Why isn't delta-v exposed in Stock (yet)?

[LukasKerman]

It's only my "theory" but I would say a Δv readout can potentially bypass a lot of gameplay. Where you would normally fly a few missions that fail and maybe lead to new missions and adventures (stranded etc.), you now pretty much know for sure that you have enough Δv to reach the Mun and return before you even launch. Besides that a Δv readout is also everything but correct. The moment you throttle for example or do other things you lose Δv. In order to make any use of the number you also had to follow very specific routes. For example knowing that you need 4000 m/s Δv to land on the Mun (made up number) you must fly exactly the same trajectory that was used to calculate the requirement. The moment you pick another starting orbit or destination orbit it's all meaningless to know that number.

Δv is only really necessary if you want to plan out a mission in every detail on paper beforehand. I think that is exactly the realm of mods especially since the readout is so unreliable when you think about the endless possibilties you can build a rocket.

What I would do is to completely get rid of Δv even from the maneuver node. I would also replace the maneuver node with a virtual orbit you can set up in the map even if you have not yet launched similar to how it's done in the new mission builder. That would give you an idea when and in which direction you have to launch but finding out what kind of a rocket you need to achieve it would be part of the gameplay.

A good method to play KSP somewhat effciently (without building huge rockets that are way to capable) is to develop rockets that can lift a certain mass to LKO and then move on from there. Imagine you have 3 rockets one able to lift 10 tons, one 20 tons and the last 30 tons. Having these you never have to think about building rockets anymore just use these as subassemblies. Now you build spaceships that are 10, 20 and 30 tons in mass. With each spaceship you try to land on the Mun without payload. The amount of fuel you have left touching down on the surface is the payload they can deliver there. So what you do is remove that spare fuel in the VAB and replace it with a payload.

You can repeat this process with more rockets and spaceships to other destinations of course. You will gradually develop a fleet of vehicles that you exactly know the mass delivery capabilities of. So if you ever want to land a 10 ton payload on the Mun or on Duna you can pick a certain rocket, a certain ship and go without the need of Δv. Developing such a fleet is at least for me a very entertaining process but everyone is different. I just noticed how people often build a new rocket for every payload they fly. It's of course not wrong but that makes using Δv and Kerbal Engineer almost a requirement.

What I would like to see added as a number is the total thrust of the current stage. Adding up the thrust to eyeball the TWR is really tedious on some rockets. They could for example add the total thrust number of all eninges that are currently free to fire with a slider for the atmospheric pressure. On the slider there could be symbols for vacuum, Kerbin and other bodies with an atmosphere. In career mode these symbols could be unlocked by landing on such a body for the first time. Not knowing how much thrust you will have launching your lander off Eve is incredibly annoying. There is no way around manually calculating it. You can bypass Δv as described above but not your thrust. We can't trust the thrust, the only thing Kerbals live for.

Edited March 11, 2018 by LukasKerman

[MinimalMinmus]

I think there should be a dV readout, but only with the VAB being level 3. This way, the carreer player will have the time to familiarize himself with everything in the game before we get to the numbers. As of the number VS graph debate, I'd be on the number side, as they are more precise, but there may also be graphs to help the newcomer.

[Waxing_Kibbous]

It should be in the game, and it should be an option- some want exact numbers, some want to figure out the numbers on their own because its fun and immersive to them, and then there are those of us who like to wing it. While we're at it lets fix the burn time calculator, have a Ap/Pe readout in the flight screen, and have a simple transfer window planner...

[magnemoe]

40 minutes ago, LukasKerman said:

It's only my "theory" but I would say a Δv readout can potentially bypass a lot of gameplay. Where you would normally fly a few missions that fail and maybe lead to new missions and adventures (stranded etc.), you now pretty much know for sure that you have enough Δv to reach the Mun and return before you even launch. Besides that a Δv readout is also everything but correct. The moment you throttle for example or do other things you lose Δv. In order to make any use of the number you also had to follow very specific routes. For example knowing that you need 4000 m/s Δv to land on the Mun (made up number) you must fly exactly the same trajectory that was used to calculate the requirement. The moment you pick another starting orbit or destination orbit it's all meaningless to know that number.

Δv is only really necessary if you want to plan out a mission in every detail on paper beforehand. I think that is exactly the realm of mods especially since the readout is so unreliable when you think about the endless possibilties you can build a rocket.

I use dV a lot just for all sort of stuff on the fly, today I had one ship jumping out into solar orbit, back I wanted to stop at Minmus to drop of crew, I set up an intercept who combined with circulation cost 1100 dV leaving 250 for landing and margin. 
Second mission was land tourists on Mun, pick up an stranded kerbal in Mun orbit and go to Minmus. Yes stranded kerbal was in retrograde orbit I was not. however 3K dV. would be enough to land on Mun, launch retrograde and do an minmus intercept and landing, option was to dock and transfer kerbals to the mobile mun base land and do irsru dock with ship, transfer kerbals and do an 180 degree plane change at high Ap, snatch kerbal and go to minmus.

The real currency in KSP is not fund but dV. 

[mattinoz]

2 hours ago, linuxgurugamer said:

But what would that colored bar indicate?  

This opens a can of worms.  Personally, I think that a basic list of dV per stage shouild be all that a minimal display should have, along with buttons which w would bring up info screens explaining what it is and what is needed to get to orbit.

Accept the fact that in order to d o well, you need to use numbers, and move on from there.

Well following HebaruSan's rule of thumb at the top of the thread. What if each segment on the bar was a Kerbin Half Orbital (kHO)?

Then a 4kHO craft should be able to make it anywhere if Orbit is half way to anywhere. As the player advances the bar get more marks for 1/2 and 1/4 kHO's. Or in interface could be a circle pip that fills up to show what part of kHO. Each stage could have a pip or two for it's Dv capacity and the Pips up and get a total for craft. Tracking station could markers on other bodies orbits to show kHO's needed, as station upgrades precision could increase to to 1/2, 1/4, even 1/8 kHO's

[GoSlash27]

6 hours ago, eightiesboi said:

Seriously, for people that play ENTIRELY in stock, how do you deal with this? Do you just massively over-engineer your rockets?

Well... I mathematically model my stages and then build them so they deliver precisely the thrust and DV I need from them. If I need to calculate DV remaining, all the pertinent data is available in the stock game. Ship mass, fuel and oxidizer units, engine Isp.

 I do the same math that KER does. I just do it either in a spreadsheet or with the calculator.

Best,
-Slashy

[SpaceMouse]

I agree this should absolutely be in stock KSP... it almost seems like they want to make you do the math, which would be completely contrary to KSP's simplified spaceflight. I can get numbers might be intimidating for new players but there should be SOMETHING. 

[GoSlash27]

3 minutes ago, SpaceMouse said:

it almost seems like they want to make you do the math, which would be completely contrary to KSP's simplified spaceflight.

 I think that's *exactly* what Squad wanted. I think KSP was intended to make the player a better rocket scientist. Becoming a better rocket scientist includes learning the math.

Best,
-Slashy

[ndiver]

5 minutes ago, GoSlash27 said:

 I think that's *exactly* what Squad wanted. I think KSP was intended to make the player a better rocket scientist. Becoming a better rocket scientist includes learning the math.

Best,
-Slashy

But in this case, aren't these maths missing in the game?

[GoSlash27]

ndiver,

 What do you mean? The game provides all the info needed to make the calculations.

Best,
-Slashy

[juanml82]

2 hours ago, LukasKerman said:

It's only my "theory" but I would say a Δv readout can potentially bypass a lot of gameplay. Where you would normally fly a few missions that fail and maybe lead to new missions and adventures (stranded etc.), you now pretty much know for sure that you have enough Δv to reach the Mun and return before you even launch. Besides that a Δv readout is also everything but correct. The moment you throttle for example or do other things you lose Δv. In order to make any use of the number you also had to follow very specific routes. For example knowing that you need 4000 m/s Δv to land on the Mun (made up number) you must fly exactly the same trajectory that was used to calculate the requirement. The moment you pick another starting orbit or destination orbit it's all meaningless to know that number.

Δv is only really necessary if you want to plan out a mission in every detail on paper beforehand. I think that is exactly the realm of mods especially since the readout is so unreliable when you think about the endless possibilties you can build a rocket.

What I would do is to completely get rid of Δv even from the maneuver node. I would also replace the maneuver node with a virtual orbit you can set up in the map even if you have not yet launched similar to how it's done in the new mission builder. That would give you an idea when and in which direction you have to launch but finding out what kind of a rocket you need to achieve it would be part of the gameplay.

A good method to play KSP somewhat effciently (without building huge rockets that are way to capable) is to develop rockets that can lift a certain mass to LKO and then move on from there. Imagine you have 3 rockets one able to lift 10 tons, one 20 tons and the last 30 tons. Having these you never have to think about building rockets anymore just use these as subassemblies. Now you build spaceships that are 10, 20 and 30 tons in mass. With each spaceship you try to land on the Mun without payload. The amount of fuel you have left touching down on the surface is the payload they can deliver there. So what you do is remove that spare fuel in the VAB and replace it with a payload.

You can repeat this process with more rockets and spaceships to other destinations of course. You will gradually develop a fleet of vehicles that you exactly know the mass delivery capabilities of. So if you ever want to land a 10 ton payload on the Mun or on Duna you can pick a certain rocket, a certain ship and go without the need of Δv. Developing such a fleet is at least for me a very entertaining process but everyone is different. I just noticed how people often build a new rocket for every payload they fly. It's of course not wrong but that makes using Δv and Kerbal Engineer almost a requirement.

What I would like to see added as a number is the total thrust of the current stage. Adding up the thrust to eyeball the TWR is really tedious on some rockets. They could for example add the total thrust number of all eninges that are currently free to fire with a slider for the atmospheric pressure. On the slider there could be symbols for vacuum, Kerbin and other bodies with an atmosphere. In career mode these symbols could be unlocked by landing on such a body for the first time. Not knowing how much thrust you will have launching your lander off Eve is incredibly annoying. There is no way around manually calculating it. You can bypass Δv as described above but not your thrust. We can't trust the thrust, the only thing Kerbals live for.

But you can have lifter subassemblies ready and a dV readout. I do just that. I build my upper stage keeping an eye in the TWR and dV requirements to do whatever the upper stage must do. When it's done, I check the weight and pull a subassembly to use as the lower stages. So if my payload is 62 tons, I just pick the "Lifter 70 Tons" and attach it.

[ndiver]

37 minutes ago, GoSlash27 said:

What do you mean? The game provides all the info needed to make the calculations

I don't remember where are (ingame) the formula allowing me to determine the delta-v :

- of my stages

- needed to go (for example) to the Mün

Because that's precisely the point. If you say that you don't need mods like KER to determine the delta-v of a rocket (which is the discussion here), because "the game provides all the info needed to make the calculations", where are the required formulas ingame to determine your delta-v?

Edited March 12, 2018 by ndiver

[Rocket In My Pocket]

5 hours ago, qzgy said:

So.... different colored bars for different stages filling up to a grand total or something?

I was thinking more like you would select your desired destination planet from a drop down list and the game would generate an empty bar based on how much Dv is needed to get there currently. (Addressing transfer windows in stock is a whole nother' issue.)

Then as you build your rocket, the bar fills up as the Dv rises, or drops if it goes down. The bar starts out red, goes to yellow as it fills, then green when you meet the minimum Dv requirement, then perhaps blue for anything extra. (We'd leave room at the top of the bar for let's say 20-25% extra Dv to encourage players to build in a "safety net."

To be clear, this isn't intended to replace actual numbers for advanced players like us, I'm just trying to keep the game as approachable and "new player friendly" as possible.

3 hours ago, klgraham1013 said:

You know.  I never really thought this was a game for casual players.  That's me though.

Part of me agrees with you certainly, but another part of me likes to think KSP is for everyone.

That's the magic of it isn't? Even a child can go to space.

I don't think KER is going anywhere, even if it was abandoned we all know @linuxgurugamer would grab it up lol. So I'm trying to look at this as a feature for not for "us" but for "them."

5 hours ago, linuxgurugamer said:

But what would that colored bar indicate?  

This opens a can of worms.  Personally, I think that a basic list of dV per stage shouild be all that a minimal display should have, along with buttons which w would bring up info screens explaining what it is and what is needed to get to orbit.

Accept the fact that in order to d o well, you need to use numbers, and move on from there.

I agree, it does open a can of worms, particularly transfer windows.

But if we are gonna include a stock Dv meter, we gotta address transfer windows at some point as well.

Like I said, numbers should totally be available, just hidden behind a menu toggle like advanced tweakables, or at least behind a button toggle.

Edited March 12, 2018 by Rocket In My Pocket

[GoSlash27]

16 minutes ago, ndiver said:

Because that's precisely the point. If you say that you don't need mods like KER to determine the delta-v of a rocket (which is the discussion here), because "the game provides all the info needed to make the calculations", where are the required formulas ingame to determine your delta-v?

ndiver,

 Oh, I see what you're saying. The game doesn't contain the tutorials for the math, valid point. The *community* has the tutorials for that stuff.

*EDIT* also, the wiki has useful info on the subject, Both how much DV is required to reach a destination, and how to calculate your rocket's DV.

Best,
-Slashy

 

Edited March 12, 2018 by GoSlash27

[klgraham1013]

1 hour ago, GoSlash27 said:

 I think that's *exactly* what Squad wanted. I think KSP was intended to make the player a better rocket scientist. Becoming a better rocket scientist includes learning the math.

Best,
-Slashy

I thought Squad wanted players to guess until they stumbled across a solution?  Isn't that the whole trial and error mantra?  I'd feel better if you were right and I actually say Squad talking about the formula's to new players.  I'm not sure they are.

edit: You address this in your next post.  My bad.  I still believe you can't truly say Squad wants players to do the math if the game doesn't say what the math is.

Edited March 12, 2018 by klgraham1013

[GoSlash27]

2 minutes ago, klgraham1013 said:

I thought Squad wanted players to guess until they stumbled across a solution?  Isn't that the whole trial and error mantra?

Perhaps. I suspect that they followed Plutarch's mantra on this; the mind isn't a vessel to be filled, but a fire to be kindled. The player would eventually grow tired of guessing and failure and go out and seek the proper way to do it.

Could be wrong though,
-Slashy

[mattinoz]

19 minutes ago, GoSlash27 said:

ndiver,

 Oh, I see what you're saying. The game doesn't contain the tutorials for the math, valid point. The *community* has the tutorials for that stuff.

*EDIT* also, the wiki has useful info on the subject, Both how much DV is required to reach a destination, and how to calculate your rocket's DV.

Best,
-Slashy

 

How many players know the forums even exist?

Steamspy and the stats here would suggest its less than 10%.

[klgraham1013]

11 minutes ago, GoSlash27 said:

Perhaps. I suspect that they followed Plutarch's mantra on this; the mind isn't a vessel to be filled, but a fire to be kindled. The player would eventually grow tired of guessing and failure and go out and seek the proper way to do it.

Could be wrong though,
-Slashy

That's what I did.  It just bothers me that players are left to searching for answers on Wikipedia or finding Scott Manley videos.  Contracts were an excellent way to guide players through these things in small steps.  Unfortunately, the beginning career contracts don't do that.  Instead, there's a tutorial part of the main menu that everyone ignores.  I'm not even sure if they're good, it's been so long since I've looked out them.  I do remember they needed to learn what "brevity" meant.

9 minutes ago, mattinoz said:

How many players know the forums even exist?

Steamspy and the stats here would suggest its less than 10%.

At this point, it's a problem that probably won't be solved is KSP1's lifetime.

Here's what is in KSP as of now.

Edited March 12, 2018 by klgraham1013

[HebaruSan]

38 minutes ago, klgraham1013 said:

Here's what is in KSP as of now.

What the... that is completely useless gibberish. Where on earth do the 200 and 100 m/s come from, why does the vessel need 200 m/s, how do they relate to each other...? No one who reads this will have the slightest clue what's going on when they see "delta V" in conversations.

[klgraham1013]

4 minutes ago, HebaruSan said:

What the... that is completely useless gibberish. Where on earth do the 200 and 100 m/s come from, why does the vessel need 200 m/s, how do they relate to each other...? No one who reads this will have the slightest clue what's going on when they see "delta V" in conversations.

I love how there's a paragraph entitled "Doing the Maths."

[Gargamel]

I think the new misison builder DLC might allow a training mission to be built to teach the math's part of this..... 

[OHara]

Hopefully, that KSPedia  page will someday show a map-view of a ship in low-Kerbin orbit, with a maneuver node to boost it to the Mun, so it can say:

The craft needs to increase its speed by 800m/s in order to boost itself into an orbit that crosses the Mun's orbit.  (This change in speed was historically computed using what was called the 'vis viva' equation.) Then the craft needs to slow down, relative to the Mun, by about 400m/s to enter circular orbit around the Mun.

The ability of the craft to change its speed is its thrust divided by its mass, T/m, times how long it can sustain that thrust with a given amount of fuel.  The mass of the craft changes as fuel is burned, but the delta-V for a given I_sp, starting mass, and ending mass, can be easily computed using what was historically called the 'Tsiolkovsky rocket equation'.  

Toggling the [wished for] Δv button in the 'Engineers Report' will show the delta-V you can potentially get from each stage.  This computation assumes that you use all fuel available to that stage, use each engine in the atmospheric or vacuum environment where it works best, and use steering and all engines in that stage to change in velocity in the same direction.

Figuring delta-V for a craft is enlightening once, but that enlightenment can be done on pencil and paper, or spreadsheet, or however each person best comes to understand. Computing delta-V while designing is tedious, involving looking up the I_sp of the engines, and figuring starting and ending masses of the burns.   But having it computed automatically, as I change the craft, helps develop intuition about when splitting stages is worthwhile.

One of Dmagic's mods does a nice job of presenting delta-V, computed using KER's code, in a simple way.  

 

Edited March 12, 2018 by OHara

[Pi_]

Quick question, if a dV display was provided in the VAB, would not players still need to consult the "subway map" for it to have any meaning?  I didn't see it in the OP, but I guess his idea is for the subway map to also be included somewhere in-game?

Full disclosure:  I'm one of those who started playing KSP in the old days (v0.16).  Personally, I enjoyed the trial and error method... having to go back to the VAB and make changes to accomplish whatever mission I was attempting.  Granted, I already had a basic understanding of how spaceflight worked, so that probably helped.

Someone mentioned that the T & E method takes too long when dealing with bodies outside the Kebin system... which is a valid point.  However, using what we used to call the cheat menu (Alt+F12) is great for jumping to a given body and testing a ship design.  And yes, I get that you would still have to use time warp for testing the transfer stage, or multiple stages in the case of a grand tour type mission.  But like I said, that is part of the fun for me personally.  And as it turns out, as someone also previously mentioned, after playing a while the T & E method will pretty much teach you what you need to get a particualar payload to a particular location.

Of course it comes down to what helps a given player get the most enjoyment out of the game.  Or I should say, get the most enjoyment out of KSP... because it's really half game and half sim.  So for those who want to make it as close to a full blown sim as possible, you should definitely install all the mods.  I don't disparage anyone in the slightest for using as many mods as they want.  But for me, stock-vanilla is great... and, I don't have to worry when a new patch comes out that my mods won't work. 

[sevenperforce]

I just do the math. 

But most players don't have degrees in physics, so...

[Gargamel]

6 minutes ago, Pi_ said:

Quick question, if a dV display was provided in the VAB, would not players still need to consult the "subway map" for it to have any meaning?  I didn't see it in the OP, but I guess his idea is for the subway map to also be included somewhere in-game?

I hope they would have to.  I think if there is an in game DV readout, it should be as simple as possible.   At best showing the DV for each stage.  Of course this would have to be unlocked or researched in some fashion, requiring the player to still try to figure out what the math themselves.   But there comes a point when you have learned something, that it becomes cumbersome to do it repeatedly.  That point differs between people, (ahem slashy ).   Having the subway map included in the game somehow might be nice, but tabbing between windows is probably easiest.