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Fuel leak

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jim dankovich

Joined: 02 May 2008
Posts: 8

Posted: Sun Sep 27, 2009 3:43 pm Post subject: Fuel leak

I have one of the Czech built 601 XL's.  There is  a fuel leak that appears to be brownish in color, running down bottom of the wing, exiting the wing at the joining of the wing to the fuselage .. on the bottom, of course. It has dramatically worsened in the last 2 weeks I am guessing it is the fuel line is deteriorating.. color of the fuel drip and have been using 93 octane auto  fuel as Rotax recommends.  I am grounded  until I find a way to fix it.  Anyone else have a similar problem?  Any suggestions on fixing (remove wings, inspection plate  (where to put it and how big) or any other ideas??  I earlier replaced a cracked fuel line on the Rotax.. on startup after the winter, it literally spewed fuel on the canopy... quick shutoff and no damage, but not a fun  experience. Thanks........ [quote][b]

leinad

Joined: 19 Sep 2006
Posts: 283
Location: Central Virginia

Posted: Sun Sep 27, 2009 4:38 pm Post subject: Re: Fuel leak

Jim,

I'm going to make some assumptions.  First that the Czech built plane is like the plans sold to builders.  Second that the plane is not equipped with the auxiliary tank option.

If those are true it shouldn't be too bad a job replacing the rubber fuel line inside the wing.

There should be an access cover where the inboard end of the tanks is.  This is where the rubber line attaches to the fuel tank.  You should be able to remove the clamp that holds the line on through that access cover. (Of course you'll drain the tank first)  Then find the place inside the cabin where the line enters the cabin.  It might be under some sound proofing or upholstery.  It should enter just in front of the seat a few inches below top of the seat.  It could be a continuation of the rubber line or it may be attached to metal fuel line at that point.  Before you pull the old line out, attach the new line to it so that you pull it through all the holes in the ribs as you remove the old one.  Attach the new line with new clamps.

Dan



[quote] "jim dankovich"]I have one of the Czech built 601 XL's.  There is  a fuel leak that appears to be brownish in color, running down bottom of the wing, exiting the wing at the joining of the wing to the fuselage .. on the bottom, of course. It has dramatically worsened in the last 2 weeks I am guessing it is the fuel line is deteriorating.. color of the fuel drip and have been using 93 octane auto  fuel as Rotax recommends.  I am grounded  until I find a way to fix it.  Anyone else have a similar problem?  Any suggestions on fixing (remove wings, inspection plate  (where to put it and how big) or any other ideas??  I earlier replaced a cracked fuel line on the Rotax.. on startup after the winter, it literally spewed fuel on the canopy... quick shutoff and no damage, but not a fun  experience. Thanks.......[\quote]

_________________
Scratch building XL with Corvair Engine

jim dankovich

Joined: 02 May 2008
Posts: 8

Posted: Mon Sep 28, 2009 5:26 am Post subject: fuel leak

Thanks, Dan..

  

  Your asumption is correct as far as I can see; ZAC said the plans are identical save the landing gear and fueelage mods required and the angle of incidence of the wing..and I have  no long range tanks. 

  Didn't see an access plate... nor did my A&P so wondering if I missed something or.... what size and location to cut an opening for the plate.  Thanks......

 [quote][b]

georgerace

Joined: 25 Oct 2006
Posts: 788
Location: Albion, MI

Posted: Mon Sep 28, 2009 6:20 am Post subject: fuel leak

Good Morning James:

  

 When I builit my airplane, I incorporated a lot of access  panels into the design.  I have been making a complete access opening kit  for experimental airplanes for some time.  It can be easily installed in a  finished wing by following the step by step insturctions.  For details see  http://www.mykitairplane.com.   If you want to build your own, there is complete installation instructions  there as well, with pictures.

  

 Hope this helps and you can find that fuel leak real  soon.

  

 George



   From: owner-zenith-list-server(at)matronics.com  [mailto:owner-zenith-list-server(at)matronics.com] On Behalf Of james  dankovich

Sent: Monday, September 28, 2009 9:25 AM

To:  zenith-list(at)matronics.com

Subject: fuel  leak

 

                   Thanks, Dan..

        

        Your asumption is correct as far as I can see; ZAC said the        plans are identical save the landing gear and fueelage mods required and        the angle of incidence of the wing..and I have  no long range        tanks. 

        Didn't see an access plate... nor did my A&P so wondering        if I missed something or.... what size and location to cut an opening for        the plate.  Thanks......

[quote]



href="http://www.matronics.com/Navigator?Zenith-List">http://www.matronhref="http://forums.matronics.com">http://forums.matronics.com

href="http://www.matronics.com/contribution">http://www.matronics.com/c

[b]

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Check out my CH-701 project at:
http://www.mykitairplane.com

klaus(at)utdallas.edu
Guest

Posted: Mon Sep 28, 2009 11:31 am Post subject: fuel leak

Hi James,



When I helped Philip Welsch disassemble his Czech-built XL, we guessed

where access panels for the tanks would have been useful, before we removed

the wings. Our guesses turned out to be quite wrong. In addition, you 

may not

have leaking tubing but a leaking tank.

Based on that experience, if I were in your position,

I would remove the wing, solve the problem, and then decide on the location

of access panels for future maintenance.



Best wishes,



Klaus

Martin Pohl

Joined: 30 Jan 2006
Posts: 118
Location: CH-8645 Jona SG, Switzerland

Posted: Mon Sep 28, 2009 12:38 pm Post subject: Re: Fuel leak

I had a leak in one of my brand-new fuel tanks (see picture attached). As Klaus said, I would also remove the wing to further investigate the problem.



Cheers Martin

FuelLeak_Arrows.jpg

Description:

Fuel Leak Wing Tank

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Martin Pohl
Zodiac XL QBK
8645 Jona, Switzerland
http://www.pohltec.ch/ZodiacXL/Main.html

leinad

Joined: 19 Sep 2006
Posts: 283
Location: Central Virginia

Posted: Mon Sep 28, 2009 3:52 pm Post subject: Re: fuel leak

Funny.. My drawings (page 6-K-1) shows a finger screen access cover, as I've built into my own wings.  I just measured it.  It's 13 1/2" from the wing root, on the underside of the leading edge skin.  It's between nose ribs 3 and 4.  

If there is doubt about the line leaking or the tank you may have to do some more diagnostics before you remove anything.   I think it should be possible to leak test the tank after you replace the line between the cockpit and fuel tank.   If there is enough of a vent sticking out of the bottom of the tank to attach a clear piece of tygon to, you could put some color water in the tygon tube and blow air into the tank from the new fuel line (only a couple psi).   If the tank is leaking the water in the tygon will not stay at the same level.  (This is test I used when I built my tanks).  

In any case you're going to need the access cover if it isn't there already.

Good luck.

Dan





[quote="jim dankovich"]Thanks, Dan..

  

  Your asumption is correct as far as I can see; ZAC said the plans are identical save the landing gear and fueelage mods required and the angle of incidence of the wing..and I have  no long range tanks. 

  Didn't see an access plate... nor did my A&P so wondering if I missed something or.... what size and location to cut an opening for the plate.  Thanks......

  	  Quote: 	
		  [b]

_________________
Scratch building XL with Corvair Engine

Ron Lendon

Joined: 10 Jan 2006
Posts: 685
Location: Clinton Twp., MI

Posted: Mon Sep 28, 2009 6:54 pm Post subject: Re: Fuel leak

Jim,



Bob Mahieu called me and asked about the access holes.  I called Zenith and Roger told me the hole goes between ribs 2 & 3.  Bob and I made holes 70mm by 140mm and have clear view and access opened.



I made the cover plates tonight and will be out there either tomorrow or Thursday before the meeting to install them.



We haven't determined yet where the fuel is coming from.

accesscovers (Small).jpg

Description:

Fuel line tank access covers

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_________________
Ron Lendon
WW Corvair with Roy's Garage 5th bearing
CH 601 XLB
N601LT - Flying
http://www.mykitlog.com/rlendon
Corvair Engine Prints:
https://sites.google.com/site/corvairenginedata/

jetboy

Joined: 22 Jul 2006
Posts: 233

Posted: Tue Sep 29, 2009 12:54 am Post subject: Re: Fuel leak

I have a CZAW built 701;  I dont know if there is any similarity but I've had the dark fuel stains coming out of seams at rear of wings under fuel tanks occasionally.  Some of this was definitely due to overfill running into the wing cavity. But when it seemed to occur lately without any spillage at the filler, I drilled out the inspection plates over the fuel senders as a first step.



There was evidence of seepage from the mounting screws, running down the back of the tank. 



I withdrew each screw in turn and coated the thread / washer (serrated)/ head area with a fuel safe gasket compound and tightened them all back down. the rubber gasket did not appear to be a problem. The lockwashers used are quite open and not what I would have expected in this area.



I dont know if this is the end of the issue. It had been occuring mainly when the tank was kept full, suggesting that if there is a leak its likely near the top.



PS. drilling out rivets on the plates: best to limit the bit depth with a piece of hose 



Ralph

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Ralph - CH701 / 2200a

z601a(at)anemicaardvark.c
Guest

Posted: Tue Sep 29, 2009 8:41 am Post subject: Fuel leak

On Monday 28 September 2009 15:38, Martin Pohl wrote:

 	  Quote: 	
		   



 I had a leak in one of my brand-new fuel tanks (see picture attached). As

 Klaus said, I would also remove the wing to further investigate the

 problem.


	


What I'm about to say won't help those who currently have problems one bit, 

but it might help those in the process of construction. I strongly recommend, 

after installing the fuel gauge sender, but before installation, doing a tank 

leakage test.



It's fairly simple to connect a source of air to the port for the quick drain 

in the bottom of the tank, and to apply a few pounds (not many!) of air 

pressure. Swipe some of your wife's (or, if you're female list members, 

borrow it from yourself) liquid dish soap. Put it in a small container, and 

add a little water. Make a water-soap mix suitable for blowing soap bubbles.



Brush the mixture around every possible seam in the tank, around fittings, and 

especially around every possible opening on/around the fuel sender. Don't be 

surprised if you get some bubbles, and have some leaks to fix. They're easier 

to fix now than later.



My tank was good, but my fuel sender installation had to be redone, and sealer 

applied at several points.



That's my free advice for today. I remind you as always that my free advice 

(or anyone else's) will be worth as much as you paid for it ... if you're 

lucky.

-- 

=============================================

                Do not archive.

=============================================

                Jim B Belcher

    BS, MS Physics, Math, Computer Science

                  A&P/IA

     Retired aerospace technical manager



     Mathematics and alcohol do not mix.

         Do not drink and derive.

=============================================

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