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  #11  
Old 06-22-2022, 09:31 AM
Freemasm Freemasm is offline
 
Join Date: Nov 2017
Location: Orlando
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Quote:
Originally Posted by bruceh View Post
Page 9-18, Paragraph 9-30 (a).
Not looking to start a fight but going to opine anyway. The listed criteria appears to pertain to forming a bend, proper. This "kink" is not. If you extrapolated the curve, I'm sure you'd find it doesn't meet minimum bend radius anyway.

That's a serious stress concentration and would appear to be nothing new. Can't believe it went unnoticed.
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  #12  
Old 06-22-2022, 10:26 AM
gasman gasman is offline
 
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Location: Sonoma County
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Quote:
Originally Posted by bruceh View Post
FAA guidance in AC43.13-1B says if the tube is flattened more than 75% of the original diameter, it is not usable.

The kink in that line looks terrible.
"Minimum bend radii values are shown
in table 9-2. A small amount of flattening in
bends is acceptable, but do not exceed
75 percent of the original outside diameter. "

In the OP's picture, the flare has been stressed and a sharp kink in the neck.... it needs to be replaced.
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  #13  
Old 06-22-2022, 01:40 PM
WingsOnWheels WingsOnWheels is offline
 
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Location: Plano, TX
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Removed and replaced this one from an RV6 during the CI recently.

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  #14  
Old 06-22-2022, 01:48 PM
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RV7A Flyer RV7A Flyer is offline
 
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Location: US
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Quote:
Originally Posted by WingnutWick View Post
Hello,

Noticed the right side fuel line in the cockpit was a bit crimped coming out of its fitting. Wondering if this is a cause for concern/needing to be fixed? 9sorry for the poor photo)

Thanks all.

Charles
Um...YEAH. Does that look right to you? I'd be checking all of my fuel and oil lines and such, if this was acceptable for installation in the first place by someone. No offense intended, I swear.
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  #15  
Old 06-22-2022, 03:47 PM
BillL BillL is offline
 
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Charles,

Is this the back of your helmet (WINGNUT) in this promotional video?
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  #16  
Old 06-22-2022, 04:31 PM
bbsdad bbsdad is offline
 
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Ok so the stress is not only on the tube at the kink(though it’s highest there) the flair is stressed as well (leaks more easily) when torquing the nut high value would show but actually lower value on the flair. And flair on tube is offset. Flair fitting could also need replacement. Be careful look close at the fitting’s flair surface all around. Also look at opposite end of tube, what does it look like?

Hope this helps
RD
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  #17  
Old 06-22-2022, 05:19 PM
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skyking902001 skyking902001 is offline
 
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Location: Gunter, TX
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Default Replace

REPLACE IT--we don't want to read an accident/incident report regarding fuel starvation or fire!
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  #18  
Old 06-23-2022, 06:49 AM
TS Flightlines TS Flightlines is offline
 
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Location: Ridgeland, SC
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Its not rocket science----or maybe it is. IF it doesnt look like a correctly bent tube, no twists, kinks, gouges, crushed areas, mangled flares, then it probably needs to be replaced. IF you are a novice on here, look for pics of properly made tubes. There are a bunch. If you are having trouble making them, seek help. There is alot of that here too.

Just because we use a CNC bender to make our production tubes, doesnt mean that we dont use a hand bender to make a concept prototypes, or even a difficult tube that our CNC dies wont accomodate. Like this one I did recently for a RV7A with an Aerolabs gascolator. 180* bend with the flare close to the start of the bend, then a 90* vertical leg, again close to the end of the original bend. Trick was all of this had to fit in a tight area.

Use a good bender, inexpensive is fine, but take your time and practice BEFORE you attempt to make a critical tube. I have a box of various bent tubes with different angled bends just for playing around. Its easy enough to see if something is doable, than to spend a bunch of time and waste tubing trying to make something that your tool cant do.

A quick word here about 3003O aluminum tubing that is provided in Vans kits. Its relatively inepensive, and soft enough to be bent by hand, given some circumstances. BUT that doesnt mean you can kink it and then go fly. It does take some care to do properly. If you arent sure, seek some guidance
from a tech counselor, or an A&P, or even your hangar buddies. A fractured fuel line under pressure in flight is a bad day waiting to happen.

Last note---INSPECT THEM. Make sure they have proper supports and cant contact a structure or something else to cause potential damage. We've seen alot of them, even on certified planes.

Tom
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  #19  
Old 06-23-2022, 09:03 AM
wilddog wilddog is offline
 
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Should not be hard to replace and I would do it before further flight. Might be worthwhile to look at the flairs on the tubes since a builder who let that go might not be very particular about flairs either.
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  #20  
Old 06-23-2022, 09:10 AM
abwaldal@gmail.com abwaldal@gmail.com is online now
 
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Location: Battle Ground WA
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Default bent lines

How many people go to school and spent tens of thousands of dollars to learn something they probably wont' use in their lifetime.
Here you can spend $50.00 for an extra coil of tubing and bend away.
By the time your done, you'll be an expert.
I've bent hundreds of lines for what ever and am pretty good at it.
But, a little practice on a scrap piece (you made scrap) is good experience
I will say that line needs to be replaced before further flight.
It isn't broken now, But, a kink can crack in two minutes or never. Seen it happen.
I've had gas smell/leak in the cockpit and it isn't a good smell at 8,500 feet over the mountains.
Life is better just around the next bend. Ha Ha
My three cents worth Art
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