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  #1  
Old 06-03-2018, 10:13 AM
Mike Miller Mike Miller is offline
 
Join Date: Apr 2005
Posts: 56
Question Proper fitting torque

I have searched the forums but perhaps not well enough. I am trying to determine what the appropriate torque is for a particular fuel line fitting. I am using an Andair fuel valve on my RV-9A, and TS Flightlines braided fuel lines (great product). I know what the required torque is for the AN fittings that supply fuel from the wings to the valve (75 to 125 inch pounds for 3/8" tubing). What torque value do I use for the stainless TS Flighlines braided hose fitting that goes from the fuel valve to the electric fuel boost pump? The reason I ask is because I know that the male fitting on the bottom of the Andair fuel valve is aluminum and the fitting on the stainless hose is steel. Is the flair inside the stainless fitting aluminum? If so, is it 3003 soft aluminum that "we" would typically use, or is it 5052 aluminum? I don't want to use too high of a torque and damage the Andair male fitting or not enough torque which would create a leak.

Certainly this is an easy answer for somebody who has been in the same situation before? What says you?

Thanks,

Mike
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  #2  
Old 06-03-2018, 11:14 AM
flysrv10 flysrv10 is offline
 
Join Date: Jan 2010
Location: Florida
Posts: 37
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Send me your email and I will send you couple of PDF files showing torque values for all aircraft hardware including fuel line fittings.
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  #3  
Old 06-03-2018, 02:24 PM
RandyAB RandyAB is offline
 
Join Date: May 2016
Location: St Albert, Alberta, Canada
Posts: 330
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Quote:
Originally Posted by Mike Miller View Post
I have searched the forums but perhaps not well enough. I am trying to determine what the appropriate torque is for a particular fuel line fitting. I am using an Andair fuel valve on my RV-9A, and TS Flightlines braided fuel lines (great product). I know what the required torque is for the AN fittings that supply fuel from the wings to the valve (75 to 125 inch pounds for 3/8" tubing). What torque value do I use for the stainless TS Flighlines braided hose fitting that goes from the fuel valve to the electric fuel boost pump? The reason I ask is because I know that the male fitting on the bottom of the Andair fuel valve is aluminum and the fitting on the stainless hose is steel. Is the flair inside the stainless fitting aluminum? If so, is it 3003 soft aluminum that "we" would typically use, or is it 5052 aluminum? I don't want to use too high of a torque and damage the Andair male fitting or not enough torque which would create a leak.

Certainly this is an easy answer for somebody who has been in the same situation before? What says you?

Thanks,

Mike
Ask Tom directly.. He helped me with the brake lines.
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  #4  
Old 06-03-2018, 05:07 PM
TS Flightlines TS Flightlines is offline
 
Join Date: Apr 2010
Location: Ridgeland, SC
Posts: 2,113
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Mike and all---
our hose ends are all 304 stainless, -3 through -8. Not just a stainless nut over a brass, aluminum or steel insert. As such, YES it does take a little extra torque to seal the connection. HONESTLY----I use 2 stubby wrenches and tighten them about 1 flat after snug. There are just some places where you cant get a torque wrench no matter how clever you are. Rocket guys with Romec pumps know what I'm talking about.

Torque specs can sometimes be misleading. Ever 'torqued' a fitting to 'specs' and had a leak? We hear of it all the time. Even have had new mil spec certified fittings that took more 'torque' to seal them.
Stainless on aluminum will be on the lower part of the scale, stainless to steel or stainless steel on the higher part. AC43-13 has a good reference table 9-2. Aeroquip has one too, and the flats method.

Our brothers using the German spec seem to have no issues. That spec is
'Goodentight'.

Oh Parker has a 40 page installation guide that covers all of this. Page 23 lists stainless fittings. https://www.parker.com/literature/Tu...stallation.pdf

Tom
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Tom Swearengen, TS Flightlines LLC
Teflon Hose Assemblies for Experimentals
Proud Vendor for RV1, Donator to VAF
RV7 Tail Kit Completed, Fuse started-Pay as I go Plan
Ridgeland, SC
www.tsflightlines.com

Last edited by TS Flightlines : 06-03-2018 at 05:17 PM. Reason: added text
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  #5  
Old 06-03-2018, 05:58 PM
Mike Miller Mike Miller is offline
 
Join Date: Apr 2005
Posts: 56
Thumbs up Torqued up

Gents, thank you all for the information. I will do as Tom says and go one flat after snug.

I've got to hand it to Tom...as others have said...his customer service is the best in the business.

Mike
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  #6  
Old 06-03-2018, 07:29 PM
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1001001 1001001 is offline
 
Join Date: Dec 2014
Location: Just Minutes from KBVI!
Posts: 750
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Quote:
Originally Posted by TS Flightlines View Post
Mike and all---
our hose ends are all 304 stainless, -3 through -8. Not just a stainless nut over a brass, aluminum or steel insert. As such, YES it does take a little extra torque to seal the connection. HONESTLY----I use 2 stubby wrenches and tighten them about 1 flat after snug. There are just some places where you cant get a torque wrench no matter how clever you are. Rocket guys with Romec pumps know what I'm talking about.

Tom, are your fittings the stainless with the silver plated threads for lubrication? If not, what do you recommend to prevent galling of the stainless/stainless joint on installation?
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  #7  
Old 06-05-2018, 11:19 AM
TS Flightlines TS Flightlines is offline
 
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Location: Ridgeland, SC
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Dave, ours are not coated. Commercially available AN818 nuts generally are not, nor are Stratoflex stainless hose ends.
That being said, some builders have applied a light film of moly lube to the threads, some used differing sprays, some nothing at all. A coating of anything will change the torque required. Most all the specs are for clean, dry fittings.

Tom
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Tom Swearengen, TS Flightlines LLC
Teflon Hose Assemblies for Experimentals
Proud Vendor for RV1, Donator to VAF
RV7 Tail Kit Completed, Fuse started-Pay as I go Plan
Ridgeland, SC
www.tsflightlines.com
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  #8  
Old 06-05-2018, 02:05 PM
Canadian_JOY Canadian_JOY is offline
 
Join Date: Aug 2007
Location: Ontario, Canada
Posts: 1,732
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To back up Tom's statements with practical observations... I've installed a fair number of aluminum fittings over the years. When assembling our aircraft using the same stainless fittings that Tom uses (hoses provided by his colleague Steve at Aircraft Specialties), all those fittings were mated with steel AN fittings. Using "standard" AN fitting torque I had three small leaks. Additional torque was required to produce a leak-free assembly. The fittings have remained leak-free for the first 50 hours of flight so I'm reasonably certain they will continue to do so.
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