Non-level flight

[wayreth]

Hi there.

Whenever I start a mission, my plane always leans toward the left or the right hand side. This happens in campaign and quick missions, and regardless of aircraft model/make.

As far as I know, my joystick is properly configured (I checked the game's calibration menu and it reacts normally to my input).

Is this issue related to the idea of "trimming" the aircraft (by pressing CTRL + left or right arrows)? When I do that I don't notice any real improvement... or perhaps it's related to the realism settings (torque?)?

For instance, on the runway, after applying moderate power to the engine, the plane starts to strongly lean to one side, like I'm pulling the stick on that direction. I need to use Z and X keys to compensate for this and it makes for crappy take-offs

To sum it all up, why isn't the goddamn plane flying level and how do I fix it?

I'm sure this is just utter noobishness on my part... Alas, such is the world.

[Tempest123]

If it is unwanted rolling motion you're referring to, this is normal, it has to do with trimming the ailerons to counteract the torque of the propellor, doing this depends on the plane type. Most of the russian, british, japanese and german aircraft (fighters) do not have adjustable aileron trim in flight, they had aileron trim tabs that where manually adjusted on the ground. Several of the Italian aircraft (Macchi's) have unequal wing lengths (i.e one wing longer than the other) to counteract torque. The American planes tend to be larger and more complicated, and therefore they have adjustable aileron trim. Try it for yourself: take a Bf 109 or Spitfire up and notice how you cannot adjust the aileron trim, then take a Mustang or Corsair and notice how you can adjust it.

There is no perfect aileron trim setting for all power settings, so in the middle of a dogfight don't worry about it. Elevator (pitch) trim is much more important to proper flight, and most of the aircraft in the sim have adjustable elevator trim, except for earlier planes like the i-16. Properly used elevator trim will allow you fly without fighting the stick, and you will gain speed and be able to hold altitude better.

On takeoff, the larger propeller and small fuselage of the WWII types causes lots of torque sideways, so before takeoff, you should trim your rudder left or right to counteract the forces, and use rudder on takeoff to guide your aircraft straight down the runway. In real aircraft the rudder is as important as the control column, and its difficult to control using the keyboard. If you think you will enjoy Il2 for a while, buy a set of rudder pedals, it makes a huge difference. Hope this all made sense, most of the forum members here are very helpful, so don't worry about asking questions.

[T}{OR]

The simplest possible explanation:

Correct, the effect causing this is called torque.

Before anything else - I would advise that you try flying planes with two engines and counter rotating propellers, much like a P-38.

With trim you can counter this but only at certain speeds. The faster you go the more airflow runs over your wings and pulling you stronger in one direction.

In IL2, much like it was in WW2, some planes don't have an option - can not be trimmed. And some planes are automatically trimmed for certain speeds. When applying trim in most cases you need to use a lot of it, especially since you're using keyboard for the job.

As for the take off - never apply full throttle. Use no more than 50-60% until you reach significant speed before you apply full power. Even then with some planes you will need to turn rudder fully in one direction. I do hope that you have at least a joystick with 4 axes (X, Y, Z for rudder and one for throttle). If not, you can disable 'engine throttle' under settings to suit your flying needs.

[Splitter]

Just to clarify the accurate information given before:

There is aileron trim, rudder trim, and elevator trim. Some planes have all of those, some only one or two. And I have yet to find a document that tells which planes have which so if you don't know the plane, you have to do some experimenting. All of these settings can change with power, altitude, and speed.

Aileron trim - keeps one wing from dipping, can be used to keep wings level.

Elevator trim - pitches the nose up or down.

Rudder trim - Possibly the hardest to master. See that little "carpenter's level" on the instrument panel? That is the slip indicator. In level flight, that black ball that keeps moving from side to side as you maneuver needs to be in the center. You can center is by applying rudder (costs you speed due to drag of the rudder going to one side) or trimming (more efficient flight because the trim tab is small and creates less drag). There is an old adage: Step on the ball. If the ball is to the right, give some right rudder to center it and vice versa.

Note that on some aircraft the slip indicator is a needle instead of a "carpenter's level" but it does the same task.

Slip is basically defined as how much your plane is sideways to the direction of travel. The more sideways it is, the less aerodynamic it is. Being sideways costs speed and makes aiming more difficult. Note that you can "slip" to reduce your speed, like when you are approaching for landing.

You need to constantly be trimming your aircraft for efficient flight. Every time something changes (altitude, speed, power, etc..) the amount of trim you will need changes. If your plane does not have a certain type of trim, you have to apply stick or rudder pressure to compensate.

Applying rudder with the keyboard is hard. Rudder pedals are great and a "twisty" joystick is ok too.

Splitter

[ruxtmp]

This is the Torque effect that you are seeing. Trimming (if available on aircraft) will reduce the load that you must apply to the stick and rudder to maintain level and coordinated flight.

On a side note I noticed that most of the flyable planes seem to have low dynamic directional stablility. This produces the highly annoying back and forth swinging when using the rudder as the nose hunts out the equilibrium point. While I have never flown any of these aircraft it seems odd that they would respond to control inputs and atmospheric distrubances in this manner.

Originally Posted by ruxtmp

This is the Torque effect that you are seeing. Trimming (if available on aircraft) will reduce the load that you must apply to the stick and rudder to maintain level and coordinated flight.

On a side note I noticed that most of the flyable planes seem to have low dynamic directional stablility. This produces the highly annoying back and forth swinging when using the rudder as the nose hunts out the equilibrium point. While I have never flown any of these aircraft it seems odd that they would respond to control inputs and atmospheric distrubances in this manner.

Roger that. In the air the planes do seem quite wobbly, even at speed. My experience has been that at a given plane's high speed they're quite solid feeling as the stability built into them is for the low speed part of the envelope. And as a long time taildragger pilot I can say that on the ground the nose only goes one way when it deviates, either left or right. Trying to go in a straight line is like using your feet to keep a ball balanced on a cylinder. The more on top of it you are the less input is required and, conversely, the worse it gets the harder it is to recover.

[Blackdog_kt]

The effects are similar, but apart from torque you also have other aerodynamic factors at work. Torque is mostly about two parts joined by a common axis, when one things turns left (for example the propeller), the other one wants to turn right (the fuselage, which means the wing opposite the prop's direction is dipping lower). This is clearly on the roll axis.

As for the sideways pull, that is on the yaw axis of motion.
The propeller's rotation creates a swirling mass of air that travels along the aircraft's fuselage. This swirling air usually hits one side of the tail more than it does the other.
Imagine having spray paint injected in front of the propeller to observe this, you would see a corckscrew shaped pattern travel from the propeller backwards and depending on the dynamics of it all (eg, propeller RPM, propeller blade shape, fuselage length etc), most of the paint along this corckscrew would hit on one side of your tail.

This effectively means that the vertical part of the tail functions like a "sail" against this mass of wind, moving your tails sideways (and turning your nose the other way as a result). I think this is called p-factor, someone correct me if it's not. This is a simplistic explanation strictly from memory, but googling about p-factor you'll be able to learn more.

The reason it's better to apply throttle smoothly during take-off has to do with this effect and the way the control surfaces work. If you hold your brakes while pushing the throttles to full, you have the maximum amount of swirling air hitting the side of your tail to fight against, but you have no forward motion whatsoever to create an airflow over your control surfaces, which means ineffective controls to fight it with.

However, if you only apply 30-50% of throttle you greatly reduce the yaw motion induced by this effect. Also, when your plane is steadily rolling along the runway your forward motion creates a relative motion of air over the control surfaces that makes them effective. So, you apply throttle about mid-way and as soon as you're moving at 50-100km/h (30-60mph) or so depending on aircraft type you can advance your throttle the rest of the way and be sure you have enough control authority to counteract the sideways pull.

There's even more dynamics into play here of course. For example, tail dragger planes rely heavily on short bursts of power to create airflow over the tail surfaces in an effort to help with ground maneuvering and taxing.

The trick here is that these are brief actions and the sideways pull doesn't have enough time to manifest. You can almost turn on the spot by applying brakes only on the wheel inside the turn ( that is, left wheel for left turn and vice versa), kick the rudder into the turn and briefly apply some throttle (or a lot of it, experiment and watch the results). The plane doesn't have enough "power on" time to start accelerating and veering all over the place, but the sudden burst of power and increase in propeller rotations creates a "block" of moving air mass that crashes into your deflected rudders and helps you turn on the spot, without having to get the plane rolling forward first.

You don't really need to fret about memorizing exact sequences of actions to perform.
The important thing is to just know that these effects are there and observe how they affect your flying. Different aircraft have different behaviours and even the same plane behaves differently depending on its weight/load-out, power settings (throttle, etc), even weather conditions.

Best thing you can do is jump in an aircraft you like (preferrably early war, since they are lighter, easier to control and have less powerful engines and thus less available torque) and run a sequence of test flights to get a feel for it. Just fire up a mission in the quick mission builder with no enemies around, go to the airfield and start practicing take-offs/landing/touch and go sequences a few times. When you are satisfied that you know how it works (it doesn't even have to be perfect, just non-lethal ), change something and observe the effects. For example, after getting comfortable with take offs using a gradual throttle input, try the same thing with abrupt throttle inputs, then with something in-between and so on. Chances are that within 5 attempts you will find the "sweet spot" between doing things fast enough but not so fast that your plane runs away under you.

[SlipBall]

Originally Posted by wayreth

Hi there.

Whenever I start a mission, my plane always leans toward the left or the right hand side. This happens in campaign and quick missions, and regardless of aircraft model/make.

As far as I know, my joystick is properly configured (I checked the game's calibration menu and it reacts normally to my input).

Is this issue related to the idea of "trimming" the aircraft (by pressing CTRL + left or right arrows)? When I do that I don't notice any real improvement... or perhaps it's related to the realism settings (torque?)?

For instance, on the runway, after applying moderate power to the engine, the plane starts to strongly lean to one side, like I'm pulling the stick on that direction. I need to use Z and X keys to compensate for this and it makes for crappy take-offs

To sum it all up, why isn't the goddamn plane flying level and how do I fix it?

I'm sure this is just utter noobishness on my part... Alas, such is the world.

What stick are you using?...if the controller also has wheels such as the CH products, then make sure that they are centered