How to make that lifter better?

[Hooch]

Hello.

This is my first rover and lifter. I managed to get it to moon without cheating (Only mechjeb).

It is very unstable lifter. It will disassemble if you accelerate to fast.

I got to mun orbit (43km) with half fuel in that last big orange tank.

Landing was easy and I have much fuel left. I got my rover to surface and 2 kerbals are having fun now.

Here is craft:

Download craft in RAR

Here are some screenshots:

Imgur Gallery

[HoY]

Having only looked at the screenshots and not the .craft, I would say to replace your staging type with Asparagus rather than pancake Firstly it is more stable because it keeps a more constant TWR than pancake type, and second it is more efficient. Admittedly you Did make it all the way there already, so what you have works, but better is better!

Stick with just 6 stacks of orange tanks around a single stack of orange tanks.

For the core engine I would use a skipper under 2 orange tanks

For the outer 6 I would use Mainsails under two orange tanks PLUS 1 of the silver tanks, the shortest of the 2.5m tanks.

Don't forget to install tail fins on the outside of each of the 6 outer tanks, and strut each of your tanks to the other one they are directly connected to

Just in case you are unfamiliar with asparagus staging click on the link in my sig, there's a quick tutorial there, and many more on the thread "the drawing board" on the tutorial sub forum.

And make sure you strut the outer tanks to the inner ones. As well as to each other!

[Hooch]

I used asparagus staging in second (counting from bottom) layer of orange tanks.

I can't use asparagus staging in the lowest part because it will not go up.

I'm using mainsails for the lowest stage. Then skippers for upper (orange big) stage. And then skipper for the singe orange tank on top.

I don't really have dV or fuel problems here. Only structural.

But I'm curious if there is way to make that lifter lighter.

[superm18]

I simply don't have the time right now to fix it due to exams, but i would strut that thing differently. Less struts and better places. I'll see if i can squeeze in the time to do it tonight, but no promisis

[Hooch]

I have exams too.

But that would be great if you would have time.

Thanks in advance.

[Johnno]

Hi Hooch, thought I'd add some of my thoughts about your design. To me it all looks very overpowered, I've done Apollo style launches myself which require docking, but even without docking you can get away with a lot less than what you've got there.

For starters, I see you've used two Mk1-2 pods. I'm not sure how you played it, if you transferred your guys back to the orange tank + pod before launch home, or went in the lander, but either way you could land with a landercan instead to save weight. And if you use the same craft to get home from the Mun, instead of transferring to a waiting ship in orbit, you could forego one of the pods. If you do meet up in orbit I'd suggest docking ports, so you can transfer any leftover fuel from the lander.

The lander seems overpowered as well, again, not sure if you took it back to Kerbin straight from the Mun, but you don't need a lot of thrust to land on the Mun. If you go with the atomic engines two should be more than enough. Also I see RCS thrusters in triplicate, huge overkill.

Your last orange tank could be cut up into two stages, using Apollo as a reference a 'third stage' that sends you toward the Mun and then a smaller tank for the pod to bring you back after you've ditched the lander.

Even then your launcher looks overpowered. I haven't opened the craft file to look at numbers, but I've gotten to the Mun with two stages of 5 orange tanks (middle + 4 around), and a smaller third stage (3/4th of an orange tank). For some extra push you can stick on some solid boosters around the first stage for liftoff.

The more you have up top the more you need in your stage below, and the more you have in that stage the more you need below it. Starting from the top (your lander) the extra atomic engines, extra pod, extra large RCS tank are all surplus weight. The I beams and girders shouldn't really be necessary either (at least in that extent). To lift all that you should be fine with orange tank + 4 around it, instead of 6, in which case your first stage wouldn't need extra tanks, likely not 6 around the central one either.

I've personally just kept my launch vehicles really simple. Starting from the bottom, stage 1 = 5 (middle +4 around) orange tanks with mainsails, second stage the same, third stage half or 3/4ths of an orange tank with mainsail (or skipper now that it's available) + payload. First and second stage are capable of bringing around 40 tons to orbit, generally I'm careless with launches and the third stage gets to push the last few hundred m/s for kerbin orbit.

Mainsails are really powerful so I usually keep my thrust around 80%, also if you use orange tanks engines will overheat easier (known issue with those tanks), even then limiting yourself to 70-80% thrust will make your lifter not tear itself apart without lots of struts.

Hope some of this helps, great looking rover by the way!

[HoY]

When I said asparagus instead of pancake I mean replace all of your lower stages with a single asparagus setup. You are carrying an extra 30+ tonnes of engines just in your lift vehicles that don't even fire the whole time, asparagus will save you fuel, part count, and most importantly be more stable because it doesn't rely on all of those truss and strut connections.

Take it or leave it, just thought you were asking for a 'better' way

[Akalaël]

Asparagus system is the best way to maximize your efficiency.

For your info (if you can spare time now...)

Temstar's Zenith Rocket Family

Discuss on Asparagus (this time Temstar explaining how he managed to build his rockets)