Strut metal

If you are modeling something in a "boneyard" I would say yes it would rust! A regularly flown aircraft would be "seviced" and not prone to show any obvious signs of corrosion. If it did I don't think you could get a pilot to fly it! Besides most struts have oil flims from the oil in the struts, brakes or hydaulic oil.

Every aircraft that I have worked on has steel struts, 4130 steel I think. The struts are chromed to prevent corrosion and provide a nice smooth sealing surface for the packings. You would not find a painted strut on an operational aircraft, they would constantly be leaking fluid as soon as a stone bounced off the srut and chipped the paint. It is also standard practice too regularly wipe the struts down to keep them clean and lubricated.

Darren

An aircraft strut is made up of several sections. The upper strut is made of cast nickel-steel. The strut is bored out and the inside is highly machined and polished to a mirror like finish. The lower strut is made of cast nickel-stainless steel and is also bored out. The outter part is machined and polished to a mirror like finish. The lower strut fits into the upper strut with several O ring seals as well as cup seals and a wiper seal. The upper and lower struts are held together by a torgue link, sometimes refered to as the Scissors Link. The completed strut is then filled with hydraulic fluid and compressed dry nitrogen. The services no longer use compressed air as it was found to cause corrosion to the inside of the strut.

The crew chief always makes sure the lower strut is kept clean to prevent damage of the seals. It is not an easy task to jack an aircraft so the strut can be disassembled for repack or replacement.

The strut is usually painted with an epoxy paint to resist chipping. It will rust if the paint is chipped and the bare metal is exposed.

Berny,
Not all use o-rings - on the A-26 main gears there were what are refered to as chevron seals (they looked like chevrons in cross section) I think the B-25 had them too. There was a special top and bottom seal and about a 1/2 dozen chevron seals between them. We had to have some specially made finally because the sources for them had dried up. It was a quite massive installation when you got them installed. The scarry part was we found that at the top of the gear, where the gear bolts to the trunion, there was one o-ring. It was about 4 inches in diameter and about 1/16 inch in thickness. We blew one on one of our A-26s in Idaho at the end of one season. Think there was some warpage between the two plates cause even an new 0-ring wouldn't seal it. To get it home before winter set in, a couple of us put the plane on jacks, hooked a come-along to the gear, undid the bolts, dropped the gear down a couple of inches and liberaly coated the plates and the o-ring with blue silicone seal. We then bolted the thing backe together, took the plane off the jacks, put nitrogen in the strut and flew it home. It was supposed to be a temporary repair, but the last I knew it was still flying with the silicon in there.
Also, the Harvard didn't use a cast upper fitting. They had several pieces of 4130 welded together to form the strut. The FAA had a hemmorage when they first saw it and if you wanted to get a Harvard certified here, you had to replace the upper strut from an American T-6. Along with that long exhaust pipe that they also used as a source of heat for the cabin heater (or disconnect the heater from the pipe)

I have done a few quick fixes my self. One year our base deployed to Korea for Team Spirit. One day we launched our F-4's out from the host base and recovered them on a highway, where we did a quick turn and launched them out again. I was the supervisor of the crew on the highway. One aircraft blew the seals in the nose strut on landing when it hit a rough spot in the road. We serviced the strut but it would leak out air and fluid as fast as we could put it in.

The F-4 will not get airborn with a flat nose strut. The strut helps it go into rotation and with the strut flat the stabs will not produce the force needed to raise the nose, no matter how fast it is going. It becomes a land locked speeding hunk of junk with useless wings.

I went through our fly away kit and found some heavy duty general purpose grease. We filled the nose strut with the grease and put in air. It held so we launched the aircraft out. I had put an entry into the aircraft 781A forms that a temp fix had been used on the strut. To my suprise four hours later the aircraft landed again. The crew chief signed off the writeup as no defect noted. We launched it our again after a quick turn and when I got back to the base that night I told the night shift supervisor what I had done. The strut was torn down and found to be so worn a new strut had to be installed.

At least it got the aircraft home where we had a hanger and equipment necessary to do the maintenance.