Mechanical pre-cocking

[Skywalker]

Let's talk about it! What you know, what you don't...and what could potentially be done. General chit chat thread. You know who you are!

[Star_folder]

Let's talk about it! What you know, what you don't...and what could potentially be done. General chit chat thread. You know who you are!

I guess I'll chime in since, to my knowledge, I'm the only one in SC with a precocking gun.

It's hard to get just right, and semi lock up is fairly common. It puts a lot more stress on a gun than normal, because in it's "rest" position, when you aren't firing the gun, the piston is all the way back, putting extreme amounts of pressure on the system. Not only that, but you need a lot of torque to get the spring out of the pulled back position. Precocking cannot be done with your normal high speed motors simply because they don't have enough torque to do it.

As for installing it in a system, you'll need to fix a gear to stop at the pre cocked position. That means you either change the position of the cut-off lever engagement nub, or you add/subtract teeth on the gear. The easiest thing to do would be to buy gears of a gun that has precocking, such as an L85, and then modify them to fit your gun.

Second, you'll need to balance the system so that the gear stops where it should every time. Not enough power and you'll get stuck in semi-lock-up every shot, too much power and you'll shoot bursts on semi. If this means having a strong spring, strong motor, and a *weak* battery, or an AB-mosfet, or some combination.

The rewards are very nice, as you get almost instantaneous trigger response.

That's about it for now, I'll soon be installing mechanical pre-cocking into one of my guns, and we'll see how that goes.

[Skywalker]

Yeah interested to see how that'll work in the fn2000.

I know that I have battery issues quite often in the PSG, too much or too little power and it doesn't cycle correctly

[Star_folder]

Right, I forgot about the psg-1. Yeah, I found a nice computerized mosfet helped me out. The AB seems to have helped alot, though the next one I'm getting has an option to turn AB off, and we'll see how that goes.

[Skywalker]

Does it control the speed of your motor?

And I wonder how Dom could/should make a pre cocking p90 dmr. ... probably electronic rather than mechanical

[Felix]

Alright im done stalking, what is this precocking you two speak of?

[SteevoLS]

Blah blah blah AWS.

http://www.awsairsoft.com/raptor-v2gb

Admittedly they are only produced for the V2 right now, but this will change soon.

[Skywalker]

Yeah steevo that's the nice high end correct route for sure. Aws is great.

Felix-- pre cocking has to do with the way that the piston/gearbox cycle. On most every AEG, you pull the trigger, the motor pulls the piston back, the piston fires which puts the bb out the barrel. In a pre cocking set up, the piston is pulled back before you pull the trigger, much like a bolt action gun. So you pull the trigger, the piston fires, then the motor spins and pulls the piston back into the pre cocked state. Its great for dmrs because there is no movement inside the gun until the bb is fired, which makes it way more consistent.

The problem is, to have this done mechanically, you need a unique gearbox design, like in the PSG-1... or you can do something fancy like we're discussing in this thread (such as dropping in a modified sector gear so that the motor is cut off at a different point in the cycle)

This can also be done electronically with a fancy enough mosfet system like what steevo posted.

[SteevoLS]

The electrical route makes the most since to me because at the end of the day you can un-precock the pistol very simply. In a mechanical setup, you'd need some sort of mechanical way to disengage it.

[Star_folder]

Personally, I would rather have the mechanical system in play. From my experience/research, using mosfets to time everything correctly is touchy and often doesn't go as planned.

But steevo is right, it is rather important that your gearbox has some way to easy disengage the arl. Some G&G Combat Machines have this, I think ICS does, some ares guns, Not sure about what else has a spring release. But you could always just switch to full auto and tap the trigger to decompress the spring.

[Skywalker]

The aws had a way to disengage the pre cocking semi auto

[Star_folder]

Well, to update the thread. I did it, it works, I just have motors too powerful to see it work.

I installed the system in my G&G FN2000, and at first, I couldn't tell if it worked or not. I have a Guarder SP140 in it, an 11.1v lipo, G&P M160 motor, and an AB Mosfet. I couldn't tell that it worked, so I tried a big 9.6v, still didn't see it working. Up until this point, the spring guide was in it's fully relaxed position. So I spun it in all the way, giving it the full force of the spring. Finally, I see the gun precocking, but the system is still too powerful, and it double fires.

I've got an 8.4v charging up, we'll see how that goes, it should slow down the system enough to actually have a reliable precocking. Even then, I'll probably remove it anyway and just stick the normal sector gear back in there.

From what I've seen, it would do better in very high fps set ups, with not so high torque motor, not an 11.1v, but the AB mosfet will still help.

[Skywalker]

If you don't use the gear i'll take it

[Star_folder]

If you don't use the gear i'll take it

psh, I'll probably put it in my P90. If that doesn't work, I'll put it up for sale. I wonder how much it would be worth...

[Skywalker]

Whats the point of a pre cocking p90? I think its worth 3 dollars and Airsoft discussions for life....