Flight Question XR5 Vanguard sending Cargo to Brighton Beach, How to find how much Extra Fuel Tanks needed?

[Krishnan]

Hello everyone! I recently started flying the XR5 Vanguard, I LOVE IT!!. Yesterday, I flew it without any cargo to Brighton Beach, and landed with 4 percent fuel remaining. I would like to send some cargo to brighton beach, and I put some cargo containers in, payload weighing about 150 tons iirc. However, I knew that I won't have enough Delta-V to get there. I will add some fuel tank containers, but how much do I add? I tried using burn time MFD's delta-v readouts, but it is inaccurate because I am doing a scram ascent. Can someone please help? I will really appreciate it. I am using the default settings BTW

 

[Marijn]

You can calculate the amount of cargo containers and consumables very precisely. But you need a spreadsheet for that which applies the rocket equation. Have a look at this pic: https://drive.google.com/file/d/1ufea-hALduwgVSB7eXWDAtlDg93Y7Ere/view?usp=sharing

It's from an old spreadsheet. The numbers can be wrong, put pay attention to the structure. Vertically, you can put stages of the mission, like Landed, Takeoff, Circulatization etc.

On each row, using three known values of the rocket equation, you can calculate the fourth (in red) and use than one on the next row. That's basicaly the idea. The amount of delta-v required for each row has to be determinded empirically. So you have to test-fly parts of the mission to know how much delta-v it will cost. Since delta-v is not depended on the mass, you have to do this once only and you can use the value for future calculations regardless of mass.

 

[Krishnan]

You can calculate the amount of cargo containers and consumables very precisely. But you need a spreadsheet for that which applies the rocket equation. Have a look at this pic: https://drive.google.com/file/d/1ufea-hALduwgVSB7eXWDAtlDg93Y7Ere/view?usp=sharing

It's from an old spreadsheet. The numbers can be wrong, put pay attention to the structure. Vertically, you can put stages of the mission, like Landed, Takeoff, Circulatization etc.

On each row, using three known values of the rocket equation, you can calculate the fourth (in red) and use than one on the next row. That's basicaly the idea. The amount of delta-v required for each row has to be determinded empirically. So you have to test-fly parts of the mission to know how much delta-v it will cost. Since delta-v is not depended on the mass, you have to do this once only and you can use the value for future calculations regardless of mass.

Is there a way to get this spreadsheet? Is there a good rule of thumb I can follow? Thanks!

 

[Marijn]

Is there a way to get this spreadsheet?

I'll see if I can revive it. The spreadsheet evolved into a web application for XR vessel planning. But then Google made changes to their runtime environment and I have to fix many problems before it works again. Here's an impression: