Simviation Forums

I downloaded the Eclipse 500 from avsim.

When I switch from the VC to the Tower view I can see the jet bouce up and down three time and then crash.

lololol

Any ideas what could cause this?

That's nothin'.  I have a jet I'm building where it works great while the tanks are full, but If I let the fuel get really low it bouces like a kangaroo!

It's caused by the contact points, check the damping ratio.

Good luck and report on your results.

I have no idea what the contact points do.

The Damping Ratio isn't used in any files that I have looked at.  Do you have a sample Damping Ratio entry?

Thanks

In the aircraft.cfg file, the Contact Points section describes and defines your gear relative to the rest of the aircraft.  It also defines the crash or "touch" points like the wing tips, the nose and tail extremities.

Part of the gear contact points describe your suspension, movement, compression, and 'shocks"  or stiffness.

The combination of the static compression, max-to-static ration and damping defines the "spring load" and stiffness.  Parameters 8 and 9 define the total suspension travel.  Parameter 8 indicates how much of the available suspension travel is used when sitting on the tarmac.  Parameter 9 defines how much of the total suspension is left as a ratio.  Ideally, these numbers will exactly match the animation in the model.

Below are the first 3 contact points for the Lear 45.  The // entries define the positional parameters in each contact point.  Contact points 1 and 2 are the main gear, and 0 is the nose gear.  Parameter 10 is the damping suggested above.

       //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
[contact_points]
point.0=1, -10.00,   0.00, -4.35, 1181.1, 0, 0.6349, 46.8, 0.3000, 2.5, 0.9100, 10.0, 10.0, 0, 260.0, 260.0
point.1=1, -37.25,  -4.75, -4.87, 1574.8, 1, 0.6349,  0.0, 0.4798, 2.5, 0.5456,  9.0,  9.0, 2, 260.0, 260.0
point.2=1, -37.25,   4.75, -4.87, 1574.8, 2, 0.6349,  0.0, 0.4798, 2.5, 0.5456,  9.0,  9.0, 3, 260.0, 260.0

The aircraft.cfg can be edited with Notepad.

Thanks for the info!

hi milton! ive a small problem with a jet as well , hoping you may be able to help. ive dealt with contact points before although without always having proper definitions of what setting does excactly what - not too user friendly please see topic 777 300 engine vibration .cheers  8)

Well I made a little progress. My aircraft still bouces some but at least it doesn't crash. lol

Milton are right if its bounce again just lower the damping again !

i have experience same thing on a projet i have made last years !  hope this help !