Rudder Control Issues

Howdy!

I don’t know if anyone else has noticed this, but the rudder for any aircraft (except the Boeing 757-200) seems to act in the opposite way as it should. For any lifting surface, the effectiveness increases with increasing speed, i.e., the higher the speed of your aircraft, the more effective a control surface should become.

Landing: When correcting for a crosswind or maintaining centerline, the rudder does not work at high speeds and the yawing moment is only noticeable and/or works when the plane slows down

Takeoff: Similar to landing, the rudder and nosewheel work just fine when beginning the takeoff roll. However, as you gradually gain enough speed, the rudder does not have an effect on yawing the airplane.

With all this said, the only time the rudder DOES seem to work very well when it should is when the nose wheel is off the ground but the main wheels are still on the ground (either during landing or takeoff).

If this is a technical issue or I am just forgetting basic airplane stability & control, do let me know!

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I think this is just a natural handling characteristic of the all of the other aircraft. I remember when the 757 got reworked a lot of people on the community were freaking out over the rudder sensitivity, and the devs had to repeatedly point out that yes, the 757 really does have a sensitive rudder.

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Hi, As for:

It is true effectiveness increases with the increasing dynamic pressure from increasing speed.

But there are some added complications, I think.

As a general background issue:

1)Rudder travel limiters (not exclusive to fly-by-wire airliners) are crucial for preventing excessive rudder deflection that could lead to structural damage.

For the range of aircraft, it’s a question how and where such limiters (irl, let alone IF) are implemented in each particular aircraft.

In terms of IF in particular:
2)

My impression has been that the degree of nose wheel contact is modelled.

So, at lower speeds, more positive nose wheel contact is experienced as more yaw response due to the turning forces from the nose wheel itself (being dominant over rudder yaw forces).

Same as above: when nose wheel contact diminishes enough (affected by trim and pitch control pressure), it coincides with when the airflow is still relatively low as far as the rudder response sensitivity.

So, it does seem like you’re losing responsiveness with increasing speed, going from firm contact to little and then no nosewheel contact.

I’m assuming this is still consistent with my comments above.

When you have the nose well off the ground, it generally is when your airspeed is higher than when your nose is settled/settling closer to the ground, so rudder response is higher (but not necessarily more responsive than nosewheel ground contact yaw response).

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After an embarrassing glitch during @Anthony_Gulluscio ‘s New York event today, I now can say that it could also be technical factors that play into rudder performance.

I have no idea why, but I was trying to taxi in the 767 and it WOULD NOT TURN AT ALL! It was crazy and very frustrating but now I think it’s pretty funny 😂😂

You where hogging my runway 🤬

lol all good

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