[1.7.3] Community Delta-V Map 2.7

[Burning Kan]

This has so no footprint but soooooooooooooo helpfuel

should be in stock kspedia 10/10

thanks @Kowgan and all of u the worked on this project

[TheAngryHulk]

I installed the map into the KSPedia but I can't find where it is. What category do I find the map? I have opened the most obvious categories with no luck. 

 

EDIT: Never mind. I installed it the wrong way. I got it now.

Edited September 12, 2018 by TheAngryHulk

[Ultimate Steve]

Question... What image editor was used to make the maps? I'm thinking about making a map for a planet pack.

[Kowgan]

@Ultimate Steve Inkscape.

[Thorn_Ike]

Hi, 

Does the DeltaV calculated count for a round-trip? Or will I have to loop back through the lines to get that?

[Kowgan]

Add the numbers from point A to point B to go from point A to point B. If you wish to return from point B to Point A, you have to add the numbers again.
Remember that segments with Aerobraking indicators are possible to complete with little to no fuel usage.

Edited November 24, 2018 by Kowgan

[Benton]

Does the map include possible gravity assists?

[Snark]

1 hour ago, Benton said:

Does the map include possible gravity assists?

Generally dV maps don't do that-- mainly because gravity assists are so problematic in KSP.  The amount of dV you get from them is fairly small... and also it's so hard to aim when setting up a gravity assist that the extra amount wasted when (almost inevitably) you have to do a correction burn tends to more than offset the savings.  Plus, how much assist you'd get would seriously depend on circumstances, e.g. what angle you approach from, how low a periapsis you can manage, etc.

In practice,

• it would be really hard to have any meaningful info on a static "dV map" that would accurately capture gravity-assist benefits, and
• in practice, gravity assists tend to be so rarely used by KSP players that it would be of marginal benefit anyway to try to add it to the map.

So, essentially, "no". 

[XLjedi]

Apologies if covered in the thread somewhere, but while adding up the dV amounts on the map... 

Do you always have to assume you are starting or ending at Kerbin? 

Start at Duna end at Jool for instance?

Edited December 13, 2018 by XLjedi

[Superfluous J]

39 minutes ago, XLjedi said:

Apologies if covered in the thread somewhere, but while adding up the dV amounts on the map... 

Do you always have to assume you are starting or ending at Kerbin? 

Start at Duna end at Jool for instance?

There is no Duna-Jool value on the map so you'll have to get that yourself. But you can pretty easily do that with maneuver nodes if you have something orbiting Duna. Just draw it out in an ideal ejection until your projected path nears Jool, and then at that projected path draw a circle out to match your Sun orbit to Jool's. Those two burns will be enough (more than actually as you're not seeing any Oberth effects at Jool's orbit) to orbit Jool. Once in orbit of Jool all the Jool numbers will be fine.

Also, you could gravity assist at Laythe or Tylo if you normally do that from Kerbin, and it'll actually be MORE effective.

IIRC someone made a full-on every-planet set of maps, but I haven't seen one in years. Like, 4 of them.

[lajoswinkler]

How was this map made? I could emulate it, but I'd rather see a template or at least know the kind of software used.

It was made for OPM in the exact same style, so that means there is something in particular I could use.

[Kowgan]

Have you read the OP? Visited github? All necessary tools are referenced there.

[lajoswinkler]

2 hours ago, Kowgan said:

Have you read the OP? Visited github? All necessary tools are referenced there.

It doesn't say in the post, but now I went to Github and found it's SVG editing in Inkscape. Too much brain work to figure it all out just to make a small map, so I'll stick to vector software I used so far. Thanks nonetheless.

[DomiKamu]

Hi, I'm using Outer Planets Mod (lastest 2.2.2, KSP 1.6.1).

About Sarnus, the low orbit (10 km above) isn't 314 km as indicated on lastest dV map, but atmo deep seems to be 580 km (= 590 km for low orbit, 10 km above).

http://outer-planets.wikia.com/wiki/Sarnus

When trying to orbit as 314 km, they're plasma around my probe.

Edited February 1, 2019 by DomiKamu

[Kowgan]

I'm afraid there are currently no maintainers for the OPM verison of the map, and it is currently outdated (last update was for OPM version 1.8.1).

[rottielover]

Is the map now outdated for KSP 1.6 +  ?      I ask because I just did a test.  Using GravityTurn Continued and Kerbal Engineer Redux to take out the human factor; I constructed a comsat to go to Keostationary orbit.   According to the map I need 4515 dv to establish this orbit.   I built the rocket with 4585 dv total (according to KER) and I'm well over 300 dv short..  

According to the way I read the description the total on the map should be to have a circular orbit?  

[Kowgan]

@rottielover Thanks for the report, I'll test it and update as needed. Meanwhile, could you do me a favor and:
- Confirm your TWR per stage is nominal?
- Use the same methods (gravityturn continued) to achieve a 80x80km orbit aroun Kerbin using 3400dV and tell us the remaining dV?

Cheers.

Edited February 22, 2019 by Kowgan

[rottielover]

Hey thanks for the quick reply @Kowgan , I have read a lot of debate on what "optimal" TWR is, so I have been subscribing to the 1.3 ish model...  not sure if that's considered to be optimal anymore?  For this sample rocket KER is reporting the following (I am reporting the MAX TWR number here):   1st stage at 1.99 TWR, 2nd stage as 1.34 and 3rd stage at 1.21  (the satellite has a small tank and engine for tweeking orbit so I'm just counting that as part of the payload and thus is not included here).   For the payload, I took off the rocket and KSP stock is reporting it to be 4.7 tons (including fairings etc).  ...

So I was thinking, maybe what I should do is get Kerbal NRAP (I think thats what its called) so that I can create a dummy payload and do testing that way with a 5 ton payload

Using Grav Turn+Mechjeb to an 80kmx80km orbit  -  KER is reporting 1,034 dv remaining  I assume that means that grav turn and mechjeb spent 3,551 dv to achieve that orbit?

I also noticed that KER is showing me vacuum dv numbers in the VAB (which it should) but is showing a lesser Dv value on the launchpad.  Now the DV map says that those numbers are vacuum, so I assume if I have KER set for vacuum it should be fine?

I am going to re-do this test to make it much more repeatable,  I'm going to get that test weight mod and report back in a bit.

[rottielover]

So I downloaded NRAP and started a sandbox save.   I created the following rocket to make things easy to reproduce: 

NRAP payload set to 5 tons.  Directly attached is a FL-T400 Tank and LV-T15 Engine as the 2nd stage.  The first stage is FL-A151S Adapter, FL-A215S adapter, Rokomax Jumbo-64 and a Skipper engine.   This actually ended up being slightly overkill as it can hit 80x80 orbit on the first stage.

  931 dv remaining from 4585 that KER is reporting in the VAB   I assume that means it took 3654 to reach 80km x 80km unless I'm reading something wrong with KER?

Maybe there is some other factor I'm not accounting for?

I repeated this test 3 more times here are the results: 

Used "improve guess" button on Grav Turn  - 

1037 dv remaining - improved by 106 over first test, 3654 - so 3548 to make orbit?

1039 dv remaining - improved by 108 over first test - so 3546 to make orbit?

1040 dv remaining - improved by 109 over first test ...

I do have quite a few mods, however I don't believe that there are any that impact ISP, engines, atmospheres, etc. Vast majority of the mods I'm running are UI type stuff like Action Groups Extended and RCS Build Aid.  I have a few Parts mods like Missing History, Universal Storage, SDHI Service Module, Feline Rovers, and DMagic Science parts.  Again, nothing that I think would / should be altering the atmospheres or engine settings.

Edited February 22, 2019 by rottielover

[Kowgan]

Yes, you should use Vacuum dV for all calculations. Well, as long as you don't have any mod that changes the aerodynamic model, planet sizes and alike, you should be fine. KER and MJ are showing expected results on your tests. As I have read on other threads, it looks like the aerodynamic models and celestial body properties haven't been changed in quite some time now, so the values for 1.3 should be valid in 1.6.

This leaves me to a few options:
- Maybe your rocket isn't aerodynamic-friendly, and is causing more drag than it should? (maybe some modded part could be interfering there?)
- Maybe gravityturn isn't being optimal at the moment? I personally like to use a profile of 1.5 TWR for most of my payloads - except when I'm launching something extremelly massive and aerodynamic non-friendly, where I prefer to use higher TWR values. But overall, 1.5 until ~40km and then full throttle all the way to victory town seems to work for me.

I hope this helps.

[rottielover]

Well I suppose the NRAP thing could possibly be considered not aerodynamic by the game, I'm not sure how to tell but I could try to repeat these tests and put a fairing on it...   My original comsat rocket had fairings and was fairly basic and used the SQUAD 1.85m sized parts for the main lifter.   The 2nd test with the NRAP I tried to go back to the typical 1.25 and 2.5m sized parts.

It could very well be Gravity Turn for all I know.   I will try using MechJeb's ascent tool and see if I get different results.

EDIT:  Used MechJeb2's ascent module auto pilot and it left the NRAP test rocket in orbit with 977 dv left.  Basically right between the Grav Turn tests.   Next I will test a fairing.

Edit 2 - fairing didn't change anything with the NRAP tester.   So this leaves me at the conclusion that it's costing me somewhere between 100-300 more m/s to reach LKO than the map states.  I'm not sure about the other destinations yet.

Edited February 23, 2019 by rottielover

[Superfluous J]

You will be a whole lot better off if you consider ANY vacuum numbers to be estimates. There is literally no way to stamp a definitive number on how much dV you'd need to reach orbit from a body with an atmosphere.

[JAFO]

1 hour ago, rottielover said:

It could very well be Gravity Turn for all I know.   I will try using MechJeb's ascent tool and see if I get different results.

You absolutely will get different (almost certainly worse) results with MJ's ascent tool, because MJ does not fly optimal ascents, just "good enough" ones.

And yes, craft design and the altitude at which you pop off the fairings will make a difference (I find higher is better - I generally go with 62-65km). 

But with the right design, GT is capable of excellent results. For instance, the usual dV quoted to reach 80x80 orbit of Kerbin is 3200. Using GT (and MJ just to circularise), I have achieved it using just 2800 dV.

Edit: Just to be sure, you ARE going through the entire multiple-launch iterative process with GT to optimise settings as much as possible, yes? Because the first few GT launches of a craft will always be far from optimal, in terms of dV.

Edited February 23, 2019 by JAFO

[rottielover]

I'm not getting anywere near that good.  I'm getting 3600 to 3800 dV needed to LKO (80x80).  So I suppose the question becomes which mod is doing something that it should not be doing, and /or should I just say screw it and get realistic atmosphere's and FAR installed and call it a day?   ... 

[JAFO]

2 minutes ago, rottielover said:

I'm not getting anywere near that good.  I'm getting 3600 to 3800 dV needed to LKO (80x80).  So I suppose the question becomes which mod is doing something that it should not be doing, and /or should I just say screw it and get realistic atmosphere's and FAR installed and call it a day?   ... 

As I asked in the edit to my post above, are you using GT correctly? Are you doing multiple sequential launches of the same craft, to get GT to optimise its settings as much as possible, or just going with the first couple of launches of a new design?