On Dec 7, 1:49*pm, Eric Greenwell wrote:
On 12/7/2010 11:16 AM, wrote:

I have an exit vent in the lower aft area of the fuselage of both my
'27 and '28. With all the other stuff done sealing rudder hinge,
elevator drive, horn splitters, etc, it improved negative pressure and
flow and resulted in less noise. This vent is a huge ass ache to put
in with the associated nozzle, has significant structural implications
requiring reinforcement, and simply, is not for the faint hearted.
The new vent on top is in a low pressure area which helps a lot with
getting flow and reduced cockpit pressure. It also takes an hour and a
half to install instead of about 10 hr. It's structural implications
are minimal. It slightly reduces available baggage storage in the top
center 4 inches.
Both my gliders will have rear vents closed this winter and '28 will
get top vent.

I got so much air from the front vent and eyeball vent on my ASH 26 E
(standard tail vents at the rudder cables) that I plugged up half the
duct work from the nose to make it easier to control. Still get tons of
air from the eyeball and scoop when I open them, so the air doesn't seem
to have any trouble getting out of the glider. I don't know where it is
leaving, however.

How low must the cockpit pressure be to assure myself the air isn't
going out the canopy/cockpit edge, gear doors or wing roots?

What is a good way to measure the cockpit pressure?

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
email me)

In my case a water manometer* connected to the static system on one
side and open to cabin pressure on the other. All I need to do is get
around to it. I've been carrying thte bits and pieces in my trailer
for a couple years now, but I always think I'm going to fly 500k, and
don't want to carry stuff around (while I actually fly 'round the
patch all day).

*just a piece of clear vinyl tubing actually