Water ballast rookie question

I fly an ASW-28. The under-surface of the wing has a nice little piece
of plastic that covers the dump valve and which is hinged by a piece
of cloth tape. When flying with water ballast my assumption is that
correct procedure is to leave the piece of plastic in place, but open
and hanging down from the cloth tape hinge. I am thinking that airflow
will keep the plastic closed and be more aerodynamic over the dump
valve but when dumping ballast it will open sufficiently to let the
ballast dump efficiently. Or should I simply remove the piece of
plastic entirely when carrying water ballast? Thanks.
Tom

Your assumption is correct. Leave it as is with or without water. The
airstream closes them in flight and water exiting will open them.

A related question: Does anybody know what to use to replace these?
Mine fell off.

All the later Schleichers have them.
If you fly without the covers, take ear plugs. It sounds like twin
jets.
Apparently they are useful for something other than swearing at while
you're washing the wings.
Jim

On 8/13/11 7:40 PM, Tom Nau wrote:
I fly an ASW-28. The under-surface of the wing has a nice little piece
of plastic that covers the dump valve and which is hinged by a piece
of cloth tape. When flying with water ballast my assumption is that
correct procedure is to leave the piece of plastic in place, but open
and hanging down from the cloth tape hinge. I am thinking that airflow
will keep the plastic closed and be more aerodynamic over the dump
valve but when dumping ballast it will open sufficiently to let the
ballast dump efficiently. Or should I simply remove the piece of
plastic entirely when carrying water ballast? Thanks.
Tom

Yes leave it in place as a hinge.

Make sure you fill and test dump and make sure everything seems to work OK.

If you've never flown with water I would encourage you to find a local
experienced pilot locally (ideally somebody who flies a Schleicher with
water) to help you make sure everything is OK and talk through with you
things like fill and ground handing procedures, flyng handling
differences, thermalling speeds, performance effects etc. And of course
read the POH. And make sure you let the tow pilot know you are
heavy/carrying water.

Darryl

On 8/13/11 8:13 PM, Barny wrote:
Your assumption is correct. Leave it as is with or without water. The
airstream closes them in flight and water exiting will open them.

A related question: Does anybody know what to use to replace these?
Mine fell off.

Cut a circle out of suitable thickness sheet mylar. Attach with Tesa
cloth tape.

Darryl

On Aug 13, 7:40*pm, Tom Nau wrote:
I fly an ASW-28. The under-surface of the wing has a nice little piece
of plastic that covers the dump valve and which is hinged by a piece
of cloth tape. When flying with water ballast my assumption is that
correct procedure is to leave the piece of plastic in place, but open
and hanging down from the cloth tape hinge. I am thinking that airflow
will keep the plastic closed and be more aerodynamic over the dump
valve but when dumping ballast it will open sufficiently to let the
ballast dump efficiently. Or should I simply remove the piece of
plastic entirely when carrying water ballast? *Thanks.
Tom

I noticed during pre-flight that my 28 had lost one so I took the
other off to save as a template. The uncovered dump ports are excited
by the airflow and "sing". Trouble is they sing at slightly different
frequencies. The beat tone is almost unbearable and I nearly
abandoned the flight. The noise stops during dumping. I don't know
if it happens with the dump valves open after all the water is gone.
I suspect they don't sing then as the port resonant frequency should
be very different with the valves open. I wanted to keep my water and
didn't try it. I keep a set of ear plugs in the glider just in case
it happens again.

I cut new ones from clear plastic sheet which I had covered with white
shelf covering. The clear plastic was available and the white shelf
covering made it look better. I attached them with 3M electrical
tape, the same as used for wing gap sealing. The home made ones have
lasted about 7 years compared to 1year for the factory ones. Perhaps
that's because I learned not to hit them when cleaning the wing. It's
also a good idea to replace the tape each year

Andy

snip

All the later Schleichers have them.

/snip

O'Leary?!

My -29 didn't come with them, I had to do it meself.

2N7O

On Aug 13, 9:40*pm, Tom Nau wrote:
I fly an ASW-28. The under-surface of the wing has a nice little piece
of plastic that covers the dump valve and which is hinged by a piece
of cloth tape. When flying with water ballast my assumption is that
correct procedure is to leave the piece of plastic in place, but open
and hanging down from the cloth tape hinge. I am thinking that airflow
will keep the plastic closed and be more aerodynamic over the dump
valve but when dumping ballast it will open sufficiently to let the
ballast dump efficiently. Or should I simply remove the piece of
plastic entirely when carrying water ballast? *Thanks.
Tom

That's how they're supposed to work.

Tape them closed when flying dry so you don't rip them off. Don't
forget to take the tape off when you put on water ballast. (Add "check
dump covers" to your preflight)

When inevitably they fall off, replace with any flat piece of plastic.
I find that the clear plastic case that holds 3m vinyl electrical tape
which I use for wing tape works great, and I usually have a large
supply of that around.

There is a larger issue of tips and tricks for water ballast which
others have covered. Some additional points:

-It is important to adjust CG using the tail tank. It's hard enough to
thermal with water without a far forward cg

-The glider is designed to carry enough water for the strongest
conditions imaginable -- smoking ridge day, 1000k attempt at Ely, etc.
On most days you do not need or want full water. Half water is a good
place to start.

- Takeoff with water ballast is harder. Carefully brief your wing
runner that the wings must be level and balanced -- no force up or
down. He or she may have to slosh the water through the internal
baffles to get it level and balanced. There must be no up or down
pressure. Ask the wing runner to let go briefly to show you there is
no pressure if you're in doubt. The wing runner must then run like
crazy, without pushing up or down. This is a good time to use partial
spoilers for roll control. Needless to say all this gets more fun at
high altitude, hot, cross-downwind at a contest. Release early if you
drop a wing!

-Enjoy! I like flying with water. It's a big performance increase for
free.

John Cochrane

Another water ballast question.

How well does a fully ballasted glider recover from a spin?

I practice spins every season, dry. The recovery is easy and
predictable. (SZD 55-1) I have never tried a spin with water. If I
accidently spin at low atlitude (1000 ft agl or lower) fully
ballasted, should I attempt to recover, or just bail?

Kerry

On Aug 17, 11:13*pm, P9 wrote:
Another water ballast question.

How well does a fully ballasted glider recover from a spin?

I practice spins every season, dry. *The recovery is easy and
predictable. *(SZD 55-1) *I have never tried a spin with water. *If I
accidently spin at low atlitude (1000 ft agl or lower) fully
ballasted, should I attempt to recover, or just bail?

Kerry

Hi Kerry,
Enjoyed flying with you at Air Sailing Sports. Good race again this
year and those AFA guys can no longer be ignored, can they?Your 55
holds a ton of water, I'd recommend you try spinning it with a half
load, then work up from there.................well maybe that's not
such a good idea because a partial load can shift to the outboard wing
tip and give a big lateral weight problem. I remember Carl Herold
telling me the 12 would tuck under to where the nose was more than
vertical when he spun her with a load of water.........Hmmm, maybe
don't spin it wet would be the best advice and if you spin it at 1000
agl, i'd do it with a BRS installed. Adding the BRS to my Genesis was
the best thing I have done lately, I feel much more secure now and
enjoy that comfortable seat (without chute).
Cheers,
JJ