FTX-2 External Fuel Duct

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FTX-2 External Fuel Duct
Part image
Fuel Transfer by
FLOOYD Dynamics Research Labs

Radial size Radial mounted
Cost (total) 150.00 Funds
Mass (total) 0.05 t [N 1]
Drag 0.02 [N 1]
Max. Temp. 2000 K
Volume  ?
Impact Tolerance 12 m/s
Research Fuel systems.png Fuel Systems
Unlock cost 6 200 Funds
Since version 0.13
Part configuration fuelLine.cfg

  1. 1.0 1.1 The mass and drag are from the part config, but the game handles it as physicsless.

The FTX-2 External Fuel Duct is the only fuel line in the game so far. It allows fuel to be drained off external (side-mounted) tanks, or tanks in latter stages. As of version 0.14.4, it is massless and dragless, despite the CFG file values.

Product description

New breakthroughs at FLOOYD Dynamics have made the FTX Fuel Duct a reality. Altough criticized by some as being no more than 'a sewage pipe painted yellow', most agree that the yellow is a relatively nice color, and that fuel lines are indeed able to pump fuel from side-mounted fuel tanks. After the recall of the FTX-1 series, All FTX-2 lines have arrows painted on to indicate the fuel flow direction, so engineers can tell which way around they are supposed to go.

FLOOYD Dynamics Research Labs


The FTX-2 allows fuel not directly connected to an engine to be used. The line must be first connected to the source for the fuel then to the destination of the fuel. It is important to observe the arrows depicted on the fuel duct as they provide a visual cue as to the direction of the fuel flow.

Any part connected to a fuel line will allow fuel flow from the fuel line, even if fuelCrossFeed = False in its CFG file. The FTX-2's links provide additional strength and stability, somewhat like the EAS-4 Strut Connector.

Fuel lines used to be a vital part of asparagus staging designs allowing for use of all engines available where fuel is first drained from external fuel tanks allowing them to be jettisoned (severing the FTX-2 External Fuel Duct) when they become empty. By the time the last external fuel tanks are jettisoned, the central or main fuel tanks left on the vessel will be at a full fuel level. Nowadays, most of this is done by setting the flow priorities appropriately, and fuel lines are no longer necessary for asparagus staging. Normally decouplers don't allow fuel crossfeed, but it can be enabled given that fuel lines are unlocked.

Fuel lines can be used to transfer fuel past parts that normally don't allow fuel transfer, such as heat shields. However, to do this, two fuel lines need to be connected, one in the direction of the intended transfer and one in the opposite direction.


As of version 1.10 this part has two variants that can be switched in the editor.

Yellow variant
Gray variant
The different variants of the fuel duct.


  • Added white variant
  • Changed the flow direction, so fuel will flow from the first-placed end of the line to the second end.
  • Initial release