't aware they were used on WW2 fighters but it makes a great deal of sense and in fact reinforces my feeling that something's not right about the FM implementation of trimming - ie. the one niggling doubt I've had is that mapping the "trimmed" new joystick centre in such a way as to give excessively large responses immediately when moved out of that position has been a deliberate and accurate way of simulating loaded control surface response (something I have no real life experience with) - but balance tabs mean that shouldn't be a factor - we should be able to have control at the same proportioning and rate as from untrimmed neutral.

Look, everyone needs to understand that my WHOLE POINT is that in the real world, for a retrimmed condition in flight the control stick (or pedals if it's rudder) will NOT BE IN THE SAME CENTRED POSITION IT WAS BEFORE TRIMMING WAS CARRIED OUT - but with our desktop joysticks the control stick DOES return to centre when we trim - that's how the "unloading" effect manifests itself - instead of releiving opposing force in the altered position of the stick PF unloads the desktop joystick back to it's unsprung centre (which of course is not realistic) - and I think that's led to a flaw in it's effect on the in game control system - with the result that the controls become excessively sensitive and twitchy.

11-10-2004, 05:40 AM
Or, to put it another way: Joystick deflection is proportional to stick force used.

11-10-2004, 06:16 AM
I agree with a lot of what's been said here:

Simulating how real life trim works on a normal non-force-feedback joystick is impossible, that's why you see the elevator respond to trimming even when there is no airflow.

Basically the developers have decided that when your joystick is centered, the elevator will be in whatever position that would give no force on the stick if the aircraft was moving. This is a compromise, in real life the elevator would hang down when the plane is static (there are exceptions of course), and it would gradually rize to the trimmed center position as speed increases (without any pilot input, just letting the wind blow the elevator into position). This is a natural choice in my opinion, it would look weird with the elevator hanging down when the joystick was centered (which would be the case if it was implemented like this: "force on joystick = force on real life stick")

The perfect solution of course, is a force feedback stick, which (if the game is implemented well) could simulate the following:
When standing still, the weight of the elevators makes them hang down regardless of trim position, the stick moves to the forward position if you let go. When moving, the stick center should reflect the fact that the elevators just follow the air flow, and with different trim settings the elevators will end up in different positions. That is, the stick center position changes with trim (impossible on a non-force-feedback stick).

(I don't have a force-feedback stick btw, so I have no idea how this works in PF...)

11-10-2004, 12:46 PM
The 'assist' tabs move in response to the elevator position, not vica versa. With no airflow, the trim tabs have no effect on elevator position. The control surface is ballanced to a certain extent and with the plane sitting there, with no stick input, will sit at some intermediate (unimportant) point.

As the plane gathers flying speed and the controls come to life, then the TRIM tab will tend to move the control surface to a particular position for thatairspeed. You will feel this as a feedbak in the stick, if you let the stick go, it would MOVE to some location related to the trim and airspeed.

To sum up, just sitting there, the stick moves the controls directly, with only a small amount of frictional resistance. The trim tabs donn'a do squat. The ballance tabs move in a direction opposite to the control surfaces, but have no effect on control forces when just sitting there. Flying, the ballance tabs reduce the force required to move the control surfaces, but provide no trim. Trim tabs which areset from the cockpit, try to fly the surfaces to a desired (trimmed) location, you feel this as a resistance in the stick if you try to move it elsewhere.

11-10-2004, 08:22 PM
I've realised that effte misunderstood where I was comming from - don't forget that all of what I'm saying has been in the context of how IRL relates to what WE end up with in Pacific Fighters - thomb314 sumarises extremely well exactly what I've been getting at - please reread his post several times - what he says is all I've ever been trying to convey (I wish I'd managed to get it as succinct as he has - it's why I'm a mechanic and not an executive I suppose).

Fliger747 - I went back and re read your first post a couple of times and realised I misunderstood what you were saying. Do understand tho that I never said the tabs only fly the surface - please have a good read of my posts and you'll realise you misunderstood in the first place - I HAVE been only speaking of trim tabs - and have not at any point suggested the tabs move the control surfaces with no effect on the primary control - at rest on the ground, if you operate the trim system the TRIM tabs will deflect without moving the whole surface (the ballance/spring tabs won't move unless the primary control moves) - and if you move the stick or pedals then the whole surface (+ spring tabs) will indeed move.

Look, way back earlier I said: "I understand perfectly how REAL WORLD trim control works both in theory and practice - ie. strictly speaking, in a real world situation the actual stick position changes with trim" - I should have been clear that I MEANT this as an illustration (not a litteral descriptive on flying a plane!) and as such it's described as it occurs IN FLIGHT and with HANDS OFF the stick - ie. from a straight/level situation with hands off the stick, if you wind in nose down trim the nose will go down and the stick will move forward because the trim tab has "flown" the elevator to a downward deflection - which is very different to your desktop joystick which STAYS CENTERED - but within the FM they must obviously be doing some sort of manipulation of the stick maps to compensate for it staying centered like that - this I'm saying is flawed somehow - that's all I've been trying to say all along!!!!.

effte, you said this: "2359, as I'm constantly referring to trimming out the control forces, it surprises me a bit that you could read trimming from a controls centered situation into my words. Very peculiar control forces which don't displace the controls from the neutral position, I'd say! " - EXACTLY MY POINT!!!!!! - IN PF WE ARE FORCED BY THE NATURE OF DESKTOP JOYSTICKS TO BE TRIMMING FROM A CONTROLS CENTRED POSITION - YES, IT'S NOT REALISTIC AND THE WAY IT'S MODELLED IN PF DOES INDEED LEAD TO VERY PECULIAR CONTROL FORCES - FORCES WHICH MAKE THE CONTROLS JUMPY AND TWITCHY WHEN ANY TRIM ADJUSTMENT HAS BEEN "WOUND IN". - and THERE lies the basis of my complaint.

11-10-2004, 08:51 PM
Try out what I'm saying like this: get into the air in your favourite plane BUT DON'T TOUCH THE TRIM (fly it level on the stick only) - then do some maximum rate turns - best to use turns rather than just pitch up as you can hold the stick deflected for longer and observe better what happens. Keep track of your airspeed and how much physical stick you're using.

Now level off and trim the aircraft to fly straight/level and once again repeat the operation above - ie. perform max rate turns - try to keep the airspeed similar to what you had above - especially at commencement - and observe how much stick deflection you're using.

When I fly in PF I get much less stick travel when trying to perform the turns with trim applied - and the stick movement required to get the response equivalent to full control deflection (usually resulting in snap stall) is nowhere near full stick deflection.

11-10-2004, 10:42 PM
Exactly so! I wonder if some of the complaints of the F4F not stalling were from out of trim conditions relating to the joystick system. In a real (WWII fighter) system you could always get full contrl deflection no matter what the trim setting, if you were strong enough.

Indeed you are right in that the 'trim' system is also moving the control input boundaries! Stabilizer trim systems in the (real) jets that I fly do that, the system in use on WWII fighters did not!

Not a misunderstanding, just moving to the next level of discovery!

11-10-2004, 11:33 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by BSS_Vidar:
Doesn't really matter if you use a rotor command, or a button. They actually work the same. The trim wheel moves the same speed either way, and the trim reaction lags behind. So, if you stay with the button, use a series of bumps and waite for the plane to respond. You'll get use to it.
Thank-the-maker the trim isn't instantanious via rotor/slider commands. That's the biggest reason PC Pilots - not gamers left CFS2.


In CFS2, the trim tab acted as an elevator in it's own right.
You could have "elevator cables shot out" message come up but still be able to fly normally using the elevator trim tab.

You could also use the elevator trim tab to loop and not be affected by blackout.

"IL-2's trim is good to go folks.They just need to get the lag input taken out, and don't allow instantanious full throw via axis and sliders. A button command is all you need either via keyboard or joystick just like a real aircraft."
With respect...it is not good to go. With a wheel trim should be able to get to a point that is spot on, using keys/ clicks the best would be somewhere close to spot on. How does the use of a slider work? where would "centre/ neutral" be?
It should take only a very, very short amount of time to trim up. A pilot should be able to trim to climb. The trim function is a vernier on aircraft and one should be able to fly, not dogfight, but fly using trim tabs only.

I guess the only true option would be for an "auto trim" function. ie...set the stick, then hit auto trim

If torque was moddeled corectly ingame, trim would be vital for carrier take off and in the case of go around, trim to be set prior to final approach for traps. Set not for landing but for throttle up and acceleration

Slightly OT but intereing nonetheless:


back to the ranch....

Killer2359...trim is used to remove the pressure applied to the stick to keep the plane level or in a fixed climb or descent

11-11-2004, 08:40 AM
"Killer2359...trim is used to remove the pressure applied to the stick to keep the plane level or in a fixed climb or descent"

HUH???? - have I EVER tried to imply any different???? - why the heck do people keep trying to correct me for errors I'm not making???? PLEASE READ MY POSTS PROPERLY!!!!

Vagueout - yes, I KNOW!!! I KNOW how trim controls operate - I WORK on them every day and I've FLOWN REAL AIRCRAFT and used this type of trim - Look, IRL the pressure you speak of occurs why?: - it occurs because to make the plane fly the way you want it you've MOVED THE STICK - so now you're holding it such that the control surfaces make the plane fly the way you want it - to KEEP it flying in that direction you're now holding the control there - this results in an opposing force on the stick (because you're deflecting the control surface and wind pressure is trying to oppose that) - so yes, you use the trim to "remove the pressure acting on the stick" - in that new position! The stick is now in a different physical position tho to where it was before you made the original control input for which you then trimmed etc. THAT'S IN REAL LIFE.

And BTW, I'm pretty darned sure that actual fighter pilots were quite often snatching trim adjutments during combat maneovers.

MY POINT has been all along that IN THE PACIFIC FIGHTERS GAME this is not how it works - in PF you move the stick and then hold it there to make the plane go where you want it - so now you're holding it such that the game makes your plane fly the way you want it but the joystick has a centering spring which is giving an opposing pressure (ooh-ah that feels realistic) - so you tap in trim to remove this pressure which is physically manifest by your being able to relax the DESKTOP joystick (I'm talking now about the game - make no mistake) back to unsprung center - BUT THIS IS NOT REALISTIC!!! - which means the controller input maps are being altered to enable this unrealistic behaviour (remember, the affected simulated control surfaces have been trimmed away from original neutral position - but the joystick is back in the original neutral position - BRAAAAP! - not physically possible in the real plane boys and girls!!!) - and I'm suggesting this is implimented INCORRECTLY - because the result (I feel) is out of whack controller input values when the stick is subsequently moved from that "trimmed" position (I'm talking about PF here - NOT ABOUT REAL AIRCRAFT).

Another illustration:- in PF you can fly the aircraft HANDS OFF on the trim as follows - keep your hands right away from the joystick - which stays in it's spring loaded centre position - and tap in trim to make pitch down/pitch up or directional changes (even aircraft without aileron trim will roll in response to rudder trim so this can be used to control heading). So with trims only in PF you can fly the airplane all over the place changing altitude and heading easily at will (or indeed making it simply fly straight and level) - the control with trim won't be responsive enough for dogfighting but it's fine for general navigation and gentle maneouvering - all performed with that joystick sitting ROCK STILL.

Now you can in fact do the same thing in a real life airplane - ie. keep your hands and feet right the heck away from all the controls and fly the plane exactly the way you did the one in PF above - BUT - the BIG difference will be that instead of sitting rock still, the controls will be doing a ghostly dance (whooooo... - scary huh?) - following the movement of the control surfaces you've been making via the trim tabs.

GET THE DIFFERENCE - GET THE FACT THAT I KNOW HOW IT'S ALL SUPPOSED TO WORK (so quite trying to teach me stuff I KNOW ALREADY) - now PLEASE try and absorb and understand what I'm trying to get at about the GAME's implementation of the trimming/control system - which to me makes the trim control unusable if you want anything near realistic dogfight maneovering - but WITHOUT a usable trim control and WITH simulated out of trim aeroplane behaviour the whole experience of flying the planes feels unpleasant (get sick of wrestling with joystick).

So IMO the development guys either need to ditch the realistic dynamic trim characteristics of the planes or correct the way the control maps are altered by the trim control system - then I'll be a happy camper :-)

11-11-2004, 09:13 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>So IMO the development guys either need to ditch the realistic dynamic trim characteristics of the planes or correct the way the control maps are altered by the trim control system - then I'll be a happy camper :-) <HR></BLOCKQUOTE>

I see that you fully understand how real aircraft work. The only problem in the game is this: there is no other way to do it. If the control maps were not altered, trimming would have no effect at all. If desktop joystick position just reflected the real elevator position, trimming just changes the imaginary force the pilot would have to apply to keep it there, but the player would not notice this at all!

Edit: I'm not sure I understood how you would have implemented it, please explain http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

11-11-2004, 09:20 AM
Now, a few years back I tested a stick with force feedback on MS Flight Simulator, and as far as I remember all this stuff was actually modelled correctly. The stick actually moved to a different position with trim, and when the plane was standing still the stick just fell to the side without any centering force. Has anyone tested this in PF?

The only thing bad about it was the force feedback didn't react quickly enough, there was a very noticable delay in the force. This bothered me so much I actually prefer flying without force feedback.

11-11-2004, 11:15 AM
Having had to take apart a couple of FF sticks over the years to make some 'repairs', they are interesting, and potentially a much better design to replicate what we are discussing here (finally). Designs vary, but motors are connected typically to spring, cable drum systems and can change the resistance and neutral positioning of the stick. This is a big advantage in not having a BIG centering spring trying to drag your hand to just on spot.

I'm not currently using my MS FF2 as it was not as optimal as the stick, throttle pedals setup I am currently using, though the 'feel' was good. One of it's other advatages was being able to feel 'airspeed' feedback and that real mushiness you get at low speed with 'needle ball, airspeed' planes.

It doesn't bother me too much as I fly airplanes (IRL) in which the 'feel' is pretty generated and not 'real'. You learn to deal with it.

A new frontier for those making and using sim flight controls!

11-11-2004, 01:46 PM
I just mapped my Elevator and Aileron Trim to one of the hats on my X45 joystick yesterday. And as many of you have stated, it acts funny. I also just tried using the key controls, and it still acts funny.

So, I took an External view and did some testing. I noticed that when I trim the rudder there is a few seconds lag, but the rudder did move to the left and 'stayed' there.

But when I trimmed the Elevator, it would move and then just pop back to center when I stopped trimming it. Then I went back into the cockpit view and looked down at the joystick. The joystick moves when I trim the Elevator, and when I'm done, it also pops back to center!

I am no airplane expert, but in my simulator experience, when you trim the Elevator, Aileron, or Rudder, the surface should stay at the trimmed position!?? Right??

Also, when you trim the Elevator, should the cockpit joystick move? I don't think so. It makes me believe that they screwed up, and just tied the Elevator Trim key controls to the joystick.

11-11-2004, 03:46 PM

As an FAA licensed pilot, I just wanted to say that I concur with you on this subject. I think it would have been better to not have modelled trim at all than to implement it in the way it has been. Yes, I understand that the way the trim was implemented was a compromise (especially for those with non-force feedback spring-centering joysticks), but it is an unrealistic implementation nonetheless. I would prefer the way trim was handled in MSFS, although that would only benefit us force-feedback users.

11-11-2004, 06:16 PM
Thanks ExpendableT :-)

thomb314 - I take your point and don't dispute the fact that they need to alter the controller maps in order to deal with the physical limitation of spring centred desktop joysticks - it's an obvious necessity - my beef is that it hasn't been done correctly - and I think it should be relatively easy to fix - but the first step in getting it fixed is for the problem to be identified and acknowledged in the first place.

To that end I've been trying awful hard here to identify the problem (getting diverted by unnecessary debates on the function of trim systems has been a frustration to that broader objective) - as more people see what I'm getting at it will get more acknowledgement and with any luck this will lead to the ultimate result of Oleg and his team correcting it - and I'll be a happy camper. I have sent an email identifying this as a bug - but I'm only one voice in the wilderness.

From a trimmed condition the PF joystick should map subsequent stick inputs as if you were back in the centre of the linear stick map - but instead it seems to instantly add the TRIMMED position of the control surface to subsequent joystick inputs - so slight movement from the newly trimmed centre gives a stick input of the deflection already trimmed, plus any input you're trying to make as well - nett result is far too much control sensitivity.

Another way of puttng it: I've trimmed my PF plane straight and level - this has resulted in stick: neutral; simulated elevator: 5 units up. Now from that ballanced flight condition I try to maneover - ie. I roll left and try to pull into a turn to the extent of - for arguments sake - the equivalent of 5 units of input on the pitch map of the joystick.... but immediately the FM maps my joystick from it's current origin to 5 units (the trimmed amount) PLUS the new 5 units I've just pulled - so my elevator responds to the extent of 10 units for an input that SHOULD equate to only 5. Result is overly sensitive controls which at best is irritating when trying to line up shots and at worst is a menace as it makes it far too easy to pull excessive control deflection with far less stick input than such deflection SHOULD take, leading to snap (high speed) stalls and such. I find in that same situation that if I try to PUSH the stick then the whole thing works the other way - I first move the stick the equivalent of 5 units and get NO response before finally getting a reaction - ie. the FM has again first added the trimmed (+5) units to my input of (-5) - result: ZERO - so I have to add another (-5) before getting a response equivalent to the original (-5) I first applied. So I've had to move the stick the equivalent of (-10) to get a (-5) response.

11-11-2004, 06:27 PM
With regard to WIldcat being too difficult to stall (ie. the complaints of being able to pull full stick and just keep turning) - this can happen at less than high speed because the Wildcat in PF tends to pitch down at high speed (necessitating up trim = excessively sensitive up elevator) - but at lower speeds the aircraft tends to pitch up so if anyone has dialled in some nose down trim then they'll encounter the opposite of what I've descibed earlier - and their stick will be LACKING in sensitivity in the stick back direction.

ie. in any trimmed situation you end up with too much sensitivity in the trimmed direction and not enough in the other direction - this exacerbates the problems of bringing guns to bear because if you're right on the changeover point you get jumpiness in one direction and mushiness in the other = FRUSTRATION!

11-11-2004, 07:16 PM
An interesting excersize, to sit in the F4F "virtual cockpit' and play with the trim. I would appear from the sim that the (simple) Wildcat used a 'bungee/spring' type of trim, without the more sophisticated adjustable tabs of the F4u. The rudder trim biases the rudder position, which has a centering spring. The 747-400 which I fly uses this system! As it should, the rudder follows the new pedal position! Now the aileron and elevator trim is a bit different, in that it is changing the position of the control surface relative to the stick position. If you were sitting in the cockpit, holding the stick rigidly in position, this is the effect that you would see. In reality, one would probably see the stick move, you can do this by neutralizing the control surface (look at it) and czech out the new stick position.

Will have to visit some resources to see how the real F4F handeled this.

Hold the presses, almost all of the above is WRONG! Consulting exploded diagrams of the F4F reveals an adjustable tab system much like on the F4U. The control surfaces should not move, nor should the stick or pedals without an airload, as far as I can tell!

Not shown in the PF 'plane' is the moveable aileron tab on the left wing, rudder tab and adjustable tab on the left elevator!


11-12-2004, 06:49 AM
Can someone please check my post on the previouse page. I would just like to get some answers, if possible, to the questions I posed.

Thanks http://forums.ubi.com/images/smilies/10.gif

11-12-2004, 07:26 AM
my apologies killer, i had no intent to offend only to offer a simpler way of puttings things across. Please don't yell at just me.

I use a forcefeedback stick and do get tired of wrestling with the stick as well.

11-12-2004, 11:02 AM
After everyone wasting a gigibite of ones and zeros lost to teh etheria, this si what it coms down to:

(1) Everyone knows how real trim is supposed to work in an AIRPLANE.

(2) PF uses a simplified visual reprsentation of the 'trim system', not attempting to replicate the actual system used on US planes.

(3) It's like the brakes, done a certain way because it's simple, fits the sim engine and is 'good enough'. I does work if you get used to it. "It's a feature, not a bug" for those that want things to need a little 'skill'.

(4) The guy that was getting a snap over of the stick, and then it's return to center was hitting and getting a response from the arrow keys, probably hitting that a millisecond before the control key.

(5) Full up to full down on the elevator takes 4 turns in the American birds here, seems to be a bit 'fast' and has a lag. Try a small hit, wait, another etc. till you get it right. Easy with the lag to go way beyond. The possible trim effectivenesses in all three axies seem pretty strong!

(6) I was able to fix some CFS 2-3 aircraft that had problems with over enthuiastic trim by going into the 'aircraft.cfg' files there and changing the 'trim effectiveness' fudge factor.

(7) This is probably fixable, at least as far as its use is concerned, probably not as to it's visual representation.

11-12-2004, 12:03 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Fliger747:
(4) The guy that was getting a snap over of the stick, and then it's return to center was hitting and getting a response from the arrow keys, probably hitting that a millisecond before the control key. <HR></BLOCKQUOTE>
Fliger, if you are refering to me, I was pressing and holding the control key, before I press any of the arrow keys, and held it until I was finished.

I am coming from lomac, so maybe the trim here just does not work the same. I assumed the control surfaces to simply move and stay where it is moved when I trim. That appears not to be the case?

11-12-2004, 09:34 PM
Vagueout - sorry about that, I got a bit frustrated with someone again stepping in to explain to me what I'd already expended a lot of energy saying myself.

effte - in this discussion a summary is definitely a worthwhile effort! I do have to say tho that ref. item 3 I disagree - it makes the whole thing feel awful and in fact terribly unrealistic IMO - and saying it just adds to the "skill" required and therefor is a good thing is like saying driving a racecar with a flat tyre simply means you need to have more skill so makes the race more challenging.

AStotzer - when you trim the elevator the stick should move because in trimming the elevator you make it move and because it's connected to the stick the stick will move (this is in hands off stick situation). Your problem with the elevator popping back to centre is definitely not right - is the "centre elevator trim" command mapped to something that is triggered when you finish making the adjustment?

11-13-2004, 08:10 AM
Nope, I did not map the center elevator trim to anything. I only mapped the elevator up and down trim to a hat on my joystick. Doesn't anybody else have this probelem of it popping back???

I was flying a B25 campaign mission last night, and was about 10th in line to take off. It appeared that all the B25s in front of me trimed their elevator up, because I could see their control surfaces go up, and stay up. But again, when I trimmed mine with the Ctrl-Up arrow keys, they just popped back. They would not stick in place. Does this happen to anyone else??

11-13-2004, 11:07 AM
Not meant to be derogatory! I got that same reaction you described by doing as you describe, but apparently was a bug in there or a keyboard problem which favored the arrow key. On MY keyboard (ancient) depressing and holding the Ctrl key before even looking at the arrow key eliminated that response. Since you were doing the same thing, I have no explanation as to what is going on with YOUR keyboard!


11-13-2004, 03:39 PM
Thanks for the reply. This must be a bug, but it seems that I am the only one it is happening to.

11-13-2004, 07:38 PM
I'd suggest mapping the elevator trim centre function to another key - then if that doesn't work then remap the elevator trim adjustment functions.