Side to side movement on the runway

HowardsRock wrote:

Does anyone else have a problem where your aircraft veers left and right on the runway both as you're taking off and immediately after you touch down on the runway?

I'm thinking it shouldn't be doing this. 😕

If it happens on take-off one possible explanation might be that you're increasing your throttle/thrust too fast.

On touch-down it's a tough guess as it depends entirely on the type of a/c you're flying - give us a few more pointers.

Aircraft type is pretty much irrelevant...meaning it happens with all of them.

Sometimes it happens to me, but its with 2 engine planes, and 1 of the engines is off. 🙄

I don't now what your problem is. Maybe post a screenie of your cockpit so we can see whats set up.

1 when u r just about to takeoff and 1 right before touchdown. ❓ ❓

My first thought when reading this post is Wind. I use ActiveSky, used the Real World weather before that, for my flights.

In calm winds I have no problems keeping the plane straight. In windy conditions though it is difficult to keep it straight depending on how strong the winds are.

One good example for this is last Saturday when the Seattle area had high winds. I tried a flight from Sea-tac to Portland and was nearly pushed off the runway at Sea-tac. I had to give up trying to land at Portland. I couldn't keep the plane lined up with the runway to land.

One possibility is if this happens with all aircraft in calm air is you may need to increase the null zone on the rudder control. If that is the problem the plane should also want to wander off while flying, if it doesn't then that probably isn't your problem.

If you are using real weather wind can cause it.

Sometimes I have this issue when I have autopilot on, then go to a new airport via the menu.

It remembers autopilot was on and it tries to steer me towards my heading when I am on the runway.

Highly annoying 🙂 Wouldn't explain your landing issue unless you are some how managing to do that with AP on.

I've noticed the phenomenon also. Aircraft sometime seem to slide sideways during roll out on landing. I believe that it's just a glitch in the program. 🙂

HowardsRock wrote:

Does anyone else have a problem where your aircraft veers left and right on the runway both as you're taking off and immediately after you touch down on the runway?

I'm thinking it shouldn't be doing this. 😕

The tendency of the aircraft to go left is addressed in the realism settings. The fact that you are wobbling left and right probably means that your null zone is too large and sloppy causing you to overcompensate. I have never understood why anyone ever wants to increase the null zone unless their sensitivities are way too hight. In that case correct the problem, rather than covering it up with a large null zone. That is like driving a car with 12 inches of play in the steering wheel.

it happens because the propellar is going to the left, and so all the air is forcing the plane to to go the left. thats the real explanation. just in case anyone is still wondering. it also has to do with the shape of the propellar.

Desmond wrote:

it happens because the propellar is going to the left, and so all the air is forcing the plane to to go the left. thats the real explanation. just in case anyone is still wondering. it also has to do with the shape of the propellar.

I would say your right, if you have your realism settings up high. Its the same in helicopters, you always have to apply a little right pedal to keep straight (depends on what helicopter your in also). On the ones I've flown the rotors are spinning in a counter clockwise direction which tends to make the a/c goes that direction unless you apply anti-torque with the pedals. Most a/c have their own tendencies to do certain things, its called the dynamics of the a/c and you have to counter act them. PS mine does the same thing, always wants to go left. I always apply right rudder (just a little really slow) and it stays straight till I get in the air then I can let go of the rudder. Also stated above, if your overcorrecting then that would put in all over the runway. You have to try and foresee whats going to happen not react once it does. Hope this helps Jeff

All this is very interesting, but I use autorudder in FS9. So this movement shouldn't be happening, right?

Just re-read the thread -- calibration of the flightstick hasn't been mentioned yet. Have you tried to re-calibrate it?

Desmond wrote:

it happens because the propellar is going to the left, and so all the air is forcing the plane to to go the left. thats the real explanation. just in case anyone is still wondering. it also has to do with the shape of the propellar.

If the prop is turning to the left then the prop-wash, moving backwards in a spiral around the fuselage, will be hitting the righthand side of the vertical stabilizer, causing the aircraft to turn to the RIGHT.

Not quite sure what you mean by the shape of the prop though.

Tailhook, I don't have a joystick. I fly with the keyboard.

HowardsRock wrote:

Tailhook, I don't have a joystick. I fly with the keyboard.

I'd love to say : ...well, that's the problem!

But that won't help you, will it? Since you've told us now that you're using the keyboard, this puts a whole new spin on the situation. Needless to say... you have less control regarding your throttle movement than you would with a stick. This could be the cause, though we're all aware that you're not the only simpilot who uses a keyboard.

Aircraft type is pretty much irrelevant...meaning it happens with all of them.

This deserves a little more scrutiny. We've established that with Props you can easily be pulled to one side at take-off if you don't increase your throttle smoothly. This can also happen with Jets, depending on the sensitivity the author has given to his project. An example: You might be flying the default 747 regularely and now you've just installed a 3rd party 747 -- but because this one is more 'realistic' in its FDE, and the fact that your previous flight was in a twin-engine such as the 737 or the Mooney for that matter, you'll be pulled to one side at take-off because you didn't realize that you have to address all four throttle levers individually.

Touchdown is obviously a different issue all together and my suggestion is at this stage not to associate the two. As take-off in general seems to cause less problems, I would just concentrate on that for the time being.

Let's use the C-172 for our experiment. Clear all weather. Once you've set up the flight -prior- to t/o, save the flight. Now choose this flight - this way we'll be able to restart exactly the same flight over and over again without having to set it up each time.
Now just apply the throttle in very small increments until you're full throttle. If you're not being pulled to one side -- that's nice. Restart the flight and this time jam the throttle to full straight away. You should be pulled to the left now.
With Jets the principle is basically the same (depending on the FDE) because all engines should be spooled up to the same degree before you release the brakes -- though the effect of pulling to one side might not be felt as immediate.

Make sure you're only using unaltered default aircraft (panel, .cfg etc.) for this experiment. If you're not a 'Heavy" -pilot, don't worry, you don't have to fly it, we're only rolling along the runway.
This should really work, if it doesn't... we'll have to do some more research, won't we. ---Of course there is always the possibility that one of our more knowledgeable members is willing to solve the mystery. We'll see what happens 🙂

Madbrit wrote:

Desmond wrote:

it happens because the propellar is going to the left, and so all the air is forcing the plane to to go the left. thats the real explanation. just in case anyone is still wondering. it also has to do with the shape of the propellar.

If the prop is turning to the left then the prop-wash, moving backwards in a spiral around the fuselage, will be hitting the righthand side of the vertical stabilizer, causing the aircraft to turn to the RIGHT.

Not quite sure what you mean by the shape of the prop though.

well you understand what i mean by the rotation of the propellar, i just mixed up directions there.