I have a problem with the rudder/aileron stability in MSFS, I’m not sure which control is the root of the issue but it is probably the rudder.
When trimmed to fly straight and level the aircraft will randomly enter a left or right turn with no input from me, and if left alone it will meander around the sky seldom staying long in a straight line. Here is a screen shot of a typical track which shows left and right turns including complete track reversals:
I fly small GA aircraft and suspected that the problem may be due to something I have added to the Community Folder. I disabled the folder and tried the C152 from the Official Folder but the problem was still there.
Has anyone else had the same issue? Better still, has anybody found a cure?
I understand you are not using the autopilot but just let plane fly unattended starting from a initial trimmed status. In that case that can simply be caused by wind changes. Nose will naturally try to point to incomming wind unless you or autopilot compensates that.
Its caused by Adverse Yaw , In real life the 152 does have a lot of adverse yaw ..
Adverse yaw is the natural and undesirable tendency for an aircraft to yaw in the opposite direction of a roll. It is caused by the difference in lift and drag of each wing.
In general, the inherent stability of an aircraft does not mean that it will stay straight and level. For example, if a wing drops (or if you lower it with your ailerons and then return the controls to neutral), the plane will stay in that rolled attitude and thus starts to turn. It will not return to straight and level automatically (for that, you will have to use the ailerons in the other direction). Small disturbances are present all the time in an non-perfect world, so you will have to do small corrections all the time to stay straight and level. The lighter the aircraft, the same magnitude of disturbance has a higher effect because of the smaller intertia of the plane.
So on first view, it looks like a normal behavior. If you suspect your control inputs to be buggy, you could (as a test) try to increase the deadzone of the inputs to make sure they do not give undesired inputs when centered.
As in real life: it depends: specifically on the construction and shape of the airplane. Irl you have gliders that return to a stable and level flight from (nearly) any attitude without pilot intervention and there are gliders that are the exact opposite and would go heywire without dedicated and accurate pilot input at all times. Usually the old training gliders are from the first category wheras the modern and highly efficient “super orchids” are from the second category.
I don’t think this is true. Wind is simply the relative movement of the air with respect to the ground, and has no effect on an aircraft if the ground is negated. I’m not a real life pilot, but have certainly never experienced a change in heading due to wind in any sim.
I believe an aircraft will only ‘weathervane’ into the wind when on the ground. This is caused by the position of the landing gear with respect to the rest of the fuselage - particularly the vertical stabiliser.
100 right! Once you take off, the aircraft is simply part of the air mass moving across the geography. The aircraft does not weather vane as it would on the ground or on water for floatplanes. Weather vaning is copletely different from the crab angle arising from the difference in wind direction and desired track.
Also most aircraft will return to level flight from minor excursions due to the dihedral angle built into the wings of the aircraft, making it self-stabilizing to a degree.
No. Wind affects all control surfaces as well as the static surfaces like wings and stabilizers, either if you are on ground or airborne.
Weathervaning effect is what indeed causes the nose willing to point to wind when there are crosswinds. If you hold a piece of paper vertically with your fingers and blow with some lateral angle you will see it´s willing to point to incomming air as well as an aircraft does.
This has nothing to do with landing gears nor even with airplanes. As your link explains even helicopters suffer it during hover so when they are not hooked to ground by anything. It´s a general physical effect that you can see also on tower cranes for instance. That´s why tower cranes indeed shall not be locked under windy conditions when not in use, but you have to let them move freely. Wind will push one side till they completely point to the wind as well because that´s the position which offers the smaller resistance to wind for the whole crane structure as air can flow on both sides at the same speed.
In an aircraft/helicopter it´s the same because their fuselages are never wider than their lenght so they will always want to have their nose/tail aligned with wind, provided that lateral wind component is still relevant compared to longitudinal air flow generated by speed once you are already moving. If it´s not relevant enough you will just notice the tail shaking effect as wind hits it but nose will not want to turn permanently.
You are in some way right (I will come to that) but I think you have the wrong picture in mind. The “wind” (meaning the airstream) that an airplane experiences that moves through the air normally always comes from head-on and that is regardless of the wind direction (with wind in the sense of moving air seen from the ground). The airplane moves with the moving airmass, so the only “wind” it experiences it the airstream coming from its forward motion. Think of the extreme case of a hot air balloon. It always moves with the wind as it has no other choice. In the gondola, it is always dead calm.
I can highly recommend reading chapter 6 “wind drift” in Wolfgang Langewiesches classic “Stick and Rudder - An Explanation Of The Art Of Flying”. You can find the book as pdf with a google search (not sure if I am allowed to link this here…). This might give you the correct mindset about the topic.
You are right in the way that if the airplane yaws to the side (direction of motion unchanged), the airstream will “push” it straight again. But this is directional stability (as also mentioned in the linked Wikipedia article).
About the hovering helicopter: The answer lies in the term “hovering”. This means it is staying above one point. For this, it must not move with the airmass (otherwise it would drift away from this point) so the pilot has to counteract this. If you are not moving with the wind, you of course experience forces that cause the weathervaning. So hovering is exactly the same than having a landing gear.
Airplane always receives all airflows, so the ones generated by its own motion (if you use engines or you dive to generate speed) but also the airflows from existing winds. The weathervaning effect is therefore always existing but it´s only relevant if you are moving slow with a soft crosswind or you have a strong crosswind while moving fast (for instance while landing).
But this is not meaning that it´s only happening while you are on ground or is caused by your landing gear being still holding you partially to the ground or something like that. That´s wrong as well as saying that hovering is like having a landing gear. The fuselage is pivoting just because forces are being applied on the tail but not on the nose. That can be generated by your tail rotor if you use pedals but also by wind hitting one side of the tail in case of crosswind. That´s why the chopper still wants to align with wind as well even if it´s main rotor is not generating any movement (no cyclic is used) so therefore you have no airflow generated by speed and just a vertical airflow that holds the helicopter mass in place.
When you leave the yoke, it will fly like that IRL. You constantly need adjustments for gusts and turbulence to fly straight. Novice pilots will even fly in a turn even when trying to fly straight.
it is true that weathervane only happens (semi) connected on the ground, but sudden changes in wind direction or partial hitting gusts (either lateral or vertical) will cause movement on the fuselage.
An hour in a C-152 at your local airport with an instructor will sort out your notions of weathervaning at altitude.You’ll see that when trimmed, an aircraft will maintain any heading regardless of the current wind direction with no urge to turn into the wind. The laws governing the physics of flight require no rewriting.
So by that logic, you wouldn’t be able to cross a flowing river swimming, because your body would weathervane to the current and you end up just swimming against current.
When in the air, the plane will flow with that body of air. It will not try to weathervane unless there’s differential pressure on the tail vs the nose, which in laminar flow is non-existent.
