Dual Trim Switches?

Maxwell wrote:
For what it's worth.

When I first checked out in an SP, the CFI told me Cessna had been
sucessfully sued when a pilot argued the tanks could not be sumped correctly
unless the aircraft was parked perfectly level.

Now you can drain the lowest point in the tank, no mater how or where you
park your SP.

I would tend to doubt that version of events. The 13 drain points were
introduced when Cessna restarted production on the redesigned 172R back in
'96. The drains were in the new version from the start, so I doubt Cessna
could have been sued. Also, we probably would have heard about it here.

Previous versions of the 172 ('84/'85) had wing tanks with no obstructions
in the bottoms. The new version had wet wings, which is what prompted the
installation of drains outboard of each rib in the tank area.

John Galban=====N4BQ (PA28-180)

--
Message posted via AviationKB.com
http://www.aviationkb.com/Uwe/Forums...ation/200710/1

"JGalban wrote

Previous versions of the 172 ('84/'85) had wing tanks with no
obstructions
in the bottoms. The new version had wet wings, which is what prompted the
installation of drains outboard of each rib in the tank area.

And all of those extra drains could have easily been eliminated if the
engineers would have done a hours worth of work redesigning the ribs to
enlarge or add crossover points in the ribs, so all of the water could get
to the lowest point in the tank.

This has to be an example of why things are screwed up in the industry,
don't you think?
--
Jim in NC

On Thu, 4 Oct 2007 21:38:15 -0400, "Morgans"
wrote:


"JGalban wrote

Previous versions of the 172 ('84/'85) had wing tanks with no
obstructions
in the bottoms. The new version had wet wings, which is what prompted the
installation of drains outboard of each rib in the tank area.

And all of those extra drains could have easily been eliminated if the
engineers would have done a hours worth of work redesigning the ribs to
enlarge or add crossover points in the ribs, so all of the water could get
to the lowest point in the tank.

This has to be an example of why things are screwed up in the industry,
don't you think?

The newer (post-restart) aircraft are sealed bladders, not wet wing,
therefore you can't just let the water seep through the ribs.

Peter Clark wrote:



The newer (post-restart) aircraft are sealed bladders, not wet wing,
therefore you can't just let the water seep through the ribs.

Peter, your information is incorrect. I'm looking at the Cessna Parts
Catalog for the new 172R, and 182S models. They most definitely employ
wet wing fuel bays, not bladders.

Happy Flying!
Scott Skylane

On Sat, 06 Oct 2007 12:04:50 -0800, Scott Skylane
wrote:

Peter Clark wrote:



The newer (post-restart) aircraft are sealed bladders, not wet wing,
therefore you can't just let the water seep through the ribs.

Peter, your information is incorrect. I'm looking at the Cessna Parts
Catalog for the new 172R, and 182S models. They most definitely employ
wet wing fuel bays, not bladders.

Interesting. I don't have my maintenance manual handy, but a quick
Google pulled this up from Cessna's website:

"The 182E also featured electrically-operated “Para-Lift” flaps,
neoprene rubber fuel bladders holding 65 gallons total, new stronger
main landing gear/fuselage attachment and improved nose wheel
steering."

(
http://www.cessna.com/news/article.c...XLJEsBa4kfBxm4
)

I wonder why they would have gone back to sealed wet-wing when they
had bladders in there years ago. I wonder where I got that the new
ones still had bladders.

"Peter Clark" wrote

"The 182E also featured electrically-operated "Para-Lift" flaps,
neoprene rubber fuel bladders holding 65 gallons total, new stronger
main landing gear/fuselage attachment and improved nose wheel
steering."

Looking at the 172R specs on the Cessna web pages, the wing tanks are listed
as Integral fuel tanks, 53 gallons useable, 5 quick drains per wing. No
fuel bladders in this model, it would appear.
--
Jim in NC

Peter Clark wrote:
/snip/

I wonder why they would have gone back to sealed wet-wing when they
had bladders in there years ago. I wonder where I got that the new
ones still had bladders.

Peter,

They didn't "go back" to a wet wing, it was an engineering development
first used in the Cessna singles in the early eighties. Originally,
172's had removable aluminum tanks in the wing bays, and 182's used
bladders.

Integral tanks ("wet wings") are lighter, easier to build/assemble, have
greater fuel capacity, and if done properly, require less mainenance in
the long run.

Happy Flying!
Scott Skylane