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[1.4][1.7.7] GravityTurn continued - Automated Efficient Launches


AndyMt
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It is very good and convenient.

But could the author consider the work of modifications to complement the Real Solar System? My problem is that my rocket starts to horizontal acceleration at the altitude of 40 kilometers. And explodes from overheating. If it was Keral - everything is fine, but for the Earth it is too low.

Also, if the takeoff is not given the support mast if they are in the next stage.

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On 3/3/2018 at 7:34 AM, Craze said:

It is very good and convenient.

But could the author consider the work of modifications to complement the Real Solar System? My problem is that my rocket starts to horizontal acceleration at the altitude of 40 kilometers. And explodes from overheating. If it was Keral - everything is fine, but for the Earth it is too low.

Also, if the takeoff is not given the support mast if they are in the next stage.

change the default options

On 2/24/2018 at 8:10 PM, Not Sure said:

So i've been messing around with FMRS and reusable stages. In combination with this mod, you can get some pretty accurate and consistent missions. My only problem arrives with my heavy version of my lifter. (FH inspired) and the issue is the auto staging. To trick the program, you can lock the fuel flow so that it thinks its empty and stages when you really save some fuel for landing. This works when you have the rocket inline (Like FH core) and have no fuel lines, but when you do it with the side boosters it will not autostage. Boosters with locked fuel next to a burning core = no staging. Boosters with no locked fuel next to core = staging. Having fuel pumps feeding into the center does not affect the auto staging. But to repeat, the core, with locked fuel or no locked fuel = staging. 
I could just press space manually like i have been doing so far but i decided to point this out as it may affect certain crafts for other players.

 

i use smart parts for this

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1 hour ago, danielboro said:

change the default options

To what?

I tried both GravityTurn and MechJeb for this on a 3.2x Kerbin and eventually gave up after many tries to find numbers that worked. I couldn't even find numbers that gave me super inefficient launches that worked, they all either burned up or nosedived into the ground.

The main reason I don't play with larger planets is that I hate the long wait to LKO and would rather just not play if I can't automate it. So I'm currently not playing.

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4 hours ago, 5thHorseman said:

To what?

I tried both GravityTurn and MechJeb for this on a 3.2x Kerbin and eventually gave up after many tries to find numbers that worked. I couldn't even find numbers that gave me super inefficient launches that worked, they all either burned up or nosedived into the ground.

The main reason I don't play with larger planets is that I hate the long wait to LKO and would rather just not play if I can't automate it. So I'm currently not playing.

i dont play whit RSS so i dont know the numbers but try different numbers
start by setting the start time to AP to 90
end time to AP can stay at 50 or try a bigger number
you did set the Ap to >120
wat is your TWR? is it more then 1.5 (1.5 is the recommended but i fond 2 to be better in kerbin)
you can try starting the turn at a higher speed and set the start angel to be smaller

try setting to move to prograde from SRFprograd to be at lower pressor

 

p.s.

GT will change the numbers after every lunch
after a fail it will start turning at a higher speed and whit a smaller angel
after a success it try's whit a lower speed and bigger angel

you can just do revert to lunch until GT finds good numbers

Edited by danielboro
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5 hours ago, 5thHorseman said:

To what?

I tried both GravityTurn and MechJeb for this on a 3.2x Kerbin and eventually gave up after many tries to find numbers that worked. I couldn't even find numbers that gave me super inefficient launches that worked, they all either burned up or nosedived into the ground.

The main reason I don't play with larger planets is that I hate the long wait to LKO and would rather just not play if I can't automate it. So I'm currently not playing.

We need to keep an eye on TWR. For Kerbin it should not be above 2.7 at the start and 3.7 to 40 kilometers. For RSS at the start it needs to be as small as possible. On some of my missiles this value is 1.08 or 1.2.

Here is an example of my launch of a rocket with a load of almost 200 tons. With the use of RSS. For governance'm using MechJeb.

https://www.youtube.com/watch?v=aI2l7VPmu0s&t=1s

 

Edited by Craze
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On 04/03/2018 at 8:06 PM, 5thHorseman said:

To what?

I tried both GravityTurn and MechJeb for this on a 3.2x Kerbin and eventually gave up after many tries to find numbers that worked. I couldn't even find numbers that gave me super inefficient launches that worked, they all either burned up or nosedived into the ground.

The main reason I don't play with larger planets is that I hate the long wait to LKO and would rather just not play if I can't automate it. So I'm currently not playing.

I've used Gravity turn in a few x3.2 games without problems.  (Although I always set the launch parameters myself, and never let GT attempt to optimise them).  If you are burning up in atmosphere, then you are either turning too aggressively, and/or have too high a TWR on the lower stage(s).  I suggest a takeoff TWR of between 1.2 and 1.4, (maybe as much as 1.8 if using short burn time SRBs).  Then each subsequent stage should have a TWR of around 1.2 at ignition.

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3 hours ago, AVaughan said:

I've used Gravity turn in a few x3.2 games without problems.  (Although I always set the launch parameters myself, and never let GT attempt to optimise them).  If you are burning up in atmosphere, then you are either turning too aggressively, and/or have too high a TWR on the lower stage(s).  I suggest a takeoff TWR of between 1.2 and 1.4, (maybe as much as 1.8 if using short burn time SRBs).  Then each subsequent stage should have a TWR of around 1.2 at ignition.

I basically never TWR over 1.3 and my upper stages frequently are near or even below 1 once horizontal.

It's been too long since I tried to remember details, but I remember feeling that there was a hardcoded "ceiling" where I couldn't get the mod to get me high enough before going horizontal.

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15 hours ago, 5thHorseman said:

I basically never TWR over 1.3 and my upper stages frequently are near or even below 1 once horizontal.

It's been too long since I tried to remember details, but I remember feeling that there was a hardcoded "ceiling" where I couldn't get the mod to get me high enough before going horizontal.

It's been a while since I used GT as well.  My current game is RO and RP-0.  A few years ago I did successfully use GT in RO as well, but that took too much fiddling with the parameters of the initial turn to be worth while.

 

Another possible reason for being too flat/failing to make orbit is pitching over too much in the initial pitchover.   (GT's defaut guess is tuned for a default sized kerbin.  On a x3.2 you probably want to pitch over around 5-6 degrees).

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18 hours ago, 5thHorseman said:

I basically never TWR over 1.3 and my upper stages frequently are near or even below 1 once horizontal.

It's been too long since I tried to remember details, but I remember feeling that there was a hardcoded "ceiling" where I couldn't get the mod to get me high enough before going horizontal.

Isn't it coded that way? On kerbin, it should go horizontal at 30-40km. However, for RSS, I don't think that altitude was changed to cope with the difference size and therefore it does it too early.

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5 hours ago, Not Sure said:

Isn't it coded that way? On kerbin, it should go horizontal at 30-40km. However, for RSS, I don't think that altitude was changed to cope with the difference size and therefore it does it too early.

I have no idea how it's coded. I just remember never ever getting it to work and feeling like there was a parameter that I needed to change, that I didn't have access to.

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As I understand GT, it isn't hard-coded.  Once your vertical speed reaches "Start m/s", GT pitches over by the amount specified in "Turn Angle".  It then tries to follow prograde, and maintain its desired time to apoapsis.  If time to Ap is rising too much GT will throttle down, if it is dropping, then GT will pitch up.  If Gt is pitching up too much, then that stage probably wants more TWR.  Alternatively you can start the launch with a high sensitivity to prevent GT throttling down, and let time to AP grow above 50, let the next stage burn some of its fuel, and then gradually drop sensitivity to bring time to AP back down.

I normally use a start ms of around 80, and a turn amount of 8.  I often have a low TWR of around 1 to 1.2 on the second stage, and often launch with sensitivity at 0.9.  If you are getting flat too early or too low,  you want to start the turn later and/or turn less.  Note that GT follows KSPs internal prograde calculations, so when the navball auto-switches between surface and orbit, the rocket's prograde marker pitches down, and required TWR to maintain time to AP grows.  Also make sure that any SRBs burn a decent amount of time, and you have a decent TRW at SRB burnout.

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3 hours ago, AVaughan said:

As I understand GT, it isn't hard-coded.  Once your vertical speed reaches "Start m/s", GT pitches over by the amount specified in "Turn Angle".  It then tries to follow prograde, and maintain its desired time to apoapsis.  If time to Ap is rising too much GT will throttle down, if it is dropping, then GT will pitch up.  If Gt is pitching up too much, then that stage probably wants more TWR.  Alternatively you can start the launch with a high sensitivity to prevent GT throttling down, and let time to AP grow above 50, let the next stage burn some of its fuel, and then gradually drop sensitivity to bring time to AP back down.

I normally use a start ms of around 80, and a turn amount of 8.  I often have a low TWR of around 1 to 1.2 on the second stage, and often launch with sensitivity at 0.9.  If you are getting flat too early or too low,  you want to start the turn later and/or turn less.  Note that GT follows KSPs internal prograde calculations, so when the navball auto-switches between surface and orbit, the rocket's prograde marker pitches down, and required TWR to maintain time to AP grows.  Also make sure that any SRBs burn a decent amount of time, and you have a decent TRW at SRB burnout.

Just to add to that: the switch from Surface to Orbit marker in the navball is controlled by GT and so is the pitch to horizontal. It is controlled by the "Pressure Cut Off" parameter. The closer to 0 the higher up this happens. Personally I started to set it to 600 for Kerbin. For RSS size games I'd suggest to set it even higher, or to 0 all together.

There is no hard-coded limit in GT in regards to pitch etc. The suggested parameters are all for stock only, they don't make sense for larger scale systems.

I occasionally played RSS with GT myself, but it's been a while. What I remember for a 1.5 TWR vehicle is this:

Increase the Start parameter to around 100
Turn Angle around 5
Time to AP, both to 60
Pressure Cutoff to 300 or even more towards 0

But as I said: it's been a while...

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Ah I wasn't aware that pressure cutoff affected the pitch to horizontal.  I thought it was for fairing deployment.  But I have pressure cutoff set lower than default as well.  

For RO, these days I highly recommend Mechjeb for launches.  The dev version has an implementation of Programmed Explicit Guidance that can put a suitable rocket into a nice circular orbit without needing throttle control, or coast to AP or engine relights.  I haven't tried that in stock or x3.2 yet.  (Maybe I'll play another x3.2 campaign once 1.4.1 is stable and mods have updated).

 

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33 minutes ago, AVaughan said:

Ah I wasn't aware that pressure cutoff affected the pitch to horizontal.  I thought it was for fairing deployment.  But I have pressure cutoff set lower than default as well.  

For RO, these days I highly recommend Mechjeb for launches.  The dev version has an implementation of Programmed Explicit Guidance that can put a suitable rocket into a nice circular orbit without needing throttle control, or coast to AP or engine relights.  I haven't tried that in stock or x3.2 yet.  (Maybe I'll play another x3.2 campaign once 1.4.1 is stable and mods have updated).

 

Yes, RO adds even more issues compared to RSS, like no throttling for most engines. That alone makes GT kind of unsuitable... I still have to try MJ's new way of doing launches :-).

Edited by AndyMt
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Just tried the current version of GT in a fresh KSP 1.4 install:

unfortunately it needs to be recompiled (at least). Not sure when I have time to look into this, because in the meantime I've changed PC and have to re-install everything... I would also have to merge my dev branch - or just do a new patch branch in GitHub.

Anyway - probably a few hours of work. Not sure if it would be better to wait for 1.4.1.

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On 3/8/2018 at 7:40 AM, AndyMt said:

Just tried the current version of GT in a fresh KSP 1.4 install:

unfortunately it needs to be recompiled (at least). Not sure when I have time to look into this, because in the meantime I've changed PC and have to re-install everything... I would also have to merge my dev branch - or just do a new patch branch in GitHub.

Anyway - probably a few hours of work. Not sure if it would be better to wait for 1.4.1.

Seemed to work ok for me.  The only issue I had was that it won't relinquish control when I click abort.

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2 hours ago, tg626 said:

Seemed to work ok for me.  The only issue I had was that it won't relinquish control when I click abort.

Exactly - you can regain control by switching to map view and back as a workaround. Don't know if MechJeb integration works after that.

Edit: actually it's by switching to the space center, then back to the vessel via the tracking station. This makes GT terminate and go away...

Edited by AndyMt
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2 hours ago, linuxgurugamer said:

Maybe because it isn't updated for 1.4 yet?  Given that the OP still says 1.3.x, you really should stop bothering mod authors until they get the mods updated

Thx :).

Today I took the effort to install Visual Studio on my new PC and got GT compiled. It seems to work, but I have to do some further testing and go through the whole release process again - of which I forgot most details... it's been a while.

Maybe I'll get a release finished end of this week.

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7 hours ago, popeter45 said:

on 1.4 im finding that when i activate gravite turn i cant abort it

If you'd bothered taking the time to read the two posts above yours, you'd know that this has already been reported, and that there's a workaround until such time as @AndyMt can update GT.

Don't be so damn lazy.. check to see if the problem has already been reported before posting. This kind of thing happens far too often around here.

Edited by JAFO
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12 hours ago, JAFO said:

If you'd bothered taking the time to read the two posts above yours, you'd know that this has already been reported, and that there's a workaround until such time as @AndyMt can update GT.

Don't be so damn lazy.. check to see if the problem has already been reported before posting. This kind of thing happens far too often around here.

im sorry

im quite bad at interriting stuff and was only pointing out issues so the dev knew about it to test for when recompiling, no intent to whine or offend 

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