ASW 24&27 rear fuselarge vents?

[Udo Rumpf]

Hi all,
to day I checked, what I thought was the rear exhaust vent of the ASW24.
I tried, after removing the rudder, insert a thin wire past the tail wheel fender.
I could not get this thin flexible wire through.
I inserted a long vacuum hose from the cockpit side, to the very end of the tail
and hook up the blower side. The results were feeble indeed.
What have other ASW 24 or 27 owners done to improve this situation?
Regards
Udo

[John Morgan]

"Udo Rumpf" > wrote in message
.. .
Hi all,
to day I checked, what I thought was the rear exhaust vent of the ASW24.
I tried, after removing the rudder, insert a thin wire past the tail wheel
fender.
I could not get this thin flexible wire through.
I inserted a long vacuum hose from the cockpit side, to the very end of the
tail
and hook up the blower side. The results were feeble indeed.
What have other ASW 24 or 27 owners done to improve this situation?
Regards
Udo

Udo,

I suspected exhaust venting may be limiting cockpit ventilation on my
ASH26E. I haven't finished testing yet, but what I have done is to hook up a
shop-vac, on blow mode (after carefully cleaning it!), to the nose inlet to
pressurize the cockpit. I didn't have the wings attached, so taped up all
the fuselage wing root openings. The only outflow I could detect was at the
rudder cable fairing at the tail - - nothing at the gear or engine bay
doors.

On my non-scientific test, the flow was obviously restricted (the shop-vac
puts out a lot of air) as my temporary wing root covers ballooned out from
the pressure.

I plan to check cockpit vent flow with and without a temporary reverse scoop
in the plexi window etc. And also repeating the shop-vac test with wings
attached to make sure none is leaking out through wing openings - - I doubt
it is.

I've seen a picture of a 26E with a reverse facing, flush scoop on the lower
cockpit fuselage side . . . so others have dealt with this issue and come up
with solutions of their own. Any other info would be welcome . . .
--
bumper - ZZ >
"Dare to be different . . . circle in sink."
to reply, the last half is right to left





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[JJ Sinclair]

Hi Udo,
My ASH-25 was emitting a very loud squeal as I went through the finish gate at
redline (above 500 feet of course). I removed the rudder and found no way for
vent air to get out, so I drilled a 1" X 2" hole in the tail wheel fender.
Worked fine and the cockpit ventilation got a bunch better. As you know, the
exit hole should be 1.5 times the entry hole size.

On my nimbus 3, I enlarged the hole in the vertical fin spar and also polished
out the rudder cable exit guides with a sanding roll on a rod, driven by a
drill motor. Unfortunately, some major sailplane manufacturers don't do much,
if anything, about providing an efficient airflow exit system and if we don't
let it out in the tail area, the vent air will go looking for a way out in
other places, like the wings, landing gear doors and canopy seal.

JJ Sinclair

[Greg Arnold]

JJ Sinclair wrote:

> Hi Udo,
> My ASH-25 was emitting a very loud squeal as I went through the finish gate at
> redline (above 500 feet of course). I removed the rudder and found no way for
> vent air to get out, so I drilled a 1" X 2" hole in the tail wheel fender.
> Worked fine and the cockpit ventilation got a bunch better. As you know, the
> exit hole should be 1.5 times the entry hole size.
>
> On my nimbus 3, I enlarged the hole in the vertical fin spar and also polished
> out the rudder cable exit guides with a sanding roll on a rod, driven by a
> drill motor. Unfortunately, some major sailplane manufacturers don't do much,
> if anything, about providing an efficient airflow exit system


Do all manufacturers ignore exit air? If not, which ones take this into
account in their designs?


and if we don't
> let it out in the tail area, the vent air will go looking for a way out in
> other places, like the wings, landing gear doors and canopy seal.
>
> JJ Sinclair

[Udo Rumpf]

> My ASH-25 was emitting a very loud squeal as I went through the finish
gate at
> redline (above 500 feet of course). I removed the rudder and found no way
for
> vent air to get out, so I drilled a 1" X 2" hole in the tail wheel fender.
> Worked fine and the cockpit ventilation got a bunch better. As you know,
the
> exit hole should be 1.5 times the entry hole size.
>
> On my nimbus 3, I enlarged the hole in the vertical fin spar and also
polished
> out the rudder cable exit guides with a sanding roll on a rod, driven by a
> drill motor. Unfortunately, some major sailplane manufacturers don't do
much,
> if anything, about providing an efficient airflow exit system and if we
don't
> let it out in the tail area, the vent air will go looking for a way out in
> other places, like the wings, landing gear doors and canopy seal.
>
> JJ Sinclair

[Udo Rumpf]

Sorry about the previous message.
I became suspicious when I noticed reams of foam
around the canopy as well as the cockpit opening,
to the point that the canopy would not line up along the fuselage line,
The brass bushing that holds the canopy down and locked was worn out, I
assume because of it.
I have a generous exit vent on my other glider and no seal on the canopy.
The fit is no better or worse than any other glider, still the cockpit is
relatively quiet through out the speed range.
Udo

[Eric Greenwell]

In article <EvTlb.190358$0v4.14757759@bgtnsc04-
news.ops.worldnet.att.net>, says...
> I suspected exhaust venting may be limiting cockpit ventilation on my
> ASH26E. I haven't finished testing yet, but what I have done is to hook up a
> shop-vac, on blow mode (after carefully cleaning it!), to the nose inlet to
> pressurize the cockpit.

What speed did the ASI show?

> I didn't have the wings attached, so taped up all
> the fuselage wing root openings. The only outflow I could detect was at the
> rudder cable fairing at the tail - - nothing at the gear or engine bay
> doors.
>
> On my non-scientific test, the flow was obviously restricted (the shop-vac
> puts out a lot of air) as my temporary wing root covers ballooned out from
> the pressure.

It might not be so bad in flight, when the air rushing past the rudder
cable fairings will assist the air leaving the fuselage.

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directly

Eric Greenwell
Richland, WA (USA)