modular construction possible?

[Belami]

Dear spacecraft engineers and cosmonauts

Most of my rockets have 2-3 stages and only the last stage differs, e.g. taxi service, station refuel, construction part, etc.

Because the first stage is the same I trie to build it once and then to assemble it with the last stage at my wish. Does anybody have an idea how to solve this problem?

I tried yet:

1. save as subassembly. drag and drop the first stage does not work because it catches only the parts in the center.

2. prebuilding the first stage. This generates a staging problem because this way I have to construct from bottom to top (parts around the axis). It separates not the stage subjacent but the stage above.

Thank you for helping

Boris

[AlamoVampire]

I am not sure how much this will help if at all, but. try building the entire rocket first. I know, sounds silly, but try it. Just build the first in the series of rockets you want, then, what ever location you want to be the cut off point for a section, break it off at the proper decoupler <taking the decoupler WITH that section you just cut off> and drop it into the subassembly thingy. Then do this again with the next section and so on, OR, you could do like me, build the whole thing, then break the rocket off at the upper most decoupler right below the uh payload <be it a lander, a probe, a satellite or what ever it may be> and call the entire thing below that junction the subassembly. Seems to work for me. hope that helped

[biohazard15]

Build your launcher from top to bottom (so the root part is on top and has a free attachment node), save it as subassembly (select a root part), then attach it to the bottom of your payload.

Or vice versa - save your payload as subassembly, then attach it to prebuilt launcher.

As for staging - you have to manually rearrange, then check, then double-check it every time. For some complicated things (cluster launches, etc) use action groups. Sadly, that's how it works in KSP for now.

[Kasuha]

There are two ways in general - lifter as a subassembly, and payload as saved ship, or vice versa.

Lifter subassembly has an advantage that you can build it "logically", i.e. you build it below some payload, then just tear it off that payload and save as subassembly. All you need to stick to then is to use the same "interface" to stick the launcher and payload together.

My approach was the opposite - I had launchers saved as ships, and payloads as subassemblies. My reason was that I had way more payloads than launchers and it made my ships folder less cluttered. It also allowed me to combine multiple smaller payloads on one lifter. I could also stick my payloads to planes if I wanted but I never did that. This approach required me to always build the payload bottom up, i.e. start at the point which will attach to the launcher. I never had problems with that, though.

Edited January 2, 2014 by Kasuha

[Skorpychan]

Generally, just use subassemblies to save lifters from the payload's decoupler down. It works fairly well for me. A standard lifter design gets all my stuff into orbit, now.

[SRV Ron]

The first two stages are the module I saved in sub assemblies. The three pics represent payloads on that orbiter and how their weight affected performance to orbit.

[Belami]

Thank you for your ideas. I am going to try this different methods.