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Landing run , NWS issues.


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No real complaints and problems, save the landing run and NWS issue I experience about 1/3 of the landing. The landing down to touchdown is OK, with threshhold speed of 150 KIAS, touchdown at 135. Then the problem starts with or without chute pop. For no reason, that I can see, the aircraft just severely turns to port with no rudder input, and if NWS is activated, the gain is so high the aircraft slips in direction of even slight rudder/NWS input. It is crazy to bring it under control. The aircraft tips, slides around and comes to rest.

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Dave,

 

I do not experience anything like this. Please make sure

 

a) that your rudder axis is definitely only assigned to your physical rudder and not to any other controls you use (look up settings)

 

b) apply a slight deadzone to your rudder so that minimal physical inputs don´t bother you and maybe flatten the curve to 60% saturation.

 

c) make sure that the behaviour is not triggered by toe brakes (check settings, maybe delete any toe brake asignement) and use instead keyboard "W" (you may assign that to your stick if you can).

 

d) just to be sure: check if there´s crosswind influence

 

At the very beginning I had some issues with my rudders being not physically centered thus resulting in veering over the runway after engaging NWS. Deadzone and saturation down cured that)

 

Willy

[sIGPIC][/sIGPIC]my rig specs: i7-4790K CPU 4.50GHz, 32GB RAM, 64bit WIN10, NVidia GeForce GTX 980 Ti, SSD+

 

A10C, UH-1H, M2C, F5E, Gazelle, KA 50, F18C, DCS 2.5x OB

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I already did those. Happens alot in instant action/cold start (when recovering).

 

 

I checked instant action/cold start on NTTR. Clean F5E, 100% fuel, weight within limits, trim and approach according to the book (same as you).

 

Result: Even when I touch down gently with around 135 kts it feels like a wobbling landing, aircraft slightly moves to the right, rudder ineffective, chute activation makes it even harder and NWS engagement results in a sudden skid to the opposite direction resulting in a u-turn as described by you. External inspection shows a blown tire right main wheel.

That never happens under conditions descibed above on my multiplayer flights. I get the idea that within instant action something is "broken".

 

Winds are not relevant.

 

Do you get this in MP flghts as well? I have really no issues there whatever loadout I have on board as long as weight stays within limits.

[sIGPIC][/sIGPIC]my rig specs: i7-4790K CPU 4.50GHz, 32GB RAM, 64bit WIN10, NVidia GeForce GTX 980 Ti, SSD+

 

A10C, UH-1H, M2C, F5E, Gazelle, KA 50, F18C, DCS 2.5x OB

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High,

I have the same landing run problem in simple mission (with cold start) I made in Mission Editor.

Fil


Edited by fil72

Mig-21Bis, M-2000C, L-39 Albatros, F-5E Tiger II, Ka-50, Su-33

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Yep. Very recreate-able mishap on my side. Glad (not really), that it is not only me. Chute pop, makes the situation worse. NWS should not be engaged until gnd speed is below 90 knots. But way above that gnd speed, with throttles at idle, and brakes applied, the ship pulls to port(left), with chute it pulls to port even more, rudder is ineffective, activating NWS (with rudder deflection) causes NWS to abruptly skid in direction of rudder, releasing rudder, or doing anything, is irrelevant. The aircraft skids to the side and off the runway. If I can keep AC on runway until gnd speed drops below 80 knots, with NWS, then I can generally slow down where NWS works good. But it is an ugly , dirty landing. Not at all with other types (A-10C, Mig-21bis, F-15C, SU-27, and SU-33D,) that have NWS as a functional system with ON/OFF.

F-5E-3 taxies, flies, takesoff, and lands (up to touchdown). Only once the nosewheel touches runway, do problems begin. My technique is 150 knots at runway threshhold, 135 knots touchdown, aerobrake until F-5E rotates down on its own. Pop chute, apply wheelbrake, regardless of shimmy behavior, wait for gnd speed to fall below 90 (80 is better) knots, engage NWS , and hope of the best. 1/3 of the times , AC goes out of control, and skids like a drifting rice burner. If I end on grass, I am stuck. If AC skids on runway, main gear bursts.

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The solution for me is to map wheel brakes like curved axes (on pedals or slider, or so) and to brake very gently. It looks like when brake button is used (like full brake here) while landing run, the wheels are almost blocked or blocked immediately (you can see black lines on runway after landing) and plane begins to skid. Tiger has no anti-skid system, but I am not sure how much this behaviour is real.

Mig-21Bis, M-2000C, L-39 Albatros, F-5E Tiger II, Ka-50, Su-33

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  • 2 weeks later...

I do have the same issue, over and over again. Make a perfect landing, decelerate and suddenly, the plane veers of to port. In my view this is not a modelled, but a scripted thing. Very bizarre and unnatural. I tried all the rudder and brake setting adjustments mentioned, but to no avail.

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NWS steering gain should be regulated by gnd speed, when there weight on wheels. So small gain at high speed, and becoming higher as landing run speed decreases. Right now NWS needs rudder to be at zero when activating NWS. So if rudder is still required to keep AC straight down the runway, then NWS grabs initially whatever rudder deflection is when NWS is activated, and AC pivots hard in rudder twist direction. So quick actions need to be taken with crosswind landing.

-Touchdown without NWS

-Pop chute, NWS still OFF, use rudder to keep AC straight until gnd speed is below 80 knots, aerobraking is finished with main and front gear on runway.

-Quickly release rudder (zero), activate NWS. NWS will activate with fnt gear straight.

-Use rudder/NWS lightly (no easy feat) to keep AC straight. Release drag chute.

-Hopefull by this time , gnd speed is low enough for breaks to be effective, and NWS responsive.

 

Must practice this. I still do. It is very sensitive.

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I avoid the chute all together in crosswind conditions. It just gives you problems.

Just make sure your AoA is right and you never have to use the chute in the first place.

Just use rudders until it's not effective anymore, then use the NWS.

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Win10 64, Asus Maximus VIII Formula, i5 6600K, Geforce 980 GTX Ti, 32 GB Ram, Samsung EVO SSD.

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I avoid the chute all together in crosswind conditions. It just gives you problems.

Just make sure your AoA is right and you never have to use the chute in the first place.

Just use rudders until it's not effective anymore, then use the NWS.

+1. With one difference though. F-5 NWS is so sensitive that I generally use it only during taxi and apply differencial braking in low speeds when the rudder is not yet effective during takoff/landing.

F/A-18, F-16, F-14, M-2000C, A-10C, AV-8B, AJS-37 Viggen, F-5E-3, F-86F, MiG-21bis, MiG-15bis, L-39 Albatros, C-101 Aviojet, P-51D, Spitfire LF Mk. IX, Bf 109 4-K, UH-1H, Mi-8, Ka-50, NTTR, Normandy, Persian Gulf... and not enough time to fully enjoy it all

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Yes there is no problem to land the F-5E, even if you do not use brakes or chutes it doesn't need the whole runway. I keep having issues with the NWS though, even while simply taxiiing. It seems like Ican only do one turn, then it becomes unsteerable.

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  • 2 months later...

If it makes you feel any better I started flying irl tail draggers when I was 15 and have over a 300 in a Cub alone. Yet still 1/3 of every landing in this plane I end up sliding sideways. How many military jets you seen ground loop?

I know the t-38's landing characteristics well, which is similar as Charles Bolden when he was a active astronaut flew in all the time and I would guess 1 outta 5 landings ruined or blew a tire so thats accurate. His mother/family live here. Other Nasa pilots would also blow tires fairly routinely. Mechs would drive all the way from Alabama iirc to change it here in SC. Gov $$ at work.

I have not sat down and really tweaked the settings other than tinker with deadzone but something is not right thats for sure.


Edited by JIMJAM
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What rudder settings are you using because with "my" setup it is not right nor realistic. Don't doubt the programming from what you guys say which leaves my "I assume" default settings.

I am using the Saitek pro pedals, realistic FM. The only thing I fooled with was deadzone which has no effect. Not afraid to admit even after flying since Microprose F-19 and all the IL series, the CURVES and related settings are very confusing and I usually make things worse.

I am not over controlling or to hard on the pedals "IRL" but they are with out a doubt way, way to sensitive. I basically have to "poke" them.

There is no feeling of a gradually increasing brake authority but on/off.

As is, it is better simply to use R-L braking for steering and a mapped brake on/off once the aircraft is straight and under say 40.

Any advice welcomed....


Edited by JIMJAM
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I find the nose wheel steering on most DCS modules unrealistically sensitive although I have flown one real world type that is as sensitive.

 

I use Slaw Device pedals and the wide stance and strong spring of the Slaw Device makes it much easier to control NWS precisely.

 

Often I leave NWS off and taxi with differential braking.

 

If I concentrate taxying with NWS in the F5E is not too difficult but the absence of side forces makes it a visual only exercise and much more difficult.

 

For what it is worth, I used to teach in $15,000,000 full motion simulators and the ground handling was always sub par no matter the effort put into trying to correct it.

 

And DCS suffers the same general ground handling errors as those high dollar devices.

 

Breakaway power too high to get rolling, over sensitive steering, brake effectiveness low and the general lack of physical feedback resulting in overcontrolling.

475th Fighter Group Discord https://discord.gg/xkKsApD

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Thanks for the reply.

I have some time in most all the small tail draggers and some h perf like the Glassair and Lancair which all will swap ends pretty dam quick if you get heavy footed. No problems with the DCS notorious German birds or P-51.

I was fortunate to work for the South Carolina Aeronautics Commission and bumming rides was fairly easy :thumbup: As I said above, Bolden flew in KCAE all the time as did other Nasa pilots in T-38s and they blew tires all the time yet I never saw any erratic swaying. One thing I am aware of and people don't realize is just how fast they are moving on the taxiway.

Agreed about simulating ground/wheel contact and lateral side forces. P3D was the worst at any ground handling ops.

I not only enjoy difficult and moody aircraft but seek them out. Just in the last week I made the leap into VR and it truly is a game changer. Both heli ops and flying the props are much more seat of the pants as you have a dramatic increase in your situational awareness and depth perception is easier to judge.

Still looking for some pedal settings to calm down the nws.

I am open to higher quality pedals but the ones I hear about are always unavailable on Amazon. Source???


Edited by JIMJAM
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You and me both brother. Hope NWS is fixed so it feels normal. Like in A-10C, and F-15C. Smooth and accurate.

I may have posted it before. I beleive there are more then one issue at play.

1. NWS steering gain is excessively high. Or how the friction moment is calculated.

2. Lack of anti-skid(anti-lock) breaks on all three gear wheels.

3. Mass-gravity moment is too low, making the plane react as a much lighter aircraft. So that the weight on wheel is low, causing low friction. May be related with 1. above.

 

One must apply wheel breaks carefully to avoid break lock .. I think the gear break locks up at 50% of wheel breaks applied.

Do not land with NWS engaged. Get the aircraft below 70 knots before turning the NWS ON. When turning NWS on, have no rudder deflection.

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  • 2 weeks later...

Thats just it....

I have lost count of how many times I do not have enough rudder authority to keep the plane straight. It's not right. You should not need a 10 thousand foot runway to stop it. ANY braking send it off towards the grass and then it goes into a classic ground loop skid that is so consistent that it might as well be a programmed event. Once it begins I simply just let go and let it come around and get it over with.

 

I have flown many planes with nasty habits such as the F-104 Starfighter which if you do or don't do something the only thing you can do is eject. You learn them and don't do it. This flight model on MY setup and it appears a lot of us is not something you learn "not to do" and "how it is" but a issue inherent to the nws and the way it is modelled. I don't accept that you touch down, hit the chute and just wait patiently as the the slows down to taxi speed before you can turn it. Rudder alone is NOT enough for us.


Edited by JIMJAM
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I watch the "Grim Reapers" on YT who fly DCS aircraft and go for realism and planning out difficult missions. They fly all the aircraft and some no doubt have hundreds if not thousand of hours.

On their latest air to ground large mission that involved F-5s I watched some land all yup, all over the place. Some at less than 50, chute out and right about when you would start braking being fish tailing with the back end wanting to swap ends.

Not going to post any more on it unless I come up with setting that work or some method that works every time. Not particularly use to leaving staying on the runway to chance.

 

BTW- I will dble check but iirc when I set the brakes and press them I can see the bar move back and forth. It does not appear to snap on and off. Have not flown in a week but will soon and see what is going on. Thanks for the reply and info. Jim


Edited by JIMJAM
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On their latest air to ground large mission that involved F-5s I watched some land all yup, all over the place. Some at less than 50, chute out and right about when you would start braking being fish tailing with the back end wanting to swap ends.

 

This is odd, having hundreds or thousands of flight hours and still not being able to land the plane … I'm far from having hundreds of flight hours on DCS but I can't remember when was the last time I lost control of the F-5.

 

While I agree that there is a centering problem, once you know that, it's hard to not compensate and learn how to do it properly. You just have to adapt until Belsimtek corrects the problem (if it is even planned).

There are only two types of aircraft, fighters and targets. - Major Doyle "Wahoo" Nicholson, USMC

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I am working through the same issue. You have to watch wheel break pressure. Gear locks up fairly low on the applied brake pressure. Mine lockup at about 20% of the slider. Though some disagree, I think this is bad on BST part. Hopefully they will fix it.

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... I do not have enough rudder authority to keep the plane straight.

 

... ANY braking send it off towards the grass ...

 

... on MY setup and it appears a lot of us ...

 

... I don't accept that you touch down, hit the chute and just wait patiently as the the slows down to taxi speed before you can turn it.

 

Rudder alone is NOT enough for us.

 

 

 

What kind of runway condition and crosswind are we talking here? I hardly ever run out of rudder authority.

My technique for braking is heavy braking once nose wheel on ground, release gradually as speed drops, eventually completely releasing if starting to encounter directional control issues (locking wheels)

Might be worth to investigate different setup possibilities? My opinion is that there is great variance in hardware performance, and the feel of operating a set of computer controllers may lead us to use them in ways we would not in a real airplane.

 

My remark on using nose wheel steering at taxi speeds only came from a conversation with a pilot that flew the F-5 for 8 years in an adversary squadron. In his words, F-5 nose wheel steering is very sensitive and should be used at taxi speeds only. Never in the TO or LDG run. He also remarked that the NWS should center and allow for forward movement when the button is released while turning. When I described the way it works on DCS he mentioned that would be a NWS failure. But this specific topic was presented and acknowledged already.

 

I do hope everyone can sort out all the issues, but I do remark that the landing roll controllability is credible enough on my system.

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