Build with beams

Put a beam in a ship to hold two parts apart, and mount things anywhere along its flanks.

Use this when a plain stack has nowhere left to put something: an engine that needs to hang below a gap, legs that must reach out past the tanks, thrusters that want to sit high and low on the same ship, or a station arm to dock modules onto.

Before you start

  1. Open the Beams tab in the parts column on the left. It is the last one, pictured with a lattice. The drawer beside it shows the Girder, the Truss and the Stack Truss.
  2. Drag a beam onto the canvas and let it go where you want it. Held against the bottom of a tank or the top of an engine, it joins the stack end to end like any other part.
    The hangar with the Beams tab open, a BX-4 Truss selected on the canvas with a Lander Engine under it and a thruster block on its flank, and a BX-1 Girder beside them.
    A Truss with an engine on its bottom point and a thruster block slid down its flank; a Girder beside it.
    To space a stack out, use the BX-6 Stack Truss where a tank would go: it is a tank wide, so it lines up with the tanks above and below it.
    The hangar with a rocket of a Command Pod, a Fuel Tank, a BX-6 Stack Truss selected with its Length slider showing, a second Fuel Tank and an engine, and an orange fuel line drawn from the upper tank to the lower one across the truss.
    A Stack Truss between two tanks, with a fuel line carrying the upper tank's fuel across it.
  3. Set its length. With the beam selected, drag the Length slider on its sheet. The beam grows down its own axis, and its mass and price grow with it — the figures along the top of the screen change as you drag.
  4. Mount things on its flanks. Drag a radial part — a thruster block, an antenna, a landing strut, a decoupler with a booster behind it — against the beam's side and let go. The side is a line, not a single point, so the part stays at whatever height you dropped it.
  5. Mount things on its ends. The top and the bottom are ordinary stack points: an engine, a tank, a pod or a second beam joins there.

What you should see

The beam sits in the ship as one piece with it, and the Mass and Cost readings along the top include it. Fuel does not run through a beam, so an engine below one cannot reach a tank above it on its own: draw a fuel line from the tank to the engine.

Note
A beam never comes off by itself. It has nothing to stage and nothing to fire, so a frame you want to drop needs a Decoupler or a Separator between it and the rest of the rocket.
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