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Wide turning circle of two AI tail draggers


hjwalter

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Hi all,

 

Two of my AI tail draggers, a Piper Cub and a Tiger Moth, don't seem to be able to make some of the tighter turns on taxiways on their way to the runway. They turn far too wide, eventually do make it to the runway start positions, followed by correct take offs, etc ... but ... only after taxiing straight through some of the addon airfield's gas pumps and it's cafe/restaurant. Not very realistic looking, to say the least.

 

It's not possible to edit the taxiway turns themselves, e.g. via the airfield's Afcad/ADE file, because they are all part of the airfield's ground scenery.

 

I've been editing both (contact point) turning angles, ranging between 40 and 180 degrees, but to no avail. I even tried editing their differential braking entries but alas, still no go. The problem seems structural.

 

Ideas and/or solutions anyone ?

 

Regards and I thank you in advance.

 

Hans

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The Tiger normally does not have any brakes, & has a skid on the tail, so is very sluggish on tarmac & in certain crosswinds impossible to go where you want it, which is why you see wingmen helping on the ground. One has to blip the throttle to get some air passing over the rudder, so if one must try to get it to turn then you would need to look into the .air file, or give it more authority to the rudder. Not sure about the Cub, could be similar rudder/ airflow problem when tail down.

Keith

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Thanks guys for your reactions.

 

I already had the feeling that the problem I described would be more or less structural, so I'm now looking for a couple of AI wingmen positioned at strategic points at sharp taxiway corners !!! LOL.

 

I guess that for the airfield in question the only real solution will be to replace both AI tail draggers by tricycle gear AIs.

 

Thanks again.

 

Hans

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Hi,

 

1. What Piper ZIP file is it

 

2. Did you check the Contact Points ?

 

3. My Piper does it PERFECT in AI !

 

My Contact Points are:

 

1. Mains are 1.0 feet in front of the COG / Reference Line Wheel radius is 0.7,

 

the Tail wheel is -15.8 wheel Radius is 0.3

 

 

G. Kirschstein

gkcherry1@t-online.de

 

P. S. My observation with OTHER Taildragger's is when the Tail wheel is WRONGLY positioned than the

wide turn.

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Quote: '...when the Tail wheel is WRONGLY positioned...'. EXACTLY right! If you would move the tail gear or skid from -15.800 to -14.800 and then -13.800 you would SEE the difference. That simple. It might 'look' funny when it turns but this adjustment will get the job done.

Chuck B

Napamule

i7 2600K @ 3.4 Ghz (Turbo-Boost to 3.877 Ghz), Asus P8H67 Pro, Super Talent 8 Gb DDR3/1333 Dual Channel, XFX Radeon R7-360B 2Gb DDR5, Corsair 650 W PSU, Dell 23 in (2048x1152), Windows7 Pro 64 bit, MS Sidewinder Precision 2 Joy, Logitech K-360 wireless KB & Mouse, Targus PAUK10U USB Keypad for Throttle (F1 to F4)/Spoiler/Tailhook/Wing Fold/Pitch Trim/Parking Brake/Snap to 2D Panel/View Change. Installed on 250 Gb (D:). FS9 and FSX Acceleration (locked at 30 FPS).
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Hey there napamule2,

 

You hit the nail (or my AI Piper Cub) right on it's head. I even needed to move it's tail wheel position forward to -10 but also it's height to -2.55. It now at least "drives" itself correctly and without needing the help of any AI wingmen.

 

Now for my AI Tiger Moth which I expect to be able to correct in the same way.

 

Thanks.

 

Hans

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Hey Hans,

Glad it worked for you. Somtimes the solution to a hard or difficult characteristic boils down to something simple. All you need it the knowledge, by experience, to 'figure' it (the reason) out. Cheers. Stay Safe.

Chuck B

i7 2600K @ 3.4 Ghz (Turbo-Boost to 3.877 Ghz), Asus P8H67 Pro, Super Talent 8 Gb DDR3/1333 Dual Channel, XFX Radeon R7-360B 2Gb DDR5, Corsair 650 W PSU, Dell 23 in (2048x1152), Windows7 Pro 64 bit, MS Sidewinder Precision 2 Joy, Logitech K-360 wireless KB & Mouse, Targus PAUK10U USB Keypad for Throttle (F1 to F4)/Spoiler/Tailhook/Wing Fold/Pitch Trim/Parking Brake/Snap to 2D Panel/View Change. Installed on 250 Gb (D:). FS9 and FSX Acceleration (locked at 30 FPS).
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Hey Chuck and Hans,

 

this case is very interesting for me. I have tried to change the contact points for the default FSX Piper_3 Cub for AI-use, but gave up as somebody told me this would be impossible.

 

Now I changed the

[contact_points]

point.0=1, -15.00, 0.0, -1.05, 1800, 0, 0.238, 60.0, 0.300, 2.5, 0.40, 0.0, 0.0, 0.0, 0.0, 0.0 (this is default) to

 

[contact_points]

point.0=1, -10.00, 0.0, -2.55, 1800, 0, 0.238, 60.0, 0.300, 2.5, 0.40, 0.0, 0.0, 0.0, 0.0, 0.0

 

Perhaps this wasn't the right way because there was no difference:(

 

Then I changed the 'empty_weight_yaw_MOI' from default 642.2 to 3000 as I have done at some other aircrafts. And now it works! :)

 

Maybe your way works only for FS9 and I play with FSX.

Edited by Flattermann

happy landings! Christian:pilot:

Intel i5-6600K CPU @ 3.50GHZ, 4 Kerne, 16 GB

MSI RX 480; M. SATA WD 500 GB;

WD RED PRO 2TB Win 10, 64 bit; FSX Gold Acc.

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Christian.

 

Chuck's solution was not really "As Real As It Gets" but it certainly worked in my FS9 and that's the most important, especially when it concerns eye candy type AI aircraft during their "driving" along sharp cornered taxiways on juicy little addon airfields. However, for the flyable versions of the same light aircraft it remains a totally different matter and you then actually need to keep them on the taxiway center lines yourself, with or without differential brakes and/or effective rudders, as Keith correctly describes.

 

Anyway, I'm happy that you have also found a solution for the same problem in FSX, albeit a different one. However, your solution could also influence your AI aircraft's flight characteristics.

Are you sure your AI aircraft still flies correctly ? To test this you could take off and fly (in formation) behind it until it lands correctly at it's "flight planned" destination airfield. I've done this myself on a number of occasions but only when certain AI aircraft, strangely enough, did not arrive at their destination airfields because.e.g. they crashed somewhere along their routes and for different reasons.

 

Regards

 

Hans

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Its a long time since I played with AI aircraft, but your posts did ring a feint bell when talking contact points. I think if one changes the contact height of each wheel by the compression value & adjust the static C of G then one is there, (pressing 'Y' in the controllable version is a check that the C of G height is correct). I noticed that AI aircraft do not show undercart deflection, so its dragging its wheels underground........

Keith

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hi,

this is NOT the REAL solution to fix this problem !!

 

It is RATHER a Pre-REQUISITE to fix this problem which is ........ the following ...

 

By the way IF you do NOT state for which Piper you need the solution to make it work in FS2004 AI environment than

every advice is meaningless.

 

The MS Piper CUB does NOT work in FS2004 AI.

 

Period.

 

Sincerely

 

g. Kirschstein

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mr. flattermann,

 

YOU are correct MOI !!

 

Pitch 640

Roll 640

Yaw 1947

 

Plus the Correct Tailwheel Distance.

 

This for the Taxi problem, there are other items in the FDE to be fixed to make it work at all in FS2004.

 

Sincerely

 

G. Kirschstein

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Hey guys,

 

thank you for answering. As I wrote (after changing Yaw) 'now it works', I only meant the taxiing. I never saw a 'unchanged' default FSX Piper J3 Cub flying as an AI. They never found the runway taxiing in the surroundings unable to make more than a little curve. Some freeware developer are using such Pipers in their sceneries and I think they never tested the flight of a Piper J3 Cub:p

 

The pilotable Piper i have never tried to change the aircraft.cfg, there was no need to do so.

So I made a non pilotable Piper and changed the aircraft.cfg as I said. Now the taxiing worked and I could see the Piper flying.

 

@Hans Yes i was not sure the aircraft flies correctly and indeed it seems the AI -pilot was drunken gravely. Sometimes it works normally sometimes it enormous sways. Nevertheless it reached the destination airport, nearly perfect landing, taxiing correct to the parking spot and this makes me content.

I don't know what I could do to make it better. Again I have to say this concerns only the FSX version!!

Edited by Flattermann

happy landings! Christian:pilot:

Intel i5-6600K CPU @ 3.50GHZ, 4 Kerne, 16 GB

MSI RX 480; M. SATA WD 500 GB;

WD RED PRO 2TB Win 10, 64 bit; FSX Gold Acc.

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hi,

this is NOT the REAL solution to fix this problem !!

 

It is RATHER a Pre-REQUISITE to fix this problem which is ........ the following ...

 

By the way IF you do NOT state for which Piper you need the solution to make it work in FS2004 AI environment than

every advice is meaningless.

 

The MS Piper CUB does NOT work in FS2004 AI.

 

Period.

 

Sincerely

 

g. Kirschstein

 

I had another good look at my FS9 yellow painted problem (now solved) AI Piper Cub's technical details and it did in fact turn out to be an AI version of the default MS flyable one. However, my AI version now behaves completely as it should, as it's flyable counterpart has always done. It's even great fun to fly in formation with the AI one but does take some practice.

 

Regards

 

Hans

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THANK YOU!!!!!!!!!

 

For a long time I struggled with my Polikarpov Po-2; exactly the same awful handling on the ground. I recognized these symptoms immediately. Moving the tail skid forward works perfectly!!!!

 

Nadlzfw

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It seems that MS did not TEST FLY the default planes and if they did they did not make the required changes. Why? I don't know. I only know they droped the ball on dynamics for default planes.

 

The FS9 and the FSX Cubs both have identical cfgs and air files. FS9 always requires more MOI than FSX. So increaseing FS9 yaw moi is correct. I would of used 1500. I would also change a couple of things in the air file for both FS9 and FSX. I would also make braking no less than 1.000. I also prefer differential braking to be 0.800.

 

In air's 1101 (Flight Dynamics) I would change 'rudder' from 7 to 30. 'rudder control factor' from 48 to 128. Also I would change 'Yaw Stability 1' from 70 to 128. 'Yaw Stability 2 remains the same. And I would change 'rudder effect on roll' from -85 to -128.

 

Back up both cfg and air file before editing. Use ONLY notepad for cfg and ONLY AirEd for air.

Chuck B

Napamule

i7 2600K @ 3.4 Ghz (Turbo-Boost to 3.877 Ghz), Asus P8H67 Pro, Super Talent 8 Gb DDR3/1333 Dual Channel, XFX Radeon R7-360B 2Gb DDR5, Corsair 650 W PSU, Dell 23 in (2048x1152), Windows7 Pro 64 bit, MS Sidewinder Precision 2 Joy, Logitech K-360 wireless KB & Mouse, Targus PAUK10U USB Keypad for Throttle (F1 to F4)/Spoiler/Tailhook/Wing Fold/Pitch Trim/Parking Brake/Snap to 2D Panel/View Change. Installed on 250 Gb (D:). FS9 and FSX Acceleration (locked at 30 FPS).
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Thank you Chuck,

 

I tried to change the FSX Piper J3 Cub airfile with AirEd but I don't find 'Yaw Stability 1'?

Only 'Cn_R - Yaw Rate= -240' and 'Cy_R - YawRate=430' can be found.

happy landings! Christian:pilot:

Intel i5-6600K CPU @ 3.50GHZ, 4 Kerne, 16 GB

MSI RX 480; M. SATA WD 500 GB;

WD RED PRO 2TB Win 10, 64 bit; FSX Gold Acc.

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It seems that MS did not TEST FLY the default planes and if they did they did not make the required changes. Why? I don't know. I only know they droped the ball on dynamics for default planes.

 

The FS9 and the FSX Cubs both have identical cfgs and air files. FS9 always requires more MOI than FSX. So increaseing FS9 yaw moi is correct. I would of used 1500. I would also change a couple of things in the air file for both FS9 and FSX. I would also make braking no less than 1.000. I also prefer differential braking to be 0.800.

 

In air's 1101 (Flight Dynamics) I would change 'rudder' from 7 to 30. 'rudder control factor' from 48 to 128. Also I would change 'Yaw Stability 1' from 70 to 128. 'Yaw Stability 2 remains the same. And I would change 'rudder effect on roll' from -85 to -128.

 

Back up both cfg and air file before editing. Use ONLY notepad for cfg and ONLY AirEd for air.

Chuck B

Napamule

 

FS2004 and FSX make use of DIFFERENT elements of the .air and .cfg file. What works for one may be unrecognized by the other...

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