Inclinometer shows erroneous indications

[mattag08]

The inclinometer (the "ball") is showing the opposite of correct indications. For instance, a right roll with no rudder will cause the ball to fly out to the left. The ball should be showing an indication into the turn if no rudder is applied due to adverse yaw. I will preempt attempts to explain this away by also noting that I am using landmarks to visibly verify the yaw. The adverse yaw is indeed present in the flight model and working as intended, the ball is simply moving in the wrong direction.

 

This seems to differ based on speed. At slow speed the ball shows accurately sometimes. At higher speeds the ball shows a greatly accelerated and inverted position. I don't remember this being a thing in past builds so I feel like it was introduced recently, but maybe I wasn't paying much attention.

[electricaltill]

I recall seeing here somewhere that this instrument is unreliable in the Tomcat, though whoever that was didn't say whether it's a bug or accurate simulation.

[Golo]

Tomcat is using spoilers (at low speeds) to roll so they behave little differently from ailerons.

 

You go stick right to roll right, spoilers on the right wing go up inducing right roll, but also increase drag on right side causing you to yaw right (ball goes left).

 

So at low AOA in the Tomcat you will experience proverse yaw (ball moving opposite of roll), but at higher AOA you will experience adverse yaw as you expect.

[mattag08]

You don't though. You can see the nose track opposite of the turn. The net yaw is adverse.

[Peaches]

Take a look at Jabbers' flight characteristics video; he concluded that the Tomcat actually has proverse yaw.

[mattag08]

The nose yaws against the turn. I don't need to watch a video to confirm what I can easily observe.

[Nealius]

"Proverse yaw" is a copout answer. The Tomcat has proverse yaw in certain flight regimes, not all the time.

 

That said, the ball goes the opposite direction because of inertia. If you have a balloon (the ball) in a car (the tube), and you make a turn, the balloon is going to "move" the opposite direction of the turn.

 

I observe this behavior in all my DCS stick-and-rudder modules. The thing with the Tomcat is that the delay between inertial movement and settling into the slip is greater than in most other aircraft. It just lags a lot. Which might be part of the reason so many Tomcats had yaw strings on the nose in real life.