Speed dependant Fw 190 aileron command (and more)

[greybeard]

I remember very well that the exceptional roll speed was explained by the fact that the transmission ratio between stick and ailerons varied with the speed of the aircraft: maximum movement at minimum speed and minimum movement at maximum speed (for the same joystick excursion, the which reduced pilot effort at high speeds, without reducing effectiveness at low speeds). The source was "Storia dell'Aviazione" by the fratelli Fabbri editori; the book was lent to me for a while by a friend who then changed cities. I can't find this information on the internet right now. Strange! I would have been curious to know how it worked and with what trend.
More generally, I wonder if the connection between controls (stick or wheel and pedals) has always been linear (e.g: 10% of stick travel = 10% of aileron travel) for all planes or has had different trends, like those that can be set in simulation games like Rise of Flight and Battle of Stalingrad.

 

[mjfur]

There's this, Fw-190: the roots of the great roll rate?

 

[greybeard]

There's this, Fw-190: the roots of the great roll rate?

Thanks, but I can't find anything I said in the link. Just an interminable discussion about wing spars where no one really knows why the Fw 190 had such a high roll rate, just guessing.
I find it a pity that this information has been lost, or rather that it has not been disseminated in the forty-nine years that have passed since its publication.

 

[pbehn]

Thanks, but I can't find anything I said in the link. Just an interminable discussion about wing spars where no one really knows why the Fw 190 had such a high roll rate, just guessing.
I find it a pity that this information has been lost, or rather that it has not been disseminated in the forty-nine years that have passed since its publication.

In the link posted by Tomo the FW 190 was better but not massively better than the clipped wing Spitfire at high speed.

http://www.wwiiaircraftperformance.org/naca868-rollchart.jpg

 

[mjfur]

I don't believe the "transmission ratio" that you mention ever existed. The 190 used aileron control rods that did not stretch under high loads unlike aileron control cables used in most other aircraft.

You could pose your question here, Flug Werk Fw 190A-8/N - Restoration - GossHawk Unlimited, Inc.
or
you could do your own research here, Focke Wulf Fw-190 A-8 Aircraft Blueprints - Download

 

[gumbyk]

More generally, I wonder if the connection between controls (stick or wheel and pedals) has always been linear (e.g: 10% of stick travel = 10% of aileron travel) for all planes or has had different trends, like those that can be set in simulation games like Rise of Flight and Battle of Stalingrad.

It's never linear like that. Even in something like a Tiger Moth, there isn't a linear relationship. It's gained by using off-centre cams for the cables, etc.
In the tiger, at full aieron deflection, you actually get both ailerons drooping.

 

[greybeard]

In the link posted by Tomo the FW 190 was better but not massively better than the clipped wing Spitfire at high speed.

it's hard to believe that the Spitfire stands so far above its contemporaries just for the removal of the wing tips... Moreover, everything else that the Fw 190 had to justify the performance would be missing (rigid rather than wired control system, etc.).

 

[greybeard]

You could pose your question here

Done! Thank you!

 

[greybeard]

It's never linear like that. Even in something like a Tiger Moth, there isn't a linear relationship. It's gained by using off-centre cams for the cables, etc.

Thank you! That was exactly the information I was looking for! Do you happen to also have some diagrams showing the relationship between stick movement and aileron movement (or other control surfaces...).

In the tiger, at full aieron deflection, you actually get both ailerons drooping.

Sorry, I don't understand how this is possible (and with what effect on aircraft control...).

 

[pbehn]

it's hard to believe that the Spitfire stands so far above its contemporaries just for the removal of the wing tips... Moreover, everything else that the Fw 190 had to justify the performance would be missing (rigid rather than wired control system, etc.).

Its hard to believe the Spitfire was not quite as good as the Fw 190 but not hard to believe the Fw 190 was the best?

 

[greybeard]

Its hard to believe the Spitfire was not quite as good as the Fw 190 but not hard to believe the Fw 190 was the best?

Of course, assuming the subject of this thread is true. But even if it isn't, there are still important structural differences (which I mentioned) in favor of the 190.

 

[pbehn]

Of course, assuming the subject of this thread is true. But even if it isn't, there are still important structural differences (which I mentioned) in favor of the 190.

It takes very little effort to roll an aircraft. If one is suspended in a museum exhibit but with the wings free to roll you can do it with your hands. The problem comes when the aircraft is moving, the wings elevators and tail do a great job of keeping it going in the direction and attitude it started with. At low and intermediate speeds AFAK it is a function of wing dimensions and rigidity and aileron efficiency, at high speeds it is mainly to do with wing rigidity. Using the rods to control may play a part but I think that lack of wing wash on the outer wing is important. There is no free lunch though, this was the cause of its nasty stall behaviour at high AoA.

 

[greybeard]

At low and intermediate speeds AFAK it is a function of wing dimensions and rigidity and aileron efficiency, at high speeds it is mainly to do with wing rigidity. Using the rods to control may play a part but I think that lack of wing wash on the outer wing is important. There is no free lunch though, this was the cause of its nasty stall behaviour at high AoA.

Please don't repeat the same assumption based discussion here from the previously linked thread!
Let's do this: let's take the curves of the famous diagram as valid, and therefore with the Spitfire which almost equals the Fw 190 in roll speed. My initial question remains to be proved; unfortunately this will only be possible with objective facts, such as physical evidence from the restorers or original Focke-Wulf blueprints.

 

[pbehn]

Please don't repeat the same assumption based discussion here from the previously linked thread!
Let's do this: let's take the curves of the famous diagram as valid, and therefore with the Spitfire which almost equals the Fw 190 in roll speed. My initial question remains to be proved; unfortunately this will only be possible with objective facts, such as physical evidence from the restorers or original Focke-Wulf blueprints.

The discussion I was referring to was by an aerodynamics engineer and specialist in WW2 aviation, not "assumption based" at all. The diagram itself is purely arbitrary as all are with roll rate. It measures with a constant stick force and altitude )50lbs @10,000ft, to make the test reproducible but that doesnt mean it is a fair test for all planes. Many aircraft were changed during the war to improve roll rate, certainly the Spitfire and P-51 were with different ailerons, hinges etc, but this wasnt given a new marque number. I dont even think this roll rate was where the Fw 190 had it real "edge" in performance because opposing pilots didnt roll over and over, they changed direction. How quickly a plane rolls into a turn and then rolls to turn the other way is a different value, even harder to measure. I have never seen anything about the Fw 190 having ailerons which worked differently based on airspeed and Ive never seen anything about anyone trying to copy such a system.