Landing issues
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Hello all
I’m having all kinds of issues with executing a stable landing. The landings i’m experiencing are roll pitch and yaw problems. no matter what speed I approach, the plane rolls pitches and yaws out of control. I have to guess with my HOTAS I move a little and the movements exxagerate. I’m online with the runway but a little high or left or right. I correct and it over corrects I bring it back and the plane wobbles like a test lunar lander. you know the one the astronauts tested in apollo. Left, right , up, down. I’ve played with saturation and deadzone to distraction with no luck. I have the old F4 Falcon sim and it lands fine, but BMS no luck. Any help would be appreciated.
Regards, Gary
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Wobbling and over correcting on landing sounds like you are too slow. The Viper is all about keeping the correct AoA. Once you set your proper flight path to the threshold, it’s all about power adjustments and slight stick corrections… and don’t fight the ground effect as you pass through it.
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Hello all
I’m having all kinds of issues with executing a stable landing. The landings i’m experiencing are roll pitch and yaw problems. no matter what speed I approach, the plane rolls pitches and yaws out of control. I have to guess with my HOTAS I move a little and the movements exxagerate. I’m online with the runway but a little high or left or right. I correct and it over corrects I bring it back and the plane wobbles like a test lunar lander. you know the one the astronauts tested in apollo. Left, right , up, down. I’ve played with saturation and deadzone to distraction with no luck. I have the old F4 Falcon sim and it lands fine, but BMS no luck. Any help would be appreciated.
Regards, Gary
Practice. The practice more. Then practice again after that.
Remove all deadzones (except for any required to keep stick stable when centred) and trust the FLCS.
Take into account sidewinds and turbulence.
Pitch is controlled with the throttle, speed it controlled by the stick.
You have to be gentle, very gentle, with the stick once on finals. It is even sometimes worth NOT trying to correct for wind shear and turbulence, and whatever you do, when using ILS do not go chasing the indicator bars once you are within 1.5 miles of the threshold. Fly visual from here.I have done literally thousands of landings for testing, and still have “moments” sometimes. Treat her kind and she’ll reward you.
Did I mention practice?
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… try different settings in Weather / Turbulence tab. (default are IMO a bit exaggerated … idea was to put something demonstrative, but it was a bit too much … it will be slightly reduced in the future)
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Pitch is controlled with the throttle, speed it controlled by the stick.
I usually try teach the 11 degree approach instead for total newcomers. Seems to work out a bit easier.
For OP’s benefit, you have two ‘options’ with your approach to land. You can fly final at 11 degrees angle of attack, or at 13 degrees angle of attack. In both cases, you are aiming for a 2.5° descent angle.
Flying at 11 degrees angle of attack, you are faster, and the engine is at higher RPM, responding more quickly to adjustments (marginally). You adjust your flight path with minor stick inputs, and adjust your speed with minor throttle corrections.
Flying at 13 degrees angle of attack, you are slower, the engine is at lower RPM, providing less thrust and giving you a slightly more optimal landing. Slower to land, less fuel burn. Your controls are ‘reversed’ in a sense, because adjusting the flight path with the stick tends to adjust your speed, and adjusting your speed with the throttle tends to adjust your flight path. So people teach it in this sense: You use the stick to control speed. Pull back to slow down, relax the back pressure to speed up. You use the throttle to set your glide angle. More power for a shallower glide, less power for a steeper glide.
I tend to prefer the former over the latter, but both are equally valid approaches.
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I
[…]
Flying at 11 degrees angle of attack, you are faster, and the engine is at higher RPM, responding more quickly to adjustments (marginally). […]I always land with boards(speedbrakes) fully opened. This way i get a higher RPM.In case i have to go around the boards closes faster that the engine would spool up.
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Thats good practice. Id recommend landing with the boards at 43° open rather than fully open (60°). IRL, landing with the boards fully open risks contacting the runway on touchdown. Once you lower the nose into the three point aerobraking attitude, go ahead and override the boards to the 60° position.
In BMS at present, its a non-factor, the horizontal tails and speedbrakes do not affect the chances of a tail scrape.
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Doesn’t landing gear extension retract the speedbrake a bit to avoid just that Bw?
That’s implemented in BMS -
@Red:
Doesn’t landing gear extension retract the speedbrake a bit to avoid just that Bw?
That’s implemented in BMScorrect
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@Red:
Doesn’t landing gear extension retract the speedbrake a bit to avoid just that Bw?
That’s implemented in BMS100% … *****
But remember guys that it can be overridden by keeping an action on air-brakes command.
*** (if I am not wrong, except in some cases in the future ;))**
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100% … *
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It does. Some people hold the switch open anyway. -1 describe this will have an upsetting effect near the ground. Roger might not be aware of the 43°/60° feature and probably means “fully open” as the maximum angle without holding the switch.
The weather can be too much, e.g. the ILS weather TE. If the airplane wobbles around a lot not due to your input, don’t worry and just let it. There’s nothing you can do. If the airplane wobbles as a result of your input then you aren’t being smooth enough on the controls.
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It does. Some people hold the switch open anyway. -1 describe this will have an upsetting effect near the ground. Roger might not be aware of the 43°/60° feature and probably means “fully open” as the maximum angle without holding the switch.
Thanks! I was about to ask how do I know it
s 43° … It
s in -1 indeed.The weather can be too much, e.g. the ILS weather TE. If the airplane wobbles around a lot not due to your input, don’t worry and just let it. There’s nothing you can do. If the airplane wobbles as a result of your input then you aren’t being smooth enough on the controls.
True, don`t fight her unless you are very close to surface.She will maintain general direction by itself.
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Hello all
I’m having all kinds of issues with executing a stable landing. The landings i’m experiencing are roll pitch and yaw problems. no matter what speed I approach, the plane rolls pitches and yaws out of control. I have to guess with my HOTAS I move a little and the movements exxagerate. I’m online with the runway but a little high or left or right. I correct and it over corrects I bring it back and the plane wobbles like a test lunar lander. you know the one the astronauts tested in apollo. Left, right , up, down. I’ve played with saturation and deadzone to distraction with no luck. I have the old F4 Falcon sim and it lands fine, but BMS no luck. Any help would be appreciated.
Regards, Gary
Do you have rudder control by twisting your stick or with pedals? If you have it by twisting test it in bms with small stick movements.
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Hello all
I’m having all kinds of issues with executing a stable landing. The landings i’m experiencing are roll pitch and yaw problems. no matter what speed I approach, the plane rolls pitches and yaws out of control. I have to guess with my HOTAS I move a little and the movements exxagerate. I’m online with the runway but a little high or left or right. I correct and it over corrects I bring it back and the plane wobbles like a test lunar lander. you know the one the astronauts tested in apollo. Left, right , up, down. I’ve played with saturation and deadzone to distraction with no luck. I have the old F4 Falcon sim and it lands fine, but BMS no luck. Any help would be appreciated.
Regards, Gary
I was having similar issues until I adjusted the “deadband” setting of the stick. In Falcon BMS Choose Setup > Controllers > Advanced (below the key mapping box) > Flight Control (tab)…
You’ll see Rudder Axis (Z - Rotation) and across from it in the “deadband” column, it’s probably defaulted to “small”… I set mine to “medium”
near the bottom of the box, same thing can be done with “Pitch Axis” and “Roll Axis”. I did not mess with the “saturation” defaults
This smoothed things out a bit for me, by reducing the sensitivity of the stick.
Hope this helps!
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The Dash-1 does however state that you shouldn’t use any rudder when landing:
@BMS 4.34 Dash 1 page 225:
Because of the ARI that connects Aileron to Rudder, the wing down sideslip is to be avoided with the F-16. The rudder should not be used when landing the F-16!
The wing level crab is the only technique for landing the F-16. Take your feet off the rudder pedals and point the aircraft nose into the wind. In high crosswind situations the FPM may drift outside the HUD field of view and you may have to centre the FPM with the DRIFT C/O switch and estimate your flight path.
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The reason for that is the possibility of a yaw transient at touchdown - a discontinuity in how much rudder input is being applied. The same pedal force applied during touchdown can lead to sudden yaws because the FLCS gains change over as the wheels spin up on touchdown.
Therefore the recommended technique is to land wings level with the nose offset into the wind, and allow the aircraft to self-steer down the runway, using rudder control after touchdown to maintain centerline. Its not a tailwheel aircraft, its main gear is behind the center of gravity, and it will more or less track correctly down the flight path after touchdown, so only minor correction should be required.
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The Dash-1 does however state that you shouldn’t use any rudder when landing:
The primary warning is not to land “one wing low” with uncoordinated aileron and rudder. That’s not exactly the same as “don’t use any rudder at all for any purpose.” There’s ARI: rudder as a result of aileron but there’s also ARI: aileron as a result of rudder. In theory that means rudder input, regardless of aileron input, results in some ARI aileron movement which gets cut out upon landing.
But it seems that a “one wing low” touchdown has magnitude of transient that justifies a specific warning but rudder for decrabbing (or in an example that seemed successful the opposite, upwind) might have a negligible upset effect. The FLCS changeover behavior has the potential to be upsetting but it isn’t unpredictable. There are techniques which run afoul of the changeover and those that don’t and it cannot be oversimplified to “don’t use the rudder.”
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The primary warning is not to land “one wing low” with uncoordinated aileron and rudder. That’s not exactly the same as “don’t use any rudder at all for any purpose.” There’s ARI: rudder as a result of aileron but there’s also ARI: aileron as a result of rudder. In theory that means rudder input, regardless of aileron input, results in some ARI aileron movement which gets cut out upon landing.
But it seems that a “one wing low” touchdown has magnitude of transient that justifies a specific warning but rudder for decrabbing (or in an example that seemed successful the opposite, upwind) might have a negligible upset effect. The FLCS changeover behavior has the potential to be upsetting but it isn’t unpredictable. There are techniques which run afoul of the changeover and those that don’t and it cannot be oversimplified to “don’t use the rudder.”
Nope
ARI is not a RAIIf you see aileron when you move your rudder this is only because of induced roll
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It is very important to not land with rider input
Indeed when you put some rudder you are obliged to put Somme roll input to compensate induced roll
By doing this you kick ARI and input rudder as well. All is fine à you can find a point of equilibrium
However when wheel spinning , suddenly the ARI is shut down and your equilibrium is lost suddenly which can provoke a very bad brutal input situation
Dont use rudder in landing , PERIOD