Mathias Fröhlich wrote
> Sent: 08 July 2004 10:38
> To: FlightGear developers discussions
> Subject: Re: [Flightgear-devel] status of aircraft carrier
> On Mittwoch, 7. Juli 2004 21:32, Vivian Meazza wrote:
> > It would be a shame if we can't model individual wires,
> then we could
> > experience hook-skip whereby the hook can miss all the
> wires. A chum
> > of mine went around 14 times trying to catch a wire in a
> Gannet aboard
> > HMS Hermes. But I think the 'wire-surface' would do quite well.
> Hmm, let me explain a bit.
> I for myself will be happy to model the relality in detail.
> That wire-surface has grown from an experience I have made
> during the past
> half year when I wanted to push changes into JSBSim. For
> example, I often
> proposed a mechanical system which much better models gears.
> This is not hard
> to do from my point of view. But Jon always told me that this
> stuff is tooo
> complicated and it is better to keep things as simple as
> possible. So that 'wire surface' has really grown from a
> extrapolation of my counterpart
> in JSBSim to the flightgear community ...
As I said, I think the 'wire surface' will do fine. KISS, at least at first.
> ... I am happy with individual wires. It is a bit harder
> since we do only have
> the position of the hook at discrete times. But I have also
> thought about
> Does the surface spanned from the hook in the previous time step
> and the hook in
> this time step intersect a wire?
> If yes we can have a probability where we catch. And if so
> apply two forces
> from the ends of the wire.
> So the API between the FDM and Flightgear will look something
> like a function
> taking a geometry of a rectangle and returning a bool which
> tells if a wire
> is caught and where the two points are where the wire leaves
> the deck. And as
> usual, how these two points move.
The wire slips through the hook, so I think that the action of the wire con
be regarded as a decelerating force acting at the hook attachment point,
along the aircraft centreline. Good enough I think.
> > It's very difficult to manoeuvre an aircraft onto a cat. You should
> > consider modelling the self-aligning rollers and chocks
> which bodily
> > shift the aircraft into the correct position. This need be no more
> > than a area on the deck on which, if the main wheels are resting on
> > it, a press of a key will automatically correctly position the
> > aircraft.
> So with a little jump to the right :)
> Sounds sensible!
Just like real life.
> > A key press should signify when the pilot is ready for launch, then
> > the cat should fire after a random interval after.
> > The Jet Blast Deflectors (JBDs) could also be modelled.
> Hehe :)
> And a cat officer showing you where to taxi :)
> And all these guys with yellow and green and whatever jackets :)
> One by one. But yes ...
I've seen it done in another flightsim. Back to bones?
> I think I will put several hundred wires onto KSFO's runway
> to do the first
> tests :)
Nothing like making it hard :-)
> > I can provide more details if you are interested.
> Yes, whatever you fell that could be useful.
> References ..
I'm looking in my library for some nice photos.
Flightgear-devel mailing list