Nerf HPA Engine (WIP)

This project still has far to go, but I thought I would release it to hopefully speed up development. Traditional Nerf HPA engines such as the sniper core, dmr core, and supercore all are quite bulky to fit inside a nerf gun. The purpose of this project is not to replace those traditional methods, but to make a smaller, easy to manufacture version; unlike the traditional versions the bolt on this one can not return on its own, meaning this design is better suited for a sniper rifle rather than a smg. I hope to one day make a similar small engine that can retract on its own, but I thought this was a step in the right direction.

I have been trying to think of a way to decrease the size of current nerf HPA engines for a while now, as I need a small one for an upcoming project; I have tried many different ideas and probably missed many other options that would work. But when I was getting rid of some old stuff I started thinking about some toys from when I was younger, one of those was those telescoping lightsaber toys. I thought why can't this be integrated into an HPA engine, it is used in cranes for their booms. So I quickly googled to see if I had anything to go off of and to my surprise I couldn't find anything about a telescoping vale/piston; I probably am not the first to come with this idea, but I couldn't find anything to off of.

if anyone is wondering where the expansion chamber in this engine is, there isn't one... well not a traditional one anyway. because of the telescoping effect the inside expands, making a hybrid expansion chamber. This project took many prototypes to get to where I felt comfortable to release it, but it is ready now. the biggest challenge has been the tolerancing between the plastic and silicone o'rings.

Bill of Materials