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my Posky 747-400's won't ground steer (Read 78 times)
Mar 4th, 2008 at 10:37am

Allen_Z   Ex Member

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100's and 200's do ok, kinda sluggish

the 400's won't turn even @ 4-7 knots I used to be able to turn 'em at 15-20kts or so at GROSS

I have reduced weight to less that half of gross and it doesn't help

these are all Posky 747's

the default turns fine, as do my DC-10's, MD-11's, 777's etc

has this happened to anyone else?
« Last Edit: Mar 4th, 2008 at 12:13pm by N/A »  
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Reply #1 - Mar 4th, 2008 at 11:52am

Sean_TK   Offline
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Downloading the plane now and will look into the problem shortly....

EDIT: Haven't taken it over 10 knots yet but turning performance seems a little too sluggish compared to what I have seen in real life. I'm going to look into the contact points section, there should be a section that can adjust the maximum angle that the nosewheel can turn.

EDIT Again: Hopefully someone can help here, but I'm sure that there is a certain value here that you can increase to increase the "steering angle", I just don't know which one:

[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,  67.333,   0.000, -13.850, 2181.102, 0.000, 5.812, 78.480, 0.859, 0.500, 0.518, 11.000, 11.000, 0.000, 0.000, 0.000
point.1 = 1.000, -12.583, -18.000, -13.833, 2574.803, 1.000, 5.812,  0.000, 0.602, 0.500, 0.551, 14.900, 14.900, 2.000, 0.000, 0.000
point.2 = 1.000, -12.583,  18.000, -13.833, 2574.803, 2.000, 5.812,  0.000, 0.602, 0.500, 0.551, 17.100, 17.100, 3.000, 0.000, 0.000
point.3 = 2.000, -49.000, -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.4 = 2.000, -49.000,  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.5 = 2.000, -92.667,   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.6 = 2.000,  88.167,   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.7 = 2.000,-132.667,   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.8 = 2.000, -14.917, -69.500,  -7.000,  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.9 = 2.000,  14.917, -39.167, -11.000,  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.10= 2.000,  14.917,  39.167, -11.000,  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, -14.917,  69.500,  -7.000,  787.402, 0.000, 0.000,  0.000, 0.000, 0.000, 0.000,  0.000,  0.000, 9.000, 0.000, 0.000
static_pitch= -1.000
static_cg_height= 13.125

// Nose gear
//point.0= 1.000, 67.333, -1.500, -15.333, 1181.102, 0.000, 2.000, 70.000, 1.859, 2.500, 0.518, 9.000, 11.000, 0.000, 240.000, 280.000
//point.1= 1.000, 67.333,  1.500, -15.333, 1181.102, 0.000, 2.000, 70.000, 1.859, 2.500, 0.518, 9.000, 11.000, 0.000, 240.000, 280.000
 

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Reply #2 - Mar 4th, 2008 at 11:58am

Groundbound1   Offline
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Auto pilot (wing leveler) on?
 

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Reply #3 - Mar 4th, 2008 at 12:02pm

Sean_TK   Offline
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He looks to be talking about ground steering, seeing as 747s cant fly between 4-20 knots... Wink

Still researching.....I think adjusting something in that contact points post will solve it, but seeing as how my plane at least turns a little bit, you don't have autorudder on in the realism settings do you? If so, turn it off and see how the plane handles.
 

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Reply #4 - Mar 4th, 2008 at 12:08pm

Allen_Z   Ex Member

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Quote:
747s cant fly between 4-20 knots...
 Grin

Thanks Sean

What is curious is that they were oK, then not, and ALL the 400's (RR, GE, PW) are that way???

Doesn't make sense but they turn EXACTLY the way Tu-154 manual describes using the 10 degree nose steering rather than switching to the 63 degree mode to taxi

weird huh?

Edit...autorudder is off
 
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Reply #5 - Mar 4th, 2008 at 12:13pm

Sean_TK   Offline
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I've been taxiing this 747 for a little bit longer now, and one thing that caught me is the fact that this bird slides around quite a bit on the ground. I have it in spot view, and have noticed that the plane is acting as if it is on ice or something, very, very strange.....

I'll mess with it a bit more, but the "grip" of the tires now seems to be the main problem.....no idea how to fix that though!

Getting ready for a short Tu-154 flight before my college classes this evening!

EDIT: Ok, been taxiing a bit more and now I am back to my nosewheel angle hypothesis. I can handle the plane somewhat ok now, but your right, it is acting like the 10 degree steering mode on the Tupolev.....

EDIT once more: Ok, I know I've been giving constant updates, but as I experiment more, it seems to be a little bit of both problems. A low nosewheel angle, and the fact that the plane for whatever reason slides   around quite a bit......
 

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Reply #6 - Mar 4th, 2008 at 12:18pm

Allen_Z   Ex Member

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Quote:
slides around quite a bit on the ground. I have it in spot view, and have noticed that the plane is acting as if it is on ice or something, very, very strange.....


EXACTLY, it's as if the mains are turning the same direction as the nose wheel

they don't, I've watched, but that is how the plane acts
 
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Reply #7 - Mar 4th, 2008 at 12:24pm

Sean_TK   Offline
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Just figured out a way around this problem to some extent.
Use differential brakes when turning, it seems to be more controllable that way.
I'm using some Saitek Rudder-Pedals with it, so I can implement differential brake controls easily, but I hope you can. If not on your control, just use the keyboard defaults.
 

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Reply #8 - Mar 4th, 2008 at 12:30pm

microlight   Offline
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Download the updated FDEs from the Posky website - it cures the problem.

Wink
 

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Reply #9 - Mar 4th, 2008 at 12:32pm

Sean_TK   Offline
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I'm assuming that your are talking about this file?
http://www.projectopensky.com/downloads.php?aircraft=8ybhk9724&location=fdepacka...

Thanks for the help in solving this mystery!!!!  Smiley
 

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Reply #10 - Mar 4th, 2008 at 12:56pm

Groundbound1   Offline
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Sean_TK wrote on Mar 4th, 2008 at 12:02pm:
He looks to be talking about ground steering, seeing as 747s cant fly between 4-20 knots... Wink

Still researching.....I think adjusting something in that contact points post will solve it, but seeing as how my plane at least turns a little bit, you don't have autorudder on in the realism settings do you? If so, turn it off and see how the plane handles.


My fault! Grin Embarrassed I missed it.
 

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Reply #11 - Mar 4th, 2008 at 1:48pm

Allen_Z   Ex Member

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Thanks microlight but something else is the problem, they still won't steer even at 4-10 knots,  medium - low weight

I used the new files on 10 models and they are all having the same problems
 
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Reply #12 - Mar 4th, 2008 at 2:53pm

Sean_TK   Offline
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All I can think of now is what I mentioned previously. Use differential braking. It seems to work well for me, and that is the only workaround to this problem that seems to work so far period.

Good Luck,
-SeanTK

P.S. Won't be able to try to help more until later today.  I have to leave to go to my college classes. See ya around, and good luck with learning the Tupolev as well!  Smiley
 

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Reply #13 - Mar 4th, 2008 at 3:29pm

microlight   Offline
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Sorry, Allen - I just checked the aircraft.cfg for my Posky 744v4, and I see that I've put the line

differential_braking_scale=1

in the [brakes] section.

Duh...

Roll Eyes
 

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Reply #14 - Mar 4th, 2008 at 4:29pm

Allen_Z   Ex Member

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hmmmm, ok

since I prefer copters, I use a stick exclusively, and differential braking with a stick is a pain, any plane that REQUIRES differential braking gets deleted

The taildraggers that will quick fix to allow twisty steering I'll keep, a tricycle gear airliner that requires differential braking to steer is a goner  Grin

gonna go land on bldgs, and fly backwards awhile, it clears me head  Wink

thanks for all help, always great help available here Smiley



....a few moments later,

aaah, that's the ticket  Wink quite relaxing actually

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