I may not be a kind of APH, but I sure have my own design for one! No guides/details yet, but I will need some time to change that. The design itself may need some fine tuning too, but it's pretty solid so far and is a slight step up from the typical SSC design everyone follows. Here is a brief overview of the features:
- Backpack reservoir: Use a camp shower or solar shower and shove it into a backpack. A camel back works too but has less capacity.
- Low pump dead space: Allows you to pump more air into the pressure chambers. Bike/air pumps are obviously unwieldy in battle, but you need some way of getting extra air in the chambers, or the APH design is pointless (too much wasted water that can't shoot far enough) and you might as well build a CPH. To achieve this, the check valves must be as close to the pump as possible.
- Modular design: Threaded parts used where possible or practical. They create issues with rotation getting thrown off easily, but this can be partially alleviated with better structure. (i.e. A proper PVC connection between the pressure chambers and pump.) Threaded parts let you replace and service the blaster better.
- Pressure chambers: You need at least two 3" chambers or 3 2" chambers. I used the former, but additional PC's will increase the weight (and thus the inbalance/top-heaviness) significantly. One pressure chamber however, does not carry a useful amount of water.
- Pump: The pump I used is a revised version of the SuperPiston MK II, found here:
http://www.waterwar.net/site_wwn/board/topic6076.html However, I'm still tinkering around for a more ideal, but the pump I ended up using for my APH works flawlessly so far. The technique involves/requires a perfect cut on a hollow aluminum dowel so that it can hold the O-ring. A machine screw is used to hold the O-ring. The problem with the MK II is the nylon spacer used, although tightening the screw with an allen wrench may have solved the problem.
Anyway, this will all be better explained later. This design is about as easy to build as any other CPH, but does require online parts (threaded check valves). It's up to you what to do, although that will also vary depending on the kind of parts available where you live. (Most of which shouldn't be a problem in the U.S. I think.)
