Aircraft ground-start location.

[Staiduk]

Hi - me again.
OK; here's the problem:
I have an airfield I downloaded from this site; looks quite nice. I want to build missions to fly out of it; but it doesn't have an entry in the info/missions.dat file. So I figured out the geographic center of the airfield; and bodged one together. I can now quite happily use the airfield for missions; so I built a quick take-off mission from it as a test.

As you can imagine; when I started the test mission; my aircraft started out no-where close to the runway. (And that farmer whose field my F-4 was sitting in is a little peeved right now. )
No biggie; I just figured out the distance; and adjusted the numbers in the .dat file. Except; it didn't work. No matter how I adjust the numbers; the plane starts in exactly the same field. (I changed to an A-10 when the farmer came out with his shotgun.)
I'm pretty sure this is because the .dat file only gives the map info - IOW where the airfield icon appears on the Advanced Info screen - but I can't find where to find the numbers to change the plane's actual starting location. Can anyone help? I and the farmer thank you.

[Staiduk]

As a backup - this only happens in a Single mission. In Free Flight; it plunks you right down on the runway right where you should be.
Confusing.

[Hagar]

Hi Staiduk

It's a while since I messed around with this stuff. I actually posted a tute on the basic priciples some years ago which was how I met Tom Sandford, now the Fox Four mission guru. http://www.simviation.com/lair/Scene2MbDb.html

The heading in airbases.dat is all-important. Everything including the start point is measured from an imaginary reference point about 1/3 or even halfway up the runway, depending on its length. You can see that for a typical start point set 400 yards back from this point (takeoff_start_pos=-400,0) - an error of 1 degree either way in the heading would make a big difference. Once you have the rough co-ords entered in airbases.dat the reference point & runway heading can be accurately checked in the MB & changed accordingly. Hope this is some help.

[Staiduk]

It worked, thanks!
I just can't figure out why it wasn't working before - I fiddled with those numbers for two hours yesterday!
Guess it's just the usual; that gremlin in my computer knows when I don't know what I'm doing.

[Staiduk]

Whoops - it worked once only; apparently. Every attempt since put me in the same position off the runway.
Grrr - I'm starting to wonder if this might be a bug in my game - I think I'm about due for a fresh install.

[Staiduk]

Oh. - Ummm; never mind, I figured out the problem.
My regular CFS2 is in my E: drive; my backup is in my C:. I was using the wrong mission builder.

In a word... DOH!!!!!

[Hagar]

Ah OK. Just spotted this. Glad you fixed it.

[Staiduk]

Yeah; works out pretty cool, actually.
I made two entries for the airfield; one named "xxx" (the airfield) and the next "xxx ramp".  So now I have the option of starting from the ramp in solo missions; and can have other aircraft taking off as I'm taxiing to the rwy (by setting them to the "xxx" airfield.)
Also; it's a double runway; so I'm working out how much I have to shift things to get them to take of on 21R and land on 21L. Heh heh - this is fun!

[engineer2]

The heading in airbases.dat is all-important. Everything including the start point is measured from an imaginary reference point about 1/3 or even halfway up the runway, depending on its length. You can see that for a typical start point set 400 yards back from this point (takeoff_start_pos=-400,0) - an error of 1 degree either way in the heading would make a big difference. Once you have the rough co-ords entered in airbases.dat the reference point & runway heading can be accurately checked in the MB & changed accordingly. Hope this is some help. (From Hagar)

Ok, maybe I'm a little dense do you adjust the heading or the takeoff_start_pos?