On Donnerstag 28 Oktober 2004 22:08, Andy Ross wrote:
> Matthias Froelich wrote:
> > This case kind of works for the arrester wires. The braking force is
> > just hacked into the gear code. But this is just to be able to test.
> What would probably be a better idea (at least for YASim) would be to
> model the braking force as a *distance* over which the aircraft will
> be stopped.  In the real world, they have to calibrate the wires for
> the exact aircraft configuration that is going to be landing.
> You would figure out what constant acceleration would stop the
> aircraft in the distance available, and simply apply that force "at"
> the tailhook and "towards" the center of the arrestor wire.
I am talking with Vivian Meazza about that topic. He has more or less own 
experiences with those wires. He knows much about them and how they are 
built. I think we will get something well suited.

> The catshot is actually harder: in real life, the force is at the
> bottom of the nosegear.  But if you apply that to the dynamics model
> the aircraft will want to tilt backwards as it accelerates.  Real
> aircraft don't do this because the nosegear is artificially compressed
> and held that way during the shot.  Maybe the easiest way to simulate
> this would be to apply the force at the nose, or some other point
> forward of the c.g. and above the gear.
Yep this is problematic. I think one should apply the force like it is applied 
in a real aircraft. Take a fixed position of the nose gear strut about 30 cm 
above the ground level. Then apply the force at this position in direction of 
a point 50cm ahead of the nose gear on ground level.
When this force is applied the nose gear is compressed and the aircraft 
accelerates. When the aircraft tries to raise it's nose the force will pull 
it back downwards ...

> I'm honestly looking for something to get me back into FlightGear
> development.  I can do the YASim integration if you guys have an
> interface ready for the "ground velocity" and "arrestor wire position"
> values.
Ok, great. May be you will get preliminary patches soon ...



Mathias Fröhlich, email: [EMAIL PROTECTED]

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