Author Topic: Accelleration F-18 Brakes  (Read 29588 times)

WilliamCall

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Re: Accelleration F-18 Brakes
« Reply #15 on: February 03, 2008, 12:31:09 am »
I don't seem to have this problem.  I use my keyboard to apply the brakes, and I stand on the brakes once I'm in a three point attitude.  I find it hard to believe that it has anything to do with the joystick or throttle.  I have the Cougar HOTAS joystick and throttle, both modified with the Hall's sensors.  I have made several changes to the aircraft.cfg file.  Listed below are the changes that I have made in the landing gear contacts section:

[contact_points]


        //0  Class
        //1  Longitudinal Position        (feet)
        //2  Lateral Position             (feet)
        //3  Vertical Position            (feet)
        //4  Impact Damage Threshold      (Feet Per Minute)
        //5  Brake Map                    (0=None, 1=Left, 2=Right)
        //6  Wheel Radius                 (feet)
        //7  Steer Angle                  (degrees)
        //8  Static Compression           (feet)  (0 if rigid)
        //9  Max/Static Compression Ratio
        //10 Damping Ratio                (0=Undamped, 1=Critically Damped)
        //11 Extension Time               (seconds)
        //12 Retraction Time              (seconds)
        //13 Sound Type
        //14 Airspeed limit for retraction     (KIAS)
        //15 Airspeed that gear gets damage at (KIAS)


;Gear     0           1          2         3            4        5        6         7        8        9       10      11       12     13    14       15
point.0 =1.000, -18.000,   0.000, -6.600, 1600.000, 0.000, 0.916, 75.000, 0.100, 3.500, 0.950, 3.000, 3.000, 0, 250.000, 300.000
point.1 =1.000, -35.500,  -5.100, -7.300, 1600.000, 1.000, 1.250,  0.000, 0.867, 1.700, 0.900, 3.500, 3.500, 2, 250.000, 300.000
point.2 =1.000, -35.500,   5.100, -7.300, 1600.000, 2.000, 1.250,  0.000, 0.867, 1.700, 0.900, 4.000, 4.000, 3, 250.000, 300.000



I've made modest changes to the gear geometry and stroking characteristics.  I find it hard to believe that these changes are the cure.   
Maybe someone who is having these problems will try my changes and report back.  Remember to make a backup of your aircraft.cfg file first.

diga

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Re: Accelleration F-18 Brakes
« Reply #16 on: February 03, 2008, 08:09:57 am »
Today I bought the Trustmaster Couger joystick because my MS Sidewinder broken down. I made a flight plan KLAX to KSFO. Left from KLAX 25R and set GPS to Land 28R at KSFO, on the way at ZURET came down to 8000ft and then MOVER came down to 4500ft. The spped was 350knts and set the ILS Freq. 111.70 Rynway 28R at KSFO. Then at SAPID pressed Activate Vectors to Final in the GPS. Then slowly reduce the speed to 180knts and when I land it was 120knts. There was no side slips at all and F-18 went to the other end of the rumway without any slipping to a side.  This was my fight landing using the F-18.
I think if we can reduce the speed to low then the landing is smooth.
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fael097

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Re: Accelleration F-18 Brakes
« Reply #17 on: February 04, 2008, 05:49:26 pm »
I don't seem to have this problem.  I use my keyboard to apply the brakes, and I stand on the brakes once I'm in a three point attitude.  I find it hard to believe that it has anything to do with the joystick or throttle.  I have the Cougar HOTAS joystick and throttle, both modified with the Hall's sensors.  I have made several changes to the aircraft.cfg file.  Listed below are the changes that I have made in the landing gear contacts section:

[contact_points]


        //0  Class
        //1  Longitudinal Position        (feet)
        //2  Lateral Position             (feet)
        //3  Vertical Position            (feet)
        //4  Impact Damage Threshold      (Feet Per Minute)
        //5  Brake Map                    (0=None, 1=Left, 2=Right)
        //6  Wheel Radius                 (feet)
        //7  Steer Angle                  (degrees)
        //8  Static Compression           (feet)  (0 if rigid)
        //9  Max/Static Compression Ratio
        //10 Damping Ratio                (0=Undamped, 1=Critically Damped)
        //11 Extension Time               (seconds)
        //12 Retraction Time              (seconds)
        //13 Sound Type
        //14 Airspeed limit for retraction     (KIAS)
        //15 Airspeed that gear gets damage at (KIAS)


;Gear     0           1          2         3            4        5        6         7        8        9       10      11       12     13    14       15
point.0 =1.000, -18.000,   0.000, -6.600, 1600.000, 0.000, 0.916, 75.000, 0.100, 3.500, 0.950, 3.000, 3.000, 0, 250.000, 300.000
point.1 =1.000, -35.500,  -5.100, -7.300, 1600.000, 1.000, 1.250,  0.000, 0.867, 1.700, 0.900, 3.500, 3.500, 2, 250.000, 300.000
point.2 =1.000, -35.500,   5.100, -7.300, 1600.000, 2.000, 1.250,  0.000, 0.867, 1.700, 0.900, 4.000, 4.000, 3, 250.000, 300.000



I've made modest changes to the gear geometry and stroking characteristics.  I find it hard to believe that these changes are the cure.   
Maybe someone who is having these problems will try my changes and report back.  Remember to make a backup of your aircraft.cfg file first.

nice try but it didnt work

BlakTiger47

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Re: Accelleration F-18 Brakes
« Reply #18 on: February 04, 2008, 10:11:39 pm »
Diga
I dont know how u did it right without slippin on ur first try. My first try i turned sideways and then spun out down 50 feet of the runway. I stopped with my nose in the air and my tail in the dirt. Had to lite full AB to get back level. I was flyin the approach about 130 and touched down at about 100 so speed wasnt the problem.
WilliamCall
Havent tried ur fix yet but i plan to.
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SUBS17

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Re: Accelleration F-18 Brakes
« Reply #19 on: February 04, 2008, 11:53:20 pm »
Try not touching the brakes at all see what that does.

fael097

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Re: Accelleration F-18 Brakes
« Reply #20 on: February 05, 2008, 01:25:44 am »
Try not touching the brakes at all see what that does.

lol i'll need a 10miles runway  :P

tutmeister

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Re: Accelleration F-18 Brakes
« Reply #21 on: February 05, 2008, 03:33:16 pm »
I have experienced this on the carrier landings and also if I use rudder on a landing. Maybe it has something to do with realism settings? I have mine full-right, bar the landing toleration, which is set to 60% as I am a helo pilot by day and like to practice auto rotation and other funky stuff in FSX.

I land at 125KIAS, I shouldn't need to tell anyone to land INTO wind. If you fly a crosswind landing, dip the wing and don't use rudder. Keep the nose up as long as it allows you and even fight to keep it up. Use air brake either throughout the approach and touchdown (I do) or use it like auto-spoilers so you extend it on touchdown. Brake only when the nose wheel forces itself down.

fael097

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Re: Accelleration F-18 Brakes
« Reply #22 on: February 05, 2008, 04:28:15 pm »
Maybe it has something to do with realism settings?
no.

BlakTiger47

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Re: Accelleration F-18 Brakes
« Reply #23 on: February 06, 2008, 01:54:20 am »
Hey Fael
Forgot to ask: Are you using the XLoad F/A-18D or the Acceleration F/A-18A? Not sure but this might have something to do with it.
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fael097

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Re: Accelleration F-18 Brakes
« Reply #24 on: February 06, 2008, 02:39:44 am »
Hey Fael
Forgot to ask: Are you using the XLoad F/A-18D or the Acceleration F/A-18A? Not sure but this might have something to do with it.

its the f-18a on the vid
i use both, and they're just the same

Great Ozzie

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Re: Accelleration F-18 Brakes
« Reply #25 on: February 06, 2008, 09:19:24 am »
Hey Guys... I'll post a couple paragraphs I posted over at AVSIM tonite... and my recommendations echo what others have said here:

"Several are having a tough time...  maybe there is something with the flight model... I mean the mains are fairly close together and maybe with the combination of the CG location and possibly having a lateral moment like one brake is slightly more effective than the other (don't ask me how and I certainly don't subscribe to that theory) or more likely...

"Wheelbarrowing" from: High Landing Speed, Too much brake and/or the stick not being full aft (or even forward to "keep" the aircraft on the runway!) which sets up a "tricycle gear ground loop".  The F/A-18 does use a stabilator, which, IRL makes an aircraft equipped with such typically more prone to wheelbarrowing (due to increased control effectiveness).

Pitch to keep an "Onspeed" indication in the AOA Indexer and Power to stay on glideslope (VASI, PAPI, LAR {Looks About Right} or whatever) and full flaps to reduce landing speed.  Remember, Groundspeed X 6 = fpm descent rate for a nice, gentle ~3 degree descent.

Mains touch... Deploy the Speedbrake and stick full aft to keep the nose wheel off as long as possible.  Light, judicious use of the brakes (don't stand on them), keep the stick aft... and you should be "OK".

Landing accidents are a big problem "in the world": probably due to excessive landing speed and improper use of flaps.  I think it's just the Hornet in FSX is a little more sensitive to technique, not that there is an inherent problem in the model."

Whoever made the video... I don't think that it's valid to compare the braking of a 737 with that of the F/A-18.  I mean... I see your point, but like I said, I think this is more of an issue of the FSX Hornet being more sensitive to technique and its ability to Wheelbarrow.

Aircraft Brakes!   :o  Wow you guys!!  Thanks to my first instructor's philosophy ("Aircraft brakes?! We don't need no stinkin' aircraft brakes!") it was more or less just something that needed to be checked on preflight... I was rarely permitted to use them.  Make sure to keep the stick aft during decel... and for pete's sake... stay off the brakes unless you "really" need them.   :)

Rob O.


SUBS17

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Re: Accelleration F-18 Brakes
« Reply #26 on: February 06, 2008, 04:34:12 pm »
Try not touching the brakes at all see what that does.

lol i'll need a 10miles runway  :P

You'll be surprised how much speed you can bleed just by aerobraking and using the airbrakes.

BlakTiger47

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Re: Accelleration F-18 Brakes
« Reply #27 on: February 06, 2008, 10:22:58 pm »
While I agree, SUBS, that aerobraking and poppin the speedbrakes (airbrakes, spoilers whatever u wanna call it) will slow u down alot. it wont bring u to a dead stop unles like Fael said u have about a pretty dang long runway. You gotta brake eventually and unless u have room to roll out until ur speed's down to about say twenty five knots ur gunna spin when u start hittin the brakes.
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fael097

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Re: Accelleration F-18 Brakes
« Reply #28 on: February 06, 2008, 10:46:33 pm »
subs.
i can land perfectly if i want, i can keep the centerline if i touch the ground @ ~130-140kts and wait until 80kts to brake.
all im trying to say is that it shouldnt slide like that, just because im braking at a little higher speed (100kts isnt too far from 80, but it is enough to "kill me" in game), i dont know what happens IRL but it cant be like that, and w/e it is, it should only happen if the realims settings are set to very realistic, or nothing should happen at all, i dont think they purposely added this sliding, since nothing happens when you do the same thing with any other plane.

sounds like a bug to me.

Great Ozzie

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Re: Accelleration F-18 Brakes
« Reply #29 on: February 06, 2008, 10:54:30 pm »
I posted a video response to your test Fael (
)... I am convinced it is due to wheelbarrowing and an induced lateral moment (from the pilot).  You can see in your video the increased force on the nosewheel from heavy braking.  Also can be seen in mine (as is 100% brakes from 155+ to 0kts) esp. when I input full forward stick (to *increase* down force on the nosewheel to increase the wheelbarrow in hopes of inducing a Ground loop).  If I input side-stick, yes I can initiate the slide, but then... that is my fault as I am using (even more) improper technique.  :o

Just because the aircraft will Ground Loop doesn't mean there is a problem with the model... the fault usually lies (as IRL groundloops) with us as buggy pilots.  ;)

Rob O.