[1.0.5] GravityTurn version 1.3.1 - Automated Efficient Launches (1.1 pre-release available)

[Overengineer1]

@mcirish3 If your lower stage is underpowered, there's not much I can do for you. GT won't get you off the ground if you can't get off the ground.  If your upper stage is underpowered, then GT will still get you into orbit if at all reasonably possible.  It pitches up if it finds that you are at max throttle and still at risk of falling.  It's even possible to fall back down for a while before building enough speed to climb again, and GT will carry on flying through that.  Some designs that have to be launched this way are actually extremely efficient, and if you spend a lot of (successful) time in RSS you will almost certainly see it.

[m4ti140]

Are you planning to make the altitude at which the turn is finished tweakable as well?

[Overengineer1]

@m4ti140 No, that doesn't sound like it would fit with how GT works.  The turn isn't ever finished, it just blends into an orbit, which is still turning.  The "finishing" time as you probably think of it would be impacted by the Sensitivity setting, higher settings may be slightly less efficient but will climb faster during the final part of the ascent.  I don't recommend prioritizing time-to-space in this way, though.  I generally just let the gravity turn run its course and do a 4x physical warp until atmosphere exit.  GT is configured to stop all time warps when it hits space.

[m4ti140]

48 minutes ago, Overengineer1 said:

@m4ti140 No, that doesn't sound like it would fit with how GT works.  The turn isn't ever finished, it just blends into an orbit, which is still turning.  The "finishing" time as you probably think of it would be impacted by the Sensitivity setting, higher settings may be slightly less efficient but will climb faster during the final part of the ascent.  I don't recommend prioritizing time-to-space in this way, though.  I generally just let the gravity turn run its course and do a 4x physical warp until atmosphere exit.  GT is configured to stop all time warps when it hits space.

I'm not prioritizing time to space, I want to perform a continuous burn ascent, ending on a circularized orbit. This would require the engines to cutoff exactly when the vehicle hits apoapsis.

[Overengineer1]

Just now, m4ti140 said:

I want to perform a continuous burn ascent, ending on a circularized orbit.

This has a lot more to do with the specs of your vessel than with anything else.  For a burn that long, your TWR has to be extremely low.  Most engines are not capable of throttling that low without cutting out, so you'd need a very low TWR stage.  This would be much easier in RSS where the velocity requirements are much higher.

If your ship is designed properly with a low enough TWR, then this is exactly what GT would do.

[trainman1000]

The UI wont show for me when I click the activation button, any idea what might be the cause of such thing as these?

[damerell]

8 hours ago, Overengineer1 said:

@mcirish3 If your lower stage is underpowered, there's not much I can do for you. GT won't get you off the ground if you can't get off the ground.  If your upper stage is underpowered, then GT will still get you into orbit if at all reasonably possible.  It pitches up if it finds that you are at max throttle and still at risk of falling.

I did notice some states (will produce craft and input settings if useful) where it chugs upwards on 1/2ish throttle until the nose dips below the horizon at circa 20km altitude. It then goes to full throttle without pitching up and fiery comedy ensues. With slightly different input settings, it flies a beautiful ascent for the same craft.

[DStaal]

A minor idea/suggestion: When a stage is just about out of fuel, it might be interesting to 'push back' the apoptosis just a bit - no more than a second and a half, just a bit.  The thought being that the lower stages typically have higher thrust, and that's the point where the stage being dropped has it's highest TWR - and in a moment, we're going to coast for a moment, then we drop to a lower thrust and TWR.  Basically, instead of forcing the higher stage to catch up to the apoptosis lead time, use the lower stage to boost it so the stage delay brings it back to the goal.

[SSgt Baloo]

I have anxiety disorders. This mod has transformed launches from unpleasant, stress-filled events, into a pleasure. Thank you.

[danfarnsy]

 

18 hours ago, mcirish3 said:

Just curious what happens if you have a slightly underpowered rocket?  I know... I know... that almost never happens.

It ends up stuck on full-throttle because you can't get your apoapsis out far enough in front. Then it tilts your rocket upwards from prograde and you lose even more dV to gravity and steering losses. You also spend too much time in denser atmosphere, racking up extra drag losses. The way I compensated without modifying my rocket design was to start the gravity turn later (at ~150 s) and make the initial turn a little smaller (at ~8 degrees).

[linuxgurugamer]

Do you think you could add AVC compatibility?  All it needs is a file containing the version (gravityturn.version) in a specific format, and an entry on the website so AVC can check to see if it is updated.  Actually, the website will even generate the file for you, to make it easy.

http://ksp-avc.cybutek.net/?page=Home

Also, if you include the miniavc.dll, then it will self-check at start time.

[linuxgurugamer]

Just downloaded and tested the latest version.

Looks much nicer in the formatting.

Bugs:  

1. If you click the toolbar button to hide the window during the ascent, it stops working, and even if you click the button to bring it back, it will still be nonfunctional until the launch is reset.
   It's almost as if you hit the abort button, however the Abort button 
   I'd suggest that hiding it via the toolbar button should not equate to a full shutdown of the mod.  It should continue to run, even if not being shown
2. Clicking the tip button (the questionmark) brings up the tip window, but clicking it again doesn't hide it.  This requires a little extra unnecessary mouse movement

Overall, a very nice improvement. 

[linuxgurugamer]

While I'm not a space shuttle pilot (speak to EJ for that), I tried the one in stock.  You may want to put an option in to not reduce the main throttle until all SRBs are detached.  I got it launched by changing the sensitivity to 0.5, but after dropping the boosters it seemed to be too high.  Not sure what is going on, when it got high enough it couldn't seem to stabilize.  Maybe due to the sensitivity being too high, but whatever the case, it was not able to get to orbit

Edited January 17, 2016 by linuxgurugamer

[Overengineer1]

@linuxgurugamer You can't please everyone every time.  Some crafts are just too hard to auto-detect.  It would be a little hard for me to make the code know whether or not it should reduce throttle just because the thrust would be out of line with the center of mass.  If you have specially designed crafts, you'll need specially designed GT settings.  I think setting a higher Hold AP Time Start is what you'd be after here, that would cause GT to maintain full throttle for longer.

[linuxgurugamer]

6 minutes ago, Overengineer1 said:

@linuxgurugamer You can't please everyone every time.  Some crafts are just too hard to auto-detect.  It would be a little hard for me to make the code know whether or not it should reduce throttle just because the thrust would be out of line with the center of mass.  If you have specially designed crafts, you'll need specially designed GT settings.  I think setting a higher Hold AP Time Start is what you'd be after here, that would cause GT to maintain full throttle for longer.

Not a problem, just reporting what I saw.  The first one, however, is a bug.  The mod should not shut down just because the window is hidden

[vardicd]

Don't know if its been reported yet, but the latest version if you set your desired apoapsis, and roll, then clikc best guess to get the setting for those, it resets to the default 80 KM and -90 roll. Is that supposed to happen.

[kopapaka]

vardict:  80 KM and -90 roll is a best settings

[JAFO]

On 14/1/2016 at 5:09 PM, mcirish3 said:

OK so after some heavy digging it turn out you are right and there is no known analytical solution to the goddard problem and to do what I was talking about would be very CPU intensive..so... sorry about all the fus I have made.  Unless this is true-http://arc.aiaa.org/doi/pdf/10.2514/6.IAC-06-E4.3.05

Have you seen this?

"Solving the Goddard problem with thrust and dynamic pressure constraints using saturation functions"

http://cas.ensmp.fr/~petit/papers/ifac2008/0637.pdf

 

Dunno how helpful it will be, but you never know..

[JAFO]

On 14/1/2016 at 9:32 AM, vardicd said:

A big problem is I'm still learning how to build with the new aero system. I'm still used to the old system. I still haven't gotten my head around how to build rockets that work well in the new system. and well, unlearning what I've learned is proving more difficult than expected.

The main thing I've found is not that the way you build ships needs to change, it's that your launch profile needs to change.. you need to keep your speed below 1500m/s as you pass through the 20-40km zone, or you'll burn up.

[AlbertKermin]

OK, I just bumped into this mod, and I must say- it is EPIC! I mean, seriously, I prefer doing my orbital accents manually, but this thing just got to space with better than twice the fuel I usually have. I'm using it in all my games from now on!

[Karyn451]

Is it possible to have a kOs script version of this?  Or is it too complicated?

[Overengineer1]

@Karyn451 I think it's possible to do a gravity turn with kOs, but making a script that is general purpose and configurable and handle all the different situations that this mod handles... It would be a lot of work for someone.

[rekrats]

I try to use GravityTurn (latest Version from CKAN) without any success. It seems that the Gravity Turn ist not high enought.

Basiacally everything goes well until around 42k, then the climb almost stops and after burning around 3700 m/s the apoapsis reaches 80k but the height is still around 44 to 45k. Engine shuts down, atmospheric drag kicks in, apoapsis starts to drop and at around 46k the climb stops and the ships drops back.

I am using FAR and Deadly Reentry and a ship with procedural fairings and it seems that at 45k the is still too much atmospheric drag to reach the final 80k. Is there a way to tweak that height?

 

Anothe strange thing is the Air Drag Loss which is higher than the total burnt delta/v.

[Overengineer1]

@rekrats Obviously one of the other mods is messing with the calculations.  It's hard to support or troubleshoot with so many other mods all potentially messing around with the atmosphere specs.  If you were able to pin it to one mod that causes a conflict, I could take a look.  But I know lots of other users use GT with FAR with good results.

[Ogre420]

Just found out that this has a conflict with the mod "Critical temperature gauge " (http://forum.kerbalspaceprogram.com/index.php?/topic/107774-105-critical-temperature-gauge/).

When I activate the "Force Show gauge" from that mod the Gravity turn ICON and the display disappear.

I have a bunch of other mods loaded so you might want to confirm this yourself.