The 109 rudder stomp

[HagarTheHorrible]

Maybe a cool name for a new type of dance, but sadly no.

 

I was just wondering if the 109 should require more rudder to the left (?) the faster it goes, at the moment it needs no rudder correction.  If it should and it doesn't, is it a sop to those flying without rudder pedals ?  I think corrective rudder was required on the Emil but I'm not sure if it had been aleviated on the later models.  Even if it was able to be preset on the ground wouldn't that only work for a certain airspeed ?

[pixelshader]

I always see the ball on the right when flying at low speed and high throttle, does that not mean it wants correction? Prop effect isn't it?

 

What unwanted effect would cause more yaw the faster the plane went?

Edited December 9, 2013 by pixelshader

[Anatta]

The bf 109 has no trimmable rudder but it can be adjusted on the ground. Usually this is set so that it goes straight at cruise speed (around 300-400 km/h). Under that, there needs to be right rudder input to go straight. Above, there needs to be left rudder input (I didn't notice this one in the game). (Everything AFAIK)

 

Edit: By the way, the effect seems especially weak if you consider that in real life there (again AFAIK) had to be constant left input to the rudder in combat.

Edited December 9, 2013 by Anatta

[Finkeren]

One of my books on the 109 talks at great length about the lack of rudder trim and how tiring it was for pilots flying long distances. Doesn't mention anything about the rudder being adjustable.

 

I may be talking out of ignorance, but what exactly was the adjustment supposed to accomplish, other than possibly allow the pilot to sit with his feet in a more even position while applying force on the pedals?

 

Even if the rudder was adjusted to the left on the ground, wouldn't the airflow immediately realign it, unless force was Applied by the pilot?

[Anatta]

It's like trimming it I guess, only it is done on the ground by the crew and then sits there in a fixed position for the whole flight. (I'm 100% sure this could be done)

Like I said it is done so the plane flies straight at a given speed without rudder input.

Edited December 9, 2013 by Anatta

[Finkeren]

It's like trimming it I guess, only it is done on the ground by the crew and then sits there in a fixed position for the whole flight. (I'm 100% sure this could be done)

Like I said it is done so the plane flies straight at a given speed without rudder input.

 

So you're saying the rudder would be locked in a fixed position while cruising? That seems highly unorthodox, I've never heard of that.

 

Was the rudder then released, when the pilot needed to apply rudder input and then locked into position again?

[DD_bongodriver]

He's not saying that, he said the aircraft was trimmed by the engineers with a fixed tab to fly in trim at about 400 km/h.

[Finkeren]

Ah ok, so he's talking about the fixed trim tab. Now it makes more sense.

 

However IIRC the fixed tap was set during factory trials and not usually adjusted in the field.

[DD_bongodriver]

If the pilot reported the trim out the engineers simply adjust it and wait for the next report, all they do is clamp it between wood blocks and bend it a little.

Edited December 9, 2013 by DD_bongodriver

[Anatta]

Sorry if I haven't explained this in an understandable way. I'm not that deep into the technical side of things.

[Scarecrow]

9minutes and 45s in this 109 pilot mentions lateral stability and groung looping are an issue.

 

http://www.youtube.com/watch?v=IbeRn1rgoIo

Edited December 9, 2013 by Scarecrow

[wastel]

Hi,

the trim tabs are only for very small corrections. with all the manufacturing tolerances no plane is like the other. The trimtabs are bent only once ..in the way that the plane simply flys straight ahead.

They have nothing to do with a adjustable trim you change often.

 

For the vertical axis, means rudder, the 109 had the asymetrical tail surface, and not like mostly common an symetrical one. means the 109 tail surface is like an vertical wing.

It produces "lift" to one direction, means an rotation around the vertical axis to cuonter the gyro effect of the motor. A profil was choosen, that resulted in an neutreal movement around the vertical axis during crusing speed.

Means, during crusing speed, the "ball was in the middle". Below and above crusing speed, of course the plane needs an constant rudder input to keep the "ball" in the middle.

[White1]

Thanks for putting that straight in a very smooth and understandable way wastel.

 

And thanks to Scarecrow for the vid. Get's me to realise how cramped that cockpit really is...

[DD_bongodriver]

For the vertical axis, means rudder, the 109 had the asymetrical tail surface.

 

I didn't know this about the 109, how many degrees was the fin incidence? do you have any scans of manuals on this?

[Sokol1]

So you're saying the rudder would be locked in a fixed position while cruising? That seems highly unorthodox, I've never heard of that.

 

 

The following is again from the "Messerschmitt Me 109 Handling and Maneuverability Tests by the Ministry of Supply. September 1940":

 

 "It is at high speeds that lack of a rudder trimmer most seriously inconveniences the pilot. At 215 mph (346 km/h) the a/c is trimmed directionally, no rudder being required. At higher speeds left rudder must be applied, and at 300mph (483 km/h) about 2 deg of left rudder are needed. The rudder is very heavy at high speeds, and a large force is required to apply even such a small amount; this becomes very tiring, and affects the pilot's ability to put on more left rudder to assist a turn to the left. Consequently at high speeds the Me 109 turns more readily to the right than to the left." 

 

 

Sokol1

[DB605]

I don't know about yours, but in my version of BOS 109 constant right rudder is needed under 400 km/h and left rudder over ~460km/h. More speed, more rudder is needed.

[Sokol1]

 

Sokol1

Edited December 9, 2013 by Sokol1

[DB605]

I didn't know this about the 109, how many degrees was the fin incidence? do you have any scans of manuals on this?

 

Can't find better drawings for now but you can see it here:

 

[DD_bongodriver]

Ah I see, not the actual fin that's offset but the rudder is rigged with a deflection.

[Sokol1]

 

In "Fair Light" 109E:

 

 

 

Sokol1

Edited December 9, 2013 by Sokol1

[wastel]

Messerschmitt Drawing of the 109E Tail that shows the wing profil of the tail fin very good.

 

Wastel

[DD_bongodriver]

Yes that is a very informative diagram, the fin airfoil is not symmetrical with a higher camber on the port side.

[Sokol1]

Yes, the camber in FairLight 109E, I think 109F have the same - they are cousins (I not able to check due my "peasant" license ).

 

Sokol1

Edited December 9, 2013 by Sokol1

[Anatta]

I don't know about yours, but in my version of BOS 109 constant right rudder is needed under 400 km/h and left rudder over ~460km/h. More speed, more rudder is needed.

 

Yes exactly. I don't know if this is realistically modelled but I almost never need left rudder. Mostly right rudder when climbing a bit. This is strange because it is always stated that the Bf 109 needed almost constant left rudder and that it was very tiresome. On the other hand I also noted in other sims that you don't need as much rudder (although a bit more than in BoS), so this might just be a sim to reality issue (because you just don't notice that much maybe).