General Question ship dives underground on takeoff

stevcast

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I have been working on a ship that I thought I had working, but after I uploaded it I went back to try it out with some different scenarios, and when I had the ship on the runway, I went to take off, and instead of the ship climbing, it went ten feet beneath the surface and then started to climb. What data in the spacecraft configuration is this attributed to?
I tried a configuration from a ship that works, and for some reason I got the same results. This is my config so far...

Code:
[CONFIG]
MESHNAME="Naboo Fighter"
SIZE=22.0
EMPTY_MASS=4000
FUEL_MASS=40000
MAIN_THRUST=2e7
RETRO_THRUST = 2e7
ATTITUDE_THRUST=5000
HOVER_THRUST=15e5
ISP=2.5e7
PMI=(20,22.01,5.3)
CW_Z_POS=0.2
CW_Z_NEG=0.4
CW_X=1.0
CW_Y=2.4
WING_ASPECT=0.7
WING_EFFECTIVENESS=3.0
CROSS_SECTION=(68,149,38)
PITCH_MOMENT_SCALE=0.00005
BANK_MOMENT_SCALE=0.00005
FOCUS=-1
ROT_DRAG=(0.10,0.13,0.04)
VISIBLE=1
CAMERA=(.46,-2.1,4.70)
LAUNCH_PT1=(0,5.0,2)
LAUNCH_PT2=(-1,5.0,-1)
LAUNCH_PT3=(1,5.0,-1)
LAND_PT1=(0,5.0,2)
LAND_PT2=(-1,5.0,-1)
LAND_PT3=(1,5.0,-1)
TRIM=0.05
COG=2.28
[AERODYNAMICS]
MODEL=dglider
[PARTICLESTREAM_1]
NAME=DGContrail
SRCSIZE=8.0
SRCRATE=3
V0=150.0
SRCSPREAD=0.3
LIFETIME=3.5
GROWTHRATE=4
ATMSLOWDOWN=3.0
LTYPE=DIFFUSE
LEVELMAP=LVL_PSQRT
LMIN=0
LMAX=2
ATMSMAP=ATM_PLOG
AMIN=1e-4
AMAX=1
[PARTICLESTREAM_2]
NAME=DGMain
SRCSIZE=2.0
SRCRATE=10
V0=150.0
SRCSPREAD=0.1
LIFETIME=0.2
GROWTHRATE=16
ATMSLOWDOWN=1.0
LTYPE=EMISSIVE
LEVELMAP=LVL_SQRT
LMIN=0
LMAX=1
ATMSMAP=ATM_PLOG
AMIN=1e-5
AMAX=0.1
[PARTICLESTREAM_3]
NAME=DGHover
SRCSIZE=1.5
SRCRATE=20
V0=150.0
SRCSPREAD=0.1
LIFETIME=0.15
GROWTHRATE=9
ATMSLOWDOWN=1.0
LTYPE=EMISSIVE
LEVELMAP=LVL_SQRT
LMIN=0
LMAX=1
ATMSMAP=ATM_PLOG
AMIN=1e-5
AMAX=0.1
; MAIN ENGINES
[EX_MAIN_0]
OFF=(5.6,-3.3,6.70)
DIR=(0,0,-1)
LENGTH=30
WIDTH=.95
[EX_MAIN_1]
OFF=(-4.80,-3.5,6.50)
DIR=(0,0,-1)
LENGTH=30
WIDTH=.95

Any help is very much appreciated.
 
Last edited by a moderator:
COG=2.28

this parameter sets the center of gravity of the vessel when landed.
Also be sure, that your landing points (LAND_PT1=(x,y,z)) are placed correctly.
These two parameters should make it. It is also good to place the landing points a bit further from each other to have more stable landing position, anyway Naboo fighter has no physical landing gears. If your Naboo fighter takes off like in the movie, launching points (LAUNCH_PT1=(x,y,z)) won't be necessary. They are usually used for vessels, that take off and land in different positions. Naboo fighter usually hovers on it's belly, landing points will work for both takeoff and landing.

All those parameters are explained in spacecraft readme file by Vinka. You can find it on Vinka's page as a part of spacecraft3 full package. Very useful readme, I must say.

Good thing, that you're creating a Naboo fighter. I call it "Spitfire of the future". Many many years ago, I created one, too. Today only screenshots remain...
 
Thanks

Cizurator, thanks for your help and input. I will try to work with the Landing points a little more and maybe I can get the thing to work correctly. Man, this can be frustrating at times!!! :facepalm:

---------- Post added at 02:46 PM ---------- Previous post was at 01:41 PM ----------

COG=2.28

this parameter sets the center of gravity of the vessel when landed.
Also be sure, that your landing points (LAND_PT1=(x,y,z)) are placed correctly.
These two parameters should make it. It is also good to place the landing points a bit further from each other to have more stable landing position, anyway Naboo fighter has no physical landing gears. If your Naboo fighter takes off like in the movie, launching points (LAUNCH_PT1=(x,y,z)) won't be necessary. They are usually used for vessels, that take off and land in different positions. Naboo fighter usually hovers on it's belly, landing points will work for both takeoff and landing.

All those parameters are explained in spacecraft readme file by Vinka. You can find it on Vinka's page as a part of spacecraft3 full package. Very useful readme, I must say.

Good thing, that you're creating a Naboo fighter. I call it "Spitfire of the future". Many many years ago, I created one, too. Today only screenshots remain...

Hate to be a pest, but I tried changing the COG, the Landing point parameters, and even made the launch point parameters the same as the landing point parameters, and it still nose dives to 10 feet underground.
I tried using the same parameters from a ship NX426 (ae7flux) that works, and my ship ends up stable on landing and take off, but 5 feet underground. When I change the height parameters in the landing points, the ship is again where I need it, but takeoff is wrong whether I leave the height alone in the launch points, make the launch points the same as the landing points, or take the launch points out all together...:idk: Any ideas??? What am I doing wrong or missing????
 
:lol: for some reason I thought this was going to be a news article :blink:
 
Steve, if you use Animator, go to Location and choose Centre about Origin, the select On Ground. It saves a lot of hassle. your pt1 etc will be around zero.
 
fixed, but I don't know why.

Steve, if you use Animator, go to Location and choose Centre about Origin, the select On Ground. It saves a lot of hassle. your pt1 etc will be around zero.

Thanks Kendo. I'll have to remember that. I just tried removing all data referring to landing points and/or launch points, and it works!! I don't know why it works, but at this point in my life you take what you can get!! :thumbup: Thanks everybody....

stevcast
 
When I change the height parameters in the landing points, the ship is again where I need it, but takeoff is wrong whether I leave the height alone in the launch points, make the launch points the same as the landing points, or take the launch points out all together...:idk: Any ideas??? What am I doing wrong or missing????

As I said, try to completely delete the launch points. If you leave only landing points, it should behave OK. It might also be the position of the landing points itself.

It is better to have them like this: -U--------U-
than like this: -----UU-----
It adds some stability.
 
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