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[CLOSED]Bf-109 Trim controls


NeilWillis

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well if the put the plane on the blocks in level flight attitude then the stabilizer at zero would also be inline with the air flow and this would mean least possible drag. Which would seem to be the optimal position for maximum range... cruising.

 

It certainly makes sense to design the plane to cruise with trimmable stab very close to inline with the airflow.

 

But it was designed like this much earlier on a lighter model. Maybe the increase in weight has messed up the cruising trim. I don't think any of us really know.

 

Saying it is takeoff trim makes no sense to me. You could just take off a few times and try some trim settings and decide which is best. There is no reason to measure it so precisely for take off trim.

 

What advantage do you see in taking off with the stabilizer at o degrees? I see none

 

I don't want to sound like I am saying your FM is wrong. I really don't know .It is very interesting discussion for me.


Edited by Dirty Rotten Flieger
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well if the put the plane on the blocks in level flight attitude then the stabilizer at zero would also be inline with the air flow and this would mean least possible drag. Which would seem to be the optimal position for maximum range... cruising.

 

It certainly makes sense to design the plane to cruise with trimmable stab very close to inline with the airflow.

 

But it was designed like this much earlier on a lighter model. Maybe the increase in weight has messed up the cruising trim. I don't think any of us really know.

 

Saying it is takeoff trim makes no sense to me. You could just take off a few times and try some trim settings and decide which is best. There is no reason to measure it so precisely for take off trim.

 

What advantage do you see in taking off with the stabilizer at o degrees? I see none

 

I don't want to sound like I am saying your FM is wrong. I really don't know .It is very interesting discussion for me.

 

Do you know about downwash skew at the stabiliser? :)

Ніщо так сильно не ранить мозок, як уламки скла від розбитих рожевих окулярів

There is nothing so hurtful for the brain as splinters of broken rose-coloured spectacles.

Ничто так сильно не ранит мозг, как осколки стекла от разбитых розовых очков (С) Me

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It certainly makes sense to design the plane to cruise with trimmable stab very close to inline with the airflow
Indeed Otto tried to use that same conclusion as "evidence" of the module's "great mistake" :D :D :D .

 

If we talk about making sense, all RL aircraft I have flown use 0 trim (or neutral, or whatever meaning 0º deflection in every case) as take off setting :smilewink:. Of course I mean Cessnas and similar GA, but P-51 works the same, neutral for TO (may be a bit nose down carrying high loads), and 109 handbook says 0 trim for TO? :shocking: :music_whistling: Is it surprising really? :smilewink:

 

Of course another "evidence" from Otto use to be you can TO with a bit nose heavy trim (not neutral, -hence it's a big mistake!!!- and so :lol:). As I mentioned P-51 handbook also tells using a bit nose heavy, and I can't tell I know any of those GA aircraft (may be some does of course) telling the same, but you don't have 1500HP and high weapons loads in GA making a soon take off dangerous as it can be in those fighters. So, does it really make sense neutral trim must be for cruising? :thumbup:

 

S!

"I went into the British Army believing that if you want peace you must prepare for war. I believe now that if you prepare for war, you get war."

-- Major-General Frederick B. Maurice

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Well in defence of poor old Otto the trim of the 109, or lack of trim, does seem to be one of the defining characteristics one notices when flying it. We have all flown badly modeled 109's in other sims/games that require constant and excessive amounts of rudder, aileron, and elevator to fly straight at cruise. It's a bit painful, where as a balanced plane that requires no trim is a pleasure to fly.

 

I imagine the German engineers were showing off by not putting rudder trim on their plane. Judging it a more a elegant and efficient solution to simply design the plane to balance out at known cruise speed rather than put extra weight of trimming mechanisms on surfaces.

 

I can understand it might be frowned upon to mention other sims but I notice that the lighter E series in CLOD trim at 1 degree nose up, the heavier F and G in BOS trim at 1 degree nose down and the heaviest K in DCS trims at 2 degrees nose down.

 

The pattern does hold assuming the increasing weights are producing more and more tail heavy aircraft. They all use roughly the same frame don't they? And of course assuming the three sims all used true data.

 

As for the zero angle stab at takeoff for least propwash effect I see your point is good. I can only imagine you agree with me that cruising with stab close to zero angle to airflow would increase range.

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Do you know about downwash skew at the stabiliser? :)

 

Indeed Otto tried to use that same conclusion as "evidence" of the module's "great mistake" :D :D :D .

 

If we talk about making sense, all RL aircraft I have flown use 0 trim (or neutral, or whatever meaning 0º deflection in every case) as take off setting :smilewink:. Of course I mean Cessnas and similar GA, but P-51 works the same, neutral for TO (may be a bit nose down carrying high loads), and 109 handbook says 0 trim for TO? :shocking: :music_whistling: Is it surprising really? :smilewink:

Of course another "evidence" from Otto use to be you can TO with a bit nose heavy trim (not neutral, -hence it's a big mistake!!!- and so :lol:). As I mentioned P-51 handbook also tells using a bit nose heavy, and I can't tell I know any of those GA aircraft (may be some does of course) telling the same, but you don't have 1500HP and high weapons loads in GA making a soon take off dangerous as it can be in those fighters. So, does it really make sense neutral trim must be for cruising? :thumbup:

Do you know anything about pitch down moment with flaps deployed.??

Nobody question why the Bf-109K4 have 6 degrees of THS trim travel for nose-up, without apparent utility??

No need to be Einstein for see that something is wrong.

 

Please read again:

In the book "Messerschmitt Bf-109; Owners' Workshop Manual" of Haynes Publishing 2009.

There is some commentaries about trim settings of Bf-109 in operations and Bf-109G2 "Black-6", the last original "Made in Germany" werk nummber: 10639, restored to airworthy condition.

 

In that book, Dave Southwood the RAF test pitot, who flew the Bf-109G2 "Black-6", He says.

In page 96:

"" In the pre -take-off check, I set 20º flaps and 1º nose up tailplane trim. The original data said 0º trim, but 1º nose up was added after the propeller ground strike on the first sortie. ""

In the page 97 of same book Dave Southwood says:

""trim settings: The ailerons and rudder fixed trim tabs were adjusted to give centralized slip ball and wings level flight with cruise power (1.0ATA, 2000rpm) set in straight and level flight. If adjustments were needed, the rudder trim had to be adjusted first before the required aileron trim tab adjustments could be made. Note that if the ailerons trim was correct at these cruise conditions, it was correct throughout almost the entire required flight envelope. ""


Edited by III/JG52_Otto_+
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I have to agree that something seems really off, here. My preference for the DCS 109:

 

Trim nose down all the way for takeoff and cruise. Even then I'm still always pushing forward on the msffb2 a little bit to keep the nose from climbing.

 

It doesn't make sense.:huh:

 

-----------

 

P.S. Finnish pilots don't have a lot to say about trimming the 109G, mostly because they did not fiddle with it very much: http://www.virtualpilots.fi/feature/articles/109myths/#trim

 

----------

 

MSFF2 - our choice! :) Get the hand away and no trimmers required :)

 

Sorry, but I'm using that stick and the 109 couldn't be less pleasant to fly in DCS right now.:joystick:


Edited by gavagai

P-51D | Fw 190D-9 | Bf 109K-4 | Spitfire Mk IX | P-47D | WW2 assets pack | F-86 | Mig-15 | Mig-21 | Mirage 2000C | A-10C II | F-5E | F-16 | F/A-18 | Ka-50 | Combined Arms | FC3 | Nevada | Normandy | Straight of Hormuz | Syria

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Then why does it have only 2 down trim and 6 up, if the plane pitches up even with full down trim?

 

After finally reading the whole thread, nothing more needed to be said after Solty's post.:book:

 

-----------

 

Now, why is there so much pointless argument going in circles in this thread? Why wasn't the 109 trim handled like the 190 aileron trim in this thread? http://forums.eagle.ru/showthread.php?t=131508&highlight=aileron+trim

 

Why can the 190 be adjusted but not the 109?

 

It is blocked.
:no_sad:
Edited by gavagai

P-51D | Fw 190D-9 | Bf 109K-4 | Spitfire Mk IX | P-47D | WW2 assets pack | F-86 | Mig-15 | Mig-21 | Mirage 2000C | A-10C II | F-5E | F-16 | F/A-18 | Ka-50 | Combined Arms | FC3 | Nevada | Normandy | Straight of Hormuz | Syria

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Hope it get's sorted out before the Spitfire get's out...

As well as the control forces for rudder ... One of the latest patches I remember introduced severe roll response delays with increasing dynamic pressure, but rudder was still unaffected, allowing even for a full roll to be performed due to yaw-induced roll.


Edited by jcomm

Flight Simulation is the Virtual Materialization of a Dream...

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After finally reading the whole thread, nothing more needed to be said after Solty's post.:book:

 

-----------

 

Now, why is there so much pointless argument going in circles in this thread? Why wasn't the 109 trim handled like the 190 aileron trim in this thread? http://forums.eagle.ru/showthread.php?t=131508&highlight=aileron+trim

 

Why can the 190 be adjusted but not the 109?

 

:no_sad:

 

I fully agree.:thumbup:

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The pattern does hold assuming the increasing weights are producing more and more tail heavy aircraft. They all use roughly the same frame don't they? And of course assuming the three sims all used true data.
I wouldn't assume any previous sim used real data to the point DCS needs it. It's easier to match 0 trim to some comfortable control for player than modelling it the closest to available data whatever it takes.

 

 

After finally reading the whole thread, nothing more needed to be said after Solty's post.
So you didn't read the whole thing :lol:. Tail heavy available trim doesn't means anything nor proves it. On the other hand I don't like 109 behaviour of course but graphs available says what they say and I can't tell it's wrong just because I don't like.

 

 

Do you know anything about pitch down moment with flaps deployed.??

Nobody question why the Bf-109K4 have 6 degrees of THS trim travel for nose-up, without apparent utility??

No need to be Einstein for see that something is wrong.

Nope, you don't need to be Einstein, you need to be a pilot who knows how it works :lol: :lol: :lol: . Flaps deployment lowers AoA (so your nose) but that doesn't mean you need to retrim raising it again (that's stupid after nose down lets you see the runway... you would know if you had ever flown). If you retrim raising nose again after flaps deployment that means retrimming for a lower airspeed, that is retrimming tail heavy, not nose heavy. Do you know something about how AoA works :smilewink:. That change has nothing to do with cruising trim and nose heavy trim available.

 

S!

"I went into the British Army believing that if you want peace you must prepare for war. I believe now that if you prepare for war, you get war."

-- Major-General Frederick B. Maurice

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Ala13_ManOWar,

 

This thread is infected with too much emotion, and you and others are making it personal. It doesn't need to be that way.

 

I will politely ask again: if we can adjust the trim tabs on the Fw 190D-9, why does ED prevent us from adjusting them on the 109K-4? Forget the charts and graphs, and focus on this very simple question.

P-51D | Fw 190D-9 | Bf 109K-4 | Spitfire Mk IX | P-47D | WW2 assets pack | F-86 | Mig-15 | Mig-21 | Mirage 2000C | A-10C II | F-5E | F-16 | F/A-18 | Ka-50 | Combined Arms | FC3 | Nevada | Normandy | Straight of Hormuz | Syria

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Ala13_ManOWar,

 

This thread is infected with too much emotion, and you and others are making it personal. It doesn't need to be that way.

 

I will politely ask again: if we can adjust the trim tabs on the Fw 190D-9, why does ED prevent us from adjusting them on the 109K-4? Forget the charts and graphs, and focus on this very simple question.

 

 

Probably because the aerodynamics model used for the K4 has that hardcoded into the FDM, due to the fact that access to all precise data was not available, and allowing fro such a change would result in unwanted effects ?

Flight Simulation is the Virtual Materialization of a Dream...

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I'm hoping ED could please give us a response.

P-51D | Fw 190D-9 | Bf 109K-4 | Spitfire Mk IX | P-47D | WW2 assets pack | F-86 | Mig-15 | Mig-21 | Mirage 2000C | A-10C II | F-5E | F-16 | F/A-18 | Ka-50 | Combined Arms | FC3 | Nevada | Normandy | Straight of Hormuz | Syria

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Ala13_ManOWar,

 

This thread is infected with too much emotion, and you and others are making it personal. It doesn't need to be that way.

 

I will politely ask again: if we can adjust the trim tabs on the Fw 190D-9, why does ED prevent us from adjusting them on the 109K-4? Forget the charts and graphs, and focus on this very simple question.

Sorry mate, you are right as Otto and Supongo are friends and we know each other :smilewink: .

 

 

I said before, I would like to see fixed trim tabs available like Dora. Why they aren't already? I don't know, may be because like other updates they're waiting for DCSW 2 release. Anyway, I also said before, don't expect trim tabs to be magic, it will change forces on stick but no more (and no less of course). Also I wouldn't be surprise to see trim tabs compromise stability at high speeds (as we also said before...). May be when available people start to complain about they get killed easily while diving... Anyway, if that happens I would prefer people getting killed (and quiet...) than this kind of discussion :lol:.

 

S!

"I went into the British Army believing that if you want peace you must prepare for war. I believe now that if you prepare for war, you get war."

-- Major-General Frederick B. Maurice

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Though both available graphs from very different sources recorded for different CoG and stabiliser setting, there is a simple way to check how these data match.

First of all, both graphs have the area near 400-450 kph where differencies in Mach number are negligable at German graph (Gr). So, 400 kph will be a good point to start at because in the Russian (Ru) graph the difference due to different CoG can be measured at the graph.

 

Then, please track my hands:

at (Ru) 400 kph 3% of CoG gives about 0.2-0.3 degrees of elevator deflection required to compensate (see the curves (Ru) for different CoG and the same stab position).

The curve for stab angle = 0 and CoG = 23.7 gives about 3.5 degrees (plus - to push!) for 400 kph. So, shifting forward for 2.5% of CoG to 21.2% (Gr) will give about 3.7-3.8 degrees of elevator.

Then set the stab to +0.75 degree. As the (Ru) graph shows, 1.5 degrees of stab gives approx. 2 degrees of opposite elevator to maintain the same trim. So, if the stab angle is changed from 0 to +0.75 (Gr) the required elevator angle REGARDING ONLY (Ru) wll be 3.7...3.8 - 1 = 2.7-2.8 degrees. (Gr) graph shows 2.2 degrees.

Regarding the fact that measurements had their own errors (see the curves plotted out of experimental points to have good spline) these engineering calculations allows to say that both reports show the same trim for the 109G.

 

And no miracle can trim the plane at high speed...

Ніщо так сильно не ранить мозок, як уламки скла від розбитих рожевих окулярів

There is nothing so hurtful for the brain as splinters of broken rose-coloured spectacles.

Ничто так сильно не ранит мозг, как осколки стекла от разбитых розовых очков (С) Me

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It is blocked.

 

Pretty please with sugar on top?:notworthy:

P-51D | Fw 190D-9 | Bf 109K-4 | Spitfire Mk IX | P-47D | WW2 assets pack | F-86 | Mig-15 | Mig-21 | Mirage 2000C | A-10C II | F-5E | F-16 | F/A-18 | Ka-50 | Combined Arms | FC3 | Nevada | Normandy | Straight of Hormuz | Syria

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IMO the stability curves from Germany and Russia for 109G are pretty conclusive evidence to that there should be a nose up trim neccesiating a push control by the pilot. It might have been intentional, i.e. if the pilot is uncouncious or unable to apply contant push on the stick, the plane will tend to go up and not down.

 

Also, one of the pilot memoirs I have read (Lt. Tobak of RHAF) also tended to refer to when they were cruising (presumably high speed?) as 'nyomjuk' or 'we (are) push(ing) it'. The oral evidence would fit in nicely with a nose-up tendency, though could also translate to hitting the throttle or hasting the machine to a hurry.

http://www.kurfurst.org - The Messerschmitt Bf 109 Performance Resource Site

 

Vezérünk a bátorság, Kísérőnk a szerencse!

-Motto of the RHAF 101st 'Puma' Home Air Defense Fighter Regiment

The Answer to the Ultimate Question of the K-4, the Universe, and Everything: Powerloading 550 HP / ton, 1593 having been made up to 31th March 1945, 314 K-4s were being operated in frontline service on 31 January 1945.

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Yo-yo,

 

One thing I have noticed is that adjusting the pitch trim in the 109 does *not* change the centering force with the MSFFB2 the way it does with the P-51. Are you using a different version of DCS where the behavior is different? Maybe that is why my experience with the MSFFB2 is so unsatisfying in the 109K-4.

 

My virtual pilot notes:

 

With pitch trim set to 0 you have to apply significant force to prevent a violent pitch-up tendency. Only when the airspeed drops below 200km/h IAS can you relax pressure on the stick.

 

With pitch trim set to 1 the required force is reduced, but the aircraft will still attempt to loop at economy settings (1.05 ata).

 

With pitch trim all the way forward the aircraft can almost fly hands off at economy setting, and requires slight forward pressure at cruise setting (1.25 ata).

P-51D | Fw 190D-9 | Bf 109K-4 | Spitfire Mk IX | P-47D | WW2 assets pack | F-86 | Mig-15 | Mig-21 | Mirage 2000C | A-10C II | F-5E | F-16 | F/A-18 | Ka-50 | Combined Arms | FC3 | Nevada | Normandy | Straight of Hormuz | Syria

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  • ED Team
Yo-yo,

 

One thing I have noticed is that adjusting the pitch trim in the 109 does *not* change the centering force with the MSFFB2 the way it does with the P-51. Are you using a different version of DCS where the behavior is different? Maybe that is why my experience with the MSFFB2 is so unsatisfying in the 109K-4.

 

My virtual pilot notes:

 

With pitch trim set to 0 you have to apply significant force to prevent a violent pitch-up tendency. Only when the airspeed drops below 200km/h IAS can you relax pressure on the stick.

 

With pitch trim set to 1 the required force is reduced, but the aircraft will still attempt to loop at economy settings (1.05 ata).

 

With pitch trim all the way forward the aircraft can almost fly hands off at economy setting, and requires slight forward pressure at cruise setting (1.25 ata).

 

Why it should? And where was 1.25 ata mention as a cruise setting? 1.15 ata is MAXIMAL CONTINUOS and this is no CRUISE. I wrote that CRUISE flight presumes maximal duration or maximal distance that requires approx 260-320 kph IAS. So, for the cruise the engine rpm/boost must be only sufficient to maintain this speed.


Edited by Yo-Yo

Ніщо так сильно не ранить мозок, як уламки скла від розбитих рожевих окулярів

There is nothing so hurtful for the brain as splinters of broken rose-coloured spectacles.

Ничто так сильно не ранит мозг, как осколки стекла от разбитых розовых очков (С) Me

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Page 44 of the manual:

 

attachment.php?attachmentid=118861&stc=1&d=1434987457

191153707_109Kmanual.png.22115acb15a8d80ddd3ca12b5e87fe03.png

P-51D | Fw 190D-9 | Bf 109K-4 | Spitfire Mk IX | P-47D | WW2 assets pack | F-86 | Mig-15 | Mig-21 | Mirage 2000C | A-10C II | F-5E | F-16 | F/A-18 | Ka-50 | Combined Arms | FC3 | Nevada | Normandy | Straight of Hormuz | Syria

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And finally: do we have different 109? Trim fulll forward. 100% fuel CoG max aft.

Screen_150622_184904.thumb.jpg.41c9c94f22bc87c2ae77f9faa180aaad.jpg

Screen_150622_185143.thumb.jpg.bd46c97866267bfa4873e34b18b25123.jpg

Ніщо так сильно не ранить мозок, як уламки скла від розбитих рожевих окулярів

There is nothing so hurtful for the brain as splinters of broken rose-coloured spectacles.

Ничто так сильно не ранит мозг, как осколки стекла от разбитых розовых очков (С) Me

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Page 44 of the manual:

 

attachment.php?attachmentid=118861&stc=1&d=1434987457

 

AFAIK we have DB 605DB engine modelled, which would mean the ata figures in manual are incorrect (or more precisly, they are for the DB 605DM engine variant). See:

 

DB605DB_limits_dec44Motorenkarte.jpg

http://www.kurfurst.org - The Messerschmitt Bf 109 Performance Resource Site

 

Vezérünk a bátorság, Kísérőnk a szerencse!

-Motto of the RHAF 101st 'Puma' Home Air Defense Fighter Regiment

The Answer to the Ultimate Question of the K-4, the Universe, and Everything: Powerloading 550 HP / ton, 1593 having been made up to 31th March 1945, 314 K-4s were being operated in frontline service on 31 January 1945.

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  • ED Team
AFAIK we have DB 605DB engine modelled, which would mean the ata figures in manual are incorrect (or more precisly, they are for the DB 605DM engine variant). See:

 

DB605DB_limits_dec44Motorenkarte.jpg

 

Yes, I just wanted to post this table. Posssibly it's the same thing we have for the Mustang 15:1 flight range with a dead engine (It could be true if P-51 shoots off prop baldes :)).

Ніщо так сильно не ранить мозок, як уламки скла від розбитих рожевих окулярів

There is nothing so hurtful for the brain as splinters of broken rose-coloured spectacles.

Ничто так сильно не ранит мозг, как осколки стекла от разбитых розовых очков (С) Me

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