Cessna Struts

I don't understand what advantage this has over simply deflating the strut,
removing the schrader fitting, filling it to the brim with 5606, replacing
the schrader, and pumping it with a gas (air or nitrogen). You can argue
for nitrogen if you want, but the sloshing of the 5606 inside that strut
keeps it pretty well oiled for plain old air. Besides, nitrogen comes out
the spigot at a pretty good pressure, and you can adjust an air compressor
down to where it won't blow the piston out the bottom of the strut.

Jim


We can all invent our own way of maintaining an airplane, but the
approved proceedures and materials, what ever they are, are in the
airframe maintenance manual. I don't know how Cessna built these, but
some struts have metering pins or other devices that won't allow them
to be completely filled unless they are extended first. Do what the
manufacuter says and you won't get in to trouble.

Ever seen water come out of your air compressor? Ever seen an aluminum
strut tube corrode from water mixed with the fluid? I've seen both.
Nitrogen is cheaper than struts. Why bother changing engine oil if
the airplane's been setting for six months? Lots of oil sloshing
around in there.

Why don't you just recommend commercial hydraulic fluid? It's cheap
and you can get it everywhere. Works fine in tractors so it must be
OK in an airplane!!

"Don Hammer" wrote in message
news:1121355676.d3689304ec05d387a512c3739194101f@t eranews...

We can all invent our own way of maintaining an airplane, but the
approved proceedures and materials, what ever they are, are in the
airframe maintenance manual. I don't know how Cessna built these, but
some struts have metering pins or other devices that won't allow them
to be completely filled unless they are extended first. Do what the
manufacuter says and you won't get in to trouble.

See Cessna Service Manual section 2-18. Don't you think Clyde's boys know
what they are talking about when they write a manual? Don't post out of
ignorance.



Ever seen water come out of your air compressor? Ever seen an aluminum
strut tube corrode from water mixed with the fluid? I've seen both.
Nitrogen is cheaper than struts. Why bother changing engine oil if
the airplane's been setting for six months? Lots of oil sloshing
around in there.

Ever seen an A&P's shop that doesn't have a water trap on the compressed
air?


Why don't you just recommend commercial hydraulic fluid? It's cheap
and you can get it everywhere. Works fine in tractors so it must be
OK in an airplane!!

Damned fool.

Jim
A&P/IA

See Cessna Service Manual section 2-18. Don't you think Clyde's boys know
what they are talking about when they write a manual? Don't post out of
ignorance.


Don't have the manual. Guess it says to use compressed air and not
nitrogen huh?

My point is I see lots of posts from "experts" here that lead people
down a not-so-good path. What I said stands - Do what is in the
maintenance manual and you can't go wrong. Am I not correct?

Out of the 100-series service manual.

I'll do this in some abbrvtd method (I don't type more than I have to):

quote on

1. Remove valve cap and release all **AIR** (emphasis mine)
2. Remove valve housing
3. Compress strut completely
4. Fill strut with hydraulic fluid to valve hole
5. Get nose wheel off the ground
6. Replace valve housing and inflate: 35 psi (or 20 psi on the 150 and 50
psi on the 182 both models after the 1961 model year)

quote off

Note they said to release AIR and not nitrogen. They don't specify WHAT to
inflate with, so it is left to the A&P to determine the correct gas.
However, you might infer from the first instruction that they expect air.

Jim



"Don Hammer" wrote in message
news:1121375152.eb841dd4e866bfcb751910a2ac0e0572@t eranews...


Don't have the manual. Guess it says to use compressed air and not
nitrogen huh?

On Thu, 14 Jul 2005 14:43:17 -0700, "RST Engineering"
wrote:

Out of the 100-series service manual.

I'll do this in some abbrvtd method (I don't type more than I have to):

quote on

1. Remove valve cap and release all **AIR** (emphasis mine)
2. Remove valve housing
3. Compress strut completely
4. Fill strut with hydraulic fluid to valve hole
5. Get nose wheel off the ground
6. Replace valve housing and inflate: 35 psi (or 20 psi on the 150 and 50
psi on the 182 both models after the 1961 model year)

quote off

Note they said to release AIR and not nitrogen. They don't specify WHAT to
inflate with, so it is left to the A&P to determine the correct gas.
However, you might infer from the first instruction that they expect air.

Jim

And "air " is what percentage nitrogen? Something like 78% nitrogen
and 21% oxygen.
That oxygen WILL slowly react with the oil in the strut, with any
rubber parts, and with the metal parts, particularly if the air is
moist. Granted, these reactions WILL stop over time, as the oxygen
gets depleted.
Nitrogen fill has NONE of these drawbacks, and NO downside over using
"air".

The advantages of "Nitrogen Fill" for tires have been debated for
decades, but the current informed opinion is that there are
significant benefits, and "aging" related deterioration of the tire is
markedly reduced.
Almost all good automotive and industrial "shock absorber"
applications use pressurized nitrogen fill - there is NO REASON not to
use nitrogen in place of air in an aircraft supension strut - and
several pretty convincing arguements for doing so.



"Don Hammer" wrote in message
news:1121375152.eb841dd4e866bfcb751910a2ac0e0572@ teranews...


Don't have the manual. Guess it says to use compressed air and not
nitrogen huh?