..ok, time for another of my stupid questions:  Mathias, does your 
new model code include tire creep?  And tire sidewall flex?

..a wee virtual demo on tire side wall flex:  Take a parked, say Cessna
172, out at the leading edge of the very wing tip, and push it straight
aft, then release, and repeat.  

..once you get your repeat pushes close to the system resonance
frequency, you will find wee pushes generates quite a yaw oscillation,
and that it will swing around a point somewhere near the nose wheel. 
System here, is, tire side wall flexibility (some people prefer doing
calculus on its inverse, "tire sidewall stiffness"), against _parts_ of
the wings + tail + nose etc masses.

..a wee virtual demo on tire creep: park an automobile sideways on a
slope, so it leans with one side down, buth with the front (and rear)
horizontal.  Mark the position of at least the up side tires. Lock the
steering wheel, say by turning off the ignition and taking the key 
out of the lock. Now get your fat ass outta the car and push it.  ;-)

..15 feet forward, then back to those marks, will do fine.
Note how far down the tires crept.  Tire creep.  ;-)

..med vennlig hilsen = with Kind Regards from Arnt... ;-)
...with a number of polar bear hunters in his ancestry...
  Scenarios always come in sets of three: 
  best case, worst case, and just in case.

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