DCS Bf 109 K-4 QUESTIONS

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hey, i'm new to the bf 109 and really enjoy flying it. (I bought in in steam sale, even though i'm not really interested in WWII dogfighting and will probably only use it for acrobatics and just cruising around) I find the official manual to be lacking a bit though...

i find that in the 109 i have always a little bit stick applied to the right (control+enter for the axis view: diamond slightly off to the right, when my joystick is centered). first i thought my joystick was faulty, but in other aircrafts it behaves "correctly". i checked the special options for the 109 and verified that trim is set to zero.

is this intended behaviour, or is it an input problem on my end?

The Bf109 is a very hands on plane. It even lacks a rudder trim (actually it is set on the ground) so it will behave rather strangely in the air under different conditions.

I believe that when flying with automatic prop pitch on, and setting the throttle to ATA to 1.1-1.15 then trimming out the pitch axis for level flight you will be able to cruise completely trimmed out, with hands off stick.

Try that and report back on your experience.

Pretty much intended, as 109 (and 190 for that matter) has neither aileron nor rudder trimmers and it's not quite possible to fly it 100% "hands off" all the time (not to mention that neither prop plane is, because of various assymetric airflow effects caused by propeller).

However:

a) 109 is designed to fly fairly balanced in cruise settings (around 1.1-ish ATA of manifold pressure) and...

b) ...if you want to balance it for non-cruise, you have to adjust fixed trim tabs to your liking (that's exactly what these settings in special options are for, to simulate tabs bent a bit up/down by mechanics).

hey, thanks for the answers. i'll consider that on my next flight.

i think, i was concerned about it, because i thought the ctrl+enter "controls view" would show control device input (game controller axis) rather than simualted stick input.

your explanation makes a alot of sense though. thx!!

another quick question:

does "full flaps" flaps mean, having flaps down until the red markers shows on the flap, or does it mean having them down as far as physical possible?

i would assume, that the red marker means "full" and everything past that would be for emergencys or special procedures?

i think, i was concerned about it, because i thought the ctrl+enter "controls view" would show control device input (game controller axis) rather than simualted stick input.

It shows both at the same time, however, doesn't it?

As for the flaps - don't overthink things . I've never bothered looking at those markers, not even sure if they're replicated correctly on all custom paintschemes. I just flip the switch on warthog throttle until they go full down. Believe me, at these deflections, a couple of degrees +/- won't make any noticeable difference during landing approach.

... As for the flaps - don't overthink things . ...

ok. will try not to overthink! :thumbup:

again about the stick deflection:

i noticed that flight stick deflection on centered controller axis only appears when flying, not on the grund.

so i assume, it has nothing to do with trim directly, but somehow simulates the force feedback on the real stick, in a way that you have to constantly apply some pressure to the left in order to counter it.

can someone confirm this?

to replicate: confirm trim in special options on zero. on the ground at standstill: check input with ctrl+enter, notice centered flight stick. in the air: check input with ctrl+enter: notice slight stick defelction to the right. also notice slight aileron deflection on par with stick defelction.

i understand the trimming characteristics of the 109, but i still find it weird for the stick to deflect, while my physical joystick is perfectly centered. i like to think of myself as a pilot with very strong arms!

CTRL + ENTER will show you your virtual stick, so yeah if there are forces acting on it it in the game that deflection will be shown in the window.

ok. will try not to overthink! :thumbup:

 

again about the stick deflection:

i noticed that flight stick deflection on centered controller axis only appears when flying, not on the grund.

so i assume, it has nothing to do with trim directly, but somehow simulates the force feedback on the real stick, in a way that you have to constantly apply some pressure to the left in order to counter it.

 

can someone confirm this?

to replicate: confirm trim in special options on zero. on the ground at standstill: check input with ctrl+enter, notice centered flight stick. in the air: check input with ctrl+enter: notice slight stick defelction to the right. also notice slight aileron deflection on par with stick defelction.

i understand the trimming characteristics of the 109, but i still find it weird for the stick to deflect, while my physical joystick is perfectly centered. i like to think of myself as a pilot with very strong arms!

Can't confirm that really, at least with fixed trims set to 0, and I've just did a couple of flights with game and sim flight mode, auto rudder on and off, take-off help on and off :D. Physical and virtual stick (as noted on indicator) always stay together until the force limit due to high speeds is reached, then the virtual one stops, obviously.

It's been like this for about two years, when Yo-Yo decided DCS warbirds should transfer physical stick input to virtual controls output based on the principle of 1:1 position, rather than force (as it worked in old Il-2 series, for example). The only time in DCS when physical doesn't match virtual (below high speed limit I mean) is when trim tabs are in non-zero position.

Which brings a question - did you discover a bug, where setting trims in special options back to zero after previous experiments doesn't quite work (thus still causing offset you described above)? I admit I've never used these, so don't know how reliable this feature is.

Which DCS version are we talking about? Does it happen as well when you reload the whole game?

Can't confirm that really, at least with fixed trims set to 0, and I've just did a couple of flights with game and sim flight mode, auto rudder on and off, take-off help on and off :D. Physical and virtual stick (as noted on indicator) always stay together until the force limit due to high speeds is reached, then the virtual one stops, obviously.

 

It's been like this for about two years, when Yo-Yo decided DCS warbirds should transfer physical stick input to virtual controls output based on the principle of 1:1 position, rather than force (as it worked in old Il-2 series, for example). The only time in DCS when physical doesn't match virtual (below high speed limit I mean) is when trim tabs are in non-zero position.

 

Which brings a question - did you discover a bug, where setting trims in special options back to zero after previous experiments doesn't quite work (thus still causing offset you described above)? I admit I've never used these, so don't know how reliable this feature is.

 

Which DCS version are we talking about? Does it happen as well when you reload the whole game?

I thought the 0.0 in the Special Options panel means no further deflection from the usual trim tab setting that already compensates for cruise AoA and power settings.

So, the tab is stil defleced to default values, and with dynamicfs pressure, the corresponding surface will deflect

Which brings a question - did you discover a bug, where setting trims in special options back to zero after previous experiments doesn't quite work (thus still causing offset you described above)? I admit I've never used these, so don't know how reliable this feature is.

 

Which DCS version are we talking about? Does it happen as well when you reload the whole game?

i'm on steam. so stable 1.5x it is.

it also happens after computer restart. i have only tested cold start so far, because that's my preferred way of doing it.

i did some testing in the air, with the game controller axis perfectly centered (i've got a new joystick, which is very precise), but flight stick and ailerons slightly deflected, but absolutely static in that defelction.

even when i violently changed throttle and played with the rudder, the slight virtual stick deflection did not change at all.

just to be sure, that i don't misinterpret the controls view: when i mean stick defelction, i mean, that the diamond is off centre to the right. this is on par with a slight deflection of the aileron, as mentioned above.

i assume it is a bug, since this deflection is static even under heavy throttle change and rudder.

just to be sure, that i don't misinterpret the controls view: when i mean stick defelction, i mean, that the diamond is off centre to the right. this is on par with a slight deflection of the aileron, as mentioned above.

i assume it is a bug, since this deflection is static even under heavy throttle change and rudder.

I had the same deflection in the chopper and had to recalibrate the stick in the Windows Game Controller settings. After that the deflection was gone. Should give it a try.

Again, I think that the 0.0 in the rudder and trim tabs in the Special Conf, means no deflection away from the default one.

But the fw190 and the 109 come with the tirm tabs deflected for cruise... These settings just allow for fine tuning.

So, whenever there is dynamic pressure over the ailerons / rudder, there will be a deflection and that will be noticeable in the CTRL-ENTER controller indicator.

Even on ground, for instance in the p51d, if you set the aileron trim tab and increase the wind speed considerably, you'll notice the ailerons starting to deflect.

Unfortunately no adjustment to the elevator trim tab was made available in the 109 or 190... It would have helped with other details of the simulation, specially imho, specially in the 109. Yes it has a stabilator, but it still had an elevator trim tab, ground adjustable just like the aileron and rudder trim tabs, for some reason....

For me the 109's trim has always been a mystery: I have to set it fully forward for every situation unless I'm landing.

Also, it doesn't use the full length of my slider axis. full trim back can be achieved by setting my slider to approx 30%, and full forward trim by setting it to 70%. Any movements above/ below those don't do anything. I know it has been reported many times, but it still hasn't been fixed.

Again, I think that the 0.0 in the rudder and trim tabs in the Special Conf, means no deflection away from the default one.

 

But the fw190 and the 109 come with the tirm tabs deflected for cruise... These settings just allow for fine tuning.

 

So, whenever there is dynamic pressure over the ailerons / rudder, there will be a deflection and that will be noticeable in the CTRL-ENTER controller indicator.

 

Even on ground, for instance in the p51d, if you set the aileron trim tab and increase the wind speed considerably, you'll notice the ailerons starting to deflect.

 

Unfortunately no adjustment to the elevator trim tab was made available in the 109 or 190... It would have helped with other details of the simulation, specially imho, specially in the 109. Yes it has a stabilator, but it still had an elevator trim tab, ground adjustable just like the aileron and rudder trim tabs, for some reason....

But if the behaviour was intentional, shouldn't the deflection be either constant (all airspeed), or dependend on the forces working on the airframe (deflection changing with heavy rudder/throttle).

What i get atm. is a perfectly centered stick when stationary. When accelerating near take-off-speed, the stick deflects slightly to the right and stays exactly (!) there even when shaking the aircraft with rudder and throttle. It only comes back to centre when airspeed is below stall speed / take-off speed.

So, I assume it is a bug. I would post this in the bug-section, but just want to make sure, the problem is not on my end. It's strange, that i am the only one, who experiencea this. Could someone check, who is also on stable 1.5xx/steam?!

I misunderstood your posts on previous page, now I know what you're on about. I can't center my physical stick precisely because of non-symmetrical extension I use, but loading missions with no controllers plugged in (i.e. zero'ed inputs) is better method anyway. After testing in 2.1.1., indeed, in flight the "diamond" symbol is offset a little to the right and I would assume Jcomm's explanation about pre-set, default, fixed aileron trim is correct. I even seem to barely recall this peculiarity was discussed years ago after the module was initially released.

Note that such behaviour (mismatch between virtual and physical stick postitions when trimming out of zero tab position) applies to all planes in DCS (or any other flight sims for that matter), 'cause that's the only way to simulate trimming with non-FFB joysticks. So that's normal and expected. The only different and puzzling thing is why the "diamond" gets centered when stationary, as it should be offset all the time, as it does when using trims in other planes.

So that might be a bug indeed, and definitely experienced by everyone, but it's so tiny and non-affecting usual flight regimes, that we don't notice it anyway (hey, you promised not to over-think things :D)

hey, you promised not to over-think things :D

i try!!! :smilewink:

But thanks for the clarification. So, the expectated behaviour would be, that the slight deflection of stick and aileron should also occur on the ground without airspeed and also the slight aileron deflection should be visible on the ground. So it is not a bug with the "control view" but probably with pre-flight trim not triggering below stall speed.

i did a flight just now and i'm now also quite confident that this bug also offsets the actual trim, meaning i could not find a throttle setting in horizontal flight, that made the 109 not to roll to the right. i tried everything from 1 ata manifold pressure up to full boost and gave it some time time to stabilize airspeed, while very carefully working the rudder if needed. only while accelerating aileron trim was no issue.

maybe the bug is somehow related to the "take off assistance" (turned off, of course), which would explain the occurance off the "over-trim" only above stall speed/take-off-speed.

Interesting indeed twistking - never looked at it that way.

I did observe the deflection, due - I thought - to the trim tab set in a way to compensate for cruise flight situations, as soon as there was sufficient dynamic pressure over the control surfaces.

What you say is that apparently, it always sums to whatever trim is set in the "Special" menu for aileron and rudder, so that no matter how I set it there it will never allow to achieve level flight ( without a rolling moment ).

Interesting indeed twistking - never looked at it that way.

 

I did observe the deflection, due - I thought - to the trim tab set in a way to compensate for cruise flight situations, as soon as there was sufficient dynamic pressure over the control surfaces.

 

What you say is that apparently, it always sums to whatever trim is set in the "Special" menu for aileron and rudder, so that no matter how I set it there it will never allow to achieve level flight ( without a rolling moment ).

Not exactly. I did find that changing the trim in special options makes a difference, both in actual roll characteristics and in aileron/stick deflection visualisation.

It just seems that for me a special options "-10" trim on aileron is a good value to get stable cruise, while i was expecting a "0" to give stable cruise.

So that's probably not a bug, but just an unintuitive slider numeric.

(on "-10" the defelction is still a tiny bit to the right. Symmetrical aileron would probably be around "-15". Untested though, as "-10" feels quite stable on cruise)

The thing, that i consider to be a bug, is that the trim only kicks in after stall speed. From my understanding the trim should deflect the stick and control surfaces not only in flight, but also without airspeed.

Or is trim on the 109 archieved exclusively by altering control surfaces through flettner tabs? Then of course, it would makes sense for the trim to only occur after the flettner "threshold".

The official manual mentiones flettner tabs, but since the 109 is my first prop plane, i am not sure how exactly the trim is supposed to work with them.:book:

If by "flettner" you mean servo tab, not all 109Ks had them all around - "ours" has it on the rudder only. Even if it had them on ailerons, though, it wouldn't change anything, as servo tabs in their primary form do not work as trimming devices (they are non-adjustable and only reduce the forces). Combined servo-trim tabs do exist, but I'm fairly sure none 109 was equipped with these. Fixed, ground-adjustable aileron trim tabs seemed to be the norm for German fighters back then (pity we don't have such a special option for DCS Dora!)

The question of how trim should affect physical-vs-virtual deflections is tricky, because it depends on whether we talk about real world, or simulation - it's physically impossible to match both :D. At least not with non-FFB joysticks. However, in stationary condition the behaviour is actually correct - trim tabs need any sufficient airflow to start pushing control surfaces at all, so they can't deflect the virtual stick/pedals when the plane is standing, or is fully stalled.

[...]However, in stationary condition the behaviour is actually correct - trim tabs need any sufficient airflow to start pushing control surfaces at all, so they can't deflect the virtual stick/pedals when the plane is standing, or is fully stalled.

ooohhhh. My (mis-)understanding was, that trim tabs would somehow apply mechnical force directly onto the stick or cables. :doh:

So no bug then, only the confusing problem of not being able to simulate trim probably without force feedback...

Thanks for all the help. No bugs smashed, but at least i've learnt sth.:smartass: