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Major F-15 Take-off Issue


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I'm a bit surprised, I was always under the impression that aircraft tyres aren't designed to experience significant side force in the same way as e.g. high speed car tyres, but but fair enough. I guess tyres are comparatively cheap compared to other components.

 

Does the manual mention anything about maximum safe cross wind speed, maximum off-runway-axis wind angle etc? I tried searching for the -1 but could only find one that's behind a paywall.

 

Yes, landing is not recommended if the 90° Crosswind component exceeds 30 knots. If the Crosswind component exceeds 25 knots, do not exceed 10° pitch. Hold the crab through touchdown and use rudder to maintain runway track, use the aileron into the wind to maintain wings level attitude. If directional control becomes difficult lower the nose and brake in a three point attitude.

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Yes, landing is not recommended if the 90° Crosswind component exceeds 30 knots. If the Crosswind component exceeds 25 knots, do not exceed 10° pitch. Hold the crab through touchdown and use rudder to maintain runway track, use the aileron into the wind to maintain wings level attitude. If directional control becomes difficult lower the nose and brake in a three point attitude.

 

Thanks for the info :thumbup:

 

30 Kts crosswind would make for an... exciting... landing!

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Personal wish list: DCS: Su-27SM & DCS: Avro Vulcan.

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I'm not really following your logic at all. Let's assume the nose wheel is fixed and aligned with the runway. There is a crosswind perpendicular to the runway heading. The fuselage will block airflow to the downwind wing thus producing less lift than the windward wing. This would result in a rolling moment in the direction of the downwind. The fuselage will also generate a side force in the direction of the wind. I assume the same would be true to the downwind vertical stab/rudder and stabilator. The effect on the vertical stab would create a rolling moment as well. So you apply crosswind controls....use the rudder to stay on centerline and use aileron in to the crosswind to keep the wing from dropping. The F-15 has a strong dihedral though and it will really get away from you in DCS if there is a realistically heavy crosswind.

 

None of this explains why a 20 knot taxi speed results in the jet being pushed off the centerline like it's made of styrofoam. The pilot should have to make minor corrections during the takeoff roll but it seems logical that CAS should be compensating to maintain commanded heading and roll.

 

Possibly a tweak in this file may help correct the issue.

C:\Program Files\Eagle Dynamics\DCS World\Mods\aircraft\Flaming Cliffs\FM\F15/config.lua

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After some trial and error, in a cross-wind I found the most controllable way to take-off is to get to 40-50kts as quickly as possible so you gain stable rudder steering as a greater influence over nose wheel steering. With nose wheel/rudder steering both engaged, brakes on, full burner, release brakes and keep it as straight as you can till 40-50kts using the most subtle nose wheel steering inputs. Once you hit 40kts you quickly start to gain full rudder steering control.

Because of the unpredictable controllability switching from wheel/rudder steering to only rudder steering at higher speeds I choose not to do it any more, I leave it with wheel/rudder steering only.

 

I still don't feel this flight modelling is accurate to RL and look forward to it getting addressed.


Edited by fitness88
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  • 4 months later...

Disengage nose wheel steering

 

By default you have to hold Ralt + Q to disengage nose wheel steering at 50 knots or you start veering around the run way. But you can't just press them once you have to hold em till your off the run way. you can find it under options F-15c nose wheel steering. as well as the "S" key which allows you to make way tighter turns using the nose wheel steering while taxing to or from run way.

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There is no need to disengage NWS and in fact it is flat out not part of T/O or Landing procedure for the F-15. You can see T/O and landing technique here, and there are some more techniques presented on that channel also:

 

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strange rudder

 

Take a look at the F15C from the tail, sitting on the RW at idle power. Move the J/S left and right (no fwd or aft pressure) and watch the rudders. Now move the stick forward and aft. I see them rudders in a very strange ways hard over left and right???

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  • 5 months later...
By default you have to hold Ralt + Q to disengage nose wheel steering at 50 knots or you start veering around the run way. But you can't just press them once you have to hold em till your off the run way. you can find it under options F-15c nose wheel steering. as well as the "S" key which allows you to make way tighter turns using the nose wheel steering while taxing to or from run way.

 

Just gave a go to the F-15 after a long time and I cant control it when taking off or when braking after landing! Tryed this but without any results. :huh:

 

Flying on 2.0 Nevada btw.

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Don't disable NWS or enable NWS maneuvering range. Just line up, roll, and try to be very gentle with the rudder.

 

If you have to, you can use left/right stick to add slight rudder...Doing that at high speeds will roll the jet, but below 100kts you get very slight yaw movement opposite of stick direction.

Lord of Salt

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T/O with NWS engaged till 50 kts then I press the NWS disable button on my throttle and I have perfect control till I rotate. You can do what Sweep mentioned only if there is no cross wind but if you go off center just a bit recovery with NWS engaged will be very scary and with a cross wind you will go off centre for sure!

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  • 3 weeks later...

I may as well weigh in here. My F15 pulls to the right while taxiing. NO crosswind and feet off of the rudder pedals. Axis centered at the neutral position . It does this in 1.5 and 2.0. Prior to the latest updates I have had no issue with the airplane doing this. This also translates into very erratic take off directional control issues. i have never had a reason to turn the nose wheel steering off in the past. Usually directional control on the ground has been very acceptable during taxi and takeoff.

There have been past problems with the F15 after updates in the recent past. I think they "fixed" it again.

It is always best to not fly too fast or fly too slow. So I fly half fast. :D

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Some more discoveries. I suspect that my right toe brake pedal on my Saiteks may have been introducing the pull to the right. After a complete failure of my right toe brake, the F-15 taxis straight and true. The take off is also normal. I am using the W key for brakes.

Unscientific but there it is for what it is worth.

It is always best to not fly too fast or fly too slow. So I fly half fast. :D

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Some more discoveries. I suspect that my right toe brake pedal on my Saiteks may have been introducing the pull to the right. After a complete failure of my right toe brake, the F-15 taxis straight and true. The take off is also normal. I am using the W key for brakes.

Unscientific but there it is for what it is worth.

 

 

 

I can't remember the key press but there is a way to see your brake pedal's range of motion as it goes through its axis range.

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  • 4 weeks later...

I have had the same problem. In control settings I found Nose wheel steering range and on/off control. S is for range but ALT+Q will turn it off. So I assigned a toggle switch on my Warthog's Throttle. I now flip the switch up and no movement within the wheel! But before I do this I look back of the aircraft and make sure the rudders are lined up completely via rudder pedals. Then I flip the switch up forward and take off with no problems. With the switch in the middle I have some steering movement and with the switch flipped all the way down I have even more steering range. No need to hold down anything. On rough take off's though you can shred your front tire up if you get too squirrel'y

 

:thumbup:

 

 

DSF:joystick:


Edited by DragonFlySlayer
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Try This

 

I had the same problem for some time.

Couldn't figure it out, almost gave up on the game.

Then some kind soul gave me the solution.

You need to set the fix in the control setup.

 

Go to Control in main menu

This is my settings.

 

Rudder control:

Deadzone = 0

Saturation X = 100

Saturation Y = 100

Curvature = 25

 

This works for me, maybe not the best for you.

But start here and fine tune for your self.

 

The problem is that the sim does not automatically set your joystick or rudder.:)

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  • 2 weeks later...

Problems Staying On Runway During Takeoff

 

I would add that I cannot get the plane into the air on takeoff. It veers from side to side, no matter how carefully I try to use the rudder pedals to steer, no matter whether NWS is on or off. I did not have this problem with earlier versions. I've had this product since the initial release. This is on the single player mode, not the network mode. I'm not sure why something this simple should be so hard. Taxi's fine to runway, with NWS steering engaged, using rudder pedals. Saitek pro rudder pedals, Thrustmaster Warthog HOTAS.

 

John


Edited by dcdefend
typos
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Sounds like there is more than one controller bound to the rudder.

DCS auto maps controls for every controller you have plugged in so go and clear the ones you dont use or unplug them from your PC.

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Takeoff Issues

 

This is a machine used only for this game. The only controllers are the Thrustmaster Warthog stick and throttle and the Saitek Pro Rudder Pedals and a wireless keyboard. I will plug a wired keyboard in to see if that makes any difference.

 

I see no place in the game setup/settings which relates to the rudder pedals. The only place to calibrate the rudder pedals seems to be the Windows controller window which I access through the Thrustmaster GUI program.

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This is a machine used only for this game. The only controllers are the Thrustmaster Warthog stick and throttle and the Saitek Pro Rudder Pedals and a wireless keyboard. I will plug a wired keyboard in to see if that makes any difference.

 

I see no place in the game setup/settings which relates to the rudder pedals. The only place to calibrate the rudder pedals seems to be the Windows controller window which I access through the Thrustmaster GUI program.

 

 

Go into the game. Top left, open "options"

At the bottom hit "Axis Assign" there you can enter the axis for the rudder, it will show as RZ.

Then under "Axis Tune" you can enter the curvature which is almost surely the problem.

Check it out. Fixed all my problems. :thumbup:

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Go into the game. Top left, open "options"

At the bottom hit "Axis Assign" there you can enter the axis for the rudder, it will show as RZ.

Then under "Axis Tune" you can enter the curvature which is almost surely the problem.

Check it out. Fixed all my problems. :thumbup:

 

Also what Svend_Dellepude was trying to say about multiple controllers being assigned, to troubleshoot use this path:

 

Launch DCS > Options (top left spoke icon) > Controls > F-15

 

Then use the drop-down to find Axis Controls (one of the first few options), then find the control called "Rudder". The menu should look something like below:

 

[TABLE] HOTAS Throttle HOTAS Stick Saitek Rudder Pedals Keyboard TrackIR Mouse

Rudder RZ

[/TABLE]

 

What we think may be the issue will look like this:

 

[TABLE] HOTAS Throttle HOTAS Stick Saitek Rudder Pedals Keyboard TrackIR Mouse

Rudder RZ RZ RZ RZ

[/TABLE]

 

You need to clear out the "RZ" out of all the controllers except the Saitek Rudder column. This typically happens every time I try to set up controllers for the first time.

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JINX_1391,

You are correct. sometimes and I have no idea why the sample will be repeated under several

headings. It can/should be under the only one you are trying to map.

This is not rocket science by any means, it only takes a little time and practice to figure out what DCS wants from you.

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