How does this fuel pump work?
Sometimes diagrams can be mystifying. This is a video of a variable displacement hydraulic pump of similar principle being torn apart (disassembled would be too gentle a term) by a foul-mouthed Canadian who gives an excellent detailed &amp; clear description of its construction &amp; operation. Language warning for those not used to frontier engineering. 


                
            

Which will prepare you for this very polite Canadian who shows an actual aircraft fuel pump. (around 7:30)