Quote Originally Posted by bigtoe01 View Post
you gain lost volume...so you are actually dialling in inefficiency, do you feel the gains in port flow outweigh the lost volume?. Air venturing work best when air is being dragged thru the port such as a carburettor on an engine, when air is being forced thru a port i think the gains are minimised somewhat. It actually looks better to have a tiny radius and a port large enough to ensure good flow but small enough to ensure the pressure build up is high enough to cushion the piston. The tiny radius minimises lost volume.

One thing I have considered and I mentioned this to Prof Mike at the Midland is a transfer port utilising the Bernoulli effect coupled with a venturi, there may be a way of increasing the amount of air behind the pellet so increasing the efficiency....not tested it though.

They use this system to blow up evacuation slides on aircraft, they have gas cylinders that if direct coupled would only fill around 1/3 of the slide, using a slick designed venturi they are able to tripple the amount of gas within the slide by dragging air into the system also.

how to fill a large bag with 1 breath... http://www.youtube.com/watch?v=UujAMPv3y-A


The trick would be closing off the ports that drag the air in as the air flow reverses and becomes negative.

I should perhaps of given a bit more detail.
By radius or bevel I meant only a tiny one..... just enough to remove the sharp square edge.
I agree that this has more benefit for drawn air than pushed air but my opinion is that sharp edges are best kept on knives
Edd.