Project Opensky B747-400 nose gear collapse

[flipside]

Why is it that the nose gear on Project Opensky's Delta B747-400 collapses when I taxi and apply the brakes at the runway threshold? What can I change in the aircraft.cfg to fix this?

bilben94@gmail.com

[Travis]

First off, flipside, I would steer clear of posting your email address on open message boards, since spambots troll for stuff like that.

Secondly, was this aircraft created specifically for FS9?  Or is this an FSX model that you have gotten to work?  Because I have noticed with some of the FSX models in FS9, the gear act a little weird.

If it isn't that, the fix is actually (I'm betting) fairly simple.

Open the file labeled "aircraft.cfg" in the folder of the 747 using Notepad.  Scroll down until you see the following:

[contact_points]

There will be some information after that.  Copy and paste it into your next reply and I'll see if I can fix your issue.

[microlight]

Hi flipside.

This is a well-known problem with the Posky 747s, and the latest FD Version 9.7, Revision D (FS9/FSX) can be downloaded from their site (downloads/747-400/FDE packages). This reputedly fixes the problem - let us know if it does.

[flipside]

[contact_points]

       //0  Class                        <0=none,1=wheel, 2=scrape, 3=float>
       //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)

point.0 = 1.000,  -30.333,    0.000, -13.833, 5181.102, 0.000, 2.042,  70.000, 0.300, 0.500, 0.880, 11.000, 11.000, 0.000, 240.000, 280.000 // Nose Gear
point.1 = 1.000, -110.583,   -6.350, -15.403, 3574.803, 1.000, 1.917, -13.000, 1.620, 1.150, 0.741, 12.900, 14.900, 2.000, 240.000, 280.000 // Main Center Gear - Left
point.2 = 1.000, -110.583,    6.350, -15.403, 3574.803, 2.000, 1.917, -13.000, 1.620, 1.150, 0.741, 13.100, 15.400, 3.000, 240.000, 280.000 // Main Center Gear - Right
point.3 = 1.000, -102.083,  -18.000, -15.403, 3574.803, 0.000, 1.917, -13.000, 1.620, 1.150, 0.741, 12.900, 14.900, 2.000, 240.000, 280.000 // Main Wing Gear - Left
point.4 = 1.000, -102.083,   18.000, -15.403, 3574.803, 0.000, 1.917, -13.000, 1.620, 1.150, 0.741, 13.100, 15.400, 3.000, 240.000, 280.000 // Main Wing Gear - Right
point.5 = 2.000, -146.000, -102.900,   7.000,  787.402, 0.000, 0.000,   0.000, 0.000, 0.000, 0.000,  0.000,  0.000, 5.000, 0.000, 0.000
point.6 = 2.000, -146.000,  102.900,   7.000,  787.402, 0.000, 0.000,   0.000, 0.000, 0.000, 0.000,  0.000,  0.000, 6.000, 0.000, 0.000
point.7 = 2.000, -189.667,    0.000,  -2.000,  787.402, 0.000, 0.000,   0.000, 0.000, 0.000, 0.000,  0.000,  0.000, 9.000, 0.000, 0.000
point.8 = 2.000,   -9.167,    0.000,  -5.750,  787.402, 0.000, 0.000,   0.000, 0.000, 0.000, 0.000,  0.000,  0.000, 4.000, 0.000, 0.000
point.9 = 2.000, -229.667,    0.000,  55.500,  787.402, 0.000, 0.000,   0.000, 0.000, 0.000, 0.000,  0.000,  0.000, 8.000, 0.000, 0.000
point.10= 2.000, -106.400,  -69.500,  -5.000,  787.402, 0.000, 0.000,   0.000, 0.000, 0.000, 0.000,  0.000,  0.000, 9.000, 0.000, 0.000
point.11= 2.000,  -76.300,  -39.167,  -9.000,  787.402, 0.000, 0.000,   0.000, 0.000, 0.000, 0.000,  0.000,  0.000, 9.000, 0.000, 0.000
point.12= 2.000,  -76.300,   39.167,  -9.000,  787.402, 0.000, 0.000,   0.000, 0.000, 0.000, 0.000,  0.000,  0.000, 9.000, 0.000, 0.000
point.13= 2.000, -106.400,   69.500,  -5.000,  787.402, 0.000, 0.000,   0.000, 0.000, 0.000, 0.000,  0.000,  0.000, 9.000, 0.000, 0.000
point.14= 2.000,    0.000,    0.000,   0.000,  787.402, 0.000, 0.000,   0.000, 0.000, 0.000, 0.000,  0.000,  0.000, 4.000, 0.000, 0.000

static_pitch= 1.000
static_cg_height= 12.500
gear_system_type=0


// Nose gear
//point.0= 1.000, -30.333, -1.500, -13.750, 2181.102, 0.000, 2.000,  70.000, 0.300, 0.500, 0.880, 11.000, 11.000, 0.000, 240.000, 280.000
//point.1= 1.000, -30.333,  1.500, -13.750, 2181.102, 0.000, 2.000,  70.000, 0.300, 0.500, 0.880, 11.000, 11.000, 0.000, 240.000, 280.000
//
// Main Wing Gear (left)
//point.2= 1.000,  -104.583, -18.000, -16.533, 1574.803, 1.000, 2.000, -13.000, 2.602, 2.500, 0.551, 12.900, 14.900, 2.000, 240.000, 280.000
//point.3= 1.000,  -104.583, -14.000, -16.533, 1574.803, 1.000, 2.000, -13.000, 2.602, 2.500, 0.551, 12.900, 14.900, 2.000, 240.000, 280.000
//point.4= 1.000,   -99.583, -18.000, -16.533, 1574.803, 1.000, 2.000, -13.000, 2.602, 2.500, 0.551, 12.900, 14.900, 2.000, 240.000, 280.000
//point.5= 1.000,   -99.583, -14.000, -16.533, 1574.803, 1.000, 2.000, -13.000, 2.602, 2.500, 0.551, 12.900, 14.900, 2.000, 240.000, 280.000
//
// Main Wing Gear (right)
//point.6= 1.000,  -104.583, 18.000, -16.533, 1574.803, 2.000, 2.000, -13.000, 2.602, 2.500, 0.551, 15.100, 16.400, 3.000, 240.000, 280.000
//point.7= 1.000,  -104.583, 14.000, -16.533, 1574.803, 2.000, 2.000, -13.000, 2.602, 2.500, 0.551, 15.100, 16.400, 3.000, 240.000, 280.000
//point.8= 1.000,   -99.583, 18.000, -16.533, 1574.803, 2.000, 2.000, -13.000, 2.602, 2.500, 0.551, 15.100, 16.400, 3.000, 240.000, 280.000
//point.9= 1.000,   -99.583, 14.000, -16.533, 1574.803, 2.000, 2.000, -13.000, 2.602, 2.500, 0.551, 15.100, 16.400, 3.000, 240.000, 280.000
//
// Main Center Gear (left)
//point.10= 1.000, -115.583, -8.000, -16.533, 1574.803, 1.000, 2.000, 0.000, 2.602, 2.500, 0.551, 13.400, 14.900, 2.000, 240.000, 280.000
//point.11= 1.000, -115.583, -4.000, -16.533, 1574.803, 1.000, 2.000, 0.000, 2.602, 2.500, 0.551, 13.400, 14.900, 2.000, 240.000, 280.000
//point.12= 1.000, -109.583, -8.000, -16.533, 1574.803, 1.000, 2.000, 0.000, 2.602, 2.500, 0.551, 13.400, 14.900, 2.000, 240.000, 280.000
//point.13= 1.000, -109.583, -4.000, -16.533, 1574.803, 1.000, 2.000, 0.000, 2.602, 2.500, 0.551, 13.400, 14.900, 2.000, 240.000, 280.000
//
// Main Center Gear (right)
//point.14= 1.000, -115.583,  8.000, -16.533, 1574.803, 2.000, 2.000, 0.000, 2.602, 2.500, 0.551, 11.500, 17.500, 3.000, 240.000, 280.000
//point.15= 1.000, -115.583,  4.000, -16.533, 1574.803, 2.000, 2.000, 0.000, 2.602, 2.500, 0.551, 11.500, 17.500, 3.000, 240.000, 280.000
//point.16= 1.000, -109.583,  8.000, -16.533, 1574.803, 2.000, 2.000, 0.000, 2.602, 2.500, 0.551, 11.500, 17.500, 3.000, 240.000, 280.000
//point.17= 1.000, -109.583,  4.000, -16.533, 1574.803, 2.000, 2.000, 0.000, 2.602, 2.500, 0.551, 11.500, 17.500, 3.000, 240.000, 280.000
//
//Scrape points
//point.18 = 2.000, -146.000, -98.900,  7.000,  787.402, 0.000, 0.000,  0.000, 0.000, 0.000, 0.000,  0.000,  0.000, 5.000, 0.000, 0.000
//point.19 = 2.000, -146.000,  98.900,  7.000,  787.402, 0.000, 0.000,  0.000, 0.000, 0.000, 0.000,  0.000,  0.000, 6.000, 0.000, 0.000
//point.20 = 2.000, -189.667,   0.000,  -2.000,  787.402, 0.000, 0.000,  0.000, 0.000, 0.000, 0.000,  0.000,  0.000, 9.000, 0.000, 0.000
//point.21 = 2.000,   -9.167,   0.000,  -5.750,  787.402, 0.000, 0.000,  0.000, 0.000, 0.000, 0.000,  0.000,  0.000, 4.000, 0.000, 0.000
//point.22 = 2.000, -229.667,   0.000,  55.500,  787.402, 0.000, 0.000,  0.000, 0.000, 0.000, 0.000,  0.000,  0.000, 8.000, 0.000, 0.000
//point.23 = 2.000, -106.400, -69.500,  -5.000,  787.402, 0.000, 0.000,  0.000, 0.000, 0.000, 0.000,  0.000,  0.000, 9.000, 0.000, 0.000
//point.24 = 2.000,  -76.300, -39.167,  -9.000,  787.402, 0.000, 0.000,  0.000, 0.000, 0.000, 0.000,  0.000,  0.000, 9.000, 0.000, 0.000
//point.25 = 2.000,  -76.300,  39.167,  -9.000,  787.402, 0.000, 0.000,  0.000, 0.000, 0.000, 0.000,  0.000,  0.000, 9.000, 0.000, 0.000
//point.26 = 2.000, -106.400,  69.500,  -5.000,  787.402, 0.000, 0.000,  0.000, 0.000, 0.000, 0.000,  0.000,  0.000, 9.000, 0.000, 0.000
//point.27 = 2.000,    0.000,   0.000,   0.000,  787.402, 0.000, 0.000,  0.000, 0.000, 0.000, 0.000,  0.000,  0.000, 4.000, 0.000, 0.000

I hope that you can figure this out.

[Travis]

Wow.  Okay.  All that stuff that has the "//" in front is stuff that is ignored by FS.  So those don't matter.  You'll want to keep that in mind for future reference, since adding stuff to CFG files is pretty much important information for FS.

But I would follow what microlight said and try the fix.  If that doesn't do the job, then come back and I will describe how to fix the issue from what you posted.

[flipside]

I downloaded the FDE from the Project Opensky site and installes the Air and cfg files into the offending aircraft and it didn't work. The nose gear still collapsed on the runway threshold. I am approaching the motivation to dump the aircraft and search out another that works.

[Travis]

Before you do that, take a look at what you posted above:

point.0 = 1.000,  -30.333,    0.000, -13.833, 5181.102, 0.000, 2.042,  70.000, 0.300, 0.500, 0.880, 11.000, 11.000, 0.000, 240.000, 280.000 // Nose Gear

The red number is what tells you that the point is a gear point.  The first one is usually the nose gear, but they also tell you on this one at the end of the entry.

The green number is how hard (in ft per second) you have to hit the gear point for it to fail.  Since this is a function of multiplying the actual weight of the aircraft for the speed at which it is moving, this number may be too low.  Try increasing it to something like 8000.  If that doesn't work, then other factors may come into play.

[flipside]

The nose gear sinks into the ground when I am taxiing in spot view. (I taxi this way to park precisely-my nose wheel on the guide line and stopped at the cross mark) If I am stopped and switch to spot view it looks alright. The nose gear sinks into the ground the instant I start to move.

[Travis]

That means there is more wrong.  It means that the compression ratio is off, which I could only help you fix if I had the aircraft.  Look at the table of numbers preceding the point.* section and you'll see "Static Compression" as well as "Max/Static Compression Ratio".  These numbers must be manipulated to fix this issue.  Unfortunately, it's something you MUST have the aircraft in front of you to accomplish, and I don't.  However, look at the following document, which describes in detail every entry in the aircaft.cfg file.  Look at the entries pertaining to the compression areas, and it should give you some idea of how to fix this.

Others could probably give you more help if you can't seem to get it to work right.  Just let us know.

Never give up!  Never surrender!

[microlight]

flipside,

I have tried to reproduce the sinking nose gear on the V4 Posky 744 and cannot make it happen (this is using the RR variant of the FD). I've tried full fuel down to 30% fuel and all kinds of rapid ground acceleration, violent braking etc etc, and the nose wheel moves on its suspension but doesn't sink. The figures for static compression (same as yours) seem to work OK for me. Can you check some things for me, like the nose gear position, reproduced from my aircraft.cfg below:

point.0 = 1.000,

[flipside]

It seems to be only in Spot view that if you stop and start to move again the nose wheel sinks into the ground.

[MiltonShupe]

Gentlemen,

You are all around the issue but not quite on it.

The issue is the max-static ratio.

[flipside]

Never mind. I dumped the aircraft.

[microlight]

Hi Milton,

Good to see you in your new identity!

Thanks for the information regarding this parameter, the FS9 aircraft container SDK doesn't give much information on what this value should be. I tried the increased value on my Posky 747 V4, and although it didn't make any difference (as the nosewheel didn't collapse originally) it's another area to try when it does happen.

flipside,
worth a try as this is otherwise a great plane.

[MiltonShupe]

Thanks.  I have done several tutorials on suspension setup and although this one is directed at modelers, reading it may help.  There are couple of nice links for reference as well.

http://www.sim-outhouse.com/sohforums/s ... .php?t=944