Power plenum for barrel?

[Arash]

Hi.

I am wondering what would happen if someone put a power plenum for barrel.

We always put a plenum for regulator but when the hammer hit the valve at first there is high air pressure in low volume of the barrel.

Then pellet start to accelerate so fast but the volume start to increase too, so acceleration will decrease by time. I believe in 1/3 of the barrel pellet will gain 1/2 of its total energy.

So if someone put a plenum on the transfer port, when the valve opens this plenum get a lot of air in it, so there is a high pressure in high volume. 

When pellet passes 1/3 or 2/3 of the barrel this high volume will maintain that high pressure.

I think this is possible for impact.

 

[dc8cappie]

You just increased the volume of the barrel. Your source of air from the valve must fill the extra volume while sending the pellet down the barrel. The less volume between the valve and pellet the better. Extra volume requires more air at higher pressure to get the same pellet speed.

OMHO. I could be wrong!

 

[vmaxpro]

Push the pellet 10” down the barrel and see what happens...If you want to maintain a more consistent pressure with no drop increase your plenum size and valve dwell.

 

[ImpactX]

The plenum is the space where the valve is. When the valve opens air rushed through the transfer port into the barrel. I dont see how a plenum can be attach to the barrel or what you are even thinking of. Might be better to include a picture. What do you even mean putting a plenum on the tp? The plenum is the space next to the tp already. Are you suggesting making the tp as big as a plenum? Then how do you load a pellet in without it falling into the tp since you want to make the tp hole same size as the plenum. 

 

[Special-FX]

is this related to why 700mm vs 500mm gets more fps for the same reg pressure?

 

[Glem.Chally]

is this related to why 700mm vs 500mm gets more fps for the same reg pressure?

The reason that is, is the pellet or slug has more time/a longer run to accelerate i believe.

 

[Arash]

I don't have any impact to do it by my own right now.

But check this pic

There is a hole behind the reg manometer that keep valve in place and transfer port made from this hole too.

So if screw comes out and a volume of air attached to it, so when we shoot, this volume get full of air.

My idea is when hammer hit the valve

1_ in a short time valve get fully opened.

2_ air comes out and accelerate pellet

3_ valve get closer and closer so less amount of air comes out.

4_ pellet passes throw the barrel so high volume of air needed to accelerate pellet.

But if extra volume attach to this thread, when valve get fully open it will easily charge this volume and while valve getting closer this volume maintain that high air pressure in the barrel.

I think 12 cc capacity for this volume is enough for 500mm 0.22 cal barrel.

 

[Haganaga]

This premise reminds me of Hitler’s supergun. The barrel was superlong on the side of a hill and used the multi charge principal to accelerate the projectile through the long barrel. I don’t think the 700mm barrel would benefit though, as the pellet, especially with an enlarged plenum, is still accelerating till the end of the barrel. Also I think there would be problems with stability as the pellet exits. But it’s fascinating to think about.

 

[Glem.Chally]

That screw is very important as it holds the rear block to the valve house. I don't think you can just remove it and add a plenum there.

 

[ctshooter]

I don't think this idea would work at all for an airgun. You will dramatically increase both your lock time and the amount of air required for each shot. 

After you pull the trigger the whole volume will need to fill before accelerating the pellet. It's the wrong solution to the problem. You need a large plenum before the valve and a longer dwell time of the valve being open if you need to continue to accelerate a pellet through a longer barrel. You could do this with a slightly weaker valve spring or a heavier hammer spring setting.