Refueler Payload and Booster

[Momocody]

Hello everyone,

I am having a little difficulty launching a refueler into LKO that can hold 4000 units of liquid fuel. Please note that I don't have access to 3.75 parts at this time. If I could see an example of a stable refueler. I'm pretty good with designing efficient and stable boosters and upper-stages, but this one has stumped me... It's just so unstable!

Thank you,

-Will Granda

[Majorjim!]

Hello,

 

 What exactly are you thinking of?

[sgt_flyer]

Here's a potential two stage design. (the 'outer' mainsails are slightly throttled down, so they burn as long as the core mainsail).

 

when installed, the fairing encapsulates both the upper stage and the payload (widest possible for a 2.5m fairing).

 

both the upper stage and the payload are simply 4x symmetry around a structural girder (any wider, and the 2.5m fairing is not large enough :p)

 

a note of warning though, in this design, the fuel tanks don't like the structural girders, so don't forget to add some struts (else the thing will shake itself to death once it separates from the upper stage)

 

the whole thing is perfectly stable. (i make a 5° pitchover just after the rocket reaches 70m/s - afterwards, i simply follow the prograde marker - the 1st stage carries me above 20000m with this ascent profile, afterwards the remaining atmosphere as not much effect on the stability of the upper stage + payload.

 

Edited January 3, 2016 by sgt_flyer