Ground handling: tail dragger needs tighter turning circle

Anyone can tell me how to adjust an AI tail dragger to have a tighter turning circle on the ground? What I effectively need to do is change the tail drag to a tail wheel.

Hi Roger,

 

I believe you will need to adjust an entry in the Contact_points section of the aircraft.cfg.

 

Each entry in a specific point.# line refers to a specific value/class. Note that the entry reads left to right and that the value/class numbering system actually starts at 0 (zero) - therefore the first entry after the point.# = sign refers to value 0 (which references the gear type class), the second refers to value 1 (which references the Longitudinal Position of the gear) and so on. The relevant entries for that I believe you need to change are values 7 (Steer Angle - displayed as degrees) and/or 8 (Static Compression (displays as feet or use 0 for rigid).

Brian, Thanks for that. There are three sets of contact points and two of them are the same, so the odd one must be the tail skid/wheel. I will increase 7 and 8 and see what happens!

Brian, increasing 7, the steering angle, improved things. Am I supposed to also increase 8, or decrease it? I presume increase it but increasing didn't seem to do a lot.

I don't think changing static compression will have much of an effect...changing the steer angle to about 60 (degrees) is the thing to do.

 

Nadlzfw

Static compression is the strut compression at rest on the ground. Dynamic compression might be regarded as the "elasticity" expressed as a ratio of static compression. It is not a twisting type factor.

 

Steering angle is the maximum angle that a wheel change direction (steer).

 

Loosely translated from the FS9 SDK for the aircraft container definition document.

I put this above all my contact points sections. Helps me know what I'm doing.

This is for FSX though. Not sure if FS9 is the same.

 

//(feet) longitudinal, lateral, vertical distance from specified datum
//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)

//------0------1------2-------3-------4---5----6------7-----8----9---10---11---12--13---14-----15--

Brian, increasing 7, the steering angle, improved things. Am I supposed to also increase 8, or decrease it? I presume increase it but increasing didn't seem to do a lot.

 

Hi Roger,

 

Sorry for the confusion WRT changing the 7 and 8 values, I should have been a bit clearer WRT my comments, especially about 8. I only pointed out 8 as you mentioned in the OP about changing the dragger to a wheel. Generally, a dragger will be set at rigid as it is fixed but a wheel, even if fixed (i.e. non steering) will often have some give (i.e. compression).

I put this above all my contact points sections. Helps me know what I'm doing.

This is for FSX though. Not sure if FS9 is the same.

 

//(feet) longitudinal, lateral, vertical distance from specified datum
//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)

//------0------1------2-------3-------4---5----6------7-----8----9---10---11---12--13---14-----15--

 

Both FSX & FS9 the class of contact for 3 is a skid, not a float!

I have found that a tailskid will be rigid having no deflection, but if the steer angle is set for 180 it will steer better. A skid will also provide better braking effect than a wheel.

I am though not sure if this is applicable to AI aircraft, I thought they followed the taxiway defined in the .bgl?

Not sure if this might help, it refers to the nose wheel steering but it might give you a clue in the contact points:

 

https://steamcommunity.com/app/314160/discussions/1/492379439676340189/

ai aircraft follow the taxiway "to the best of their ability" which in this case meant in a circle three times the radius of the corner. Anyway, the tail skid is not set at "rigid" and the turning degree is set to 210 degrees and that just about does it. Thanks all.