Keeping straight on takeoff

  • Hi,


    I'm getting some weaving on takeoff that's difficult to cancel out with my rudder pedals. Most noticeable in the F-18, it starts to deviate from a straight line, then whatever I do with the rudder pedals tends to overcorrect it, leading to an oscillation. Often results in a crash.


    I probably need to change some settings (would appreciate a tip :) but I also wonder if this is correct physical behaviour. During the takeoff roll I should expect the a/c yaw stability to improve as the speed increased?


    Also, I think I ought to be able to lock the nosewheel, but there isn't a command for that yet AFAIK. Is that a thing that could be modded?

  • 1.I'm getting some weaving on takeoff that's difficult to cancel out with my rudder pedals. Most noticeable in the F-18, it starts to deviate from a straight line, then whatever I do with the rudder pedals tends to overcorrect it, leading to an oscillation. Often results in a crash.
    2.During the takeoff roll I should expect the a/c yaw stability to improve as the speed increased?
    3.Also, I think I ought to be able to lock the nosewheel, but there isn't a command for that yet AFAIK


    1.That's a problem with most pedals due to the lack of real airplane feedback, low quality and almost most important, that on most pedals both feet rest completely on the pedals.
    That's a problem IRL as well, and if it's possible to keep the heels on the floor, the danger of overcontrolling is much reduced.


    2. Stability does increase slightly but if your corrections are already too high at low speed, this problem is of course magnified at high speed.
    The higher the speed, the smaller the input.


    3. There's no such thing as a nose wheel lock IRL either and it's not necessary. Normally during take off, the nose wheel steering, which is responsible for the large deflections, is turned off. Nevertheless the nosewheel still moves with rudder input.
    Don't know if this is the same on the FS2 F/A-18 because I've uninstalled it a long time ago.

  • Currently the front gear steering is permanently on. Because of that you need to use quite small rudder inputs on the takeoff roll and roll out after landing. The real F18 has a switch that you hold down (same as the autopilot disconnect) and that enables the nose gear steering. This switch is already working in the Aerofly FS 2, but currently there is no way to activate it because you can't see if from the pilots seat (its in front of the stick) and there is no disconnect assignment in the controls setting for it yet. I'll see what I can do.

  • On a standard joystick it would be a bad a idea if you would need to keep the button constantly pressed.
    A on/off button/key would be much more suitable IMO or how about a speed dependent steering (like it's on many planes IRL) e.g. on below 30kts.

  • Thanks jetpack - most eagerly awaited, I would love to show off the F-18 to other people and let them fly it in the Vive. There's nothing quite like an afterburner takeoff in AF2 (as long as you keep it straight on the runway).


    From the other responses above I'm guessing that turning off the steering will not completely lock the nose wheel (i.e. it will still castor because of the way it's mounted) but the magnitude of the response be lowered somewhat.

  • Jet-Pack (IPACS)
    1. You always have the information in the HUD displayed if the NWS is on or off.
    2. The NWS is switched on with a momentary push of the NWS button, it's just if you want to enage the NWS HI mode (also displayed in the HUD) that requires you to hold the button down continously.
    3. NWS can't be accidently engaged before landing because the WOW switch turns it off automatically after nose wheel lift off.

  • Okay, maybe we can just disable the toggle in the air and set it to off whenever the aircraft leaves the ground. But then there are probably users that what to hold down the button instead... what do we do then? And then again, what do we do with the ipad users, when do we allow them to use full range steering? We could implement a protection system into the nws, like in the a320. It reduces the maximum deflection by the tiller depending on the speed. But that wouln't be as realistic...


    NWS in the air is already disabled. As soon as the nose gear damper is compressed the steering is engaged again.

  • IMO 'realistic' operation with holding down the steering button continuosly only makes sense if you have a 100% replica of an F/A-18 stick and throttle.
    If it's only a desktop sim a lot of compromises have to be made I'd expect.
    Normal steering angle is approx 16° IIRC and the HI mode 75°. You never need 75° above 5-10kts IRL.
    The Metro has exactly the same steering. The button has to be continously pressed to achieve the HI mode and IRL you only use it during e.g. the final turn to parking where really tight 90° turns are required and you don't exceed 5kts during such turns.

  • In the MB339 there is a switch on the stick to set steering mode on or off. When it's on a light on the fron panel will warn you with the word "STEER".

  • The only castoring plane than I tried was the French Socata Rallye. It felt a bit funny but was OK after a few moments. I think (25 years ago) it was brakes first on take-off then rudder with gained speed, the single engine airflow over the vertical stabiliser and rudder helped early on. Wonder what the Robin in Aero FS did?
    Would a locked nose wheel be that worse than a locked tail wheel? I would imagine that in a yaw on the ground the drag from the main gear behind the COG would be very big? (fixing the yaw). Perhaps with brakes applied, the long nose wheel moment arm from the COG would be very significant? (making the yaw worse).
    The tail wheel lock in the FS 2 Corsair (left console) does not work in FS 2.

  • The real Robin DR400 has an auto-lock system on the front wheel, that reduces wheel deflection to some 5° (or is it 10, not sure anymore).
    You need to compress the front wheel shock absorber to release the lock and allow full deflection, linked to the rudder pedals. Technically, at take-off the nose wheel locks and applying moderate or full rudder doesn't make a difference on the front wheel, on rudder only.
    After landing, when braking, the front wheel sock absorber compresses and unlocks the steering...
    On several occasions however, in case of very soft landing without much braking, the lock didn't release and I was unable to steer to vacate. A short, firm braking quickly releases then the lock.
    When leaving the aircraft you walk down the rear of the wing, which in some occasions also happens to lock again the front wheel, preventing you from steering with the bar. You just hang yourself to the propeller, and hear the clung noise during compression, telling the steering wheel is now unlocked again...


    This system has never been modeled in sims. The AFS1 Robin was rather easy to keep centerline at takeoff, but I'm used to steer with toes only...


    Cheers
    Antoine

    Config : i7 6900K - 20MB currently set at 3.20GHz, Cooling Noctua NH-U14S, Motherboard ASUS Rampage V Extreme U3.1, RAM HyperX Savage Black Edition 16GB DDR4 3000 MHz, Graphic Card Gigabyte GeForce GTX 1080 8GB, Power supply Corsair RM Series 850W, Windows 10 64 bit.

  • If the nosewheel can deflect 5 or 10deg it's not locked. On the DR400 it's basically a fully automated switch between low and hi.
    E.g on most airliners steering with the pedals is around 6deg and when using the steering tiller around 70deg.
    5 or 6deg is enough for any correction during take off or landing.
    BTW, the DR400 is my favourite single engine GA plane IRL..(despite its really dangerous stall characteristic when fully loaded)