07-11-2005, 05:54 AM
HOW TO SET COORDINATE IN THE PAYLOAD EDITOR ?
What are the coordinate mean for in the payload editor ?
PosZ in the payload editor is the front-rear position of a payload point in feet.
PosY is the vertical position of a payload point in feet.
There is no lateral position as FsP was done first for airliner.
How work the coordinate system in the payload editor ? (IMPORTANT)
Unfortunately each aircraft use their own scale for their model and the "zero position" is
often not at the same place on the model.
Also the value "zero CG" position don't exist in Fs2004, So FsPassengers when you call the
payload loader do several test with various weight on the empty aircraft to find the zero
position on the empty aircraft
Now with FsP the PosZ position in the payload editor is always RELATIVE to this ZERO CG position on the EMPTY aircraft.
in brief -5 will be 5 feet back to the calculated CG position on the empty aircraft and + 10 will be 10 feet in front
of the zero CG position. Notice a -5 feet here may NOT match a -5 in the aircraft.cfg (this is important
for the explaination below) This method was done to avoid many problem with aircraft and it seem to
work on the majority of the aircraft. (see "Why FsP by default need to calculate...")
Now some poorly designed aircraft (those that are unflyable without a payload because
the designer loaded first the payload and then tuned the flight dynamic with the aircraft loaded)
this method may fail. So you have a parameter in the payload editor "Disable position calculation"
if this parameters is checked the PosZ will now be ABSOLUTE, mean exactly the same than in
the aircraft.cfg without any recalculation. Such a payload model may work thus only for one model.
So what should I put as number in the payload editor ?
As long as you don't check the "Disable position calculation" in the payload editor
consider always that your coordinate are RELATIVE to the center CG. It's up to you
to find the overall lenght of your aircraft in feet and put the payload point at an estimation
of the position based on the CG((always about 1/3 of the wing) the zero being at that CG,
negative number back and positive in front (see image below) You should also take care
that your weight are equally set around the CG.This is important especially for big payload point as
"100 passengers economic" class, if you put them at -40 feet "back of the CG" and don't put anything
in front of course the CG will be completely wrong, so usually you should put 100 pax at -40 and 100 at +40
Now you can tune the point as they make look in real for example if there is a back cargo on a baron 58
of course it will move the CG back.. as in the real aircraft. If you have a first class in front with a low pax count
you can put for example: "35 first class at +40ft" "90 economic class at -15ft", fully loaded the aircraft will
be well balanced. (this is an example)
Now nothing replace trial & error to fine tune your model, as you don't need to exit Fs2004 to see the change in your payload
model the job is really simple: In Fs2004 call the payload dialog, see CG with full aircraft, if not good switch to payload editor,
make change, save, switch to Fs2004 call again the payload dialog... etc etc.
To resume: The zero position in feet is always at the CG position (about 1/3 wing) up to
you to guess the total lenght of your aircraft and place the point at the correct position.
Why FsP by default need to calculate the zero CG and place the point relative to it ?
Because each aircraft is different and may use different coordinate system.
In aircraft.cfg for the same type of aircraft (example 737) you can see some aircraft having the pilot
at +40 feet and on some other it may be at +10ft or even -20 ft depend where the model's center is.
Thus a "737" payload model would work only for one model and fail for all others.( mess completely the CG when loaded)
So by calculating the zero CG position and placing the payload station evenly relative to this point
(say 80 pax at -10ft and 80 pax at +10ft) you are assured that this payload model would work on
the majority of the aircrafts and don't mess the CG.
One image worth thousand words:
Fig A Show an aircraft designed by Mr "A" he make the model with the CG at 22ft.
In the aircraft.cfg you'll have the payload point of the pilot at 25ft and the passengers at 10ft
Fig B Show an aircraft designed by Mr "B" he make the model with the CG at 10ft
as you see a payload model with ABSOLUTE position as in aircraft.cfg can't work for
both "A" and "B" aircraft.
In NORMAL situation without checking the "disable calculation"
in payload editor both aircraft will have the zero position as in the image above.
Thus it's simple to make a payload model that work well for both aircraft
+3ft for pilots and -5ft for passengers and -12ft for luggage in this case
(just and example the lenght scale is not right here)
Hope it help ?
Dan
Post Edited ( 11-07-05 06:11 )
What are the coordinate mean for in the payload editor ?
PosZ in the payload editor is the front-rear position of a payload point in feet.
PosY is the vertical position of a payload point in feet.
There is no lateral position as FsP was done first for airliner.
How work the coordinate system in the payload editor ? (IMPORTANT)
Unfortunately each aircraft use their own scale for their model and the "zero position" is
often not at the same place on the model.
Also the value "zero CG" position don't exist in Fs2004, So FsPassengers when you call the
payload loader do several test with various weight on the empty aircraft to find the zero
position on the empty aircraft
Now with FsP the PosZ position in the payload editor is always RELATIVE to this ZERO CG position on the EMPTY aircraft.
in brief -5 will be 5 feet back to the calculated CG position on the empty aircraft and + 10 will be 10 feet in front
of the zero CG position. Notice a -5 feet here may NOT match a -5 in the aircraft.cfg (this is important
for the explaination below) This method was done to avoid many problem with aircraft and it seem to
work on the majority of the aircraft. (see "Why FsP by default need to calculate...")
Now some poorly designed aircraft (those that are unflyable without a payload because
the designer loaded first the payload and then tuned the flight dynamic with the aircraft loaded)
this method may fail. So you have a parameter in the payload editor "Disable position calculation"
if this parameters is checked the PosZ will now be ABSOLUTE, mean exactly the same than in
the aircraft.cfg without any recalculation. Such a payload model may work thus only for one model.
So what should I put as number in the payload editor ?
As long as you don't check the "Disable position calculation" in the payload editor
consider always that your coordinate are RELATIVE to the center CG. It's up to you
to find the overall lenght of your aircraft in feet and put the payload point at an estimation
of the position based on the CG((always about 1/3 of the wing) the zero being at that CG,
negative number back and positive in front (see image below) You should also take care
that your weight are equally set around the CG.This is important especially for big payload point as
"100 passengers economic" class, if you put them at -40 feet "back of the CG" and don't put anything
in front of course the CG will be completely wrong, so usually you should put 100 pax at -40 and 100 at +40
Now you can tune the point as they make look in real for example if there is a back cargo on a baron 58
of course it will move the CG back.. as in the real aircraft. If you have a first class in front with a low pax count
you can put for example: "35 first class at +40ft" "90 economic class at -15ft", fully loaded the aircraft will
be well balanced. (this is an example)
Now nothing replace trial & error to fine tune your model, as you don't need to exit Fs2004 to see the change in your payload
model the job is really simple: In Fs2004 call the payload dialog, see CG with full aircraft, if not good switch to payload editor,
make change, save, switch to Fs2004 call again the payload dialog... etc etc.
To resume: The zero position in feet is always at the CG position (about 1/3 wing) up to
you to guess the total lenght of your aircraft and place the point at the correct position.
Why FsP by default need to calculate the zero CG and place the point relative to it ?
Because each aircraft is different and may use different coordinate system.
In aircraft.cfg for the same type of aircraft (example 737) you can see some aircraft having the pilot
at +40 feet and on some other it may be at +10ft or even -20 ft depend where the model's center is.
Thus a "737" payload model would work only for one model and fail for all others.( mess completely the CG when loaded)
So by calculating the zero CG position and placing the payload station evenly relative to this point
(say 80 pax at -10ft and 80 pax at +10ft) you are assured that this payload model would work on
the majority of the aircrafts and don't mess the CG.
One image worth thousand words:
Fig A Show an aircraft designed by Mr "A" he make the model with the CG at 22ft.
In the aircraft.cfg you'll have the payload point of the pilot at 25ft and the passengers at 10ft
Fig B Show an aircraft designed by Mr "B" he make the model with the CG at 10ft
as you see a payload model with ABSOLUTE position as in aircraft.cfg can't work for
both "A" and "B" aircraft.
In NORMAL situation without checking the "disable calculation"
in payload editor both aircraft will have the zero position as in the image above.
Thus it's simple to make a payload model that work well for both aircraft
+3ft for pilots and -5ft for passengers and -12ft for luggage in this case
(just and example the lenght scale is not right here)
Hope it help ?
Dan
Post Edited ( 11-07-05 06:11 )