Stock DeltaV Calculator?

[SuperNova2015]

So up until now I've been playing KSP without ever knowing how much deltaV my rocket had. I didn't see anything wrong with that. Until recently after I flew a mission to Duna. My fuel was low and my first launch window for Kerbin required a lot of deltaV so I waited years for a smaller burn only to discover that I had plenty of remaining fuel to make that first burn. In the end what would have been a 2.5 year mission ended up taking nearly 5 years all because of my faulty guessing. Feeling like a failure, I looked up how to calculate the deltav and then wrote a simple program in c++ that calculates how much deltaV a rockets current stage has.

Here's the C++ code:

#include <iostream>

#include <math.h>

using namespace std;

int main()

{

double totalMass, fuelMass, engineVelocity, deltaV, Isp;

cout << "What is the total mass?" << endl;

cin >> totalMass;

cout << "What is the fuel mass alone?" << endl;

cin >> fuelMass;

cout << "What is the engines Isp?" << endl;

cin >> Isp;

engineVelocity = 9.8 * Isp;

deltaV = engineVelocity * log(totalMass / (totalMass - fuelMass));

cout << "The DeltaV is " << deltaV << "." << endl;

cin.get();

cin.get();

}

After building this and using this little calculator for a few missions, I now feel idiotic for not doing this before. Until now I never realized just how big of a handicap I had been playing with.

So in conclusion I now strongly believe that the deltav for rockets is the single most crucial peace of information missing from the stock game. In the least a level 5 pilot or engineer should be able to calculate the remaining deltav for the current rocket stage. Which could keep players like me all stock. And I have to ask if anyone else thinks Squad should add such a feature to the game.

[Rusty6899]

I do always calculate it myself, but I'm starting to come round to the idea of having a delta-v calculator in stock, albeit at a high tech level or with an engineer at a high level.

I actually found that learning about delta-v and how to calculate it was much more rewarding than just being given it, but now that I understand it, it seems more of a nuisance to work it out myself.

If it is available to a level 5 engineer then it requires a number of interplanetary missions to be carried out before it becomes available, so that would probably be the best option.

[sal_vager]

Squad are adding this for 1.0 already

[Superfluous J]

And I have to ask if anyone else thinks Squad should add such a feature to the game.

Not only should they, they ARE. Hopefully they'll discuss it in today's Devnotes, which should be coming out any time now. But they teased it 2-3 weeks ago on Twitter.

[SuperNova2015]

Oh, sorry for opening this thread then. It seems I missed that bit of news.

[AbacusWizard]

I've always enjoyed calculating the ∆v myself (as a spreadsheet or on a calculator), and will probably continue to do so at least some of the time, but I do think it makes a lot of sense for it to be included in stock.

[Renegrade]

engineVelocity = 9.8 * Isp;

It's actually 9.82 for Standard Gravity in KSP for whatever derpy reason, FYI. Also, if you took the arguments from the command line instead, you could use your OS's command history for repeated calculations

(That's pretty much what I did, only in perl)

[Valley]

I have been using Mech Jeb 2 and just started using its DeltaV display during the building process and found it very useful. I can tell before even launching if my ship has a chance or not of reaching orbit. While I doubt I will ever NOT use Mech Jeb or mods, I can see what people who only use Stock may wish to have such a calculator - it could prove to be very helpful for those who have problems building ships. And help others improve on already working designs, making them more effective.

Edited March 11, 2015 by Valley

[TMS]

Don't put the stock calculator behind some arbitrary pilot/engineer level system.

If the data is as fundamental as is being claimed, gating it behind another grind-fest makes no sense.

[Rusty6899]

Don't put the stock calculator behind some arbitrary pilot/engineer level system.

If the data is as fundamental as is being claimed, gating it behind another grind-fest makes no sense.

It isn't as fundamental, though. I also like the early game lack of patched conics and think it is a similar issue with delta-v. As delta-v has never been included in the game, it won't be missed before a higher tech level, and it provides incentives for levelling up engineers. Newer players won't be met with a string of numbers that they most likely won't understand as well, and will have to grasp the concepts behind space flight before being given the numbers.

It would obviously be available immediately in Sandbox, so you could design a ship there and then move it to your career save if you wanted to get around it.

[RainDreamer]

I think the soon to be added features (forgot the name) where it will tell you whether you are missing things on your rocket will also report your dV.

[Kegereneku]

It is missing as soon as you get Maneuver node.

Maneuver node give you the cost of fuel in m/s but no way to know how much your spacecraft have.

Even misinterpreting the concept, any new players can understand that bigger dV = "more range" or a least "= better" and if given the opportunity to see this in the VAB anyone will quickly get to the conclusion that some engine are more fuel efficient but produce less thrust.

And this is not something to be left to the Engineer, at least not alone.

It should come with VAB upgrade to at least know if a spaceship have a remote chance of having enough fuel to do its job.

THEN, if you want to require an Engineer to display Dv during flight, myself I'm not against, but I would ask for a 1.25m 2 seats pods.

[Rusty6899]

And this is not something to be left to the Engineer, at least not alone.

It should come with VAB upgrade to at least know if a spaceship have a remote chance of having enough fuel to do its job.

THEN, if you want to require an Engineer to display Dv during flight, myself I'm not against, but I would ask for a 1.25m 2 seats pods.

I had actually thought that might be the best way to do it. Maybe a 3rd tier building upgrade gives Dv in VAB (not sure which building as there is no point in having separate upgrades for SPH and VAB). Require an engineer for DV in flight, or maybe a top tier probe core.

[klgraham1013]

I am not a fan of locking necessary information behind a paywall.

[Kegereneku]

are you a fan of "game progression" ?

[Zephram Kerman]

It sounds quite a bit like a learning environment. Nobody tried to teach me math with a helpful tool that would do the math for me. While learning arithmetic there were no calculators allowed. While memorizing formulas there were no references allowed. After a short time like that, it was assumed the concepts were well understood and memorization was completed. That's when tools appeared to streamline the work so that we could focus on the next things.

On the other hand, I'm fascinated by the idea of learning rocket science concepts intuitively in a math-free environment. It seems impossible, yet it's working!

So I'm comfortable with the way things are planned. dV calculator handily present in sandbox mode and late-career mode (or to anyone who sets up Supernova2015's very handy tool), but missing in the more challenging early career.

[TMS]

It would obviously be available immediately in Sandbox, so you could design a ship there and then move it to your career save if you wanted to get around it.

Yep, that sounds like fun. I can't imagine how that would get frustrating.

Maybe we could have the fuel level disappear until the player grinds out enough XP from flag planting?

Or maybe just have it obnoxiously give out random readings for the lulz until you get Level 5 pilot eyesight?

As delta-v has never been included in the game, it won't be missed before a higher tech level...

Well, the revised SAS wasn't available prior to 0.23 (or whenever it was finally iterated into user acceptance). Maybe 0.24 should have saved the old SAS system for lower-tier pilots? After all, what's wrong with basing your final design specification on the flawed implementation, oversights and exclusions of earlier versions?

[Rusty6899]

Yep, that sounds like fun. I can't imagine how that would get frustrating.

Maybe we could have the fuel level disappear until the player grinds out enough XP from flag planting?

Or maybe just have it obnoxiously give out random readings for the lulz until you get Level 5 pilot eyesight?

Well, the revised SAS wasn't available prior to 0.23 (or whenever it was finally iterated into user acceptance). Maybe 0.24 should have saved the old SAS system for lower-tier pilots? After all, what's wrong with basing your final design specification on the flawed implementation, oversights and exclusions of earlier versions?

You're welcome to your own opinions, although I think you line of argument was fairly fallacious.