I've been enjoying the string on remote organ blower installations.
With pressure or vacuum, it's generally agreed that a smooth interior
surface in the pipe allows for faster air movement.
Has anyone tried waxing or coating the interior of the pipe to make it
slippery? Would this further increase the movement of air or would it
just allow for less friction and cooler air movement?
[ Airplane enthusiasts apply wax to the airfoils as you suggest, but
[ the biggest improvements come from eliminating surface bumps. The
[ inner surface of PVC pipe is already pretty smooth, but take care
[ at the couplings: No bumps or voids allowed! -- Robbie