About this app

Have you ever wanted to see how the total delta-v of a rocket changes when you add an additional stage?

This app allows you to calculate the total delta-v of a multistage rocket. Instead of just applying the rocket formula to one stage, this app display's the delta-v for each individual stage and also the total delta-v of the rocket down to that stage.

You can save and load rockets or individual stages. You can insert a new stage at the beginning, at the end, or in-between stages.

This can be very useful in space simulators like Kerbal Space Program. This is not only useful for designing the rocket. This can also be vital when planning a new maneuver in order to see if you have enough delta-v left in your rocket.

The saved rockets and stages are stored in the /data/data/com.evandisoft.multistagedeltav.app/files folder on the device. There is also an auto-save feature. The auto-save file is stored in the same folder and its name is "autosave.json".

How to use:
To use this effectively, you have to separate each stage and calculate that particular stage's full mass (mass when full of fuel), dry mass (mass when missing fuel), and ISP (which is easiest to do with one type of engine per stage). The fuel you remove to find dry mass is only the fuel that will be spent in that stage. Make sure when you calculate the full mass and dry mass of a particular stage you do not have any other stage attached.

How to use in Kerbal Space Program:
In Kerbal Space Program, the game will not calculate DeltaV for your spacecraft but it will tell you the mass of the rocket.

To calculate "Full Mass" and "Dry Mass" in Kerbal Space Program it is easiest to isolate each stage and use the games mass calculation once isolated. You can isolate a stage by using the "Root tool" (which changes which part you have to click on to move the rocket about) to make some part of that stage the new "Root".

Once that part is the new "Root" you can remove other stages easily. With other stages removed (just have them set aside and don't leave the VAB until they are re-attached or those other stages will be lost) the mass on the bottom of the screen will tell you the mass for that particular stage only.

Full mass is displayed before you have removed the fuel from that stage. Dry mass is displayed after you have clicked each fuel tank and dragged down to 0 all the fuel and oxidizer amounts. Only do this for fuel that will be spent on that stage.

The above method works well for stages that are in the vertical stack of stages, for stages attached to the sides of a rocket it is more difficult to calculate. However, one can make those stages be simple standard lifting stages and use them over and over again. With the save/load stage features of this app, that reuse is very easy.

Don't forget to refuel the tanks after you have obtained the numbers!
Don't forget to reset your command module or probe as "Root" after you are done.

Note:
I have the stage numbers "backwards". What one would normally call the first stage has the highest n in the label "Stage n" of all the stages. The reason for this is that it lines up with how the stages are numbered in Kerbal Space Program. What is numbered as "Stage 0" is actually the final stage of the rocket.

Disclaimer: I'm not liable for any damages resulting from any possible inaccuracies of my app or failure to calculate perfectly or at all correctly. I think it works, I've used it a lot, and I like it a lot. But I'm not willing to bet my life on it! Don't depend on this app if you are designing or using real rockets!

New features

Stage buttons lined up better.