VansAirForceForums  
Home > VansAirForceForums

- POSTING RULES
- Donate yearly (please).
- Advertise in here!

- Today's Posts | Insert Pics


Go Back   VAF Forums > Main > RV General Discussion/News
Register FAQ Members List Calendar Today's Posts

Reply
 
Thread Tools Search this Thread Display Modes
  #11  
Old 10-27-2011, 06:15 AM
Walt's Avatar
Walt Walt is offline
 
Join Date: Aug 2005
Location: Dallas/Ft Worth, TX
Posts: 5,687
Default

Quote:
Originally Posted by humptybump View Post


Walt - I think I am close but I'll remove the image if you disagree.
You nailed it, thanks! It is clearly visible when looking at it with a 5X loupe, this was the best pic I could get with my amatuer photograpy skiils.
__________________
Walt Aronow, DFW, TX (52F)

EXP Aircraft Services LLC
Specializing in RV Condition Inspections, Maintenance, Avionics Upgrades
Dynamic Prop Balancing, Pitot-Static Altmeter/Transponder Certification
FAA Certified Repair Station, AP/IA/FCC GROL, EAA Technical Counselor
Authorized Garmin G3X Dealer/Installer
RV7A built 2004, 1700+ hrs, New Titan IO-370, Bendix Mags
Website: ExpAircraft.com, Email: walt@expaircraft.com, Cell: 972-746-5154

Last edited by Walt : 10-27-2011 at 07:28 AM.
Reply With Quote
  #12  
Old 10-27-2011, 06:24 AM
Walt's Avatar
Walt Walt is offline
 
Join Date: Aug 2005
Location: Dallas/Ft Worth, TX
Posts: 5,687
Default

Quote:
Originally Posted by rhill View Post
Not the first time I have heard this,Weight vs Safety,I would like to know which grade of aluminum tubing is best for this use,or would stainless steel be
x times safer? Over the years,and now on the Ten's,Fuel fires have been an issue.
The 3003 tube Van's supplies is more than adequate for the RV systems IMO, if you want something a little better go with 5052 but it's also a little harder to work with. Stainless is way over kill unless you have a 3000 PSI hyd system going in.

I do recommend and use 5052 for the brake lines going to the calipers due to the higher fatigue life.

No matter what you use, if you don't manufacture it correctly it can/will fail.
__________________
Walt Aronow, DFW, TX (52F)

EXP Aircraft Services LLC
Specializing in RV Condition Inspections, Maintenance, Avionics Upgrades
Dynamic Prop Balancing, Pitot-Static Altmeter/Transponder Certification
FAA Certified Repair Station, AP/IA/FCC GROL, EAA Technical Counselor
Authorized Garmin G3X Dealer/Installer
RV7A built 2004, 1700+ hrs, New Titan IO-370, Bendix Mags
Website: ExpAircraft.com, Email: walt@expaircraft.com, Cell: 972-746-5154
Reply With Quote
  #13  
Old 10-27-2011, 06:38 AM
AlexPeterson's Avatar
AlexPeterson AlexPeterson is offline
 
Join Date: Sep 2005
Location: Maple Grove, MN
Posts: 2,334
Default

A perfectly flared, properly torqued tube can crack if there is not good alignment. In other words, the B nut should thread on by hand. If it isn't easy to do so, the tube is probably not aligned. Now add a little cyclic loading, either bending or tension, and it will fatigue crack. I'm guessing the tube in the first picture was not cracked at the time of flare or tightening. I certainly could be wrong.
__________________
Alex Peterson
RV6A N66AP 1700+ hours
KADC, Wadena, MN
Reply With Quote
  #14  
Old 10-27-2011, 06:41 AM
rhill rhill is offline
 
Join Date: Feb 2006
Location: Valley Forge, Pa
Posts: 636
Default

No matter what you use, if you don't manufacture it correctly it can/will fail.[/quote]

Thank You Walt for this thread,I remember a 8 driver who bailed out sans chute due to a cockpit fire.Smoke in the cockpit put Ted Chang down in a field this year (up right I might add) and now Rick Gray is recovering from burns he received when he had to put a Ten down.(Best wishes Rick,get well soon!).
This is a very important safety issue that needs more attention than it gets now.IMHO
Bob
Reply With Quote
  #15  
Old 10-27-2011, 06:42 AM
Captain Avgas Captain Avgas is offline
 
Join Date: Oct 2005
Location: Melbourne, Australia
Posts: 1,868
Default

Excellent comments as usual from Walt. In addition this recent thread below contains my comments on the damage that can be done to flares on aluminium lines if the AN-818 nuts are done up to the same torque as specified for aluminium fittings. I am amazed at how many builders are unaware that the specified torque values for AN-818 nuts are dramatically different for aluminium tube and aluminium fittings.

Sometimes builders make nice flares and then stuff them by over-torquing the AN-818 nut.
http://www.vansairforce.com/communit...037#post589037
__________________
You’re only as good as your last landing
Bob Barrow
RV7A
Reply With Quote
  #16  
Old 10-27-2011, 06:58 AM
Don's Avatar
Don Don is offline
 
Join Date: Jan 2005
Location: Richmond, VA
Posts: 696
Default

I would love another thread on how to properly torque these fittings. I read where counting flats was a suitable method where a torque wrench won't fit. I'm still tracking down info on how many flats to turn for what size and material. No joy yet and I am the point of plumbing my 9.

I hate regular plumbing...can't imagine this is going to be a fun part of the build for me. I just want to do it correctly for all of the obvious reasons.
__________________
Don Alexander
Virginia
RV-9A 257SW Purchase Flying - O-320, Dynon D100
RV-9A 702DA (reserved) Finish Kit IOX-340
www.propjock.com
Reply With Quote
  #17  
Old 10-27-2011, 07:10 AM
HSANTIBANEZ HSANTIBANEZ is offline
 
Join Date: Sep 2010
Location: Chile, Valparaiso
Posts: 294
Smile

thank you, lot of learning here
Reply With Quote
  #18  
Old 10-27-2011, 08:16 AM
RV7Ron's Avatar
RV7Ron RV7Ron is offline
 
Join Date: Jan 2009
Location: Denver, CO
Posts: 590
Default

Quote:
Originally Posted by Don View Post
I would love another thread on how to properly torque these fittings. I read where counting flats was a suitable method where a torque wrench won't fit. I'm still tracking down info on how many flats to turn for what size and material. No joy yet and I am the point of plumbing my 9.

I hate regular plumbing...can't imagine this is going to be a fun part of the build for me. I just want to do it correctly for all of the obvious reasons.
Go to the Van's site and click on the "Torque specifications for aluminum fittings" link for the "flats" method...its a handy document to have in the shop

http://www.vansaircraft.com/public/confaq.htm
__________________
Ron Duren
Mechanical Engineer
"SportAir PhD"-RV Assembly/Composites/Electrical
Denver, CO (KBJC)
RV-7 'Tip Up'
Flying!! as of 3/16/14
IO-375/WW 200G-CS/SkyView/Dual P-mags
N531R "Wablosa" Wings of Red
http://www.ronsrv7project.blogspot.com
Reply With Quote
  #19  
Old 10-27-2011, 08:41 AM
flion's Avatar
flion flion is offline
 
Join Date: Dec 2007
Location: Flagstaff, AZ
Posts: 2,653
Default

This thread would also be handy. This may be the first one I've rated and I've given it 5 stars.

Walt, is there a good way to test your finished flares? The reason I ask is that my friend who built the PropJet had a pressure fitting fail on him. It didn't break, it just un-flared and pulled out of the fitting. A metallurgist's report showed that the tubing was incorrectly marked by the manufacturer. Fortunately, it caused the gear to fail to retract, not the other way around. I'm just wondering if it could have been caught before the failure.
__________________
Patrick Kelley - Flagstaff, AZ
RV-6A N156PK - Flying too much to paint
RV-10 14MX(reserved) - Fuselage on gear
http://www.mykitlog.com/flion/
EAA Technical Counselor #5357
Reply With Quote
  #20  
Old 10-27-2011, 08:54 AM
alpinelakespilot2000 alpinelakespilot2000 is offline
 
Join Date: Jan 2005
Posts: 3,646
Default

Quote:
Originally Posted by RV7Ron View Post
Go to the Van's site and click on the "Torque specifications for aluminum fittings" link for the "flats" method...its a handy document to have in the shop

http://www.vansaircraft.com/public/confaq.htm
Actually, this may not be correct for the soft alumininum tube, Ron. That guide is from/for Aeroquip hoses which use harder fittings. If you read the thread referenced below in Bob B's post, you'll see that Van's provides (seemingly) contradictory torque values in other sets of instructions. I picked up on this when I was doing my fuel tank service bulletin. Van's SB recommended 110-130 in-lb for that size 6 fitting. The Aeroquip guide was 150-195 in-lb for a size 6. Thus, the number of flats one would add would be different as well, depending on what type of tubing/fittings you're using.

The problem seems to be that Van's posted that Aeroquip guide without making a distinction between the type of tubing/fittings you're using. So builders use those Aeroquip values for connections other than their FWF hoses. That said, maybe the difference between 130 and 195 in-lb is insignificant for our purposes (??? I really wouldn't know ???), but still it's a contradiction that it would be nice to get some clarification on.

Quote:
Originally Posted by Captain Avgas View Post
Sometimes builders make nice flares and then stuff them by over-torquing the AN-818 nut.
http://www.vansairforce.com/communit...037#post589037
__________________
Steve M.
Ellensburg WA
RV-9 Flying, 0-320, Catto

Donation reminder: Jan. 2021

Last edited by alpinelakespilot2000 : 10-27-2011 at 10:31 AM.
Reply With Quote
Reply



Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -6. The time now is 07:51 AM.


The VAFForums come to you courtesy Delta Romeo, LLC. By viewing and participating in them you agree to build your plane using standardized methods and practices and to fly it safely and in accordance with the laws governing the country you are located in.