Project Multistage2015 - Development Thread

[gattispilot]

Ok:
Stages
Only one stage can be fired at a time, when the fuel mass of the current stage reaches 0, the stage is jettisoned and the next stage (if any) is ignited. If the first stage is running out of fuel and boosters are still thrusting, the first stage separation will be delayed until all boosters are jettisoned. You can define up to 10 stages.

So On my Saturn 5 because the fuel still remains in Stage 1 the sequence for Stage 2 doesn't start.

 

[fred18]

Ok:
Stages
Only one stage can be fired at a time, when the fuel mass of the current stage reaches 0, the stage is jettisoned and the next stage (if any) is ignited. If the first stage is running out of fuel and boosters are still thrusting, the first stage separation will be delayed until all boosters are jettisoned. You can define up to 10 stages.

So On my Saturn 5 because the fuel still remains in Stage 1 the sequence for Stage 2 doesn't start.

I'm not 100% sure you're right, but anyway you can play with jettison() and engine() commands to get past this issue

 

[gattispilot]

Thanks.

So with this ini file.
Multistage 2015 Automatically Generated Guidance File
Vehicle: SATURN5
5.000 =engine(0.00,110.00,5.00,0.00,0.00,0.00) stage 1 fires at MTD 5
50.000 =engine(100.00,85.00,3.00,0.00,0.00,0.00) stage 2 fires at MTD 5

This is from the sls. But it looks like the 2nd engine command says go from 100% to 85% in 3 time?

Didn't see any jettison command

 

[jacquesmomo]

Thanks.
Didn't see any jettison command

Hello :tiphat:
Write this (for exemple) :

5.000 =engine(0,110,5) stage 1 fires at MTD 5
49=jettison() jetisson stage 1 (if no boosters)
50.000 =engine(100,85,3) stage 2 fires at MTD 5


If the rocket has boosters and if they are not jettisoned (if they are 2 for ex)
type this :

5.000 =engine(0,110,5) stage 1 fires at MTD 5
49=jettison() jetisson booster 1
49.1=jettison() jetisson booster 2
49.2=jettison() jetisson stage 1
50.000 =engine(100,85,3) stage 2 fires at MTD 50

Saturn 5 has no booster, so take the 1st example....

The command "tt=Jettison()" is not in the doc (read before) but still exist...

 

[fred18]

Thanks jacques!

The command you read in the SLS example is a simple throttle down due to MaxQ.

Here's an example from the Multistage2 Jarvis addon:

-125=engine(0,0,1)
-30=PlaySound(sound\jarvis\countdown-30_un.wav)
-5=engine(0,100,5)
0=disable(jettison)
0=engine(100,100,5)
7=roll(5,90,90,84,1)
31=pitch(84,-10,210)
50=PlaySound(sound\jarvis\Max-Q.wav)
173=PlaySound(sound\jarvis\BurnOut.wav)
[B][COLOR="Red"]177=jettison()
177=jettison()
177=jettison()
177=jettison()
177=jettison()
178=PlaySound(sound\jarvis\Separation.wav)
180=engine(0,100,1)
181=engine(100,100,5)[/COLOR]
[/B]200=fairing()
241=pitch(-10,0,153)
394=pitch(0,0,20)
414=pitch(0.0,0,4)
418=pitch(0,0,10)
420=engine(100,0,2)
422=engine(0,0,5)

 

[gattispilot]

Thanks
I have this as the guidance:
Multistage 2015 Automatically Generated Guidance File
Vehicle: SATURN5
5.000 =engine(0.00,110.00,5.00,0.00,0.00,0.00)
154=jettison()
156.000 =engine(0,100.00,156.00,0.00,0.00,0.00)
596=jettison()
600.000 =engine(0,100.00,600.00,0.00,0.00,0.00)

now I need to get in Orbit. We had it working in Velcro but Velcro doesn't work well in 2016

 

[fred18]

I don't understand this:

156.000 =engine(0,100.00,156.00,0.00,0.00,0.00)

it should be something like 2 or 3 seconds.
the third number is the time it takes to get from first level to second level, in your example from 0 to 100.

taking your example: at 156 you start from engine at 0 to get to engine at 100 if you put for example 2 seconds at 157 you'll be at 50% and at 158 at 100%. Hope it's clear.

now I need to get in Orbit. We had it working in Velcro but Velcro doesn't work well in 2016

Well that's the purpose of the new guidance system of multistage2015, if you just add something like

-10=orbit(185,185)

to your guidance it will fly to it. Or choose your desired inclination. It should be quite easy with the saturn

 

[gattispilot]

Thanks

Multistage 2015 Automatically Generated Guidance File
Vehicle: SATURN5
5.000 =engine(0.00,110.00,5.00,0.00,0.00,0.00)
154=jettison()
156.000 =engine(0,100.00,5.00,0.00,0.00,0.00)
519=jettison()
521 =engine(0,100.00,6,0.00,0.00,0.00)

When I added the
-10=orbit(185,185)
The timing of jettison and stage ignition was off

 

[fred18]

What does "was off" mean?

 

[gattispilot]

-10=Orbit(185,185)
5.000 =engine(0.00,110.00,5.00,0.00,0.00,0.00)
154=jettison()
156.000 =engine(0,100.00,5.00,0.00,0.00,0.00)
519=jettison()
521 =engine(0,100.00,6,0.00,0.00,0.00)

It is like all the timing was sped up. The stage all drop off earlier. But maybe it needed to get get into Orbit?

 

[fred18]

But maybe it needed to get get into Orbit?

No, it shouldn't be anything like that. I don't know, post the log in case you need further help

 

[boogabooga]

gattispilot,

"Orbit" command should take you from ground to orbit without hassle. Stages should jettison automatically as they run out of fuel. When you add "jettison" commands, your stages will jettison at non-optimal times. I don't understand why people were telling you otherwise. That might be messing up the timing of the other stages starting.

Try:

-10=Orbit(185,185)
-3=engine(0,100,3.0)

Two lines. That's it.

 

[gattispilot]

So then do I need to add the jettison and engines for the 2nd stage,....

 

[boogabooga]

Try those two lines only.

IIRC, 2nd stage should start and throttle to 100% on its own. You only need to intervene in the guidance file if you want it do something else, like throttle back or roll or something.

 

[jacquesmomo]

Hello Fred

Just to tell you that thanks to your explanations now my ELA2-crawler can be an autonomous vehicle (spacecraft4) and can go anywhere with the rocket. (but this is not recommended)...

And of course the rocket (here is an Ariane-2) can lift off where the crawler is...

 

[gattispilot]

-10=Orbit(185,185)
-3=engine(0,100,3.0)


Nope this launch and then also first and second stage separate and 3 stage never fired.

 

[boogabooga]

-10=Orbit(185,185)
-3=engine(0,100,3.0)


Nope this launch and then also first and second stage separate and 3 stage never fired.

Could you please elaborate? Did you get into orbit at least?

If you are modeling Saturn V, it is entirely possible that the third stage is not needed to get into orbit. The real Saturn V was capable of getting a "small" payload to orbit on only two stages and did exactly that with skylab. The third stage was mostly there to get to the moon.

 

[gattispilot]

No. on orbit
LAUNCH

1ST STAGE Seperated

2nd stage separated and stage 3 never fired.

2nd stage interface still there.

 

[boogabooga]

Do the stages run out of fuel before they separate?

Please just zip everything that I would need to get this running (meshes, textures, configs, etc), post it, and I will take a look myself.

 

[gattispilot]

here you go:
https://drive.google.com/open?id=0B0JgX41wexYRNk5na0FPNUFLLU0