Roll Axis

[Kiwikat 2]

On my first flight I noticed that when I move the plane on its roll axis, the tail slides a good amount to the right or left causing a rather unnatural feeling effect. I talked to a real world pilot about this happening in real aircraft and he said it doesn't happen in anything he has ever flown.

Is this an issue with the flight model or is it something that is experienced on the real Catalina? Other developers, even freeware ones, have issued patches in the past to fix this on their various aircraft. That is what's leading me to believe it is an issue.

[Kiwikat 2]

I found that track IR was changing my view a bit. I turned it off and used locked spot. It appears that the whole plane is sliding when you roll the plane, not just the tail. It is really hard to explain with words. It doesn't feel natural though, from external view or the VC.

[Aerosoft Team [Inactive Account] 51558]

I found that track IR was changing my view a bit. I turned it off and used locked spot. It appears that the whole plane is sliding when you roll the plane, not just the tail. It is really hard to explain with words. It doesn't feel natural though, from external view or the VC.

We'll investigate this, nice observation though.

[fanavion 0]

On my first flight I noticed that when I move the plane on its roll axis, the tail slides a good amount to the right or left causing a rather unnatural feeling effect. I talked to a real world pilot about this happening in real aircraft and he said it doesn't happen in anything he has ever flown.

Is this an issue with the flight model or is it something that is experienced on the real Catalina? Other developers, even freeware ones, have issued patches in the past to fix this on their various aircraft. That is what's leading me to believe it is an issue.

I asume what you observe is a quite strong adverse yaw effect. That is a yaw created by different drag produced by the upward resp. downward deflected aileron.

Display the red ^-V^- in View Options and point it at a distant cumulus cloud , hill, or any other scenery object. When you roll the plane you will observe that the axis indicator will wander against the direction of the bank. On small deflectios the effect will be barely perceptible on large deflections it will be strong. You can counter the adverse yaw with rudder as in real life.

In fact the coefficient in the .air-file of this Catalina which determines adverse yaw shows a value which is way higher as found generally with other aircraft. Setting this coefficient to zero for a test eliminates this opposite swing on applying the ailerons.(for those who are familiar with the .airfile :Cn_da Yaw Moment aileron in YAW section of record 1101 "Primary Aerdynamics").

The question is now how the magnitude of this Anverse Yaw coefficient was determined by the developers:

(1) taken from a real life source,

(2) estimated by programs like the MSFS specific Air Wrench or a professional real life program

(3) tweaked by trial an error.

In the last case ,as with creating any other FS aircaft , we have the problem that we judge the handling behaviour of the simulated arcraft subjectively and qualitatively and compare it with real life statements , which are as well subjective and only qualitative.

Like in this flight test report of the Catalina

As Rod had briefed me I wasn't surprised at how sluggishly the ailerons performed. To make a turn it was a matter ofinitially applying rudder in the direction of theturn, followed up with aileron. This prevents the marked adverse yaw that would be causedby aileron input alone (no wonder the group is called Plane Sailing – it did feel a little like steering a boat through the air). http://www.iaopa.eu/mediaServlet/storage/g...06/Catalina.pdf

Or in he following thread where the Catalina is called man's greatest monument to adverse yaw.

http://www.pprune.org/archive/index.php/t-48555.html

In other words: How marked is marked or great is great ?

Carl

[fliger747 0]

As a 20,000 hr pilot, the adverse yaw effect here seem quite reasonable for the type of aircraft. Even if one had some experience in the real aircraft it is somewhat difficult to translate this to the FSX version as our control setups vary considerably, we lack the seat of the pants feel of the adverse yaw which helps in coordinating the turn and generally our controls lack significant resistance. Such aircraft often required quite a bit of physical force to move the controls! With large control surfaces, one might be able to theoretically have rather larges rapid changes in direction if you were able to apply such force. However in the real aircraft such control forces were not easily applicable and the aircraft has a much more stately flying style. This is somewhat replicated by using larger moments of intertia for the control axies, but is not a perfect solution.

To best replicate the flying experience, use smooth and small control inputs, and keep in trim. Coordinating the turns, watch the "Ball" and follow the advice on stepping on the ball (if it is to the right, use right rudder etc). Act like you are having to apply a lot of effort to the controls!

My impression is that the rudder may be a bit too effective as one can fly single engine out at slower than the minimum control speed in the air (VMCA) at which one is supposed to run out of rudder compensation and begin to loose directional control without reducing power on the good engine.

Cheers: Tom