The superpump

The problem with these pumps is the internal restriction to the flow of air. This is quite apparent by the effort you have to exert to 'pump' even when the pump is not connected to anything... These pumps are poorly designed from a performance point of view. If you pull one apart, there are a couple of points in the flow path where the air is forced to flow through a restriction with a diameter of approx 5mm. This is far from ideal. Adding two of these pumps together in parallel will certainly give you double the volume per stroke, but this will come with twice the effort. I have played around with modifying one with a view to removing the flow restrictions. The standard pump routes both the intake and exhaust air flow through the center shaft, with both inlet and outlet valves in the piston. I reversed two of the valves and removed the center tube (within the aluminium tube) to turn the shaft into an inlet only. This removed the two significant restrictions and opened up the flow path. I then used PVC pipe to connect the top and bottom of the pump for the outlet. I had to fabricate two one way valves, one I placed in the insert in the bottom of the pump and the other I had to place inline in the PVC pipe. Though far from ideal, this is an improvement over the standard pump with significantly less effort required while pumping your kite. This setup is not optimal, being put together with what I had on hand, but it does show that there is plenty of room for improvement.