1. Concepts
1. What is an electropneumatic/electronic gun?
The mistake many people make when confronted by the term "electronic gun" is to assume one of two styles is at work:
- The gun is a "sear tripper" electro, working exactly like a normal gun in all respects except that, instead of the movement of the trigger directly undoing the tiny hinge that causes the bolt to fly forward, a solenoid trips the sear for the user. Sear-trip electro guns do exist, and are fairly popular, but they are still subject to all the failings of their mechanical parts, and they are often retrofits, bulky, ungainly, and requiring batteries that wear out quickly.
- The gun is a "pure electro"—a solenoid physically moves the bolt forward. In reality, the forces required to accomplish this would require a giant solenoid and would drain batteries after only a few shots.
In fact, an electropneumatic gun like your Angel uses air for more of its operations than you might think.
2. Why does the Angel use so many regulators?
Another common question. The issue is, each section of the gun needs different pressures of air. The least valid of these needs is at the tank—mini-reg interface. The tank's output is standard across the industry—from 450 P.S.I. (commonly called "LP" tanks) to 850 P.S.I. The mini-reg's job is to get that pressure to the proper pressure such that your gun shoots at your field's limit. Obviously, if the mini-reg output pressure and the tank output pressure are the same, there's no need for the mini-reg. Since each time you regulate air, you're restricting flow a little, this is one of the most convincing arguments for adjustable regulators on tanks.
The LPR is there to get a lower pressure for the pneumatic cycle, because moving the hammer back and forth doesn't require 500 (or, indeed, even 150) P.S.I. Obviously, unlike the mini-reg, there is never a circumstance in which the LPR is an optional component.
2. The Flow Path
1. The mini-reg
This is the first taste your Angel has of its incoming air. The mini-reg’s job is to get the 350 or more PSI coming out of your tank down to the marker’s operating pressure. With the longest volumizer on, that’s somewhere between 150 and 200 PSI.
2. The flash tank.
There is talk of an ancient South American culture, cut off from the world for four millennia, which has discovered the purpose of the flash tank. I, however, am not a member of that culture. As far as I’m concerned, it’s a place to interface between the gun and the mini-reg, and the operating pressure gauge on guns so equipped, and that’s about it.
3. The Main Pressure Chamber
This is the chamber behind the exhaust valve, on the right side of the gun as you look along its length from the back. This is the chamber which is enlarged by the volumizers. The air that enters this chamber is undoubtedly very near and dear to your heart—it’s the air that will be used to actually launch the paintball. This is the air that will eventually exhaust down your barrel. Its pressure, which is the same as shows on the gauge on your flash tank if your gun has one, is often referred to as the “operating pressure” of the gun.
4. The LPR (Low-Pressure Regulator)
Connected to the main pressure chamber by a small air passage is the LPR. The LPR drops the operating pressure even further—to about 100 PSI on LCD Angels, 50-82 PSI on stock Angel 4’s, and less than 50 PSI on Fly and newer A4’s. There’s not much to the LPR beyond that.
2. The Firing Sequence
1. In the beginning… or, "How does the Angel know that I’ve fired?"
We’re finally to the part you care about… it’s time to pull the trigger! Here’s goes! (Sorry, but the first part of this is tailored to Angels with toe screws and Opto switches. If that’s not you, read between the lines a bit; the operation is almost the same.)
When you pull the trigger, a set screw on the back of the trigger pushes against a sheaf of metal known as the “leaf spring”. When at rest, the leaf spring occludes (blocks) the light from a small LED above the spring, preventing it from reaching a sensor on the other side. A picture would probably be helpful at this point:
The blue portion of the trigger is what is externally visible on the gun. The two protrusions on the top with green arrows pointing at them are the blocks which interface with the vernier adjustment wheels. When you pull on the trigger, the entire blue, black, and dark-grey assembly rocks back, pushing on the leaf spring, which I have drawn a lighter grey here. (The black spot is just the leaf spring's anchor point into the board.) The red is the light emitter, the yellow the detector; they stay still as the spring is deformed to slide its bottom leaf backwards by the force of the trigger pull. There is a small hole drilled into the bottom leaf that, when the trigger is at rest, sits forward (towards the barrel-end of the gun) of the emitter and detector. When the spring is deformed by a trigger pull, however, the light is able to pass through this hole, which triggers the firing sequence.
2. Arrrrr, we’ve spotted software o’er the starb’rd bow, cap’n!
Trust me when I pompously claim that the way in which the software accomplishes various things is beyond the ken of mere mortals. (By which I mean, people who aren’t programmers or electrical engineers by trade. Preferably both.) Suffice it to say that the software wants to ensure that there’s a ball in firing position (unless the Sensi/COPS mode doesn’t care about that), and that the gun is in live mode. If this doesn’t seem like much, don’t worry; the software will be a recurring character from here on out in the firing sequence.
3. Fire solenoid, full, Mr. Sulu!
Pressure from the LPR snakes along a small tube inside the body of the gun, until it ends up at the 14-way valve at the rear of the gun. The solenoid’s movement serves to unblock this air and direct it down a passage into the ram, where it extends the hammer for a period of time known as the “dwell”. Dwell is measured in milliseconds, by the way, in case anyone is of the curious type. The dwell is controlled by the software. (Okay, technically, on very early Angels, it’s set by hardware, but let’s not pay attention to that right now, okay? Thanks.)
4. The bolt on the move.
When the hammer gets extended out of the ram, it pushes along a bar that is attached to the bolt. If you don't have an Angel, go find a picture of this setup; it's rather hard to draw a good two-dimensional representation of the entire bolt/breech/chamber/hammer system. Anyway, so the bolt moves forward within the breech, filling the area directly underneath the feedneck (and thus preventing the dreaded "blowback" up the ball stack). Moving forward in this manner, it pushes the ball past the ball detents; at this point, if you had somehow extended the ram but managed to keep air pressure out of the main pressure chamber, the ball would be quite happy to roll out the barrel if given the chance.
5. ...And the ram met the exhaust valve, and it was good
Luckily, however, we don't have to worry about that, because at the moment the bolt is at full extension, the hammer rams into the back end of the main pressure chamber, which was fortuitously equipped with an exhaust valve. Handy, eh?
6. Flow.
So now that the exhaust valve is depressed (poor fella, we oughta send it a psychiatrist), the air rushes out and goes up into the bolt. In the bolt, it's directed forward, through the Venturi, onto the ball.
7. Splat!
You win.
8. Withdrawing the hammer.
The dwell having expired, the hammer is returned to its rest position by returning the solenoid to rest position, which directs air from the LPR into the front of the ram and allows air from the back of the ram to exhaust.
9. HOP activation, shot count, etc.
Activate the hopper according to shot interval Ax; activate hopper for y seconds in Ty if (curshot % x == 0). Increment shot counter. Etc., etc., etc. "Software stuff".