Incorporation of hopup...

[Molybdenum]

A while back, I made this, and as you can see, I did say I would make a version 2.

Now, version two will have almost exactly the same design, and I want to incorporate hopup. The problem is, I can't find a way to fit my hopup unit on the muzzle without making the thing impossible to reload. the problem is that the barrel goes through the endcap, so the hop unit blocks it from coming off. Any one have any ideas?

this is the hopup unit

[qwerty]

I don't think the hop-up goes at the muzzle. I'm pretty sure it should be at the breech.

[lozz08]

As above, putting your hopup at the muzzle will ruin everything. You need to make a detent system just after the vortex block. There are plenty of posts about that use search.

[Molybdenum]

I have found that the hopup works just as well on the muzzle. See APEX tip.
The reason I want to do muzzle as opposed to breach en hopup is that
1) my skills and tools are limited, and
2) This would severely limit my ability to adjust the hopup.

[jackssmirkingrevenge]

One good reason to put it at the breech:

- it will block each BB briefly at the breech allowing pressure buildup giving better muzzle velocity

Two good reasons not to put it at the muzzle:

- when it hits the hop-up unit the projectile will be at its maximum velocity, and the hop up unit will slow it down

- wear and tear on the hop up unit will be significantly increased

The question really is do you want this for skirmishing and are therefore limited to a particular velocity, or for plinking? In the latter case it would be better to optimise performance which will give better velocity and a flatter trajectory, rendering hopup less important.

[Molybdenum]

Thank you JSR, I hadn't thought of those things. I still don't know how I would incorporate a breach end adjustable hopup (well, I have some ideas, but nothing that is in my means to fabricate).

Any one have some diagrams?

Edit: Just drew this up. would this work?

[jackssmirkingrevenge]

would this work?

That should do nicely

[lozz08]

Second that, it looks easy to make and effective.

[ThornsofTime]

This is a subject near to my heart as I am currently building a vortex as well. The hop-up I was planing on using is basically the same thing BUT would be installed on the barrel a few cm past the vortex block.

A) Is this an acceptable hop-up design?
B) Is there any real benefit to having the hop-up at the ABSOLUTE beginning of the barrel?? or is it just as good to have it in front of the vortex block??

EDIT: sorry for the sub-par paint work... didn't feel like wasting 2hrs getting a point across. I believe its serviceable.

[jackssmirkingrevenge]

A) Is this an acceptable hop-up design?

It terms of spinning the projectile, it should work.

B) Is there any real benefit to having the hop-up at the ABSOLUTE beginning of the barrel?? or is it just as good to have it in front of the vortex block?

What could happen is that while the BB is stuck in the hopup, a following BB is "queued" behind it, so when the first BB fires the second one will blow the air flow and result in a weak shot.

[ThornsofTime]

Is this avoidable??

it seems to me that any way of achieving hop-up requires a physical "touch" to the bb to induce a spin. that being said every hop-up mechanism will have that moment when one bb is "stuck" in the hop-up and there is another bb cued behind it (even if the hop-up is in the vortex like above, air pressure will hold a bb behind the one in the hop-up).

So other than bending your barrel... like on a Tippman paint-ball gun flat-line barrel (where spin is made by forcing prolonged contact with different parts of the barrel)
http://www.bakati.com/p~p-710888929~b-1 ... arrel.aspx
its all basically the same isn't it??

EDIT: for better link showing "bent" barrel
http://www.getintosports.com/product.ph ... ctid=16141

[jackssmirkingrevenge]

As yourself the following:

The question really is do you want this for skirmishing and are therefore limited to a particular velocity, or for plinking? In the latter case it would be better to optimise performance which will give better velocity and a flatter trajectory, rendering hopup less important.

[lozz08]

The problem with the screw design is that it will either not put on much spin, or it will completely block the barrel. Why?

Look at airsoft hopup designs. The thing that pushes against the bucking (the rubber around the barrel) is pushed down by another little nub of rubber, this little nub is pushed down by a spring.

This means that even if the bucking is pushed far into the barrel (say it sticks in 1/3) the bb can still push through because the nub is spring-loaded.

In the case of a screw, in order to get adequate spin, you'd have to screw it in pretty far. But the bb can't push past the screw, because it's not on a spring- its rigid.

Which means your hopup will have to be set lower, and you won't get as much spin. Any amount of spin BELOW the sweet spot will actually make the bb dip down more than a bb with no spin at all. Here is the proof:

http://mackila.com/airsoft/ATP/03-a-01.htm

Scroll down to the graph of range vs. Spin.

[ThornsofTime]

gooooottttttchaaaa. Yeah that makes good sense. Well explained and backed up.

What if I were to switch out the screw with a variable pressure ball detent? Everything else the same.

@JSR- I want both gonna use a paintball HPA and inline regulator, giving me the option to turn it down and shoot friends OR crank it up and plink.

the regulator: 900psi in and 100-800psi out
http://www.zephyrpaintball.com/product/ ... Black.html

the tank
http://www.zephyrpaintball.com/product/ ... ssure.html

not my exact parts, but gets ya on what im gonna be working with. Now to find a "blowgun" (or similar) valve that can handle low and high psi....

[jackssmirkingrevenge]

What if I were to switch out the screw with a variable pressure ball detent? Everything else the same.

Sounds like a plan.

Now to find a "blowgun" (or similar) valve that can handle low and high psi....

In my experience most ordinary shop blowguns will happily take 400 psi or so before they start to leak, another option if you want the facility to take it to the full 800 psi is either use a pressure washer valve like I did here or use a ball valve that will give you the benefit of better flow, and can be easily fitted with a spring return to close it when trigger pressure is released.