Cancel it.
Frowning takes 68 muscles.
Smiling takes 6.
Pulling this trigger takes 2.
I'm lazy.
Posted on 12/17/2010 8:07:36 PM PST by ErnstStavroBlofeld
Lockheed Martin Corp.’s F-22 jets began corroding soon after introduction into the U.S. Air Force in 2005 and the Defense Department plans to spend $228 million through 2016 to fix the deteriorating aluminum skin panels, the Government Accountability Office said in a report today.
The newer F-35 aircraft, which are also built by Bethesda, Maryland-based Lockheed, have an improved design and use updated materials and paint to prevent the corrosion seen on the F-22 jets, according to the report sent to the Senate and House Armed Services committees.
“Corrosion of the aluminum skin panels was first observed in spring 2005, less than six months” after the F-22 jets were first deployed, the report said.
By October 2007, 534 cases of damage to the panels were documented, the report said, and “corrosion in the substructure was becoming prevalent
(Excerpt) Read more at businessweek.com ...
Issues?
These designs are from the mid 80’s.
Their ‘issues’ period is overdue by 10 years or so.
I worked on some of the contractor parts, Lockheed needs to go.
Doesn’t seem very Mil Spec does it?
Hey, cut them some slack! Using painted aluminum panels on jets is cutting edge technology! Why, it's only been in use on jets since 1941 and the ME-262... ;-/
Cancel it.
No it doesn’t. If I was in procurement I would be down their throat setting a trebble hook if they did not fix it at their expense. Good gawd man, corroding aircraft skin after only 6 months!!!!
IIRC, this is corrosion between the aluminum and the radar absorbent material. A new problem with construction of stealthy aircraft. Not a simple aluminum corrosion problem.
“I’ve seen airplanes go leave the desert in good condition and not be able to pass a corrosion inspection after a year in coastal Florida.”
Perhaps that’s why aircraft are stored as Davis-Monthan instead of Eglin?
;-)
Someones metallurgy or corrosion control needs revision.
“Duh, park airplanes in Panama City, Florida and you get corrosion issues”
Or Guam....
I would bet it was a revision that caused it.
Someone (EPA?) probably declared the standard (many decades) acid etch, alodine and epoxy primer process for aluminum to be “non-green”.
I'm sure these F-22 are new enough to get green credentials, it's just a pity that the green materials don't work as well.
Heck, the Navy has parked their aluminum planes on carriers surrounded by lots of salt air - they don't get corroded in less than 5 years.
What about the Baby Boomer aged B52s at Barksdale AFB in LA? They would have corroded before the first season of Gunsmoke if they were made using this new technology.
Probably. A lot of planes have used it over the past 75 years. Corrosion after a couple of years use seems a little sub-par.
az was probably on target about the “green” crap.
I remember something about the reason the insulation was falling off the Space Shuttle external fuel tanks and hitting leading edges during launch, was direct related to “green” as opposed to the good stuff that stayed in place.
• The F-35 program is mitigating corrosion risk associated with conductive gap filler and paint by using a gap filler that is less galvanically dissimilar from aluminum, an alternative to the conductive paint, a design with fewer seams that require gap filler, and more representative verification and qualification testing. Many of the F-22’s corrosion problems were linked to problems with gap filler materials and paint.
The F-22's corrosion problems have been linked to two factors: Galvanic action between the stealth coatings and the aluminium, and inadequate drain holes in the aircraft.
Also, conspiracy theorists can blame the Green movement:
• Environmental and occupational health concerns drove the initial use of a nonchromated primer on the F-22 that did not provide corrosion protection, and the program later switched to a chromated primer. The F-35 has also chosen to use a nonchromated primer that has never been tested on an aircraft in a corrosive operating environment.
I wonder how the F-35B and -C will hold up at sea?
Agree with USNBandit. The 22’s are deployed in Hawaii and Guam...salt air environment.
Also, corrosion is the result of poor corrosion control procedures by the maintenance crews and/or contractors. All aircraft in a salt air environment experience corrosion. The aircraft manufacturer is only at fault if they failed to properly prep/treat/coat/paint the parts before delivery.
Yes, your point is correct that when you mix metals or have mixed metals and composites, the stucture becomes like a battery and electrons ‘flow’ between the materials, eating away at one or the other. Boats in salt water handle this by mounting lead fish on the hull. The lead gives up its electrons faster than the steel hull, and the lead fish corrodes, reducing corrosion to the hull itself.
For stealth aircraft to maintain their stealth properties, I do not know if there is an easy solution like with a boat.
Yes and no...
The fix to the galvanic action you mention is to provide an insulating barrier interface. In this case it probably (pre-green) would have been a Mil-Spec strontium chromate epoxy primer.
I bet this is the stuff they didn't use...
Aluminum isn’t new in fighter jets. The F-15 and F-18 both make fairly extensive use of aluminum, IIRC. My impression is that the material isn’t the issue here, it’s the grade and construction. The popular opinion at the time of the ATF competition was that the then YF-22 was selected because it was cheaper and had thrust vectoring, while the YF-23 was more expensive and didn’t have thrust vectoring at the time of the competition even though plans were on the table to add that particular capability. So the Air Force cheaped out on a plane that eventually was produced in very limited numbers, and now we get this story about corrosion—well, I’m not surprised.
Tell that with a straight face to all the airdales performing CC on new Super Hornets in embarked CVWs or at Lemoore, Oceana, Whidbey, Atsugi, et al
The best way to prevent electrogalvanic corrosion is to plate the parts, e.g., steel fasteners, with cadmium.
The best way to prevent corrosion of the aluminum structures and skin is alodine (hexavalent chromium conversion coating). DoD rolled over and banned both materials in the new aircraft.
Both of the tried-and-true materials above have been targeted by the environazis even though the amount released to the environment is miniscule.
As to the question about the Shuttle External Tank foam falling off, YES, the excellent adhesive was replaced with a “green” (defective) adhesive. NASA could have gotten a waiver, but the NASA Administrator, Golden, had his lips sewed to Al Gore’s butt.
BTW, I am a retired Shuttle engineer and currently own an electroplating company, so I AM the source of the facts stated above.
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