air migration and the rear dump..

[wilbo]

Originally Posted by Gledders

The rear dump only really works when you are horrizontal. I have an Agir wing too and use the rear dump all the time now - but this took a lot of getting used to. Try reaching for it when you are swimming along and experiment - but be able to use both.

HTH

What Claire said in the harness rigging thread. New post, as I didn't want to hijack the original thread..

I actually think that there is a minor design 'flaw' in having the rear inflator where it is.
The reason is that when you are using your wing for bouyancy changes as you descend, the wing fills slightly with the required gas. Accepted.
When you start to ascend, you dump gas as required. Accepted.
Now using the rear dump, you must make sure that the dump is at the highest point so the gas will migrate there. That takes care of the left hand side of the wing. But what about the gas in the right hand side of the wing?
I am interested here, as I end up doing the 'funky chicken' in the water while trying to migrate the gas from the right hand side over to the left. I end up going into a more vertical position and then rolling off to my right and then going horizontal. This works and the gas migrates. then I can dump the remainder..

[Lou]

(no devil smiley....)


That's what bungees are for!

I nall honesty though it is more of a small body roll than the funky chicken, but you do, of course, have to move to redistribute the air after dumping.

[Clare Gledhill]

Yup - you have a point - and I think this is why Halcyon have developed their new wing which is doughnut shaped rather than horseshoe shaped (I'm sceptical about this but, hey, what do I know ).

To be honest though it is only a small movement, as Lou said, in the same way that if you turn round, stick your head in a hole, carry a few stages etc., you may have to roll slightly to migrate air from one side to the other. But the alternative method of dumping requires you to go heads up (to some extent) to dump so which ever method you use you are going to have to be aware of the "bubble" and reposition yourself to suit.

[Scuba1]

Originally Posted by Lou

(no devil smiley....)


That's what bungees are for!

You beat me to it

[wilbo]

Sorry - the 'funky chicken' was an exaggeration.. it is more of a graceful sweep. Nope. still not quite there. maybe somewhere in between.

[vid]

Originally Posted by wilbo

Sorry - the 'funky chicken' was an exaggeration.. it is more of a graceful sweep. Nope. still not quite there. maybe somewhere in between.

it doesn't mater how good your buoyancy is, if you're moving around you will not stay absolutely horizontal - there'll always be some lateral vertical movement, so the gas will move from one side of the wing to the other side. UNLESS there's very little gas in the wing, in which case, how much difference is dumping it, going to make to your overall buoyancy anyway - not as much as the difference in gas flow from your lungs.

vid