Kerb Calculator - Better than the back of an envelope

[awbeck]

Kerb Calculator

Version 0.2

This one's for all the engineers, physicists, and mathematicians out there:

Kerb Calculator is a simple MATLAB .m file that will easily, and precisely (to ~12 decimal places) calculate the amount of delta V is in a stage. The program already knows the mass of all stock fuels, so all you have to do is plug in how many units are in the tanks. Have you ever been stuck in a high orbit of Kerbin wondering if you have enough fuel to get home? Now you know!

As the code progresses, I will update the link below:

Current Version: 0.2 (Feb 2, 2016)

https://drive.google.com/open?id=0B6MhbnaSc1H4c2tQQy1mVW9lcnM

 

Version history: (none)

Edited February 7, 2016 by awbeck

[fredinno]

12 hours ago, awbeck said:

Kerb Calculator

Version 0.2

This one's for all the engineers, physicists, and mathematicians out there:

Kerb Calculator is a simple MATLAB .m file that will easily, and precisely (to ~12 decimal places) calculate the amount of delta V is in a stage. The program already knows the mass of all stock fuels, so all you have to do is plug in how many units are in the tanks. Have you ever been stuck in a high orbit of Kerbin wondering if you have enough fuel to get home? Now you know!

As the code progresses, I will update the link below:

Current Version: 0.2 (Feb 2, 2016)

https://drive.google.com/open?id=0B6MhbnaSc1H4c2tQQy1mVW9lcnM

 

Version history: (none)

Umm, I thought we already had things like Kerbal Engineer that will automatically do this for us?

[Findthepin1]

We do. The wiki has a bunch of them in a list. Page is called Calculation tools. 

[awbeck]

The current version only has the one dV calculation. later versions will include things like calculating dV between 2 circular orbits, dV to circular and escape velocities, inclination changes (including best burn angle), dV to transfer between any 2 elliptical orbits, transfer to other planets, and more.

[Stone Blue]

@awbeck You might get better/more exposure for this if you moved the thread, or asked for a mod to move it, to the Add-on Releases forum...

[GoSlash27]

9 hours ago, awbeck said:

The current version only has the one dV calculation. later versions will include things like calculating dV between 2 circular orbits, dV to circular and escape velocities, inclination changes (including best burn angle), dV to transfer between any 2 elliptical orbits, transfer to other planets, and more.

I would really love to have someone who's fluent in Matlab to create an online version of my stage design spreadsheet.

Basically it does the DV calculation backwards for every engine. You plug in the mass of your payload, DV requirement, minimum acceleration, reference body, and % atmospheric density.

 It spits out how many tanks you need, how many engines, total mass, and total cost for all engines. This allows you to see at a glance which engine you should use for a stage, as well as exactly how to build it.

 

^ Example screenshot.

 If you're interested in tackling this, I'd be more than happy to walk you through how the math works.

Best,
-Slashy

 

[PB666]

On 2/7/2016 at 7:54 PM, awbeck said:

Kerb Calculator

Version 0.2

This one's for all the engineers, physicists, and mathematicians out there:

Kerb Calculator is a simple MATLAB .m file that will easily, and precisely (to ~12 decimal places) calculate the amount of delta V is in a stage. The program already knows the mass of all stock fuels, so all you have to do is plug in how many units are in the tanks. Have you ever been stuck in a high orbit of Kerbin wondering if you have enough fuel to get home? Now you know!

As the code progresses, I will update the link below:

Current Version: 0.2 (Feb 2, 2016)

https://drive.google.com/open?id=0B6MhbnaSc1H4c2tQQy1mVW9lcnM

 

Version history: (none)

As long as Jeb has the back to push, I always have enough fuel. lol.

[awbeck]

@GoSlash27 that would be really interesting. i literally just started learning matlab though, i'm not sure i could have it design a whole rocket & give that output

[GoSlash27]

29 minutes ago, awbeck said:

@GoSlash27 that would be really interesting. i literally just started learning matlab though, i'm not sure i could have it design a whole rocket & give that output

awbeck,

 No worries. If you get to the point where you think you can do it and want to give it a go, hit me up.

Best,
-Slashy

[dlazerka]

On 2/7/2016 at 7:55 PM, GoSlash27 said:

I would really love to have someone who's fluent in Matlab to create an online version of my stage design spreadsheet.
...
Best,
-Slashy

Hey Slashy, you can upload your spreadsheet to Google Docs and it will be online! You can share it with others too.

[KAL 9000]

On February 7, 2016 at 8:55 PM, GoSlash27 said:

I would really love to have someone who's fluent in Matlab to create an online version of my stage design spreadsheet.

Basically it does the DV calculation backwards for every engine. You plug in the mass of your payload, DV requirement, minimum acceleration, reference body, and % atmospheric density.

 It spits out how many tanks you need, how many engines, total mass, and total cost for all engines. This allows you to see at a glance which engine you should use for a stage, as well as exactly how to build it.

 

^ Example screenshot.

 If you're interested in tackling this, I'd be more than happy to walk you through how the math works.

Best,
-Slashy

 

What calculations do you do?

[GoSlash27]

KAL9000,

 Basically this:

I start with the environment to determine how much mass 1 engine can lift. Then I use the reverse rocket equation and DV requirement to determine how much payload can be handled by a single engine.

 From that, I extrapolate how many engines are required. With that, I use the reverse rocket equation to pin down exactly how much fuel and tankage is required for the stage.

 Finally, I estimate total stage mass and cost.

This is done simultaneously for all engines and the results are placed in tabulated form with table filtering to highlight the best options.

Best,
-Slashy

[KAL 9000]

5 hours ago, GoSlash27 said:

KAL9000,

 Basically this:

I start with the environment to determine how much mass 1 engine can lift. Then I use the reverse rocket equation and DV requirement to determine how much payload can be handled by a single engine.

 From that, I extrapolate how many engines are required. With that, I use the reverse rocket equation to pin down exactly how much fuel and tankage is required for the stage.

 Finally, I estimate total stage mass and cost.

This is done simultaneously for all engines and the results are placed in tabulated form with table filtering to highlight the best options.

Best,
-Slashy

Thanks! I've always wanted something like this!