Interesting. Saw this posted on the ShortWingPipers.org site.
http://www.supercub.org/photopost/da.../SAFO10018.pdf
Interesting. Saw this posted on the ShortWingPipers.org site.
http://www.supercub.org/photopost/da.../SAFO10018.pdf
Steve Pierce
"When everything seems to be going against you, remember that the airplane takes off against the wind, not with it."
Henry Ford
they need to drill at the top like piper and the old AD required... since that was THE approved & REQUIRED place to drill the hole.... put magic inside and weld shut... then touch up with paint...
awful lot of mumbo jumbo the sky is falling in that letter..... not to much basis of experience..... but I am sure we somehow will get a goofy/strange reg out of it
Interesting as well, they did not Identify the manufacture of these struts and if they were both front and back or just front.
I believe thats why old Airframes Inc (Lee Budde) only powder coated heavy rear struts, as the fronts were to thin (shape of airfoil) to P/C and would deform for an 18.
jk
The original struts where open when the fork was removed. Why not drill and tap, re-oil after powder coating and insert a set screw with PRC to seal. Structural integrity? Where did they get that?
Steve Pierce
"When everything seems to be going against you, remember that the airplane takes off against the wind, not with it."
Henry Ford
If such a problem, I wonder about any other tubing that is welded shut. Anyone gone around your fuselage with a caliper to see if your tubing is any bigger ( expanded) after powder coating, I have not. If it is only a problem with steamlined tubing, we do have some in the Pacer fuslages and I have not noticed anything abnormal after a powder coating in the fuselage, or struts. I'm a little curious as to how much pressure 450 degrees of temp could produce inside a sealed strut to cause any expansion. How much air temp rise is there in the process of welding? Is the steel so weak that it can not handle what I would think is a relatively small pressure? I would hope the FAA would test that out before going off the deep end, however we do know the FAA does not tolerate logic or common sense.
Steve
The internal air pressure would be roughly double atmospheric at 450 deg F. About 15 psig.
Gordon N4328M
My SPOT: tinyurl.com/N4328M (case sensitive)
Thanks Steve. Was just getting ready to Powder Coat a set.
Roger
Based at O8XS. Sweeny Texas (Winter)
Finlayson Lake, Ontario (Summer)
I plan on living forever.......so far, so good !!!
I remember someone talking about them swelling up like hot dogs on here a long time ago. Something to remember is that the struts are mild steel except for the Airframes heavy duty if memory serves me correctly.
Steve Pierce
"When everything seems to be going against you, remember that the airplane takes off against the wind, not with it."
Henry Ford
its not talking of the swelling with just air inside, its talking about when oiled inside and sealed.. thats when they go back to round.... dans had a whole nice set in early mid 90's like that... only took one set for everyone else to learn
I`m not a big fan of powdercoating anyway, I have seen powdercoated parts with cracks hidden underneath the coating and the only way the crack could be seen is remove the coating,
From what I have heard the sealed front struts, I believe from Univair, do bulge out when powder coated and it is not recommended.
Some how the previous posts are date Saturday and it is still Friday.
you have your profile timezone set wrong look at profile at top of this page...Originally Posted by hondacubber
Had it at +8 but should have been -8.
Thanks
Forget powder coat I want color coordinated pick up truck bed liner! http://www.rhinolinings.com/products/solarmax (at least from the jury strut to the lower fork).
Update: http://http://www.rhinolinings.com/a..._dusting_plane
Last edited by OLDCROWE; 12-07-2010 at 11:08 AM.
"Illegitimis non carborundum"
Landing gear too.
Steve Pierce
"When everything seems to be going against you, remember that the airplane takes off against the wind, not with it."
Henry Ford
Yep, and the bungee covers too!
"Illegitimis non carborundum"
Jim Dyer from Univair warned me about this when I was having my fuse powder coated. I elected not to powder my struts as the sealed struts do have oil in them. Jim said that the oil will boil and warp the struts. They were and have been very aware of this and have always advised not to powder sealed struts. I elected to drilled vent holes in the fuse and filedl it with oil after the powder coat. Worked great and and I did not find any problems.
One other note is that the struts are mild steal not 4130 like most think!!!
FYI
airframes inc. are made from 4130....
univairs are?????
Univairs are mild steal. They also supply many outlets with the streamlined tube, so most are mild steal. Making the tube this shape is a cool process of heating and rolling through a series of shaped rollers for the final shape.
BRANDON
airframes has their own roller machine big long thing.....
when boodie first got it, it took some tuning to get right....
hence if you look at the first struts they are kinda a banana shape front to back..........
I thought only the Airframes heavy duty rear struts were 4130?
Steve Pierce
"When everything seems to be going against you, remember that the airplane takes off against the wind, not with it."
Henry Ford
Univair PA-18 Heavy Duty Rear Lift Strut (p/n U89498-102) is fabricated from 4130 tube. The PA-18 Heavy Duty Front Strut (p/n U89497-102) is fabricated from mild steel with an inner stiffener channel, similar to a PA-22 strut.
NHRA rules will not allow powder coat. something about can't see cracks well enough
but then they have 5000HP in top fuel
looks like it..
Airframes Alaska’s Lifetime Struts satisfy all current FAA Airworthiness Directives and do not require annual inspections. Our Heavy Duty Rear Struts are manufactured from specialty steel that provides significantly enhanced tensile strength and protects valuable wings from wind and snow load damage. Struts come bare metal or powder coated to your specifications.
Actually Mike, I know the DER responsible for doing the analysis and paper push for getting the Univair 4130 heavy duty rear strut approved as an alternate material to the original mild steel U89498-002 strut. Both are FAA/PMA Approved replacement units resulting in terminating action of the AD...looks like it..
sorry, my quote was to clarify that I mis-spoke and said both of airframes were 4130.... didn't mean anything against univairs...
no worries
Local powdercoater just ruined a set of struts a couple of weeks ago, The owner insisted on powder coating the struts even though the mechanic told him not too. They swell up pretty good I was told.
Drill a small hole (centered) up inside the fork barrel. Stand them in the corner in a pan to drain for a few days. Powder coat. Tap a #8 thread into the hole. Re-oil with ACF-50. Install a #8 SS pan head screw with a nylon sealing washer. DONE!
Crash
Last edited by Crash; 12-08-2010 at 02:03 AM.
"The fear of God is the beginning of wisdom". Psalm 111:10
I think that is the topic of this Safety Alert For Operators issued by the FAA. http://www.supercub.org/photopost/da.../SAFO10018.pdf
Steve Pierce
"When everything seems to be going against you, remember that the airplane takes off against the wind, not with it."
Henry Ford
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