Idea 2016 landing points from scenario

[4throck]

I think the 2016 touchdown points need proper testing.
I'm intrigued by the reports of completely different results with the same points.
I suggest we create a test suite based on the DG because we have .dll and SC4 versions of it.

So let's start with the default DG.

Using the same points for the DG as on the C++ code:

POINT_1 =  0.0 -2.57 10 1e6 1e5 1.6 0.1
POINT_2 = -3.5 -2.57 -1 1e6 1e5 3.0 0.2
POINT_3 =  3.5 -2.57 -1 1e6 1e5 3.0 [COLOR="red"]0.2[/COLOR]

I get a ship that turns to the right!

Checking the plugin:

TD Points Updater: Vessel Definition found for name DeltaGlider
point1 : 0.000 -2.570 10.000 1000000.000 100000.000 1.600 0.100
point2 : -3.500 -2.570 -1.000 1000000.000 100000.000 3.000 0.200
point3 : 3.500 -2.570 -1.000 1000000.000 100000.000 3.000 [COLOR="Red"]3.000[/COLOR]

It seems not to read one of the values!
What do you guys get? Remember to exit Orbiter and reload to avoid values not updating.

 

[jacquesmomo]

Bonjour Fred

it can happen for many reasons. I noticed that orbiter itself waits 5 seconds to establish that the vessels are landed when a scenario is open. So if you don't wait for 5 seconds the vessels will be orbiting instead of landed. Moreover, also if the vessels is not in a perfect flat terrain and the friction is not enough it will start to slide, even very slowly and this will prevent the landed status to be reached. It's a mix of things to keep controlled.

I noticed that too ...

I thought about this many times. One option to try could be to implement the GV so it transmits velocity to attached vessels, so basically you can use a ghost GV to taxi and then for take off, like a catapult of an aircraft carrier.

I already had tried this : I set a GV "docked" with the plane, but it does not work : the GV can not move the plane ....
I thought the plane was too heavy. I adjusted the weight to 10 (EMPTY_MASS and FUEL_MASS) - if less Orbiter crashes - but it is the same.

Funny, but the plane can move both (GV + aircraft) and can take off (see the image)

Anyway if you can't turn while taxiing, try to press the "." and the "-" keys on the keyboard (or the correspondant in the french layout), they apply differential braking and allows to turn while taxiing.

Yes, but... it did not work... And I'd this idea :
I increased the distance between points 2 and 3 (13.5 insted of 3.65) and the BRAKE_FORCE (in the spacecraft ini file) to 2000000000000000 (!!!) and.... that works !!!

Now, I can turn right and left on the taxiway.

So, here are (for now) my values :

a) in Spacecraft.ini file :

[COLOR=red][B];[/B][/COLOR][COLOR=black][[/COLOR]LANDING_GEAR]
WHEEL_FRICTION=0.001
BELLY_FRICTION=100000000000000
BRAKE_FORCE=2000000000000000
SEQ=14

And... something strange : look at the ";" before [LANDING_GEAR] :
if no ";" the plane is sent in the deep space....(not a CTD, but nearly same) I don't understand why... With ";" the brakes works fine.... :facepalm:

b) and in the cfg file (in the TD_Pts_Updater folder) :

N = 3
POINT_1 =  0  -2.45 10.34  300000  45000 5 0.01
POINT_2 =  -13.5 -2.5   -2.3  300000  45000 4 0.01
POINT_3 = 13.5  -2.5   -2.3  300000  45000 4 0.01

So there is a big progress: my plane now can roll on the taxiway to the runway and can take off ....
I'm happy.....:lol:


I will continue my tests and keep you informed
Amicalement
Jacques

 

[4throck]

Jacques, all this is dynamic.

If you are not landed, for each Orbiter step, forces are calculated.

Brakes can apply large forces instantly.
The force has to go somewhere. Your landing points only allow the force to go up, so you go into space.
In reality brakes are not instant!

All values must work together.
Friction and stiffness must work with brakes so that you get small forces acting on the vessel.


If the forces are small, the vessel will eventually settle into the landed state.

 

[fred18]

I think the 2016 touchdown points need proper testing.
I'm intrigued by the reports of completely different results with the same points.
I suggest we create a test suite based on the DG because we have .dll and SC4 versions of it.

So let's start with the default DG.

Using the same points for the DG as on the C++ code:

POINT_1 =  0.0 -2.57 10 1e6 1e5 1.6 0.1
POINT_2 = -3.5 -2.57 -1 1e6 1e5 3.0 0.2
POINT_3 =  3.5 -2.57 -1 1e6 1e5 3.0 [COLOR="red"]0.2[/COLOR]

I get a ship that turns to the right!

Checking the plugin:

TD Points Updater: Vessel Definition found for name DeltaGlider
point1 : 0.000 -2.570 10.000 1000000.000 100000.000 1.600 0.100
point2 : -3.500 -2.570 -1.000 1000000.000 100000.000 3.000 0.200
point3 : 3.500 -2.570 -1.000 1000000.000 100000.000 3.000 [COLOR="Red"]3.000[/COLOR]

It seems not to read one of the values!
What do you guys get? Remember to exit Orbiter and reload to avoid values not updating.

i think you missed this a couple of posts above:
https://www.orbiter-forum.com/showthread.php?p=587419&postcount=34

Ok, first of all thanks jacques, I think you found a small bug in the module: while writing the code that reads the values from the cfg file I was thinking in a "0 based" world, so 0, 1, 2... but for being user friendly I had set the points to be "1 based" so 1, 2, 3 and the value of mu longitudinal of the third point got caught in this. I corrected this and at the same LINK you can download the corrected version of the plugin!

Bonjour Fred

I already had tried this : I set a GV "docked" with the plane, but it does not work : the GV can not move the plane ....
I thought the plane was too heavy. I adjusted the weight to 10 (EMPTY_MASS and FUEL_MASS) - if less Orbiter crashes - but it is the same.

Funny, but the plane can move both (GV + aircraft) and can take off (see the image)

nope, just attachment could work but GV won't transmit any velocity to the aircraft so the second you detach, the aircraft will detach immediately. That's a possible correction to implement to GV in the future.

And... something strange : look at the ";" before [LANDING_GEAR] :
if no ";" the plane is sent in the deep space....(not a CTD, but nearly same) I don't understand why... With ";" the brakes works fine.... :facepalm:

that's something curious to ask Vinka... if you put the ";" SC3 will not read the landing gear section... but from you are reporting it seems that some values are read anyway like brake force... if you take out the ";" the landing gear section will be read by SC3 and it seems to me that i tries to set the touchdown points in the old way, so (as I made an example about) the stiffness and damping are messed up and the aircraft get shot away from the face of the earth...

 

[4throck]

Don't see the connection between the possible parsing problem and your earlier post.

It does seem to be a parsing problem, because it works perfectly if I use floats for all numbers:

N = 3
POINT_1 =  0.0 -2.57 10.0 1000000.000 100000.000 1.6 0.1
POINT_2 = -3.5 -2.57 -1.0 1000000.000 100000.000 3.0 0.2
POINT_3 =  3.5 -2.57 -1.0 1000000.000 100000.000 3.0[COLOR="Red"] 0.2[/COLOR]

I get

TD Points Updater: Vessel Definition found for name DeltaGlider
point1 : 0.000 -2.570 10.000 1000000.000 100000.000 1.600 0.100
point2 : -3.500 -2.570 -1.000 1000000.000 100000.000 3.000 0.200
point3 : 3.500 -2.570 -1.000 1000000.000 100000.000 3.000 [COLOR="red"]0.200[/COLOR]

All the values match as expected. Before they didn't...

And of course that it now works OK with steering using brakes.

 

[fred18]

Don't see the connection between the possible parsing problem and your earlier post.

The first lines were addressing this issue:

Ok, first of all thanks jacques, I think you found a small bug in the module: while writing the code that reads the values from the cfg file I was thinking in a "0 based" world, so 0, 1, 2... but for being user friendly I had set the points to be "1 based" so 1, 2, 3 and the value of mu longitudinal of the third point got caught in this. I corrected this and at the same LINK you can download the corrected version of the plugin!

 

[4throck]

How do you feel about redistribution of your plugin?
Do we include it with add-ons ? Are you planning on uploading it to OH?

If I might ask, could you please add the ability to define new brake strength?
I think it's the only major parameter that's missing.

 

[fred18]

How do you feel about redistribution of your plugin?
Do we include it with add-ons ? Are you planning on uploading it to OH?

it started as a test, but if it works and users gets benefit from it I will write a very quick documentation and will upload it on OH within this week.

I think the best option is to let it free to redistribute but with the obligation of mentioning of the download link so users can be sure to always have the most updated version.

If I might ask, could you please add the ability to define new brake strength?
I think it's the only major parameter that's missing.

Sure that is quite easy to do, it will be added in the next update.

 

[4throck]

Yes, I'm sure many people are interested in an official release.
It will be used, no doubt about it.