Named after the originator of this design, First in Fright, the Fiffer machine uses a remote drop counterweight with a scissoring linkage to power the arm. The design seems both stable and powerful, a useful combination. It allows for a near vertical counterweight drop without the need for wheels or tracks. This eliminates the chances of becoming derailed.


The original Fifer:
First in Fright
A small prototype without counterweight to show the general motion in HD

Power Source



  • Stable platform since only pin type connections are used (no slides or wheels)
  • Counterweight has a lot of leverage at the top when it is moving slow
  • Leverage decreases but velocity increases as the counterweight falls pulling the arm faster
  • Counterweight can be caught on the ground instead of swinging through, or thrashing the axel back and forth in FAT style trebuchets
  • Depending on sling and machine length you don't have to load the sling under the counterweight
  • With the remote drop the long arm can still be placed in the vertical position allowing a 180 degree swing


  • More moving parts than a FCW or a HCW.


A brief explanation of a Fiffer machine

A slow motion launch

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