The Tow Gun
The Tow Gun is a hand held tool that dispenses wetted fibres through a nozzle. It can be pulled around jigged inserts according to a designed sequence to bring forth a truss like structure. It is designed to allow good handling to negotiate complex geometries. It can also be used for dispensing wetted fibres for filament winding.

The need for manufacturing a vast array of different ultra lightweight components inspired the development of the Tow Gun. Using tows rather than woven sheets allows a more load path efficient design for many applications.

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 CAD image of the tow gun              

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The Tow Gun comprises of a reel of tows mounted on a handle. Inside the frame is a tank containing the resin. The fibres are drawn from the roll through the tank where they get impregnated. The wet fibre travels through the tool through a pipe and exits through a sharp nozzle. 

The Tow gun in action, used 
to make an Exulans main 
spar test component

 For weight-optimised lay-ups it is important that the amount of impregnated resin per unit length of tow is well controlled and repeatable. The current design achieves very good stability in resin content. The simplicity of the design allows easy cleaning and quick assembly and reloading. All components are light and small enough to give good ergonomics. The Tow Gun is resin tight and allows clean working at almost any working angle.

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The Tow gun used for 
winding fibres onto an 
Exulans cockpit component