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[CLOSED]Bf-109 Trim controls


NeilWillis
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2/ I have not flown a Bf-109k4 real, ..but I can read, and I have read many books about this aeroplane, and comments from many pilots who have flown a Bf-109, .. and they do not talk anything about the nose-up attitude, with the elevator trim set in zero.

 

And so can Yo-Yo, I am pretty sure this is what he does for a living, and that he takes his job pretty seriously. Its why he travels to places like Germany to talk to ex-Luftwaffe pilots with real experience, he reads reports from not just the internet but other sources all over the world. So I am not why you think your experiences reading should outweigh anyone elses.

 

I have read about nose up attitude, mostly under high power. Do I think the trim should do more? In my mind I would think so, but I am not an engineer, I am not a professional FM builder, I am not an experienced 109 pilot, so if Yo-Yo tells me its right, then why shouldnt I believe him? Its been questioned before, if something requires fixing, it will get fixed, but dont assume because you read some books you know how the 109 will fly in full combat trim.

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The Bf-109 is different, it is a more simple and advanced design, it is equipped with THS (Trimmable Horizontal Stabilizer) as modern Airbus.

The trim tabs are fixed and adjusted on the ground to level the aircraft in cruise flight.

But, like the P-51D, ..the zero mark in the trim control is for leveled flight.

open the spoiler for details

 

 

Bf-109 elevator system with elevator adjustable pitch

MesserschmittBf109K-4HandbookpubNovember1944121_zps2048d5d0.jpg

 

P-51 elevator system with in-flight adjustable servo trim tabs.

P51_Av_4407_DA_tabs_p146_W.png

 

 

 

Please show the quote where 0 is level flight for all conditions, speeds and weights, because that would be some incredible trim... I mean what happened over the years that engineers managed to not make this magic trim on all aircraft?

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First of all, I no longer use DCS for any ww2 aircraft, but my last flights with the Bf109 explored a "technique" which I believe is closer to that used by real pilots while taking off - Max 1.4 ATA, NEVER Throttle to the wall !!!

 

Taking off, under a wide range of Gross Weights without exceeding MAX 1.4 ATA worked beautifully even setting the stabilator to 1 nose heavy instead of 2, as per the Manual.

 

I'm not a ww2 expert although I am aware that some of you are, and I do not have access to all of the good reading sources you have, but, was it common practise to takeoff at MAX 1.9 ATA power settings ?


Edited by jcomm

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1/Please, No offense you for my comments.

 

2/ I have not flown a Bf-109k4 real, ..but I can read, and I have read many books about this aeroplane, and comments from many pilots who have flown a Bf-109, .. and they do not talk anything about the nose-up attitude, with the elevator trim set in zero.

 

3/ Unknown to the sources used by E.D.to model the Bf-109K4, but obviously something is wrong ..no need to be Einstein to realize it.

 

Without entering the prohibited discussion about other sims, the "other" one if you look closely also models heavy nose down trim from the moment you enter (spawn into) the plane. While I certainly will not use one sim as a proof, you will have to provide more evidence from "I've read about it" to dispute FM modeling / conclusion two experienced development teams have reached. ;)

 

 

Taking off, under a wide range of Gross Weights without exceeding MAX 1.4 ATA worked beautifully even setting the stabilator to 1 nose heavy instead of 2, as per the Manual.

 

I'm not a ww2 expert although I am aware that some of you are, and I do not have access to all of the good reading sources you have, but, was it common practise to takeoff at MAX 1.9 ATA power settings ?

 

Seconded, for both the TO method and question.

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But, like the P-51D, ..the zero mark in the trim control is for leveled flight.

open the spoiler for details.

 

 

 

Level flight? That's a little vague. Trim is depended on the aircraft relative position in all aspects (speed, pitch, bank, etc). As you increase speed, the aircraft (assuming it has characteristics of positive dynamic stability) will require nose down trim. Vice versa as you slow down.

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All pilots know that the zero mark in the elevator trim control is neutral attitude, ..and that applies to all aircraft which have this mark, including the Bf-109.
False, all pilots know neutral trim is straight control surfaces without trim and for instance in a Cessna is used as take off setting, no cruise at all. Why on Earth you think neutral trim means cruise setting? You can't talk as a representative of "all pilots".

 

 

2/ I have not flown a Bf-109k4 real, ..but I can read, and I have read many books about this aeroplane, and comments from many pilots who have flown a Bf-109, .. and they do not talk anything about the nose-up attitude, with the elevator trim set in zero.
They saying nothing doesn't means it's the way you want it to be. We don't need to be scientifics to apply basic scientific method.

 

 

But, like the P-51D, ..the zero mark in the trim control is for leveled flight.
And here we go, you don't even know the P-51 because neutral trim in P-51 also means TO setting. Same as a Cessna. Coincidence? Just P-51 is plenty of trim control in all axes because it's design for long flight comfort, but 109 wasn't.

 

 

 

I'm also not sure about 109 trim, I just don't understand why by design there's so few nose down trim if we follow DCS model. BUT, the problem is quite apparent for people with short sticks, I use a long stick mod and flying everything, also Bf109, is a pleasure even though I would like having a bit more nose down trim. In real aircraft it isn't a big deal holding a long stick a bit more or less forward. So IMHO I guess the problem here is mainly a realism one... when extreme realism means you also need extreme realistic controls... and long time ago we were warned about how Spitfire will be with absolute realistic controls. I still feel 109 trim is awkward if the real thing was like this, and I don't know if it's a trim problem, a CoG problem, a crazy prof. Messerschmitt design problem, or what. Anyway when adjustable trim tabs are available like in Dora people will be able to adjust a bit to their taste/controls 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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False, all pilots know neutral trim is straight control surfaces without trim and for instance in a Cessna is used as take off setting, no cruise at all. Why on Earth you think neutral trim means cruise setting? You can't talk as a representative of "all pilots".

like I said previously, the ZERO TRIM mark means neutral. in the P-51D trim handwheel, gets on capital letters the word "NEUTRAL".

The mark "take off" in your Cessna, no meaning necessarily NEUTRAL, because some airplanes as P-51D must be take-off in different angle of pitch.

In some airplanes the take-off elevator trim configuratión matching with elevator trim configuration at cruise speed, i.e. cero degrees.

open the spoiler and see evidences.

 

P-51 trim controls

newsfeb13_04.jpg

 

cessna trim handwheel

img_0233.jpg

 

 

 

 

And here we go, you don't even know the P-51 because neutral trim in P-51 also means TO setting. Same as a Cessna. Coincidence? Just P-51 is plenty of trim control in all axes because it's design for long flight comfort, but 109 wasn't.

Completely false, if you read the original manual of the P-51D, you need to adjust the elevator trim 2 or 4 degrees nose-down for takeoff, depending on fuel load in the fuselage tanks.

Please, read the manual here:

http://issuu.com/tiamat2013/docs/p-51_poh/51?e=9282774/7894667


Edited by III/JG52_Otto_+
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like I said previously, the ZERO TRIM mark means neutral. in the P-51D trim handwheel, gets on capital letters the word "NEUTRAL".

The mark "take off" in your Cessna, no meaning necessarily NEUTRAL, because some airplanes as P-51D must be take-off in different angle of pitch.

In some airplanes the take-off elevator trim configuratión matching with elevator trim configuration at cruise speed, i.e. cero degrees.

open the spoiler and see evidences.

Really mate? I know the aircraft where I learnt to fly pretty well, neutral in Cessna means NEUTRAL, zero trim, straight tab, I have helped my instructor tighten the nuts on trim and fixing the tab to straight position, I know it's default position in every preflight check I've done in my life :thumbup:. You can't use neutral trim for cruise, you have to use lots of nose down.

 

 

Completely false, if you read the original manual of the P-51D, you need to adjust the elevator trim 2 or 4 degrees nose-down for takeoff, depending on fuel load in the fuselage tanks.

Please, read the manual here:

I did read the P-51 manual way before you. I have a RAF pilot notes on Mustang III in my hand. I know the recommendation, and it's a recommendation not mandatory in some load cases. In DCS I take off easily in P-51 always with neutral trim, and neutral means neutral, no trim, straight tab. You CAN'T use neutral trim in P-51 for cruise (clearly you haven't flown enough P-51), you need lots of nose down. I'm having a déjà vu right now... :smilewink:

 

 

INDEED mate, that P-51, Cessna, and most north American aircraft design standard of neutral trim for take off and lots of nose down trim for cruise is what you are really claiming for 109, but 109 isn't a north American aircraft and 40's aircraft were far from being standardly made throughout the World.

 

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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Here many people reads Supongo, even Spanish ;) . Be careful.

 

I know Mustang III is P-51C. Never mind, the aircraft is pretty much the same, you realize if you read the different handbooks out there.

 

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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False, all pilots know neutral trim is straight control surfaces without trim and for instance in a Cessna is used as take off setting, no cruise at all. Why on Earth you think neutral trim means cruise setting? You can't talk as a representative of "all pilots".

 

 

They saying nothing doesn't means it's the way you want it to be. We don't need to be scientifics to apply basic scientific method.

 

 

And here we go, you don't even know the P-51 because neutral trim in P-51 also means TO setting. Same as a Cessna. Coincidence? Just P-51 is plenty of trim control in all axes because it's design for long flight comfort, but 109 wasn't.

 

 

 

I'm also not sure about 109 trim, I just don't understand why by design there's so few nose down trim if we follow DCS model. BUT, the problem is quite apparent for people with short sticks, I use a long stick mod and flying everything, also Bf109, is a pleasure even though I would like having a bit more nose down trim. In real aircraft it isn't a big deal holding a long stick a bit more or less forward. So IMHO I guess the problem here is mainly a realism one... when extreme realism means you also need extreme realistic controls... and long time ago we were warned about how Spitfire will be with absolute realistic controls. I still feel 109 trim is awkward if the real thing was like this, and I don't know if it's a trim problem, a CoG problem, a crazy prof. Messerschmitt design problem, or what. Anyway when adjustable trim tabs are available like in Dora people will be able to adjust a bit to their taste/controls available.

 

S!

 

Its not about it being wrong. The plane would probably behave as it behaves. The problem is that elevator trim (manual trim tabs) were completely ommited. I've given sources before, how they work. In dcs they seem to be set on neutal., which combined with horizontal stab trim at 0 gives us a strong pitching moment.

 

If they were set for cruise we wouldn't really have to set the additional trim on take off just like in 51.

 

IRL they were set by the ground crew. Pilot has no ability to change them in flight.


Edited by Solty

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Its not about it being wrong. The plane would probably behave as it behaves. The problem is that elevator trim (manual trim tabs) were completely ommited. I've given sources before, how they work. In dcs they seem to be set on neutal., which combined with horizontal stab trim at 0 gives us a strong pitching moment.

 

If they were set for cruise we wouldn't really have to set the additional trim on take off just like in 51.

 

IRL they were set by the ground crew. Pilot has no ability to change them in flight.

I haven't seen your posted sources, but while we don't have them yet and hope so I still hardly doubt fixed trim tabs can so greatly impact in controls to change 0 trim setting from a take off position (~200Km/H) to a cruise position (~400-450Km/H). Fixed trim tabs only helps a bit. Almost all aircraft use them, Cessna included, and rudder trim tab in a Cessna being fully deployed (permanent bent I mean) only helps slightly dealing with torque during take-off but while airborne you still have to centre the ball. Not to mention it moves control surface and it's at the cost of reducing available surface deflection so a fixed trim tab capable of a so great change in stability (neutral trim from 200 to ~400Km/H) would reduce available control a lot. It's a help, but it isn't magic.

 

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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When the Fw190 was released it had that huge left rolling tenndency at cruise, and I found where in one of the configuration files the ground adjustable aileron trim tabs were set, adjusted it, and in a subsequent update that mod was already adopted.

 

I don't even have DCS installed anymore, but I wonder if such adjustments aren't available for the Bf109 K4 ground adjustable elevator trim tab ?

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Ok guys, talk it over with Yo-Yo some this morning, raised concerns with trim that some had, and for the most part what I found was correct. He shared with me a chart showing what I think is exactly what we experience in the sim, if you take into account the shorter flight sticks we all use:

 

trim-effectiveness_zpsemfcefuc.png

 

I did also raise concern about air starts, I still feel like it couldnt hurt to have the aircraft trimmed to 1.5 on an air start, but its not a blocking issue. I will request it, along with the ability to change manual trim tabs were available on the 109.

 

So with all that, I really am going have to say that I am confident the 109 is modelled pretty damn well in this case, and if other sims that we might have played in the past dont fly like this, they have tweaked for player comfort over accuracy.

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I haven't seen your posted sources, but while we don't have them yet and hope so I still hardly doubt fixed trim tabs can so greatly impact in controls to change 0 trim setting from a take off position (~200Km/H) to a cruise position (~400-450Km/H). Fixed trim tabs only helps a bit. Almost all aircraft use them, Cessna included, and rudder trim tab in a Cessna being fully deployed (permanent bent I mean) only helps slightly dealing with torque during take-off but while airborne you still have to centre the ball. Not to mention it moves control surface and it's at the cost of reducing available surface deflection so a fixed trim tab capable of a so great change in stability (neutral trim from 200 to ~400Km/H) would reduce available control a lot. It's a help, but it isn't magic.

 

S!

 

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

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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?

 

But how do they work, I mean what do you trim for? Cruise? Combat? Bombs? if you trim for cruise, you could hurt combat performance, etc... I would need to see detailed info one when and why they would trim the manual tabs. I still would like to see them as a ME option or ground crew changeable... but I think we are too hung up on their importance...

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Ok guys, talk it over with Yo-Yo some this morning, raised concerns with trim that some had, and for the most part what I found was correct. He shared with me a chart showing what I think is exactly what we experience in the sim, if you take into account the shorter flight sticks we all use:

 

trim-effectiveness_zpsemfcefuc.png

 

I did also raise concern about air starts, I still feel like it couldnt hurt to have the aircraft trimmed to 1.5 on an air start, but its not a blocking issue. I will request it, along with the ability to change manual trim tabs were available on the 109.

 

So with all that, I really am going have to say that I am confident the 109 is modelled pretty damn well in this case, and if other sims that we might have played in the past dont fly like this, they have tweaked for player comfort over accuracy.

 

G2 graphics or the K4 Graphics?

 

Stick Fordward or stabilizer trim?

 

 

Supongo

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Ok guys, talk it over with Yo-Yo some this morning, raised concerns with trim that some had, and for the most part what I found was correct. He shared with me a chart showing what I think is exactly what we experience in the sim, if you take into account the shorter flight sticks we all use:

 

trim-effectiveness_zpsemfcefuc.png

 

I did also raise concern about air starts, I still feel like it couldnt hurt to have the aircraft trimmed to 1.5 on an air start, but its not a blocking issue. I will request it, along with the ability to change manual trim tabs were available on the 109.

 

So with all that, I really am going have to say that I am confident the 109 is modelled pretty damn well in this case, and if other sims that we might have played in the past dont fly like this, they have tweaked for player comfort over accuracy.

 

SiThSpAwN Are you sure of that chart is showing the angles of the elevator incidence or angles of fixed trim tabs??

That you are marking in the image as "elevator angle" and the angle which is displayed on the label "trim" are incongruous.

 

The elevator and aileron trim tabs were adjusted on ground as you see in this picture

11427354_10207205332993933_8082687452395721000_o.jpg

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Incongruous based on what?

 

Yo-Yo has the full report, I am sure it would have stated if they were something other than what I labeled. You need to bring more to the table that guesses and random pictures...

 

If what I have labeled as elevator angle were the fixed trim tabs, how do their angles change through flight??


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SiThSpAwN Are you sure of that chart is showing the angles of the elevator incidence or angles of fixed trim tabs??

That you are marking in the image as "elevator angle" and the angle which is displayed on the label "trim" are incongruous.

 

The elevator and aileron trim tabs were adjusted on ground as you see in this picture

11427354_10207205332993933_8082687452395721000_o.jpg

 

You really made my night....

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Yep, they both are quite funny guys indeed... I laugh a lot with them :lol: :lol: :lol: :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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But how do they work, I mean what do you trim for? Cruise? Combat? Bombs? if you trim for cruise, you could hurt combat performance, etc... I would need to see detailed info one when and why they would trim the manual tabs. I still would like to see them as a ME option or ground crew changeable... but I think we are too hung up on their importance...

As my source I have posted said, they are for cruise setting.

 

I am reposting it again so you can read it. http://www.wwiiaircraftperformance.org/me109/Diving_Test_109F_W.Nr.9228_ger_eng.pdf

 

"These were fixed trim tabs and not movable by the pilot. They were bent by the ground crews at the first flights. So the Me109 was pre-trimmed for cruising "

I doubt anyone has made "detailed info" about their use in different conditions, but if there is, I don't have it.

 

To me in aircraft design, if something exists it has its purpose. If every Bf109 in mass production since 1930s to 1945 had those trim tabs, why would they be there, if nobody would use them? And I remember reading about them beeing used normally and you have a report above that states that too.

 

To me it just feels incomplete with +2 and -6 while plane is going into a loop with 0 trim on horisontal stab. What are the -6 stages for if the plane is nose light even at slow speeds with 0.:huh:

 

I am all for them beeing an option. So that they could be adjusted on the ground. :smartass:

[sIGPIC][/sIGPIC]In 21st century there is only war and ponies.

 

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