Is it possible for rocsim to handle an internal tube (i.e. motor mount tube) that also has paper transitions and another diameter tube at the opposite end?
Then this 'hourglass' shape mmt tube would be put inside another larger tube.

Is it possible in the first place?
Would it require the latest version?
Can it be saved as a sub-assembly?

Imagine the estes Ramjet kit bit with the hour-glass shape to the internal tube.

Chris 'rocsim rookie' Timm