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tank troubles

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lcottrell

Joined: 29 May 2006
Posts: 1494
Location: Jordan Valley, Or

Posted: Sun Jan 28, 2007 6:31 pm Post subject: tank troubles

I still seem to be having more problems than I can fix. Sigh!,  some days are like that. My problem now is that my two tanks that are hooked  together with a "Y" do not pull fuel the same. I had wanted to do that since my  EIS only has one aux feature to read the fuel levels. 

    

 I had thought that the pickup tubes were getting kinked, so I  took the pickups out of the tanks, cut the metal tube to about 3 inches,  installed a flex fuel line and a brass strainer to the bottom. I still have the  problem, and it is not always the same tank that is pulling more. I have decided  that I am going to have to install a selector valve and a two way switch to  switch back and forth from the front to the rear tank to see how much fuel I  have. I really don't want to, still trying to follow the KISS principal.  

  

 I am at a loss. 

 Larry, Oregon

  

 do not archive

    [quote][b]

John Hauck

Joined: 09 Jan 2006
Posts: 4639
Location: Titus, Alabama (hauck's holler)

Posted: Sun Jan 28, 2007 6:50 pm Post subject: tank troubles

I really don't want to, still trying to follow the KISS principal.



I am at a loss.

Larry, Oregon



Hi Larry:



I never had an airplane with this "screwy" system of pulling fuel from 

two tanks through one line.



If I did have two tanks, you can be assured I would be pulling from 

the bottom of both into a T.  I can assure you you will then be 

getting equal draw from each tank.



There is a neoprene grommet and elbow fitting available from Kolb or 

most any UL parts house for tapping a plastic or metal tank.  I have 

used them for many years and many hours with great success.



If you still want to pull fuel from the top of the tank, then tap the 

bottoms, tie them together so gravity can do its job for you.



Why switch back and forth between tanks with your fuel level sender 

when you are working with a flow system that doesn't work logically?



My thoughts for what they are worth.  2 cents.



john h

mkIII

_________________
John Hauck
MKIII/912ULS
hauck's holler
Titus, Alabama

jindoguy(at)gmail.com
Guest

Posted: Sun Jan 28, 2007 7:55 pm Post subject: tank troubles

If it helps any Larry, you're not the only one in this boat. When I found a cracked grommet that was just beginning to weep fuel, I was determined to keep all fuel taps on the top of the tanks. I figured out how to modify a Weatherhead valve so I could have right, left, both and off, but the fear of running a tank dry and sucking air has me debating the real merits of this set up.  

I haven't come up with anything better than John's method of putting an interconnection between the tanks on the bottom and let them self level.

Until I get the rewiring program accomplished I've been doing the Scarlett O'Hara method. "I shall think about that tomorrow". 



Rick



On 1/28/07, John Hauck <jhauck(at)elmore.rr.com (jhauck(at)elmore.rr.com)> wrote: 	  Quote: 	
		   --> Kolb-List message posted by: "John Hauck" <jhauck(at)elmore.rr.com (jhauck(at)elmore.rr.com)>



  I really don't want to, still trying to follow the KISS principal.



I am at a loss. 

Larry, Oregon



Hi Larry:



I never had an airplane with this "screwy" system of pulling fuel from

two tanks through one line.



If I did have two tanks, you can be assured I would be pulling from 

the bottom of both into a T.  I can assure you you will then be

getting equal draw from each tank.



There is a neoprene grommet and elbow fitting available from Kolb or

most any UL parts house for tapping a plastic or metal tank.  I have 

used them for many years and many hours with great success.



If you still want to pull fuel from the top of the tank, then tap the

bottoms, tie them together so gravity can do its job for you.



Why switch back and forth between tanks with your fuel level sender 



	


-- 

Rick Girard

"Ya'll drop on in"

takes on a whole new meaning

when you live at the airport.  [quote][b]

lcottrell

Joined: 29 May 2006
Posts: 1494
Location: Jordan Valley, Or

Posted: Sun Jan 28, 2007 7:58 pm Post subject: tank troubles

---

lcottrell

Joined: 29 May 2006
Posts: 1494
Location: Jordan Valley, Or

Posted: Sun Jan 28, 2007 8:08 pm Post subject: tank troubles

---

John Hauck

Joined: 09 Jan 2006
Posts: 4639
Location: Titus, Alabama (hauck's holler)

Posted: Sun Jan 28, 2007 8:27 pm Post subject: tank troubles

Larry C:



The push in grommets and fittings have a proven track record, a hell 

of a lot better than your current fuel system.



I have some in my fuel tank that have been in service for 15 years.



john h

mkIII

_________________
John Hauck
MKIII/912ULS
hauck's holler
Titus, Alabama

jindoguy(at)gmail.com
Guest

Posted: Sun Jan 28, 2007 8:29 pm Post subject: tank troubles

If it is the vents, try switching the caps between the two tanks and see if you get the same results. My old system always drew evenly from both tanks.

WARNING, the following is an untested idea, but I will be using it to vent my tanks. 

I drilled a 1/4" hole through the little cap on the tank handle and the threaded boss it screws onto. I beaded a short piece of 1/4" aluminum tubing on both ends (put the cap on this tube before doing the second bead, you can guess how I learned that one) Bead one end about a 1/2" from the end so there is tubing to go down in the boss rather than just setting on top. Slide a piece of fuel proof line onto this and connect the two tanks with a tee. Run the single line from the tee up to the engine mount tube then back down and out the bottom of the cabin. I believe this will do two things. One, prevent any kind of fuel spill in case of being flipped over, and two, pick up ram air to pressurize the tanks and take a bit of load off the fuel pump. I stole this idea from the LongEZ guys. 



Rick



On 1/28/07, Larry Cottrell <lcottrell(at)fmtcblue.com (lcottrell(at)fmtcblue.com)> wrote:[quote] --> Kolb-List message posted by: "Larry Cottrell" <lcottrell(at)fmtcblue.com (lcottrell(at)fmtcblue.com)>

---

George Alexander

Joined: 10 Jan 2006
Posts: 245
Location: SW Florida

Posted: Mon Jan 29, 2007 6:53 am Post subject: tank troubles

Larry:

Rick's suggestion of switching caps is the most likely to find the source of

your dilemma.  The way you describe the current setup and the results,

improper venting is most likely.  Odds are that them 'daubers (or some

eight-legged critters) did their do before the single digits set in.



As for pickups in the bottom of the tanks..... If the grommets are installed

correctly there shouldn't be a problem.  



Before I got religion and switched to a Kolb, I had 8 years in a couple of

Quicksilvers.  The Quicksilver tanks hang over the root tube and have a

cross over loop to equalize the fuel in the areas below the root tube. Also

has the pickup on the bottom.  As part of the spring ritual, would change

out the grommets (two on the cross over and one on the pickup), all fuel

lines and filter.  (My original FS also had the feed from the bottom.  Same

spring routine.)  Probably overkill, but it made me feel better.  



I found that a little oil on/in the grommets first, put them in the tank,

then push the elbow straight in... as opposed to twisting and turning and

yanking and cranking and pulling and cussing.  Use a pair of locking pliers

to hold the elbow because it does take some force to get it into the

grommet.  Never had a leak (of fuel that is) in 10 years of this routine.



Rick's method of vent/overflow is also a good ideee.



As Beauford would say..... Worth what you paid for it.



George Alexander

http://gtalexander.home.att.net



DO NOT ARCHIVE



--

_________________
George Alexander
FS II R503
E-LSA N709FS
http://www.oh2fly.net

ceengland(at)bellsouth.ne
Guest

Posted: Mon Jan 29, 2007 6:18 pm Post subject: tank troubles

John Hauck wrote:



 	  Quote: 	
		  



  I really don't want to, still trying to follow the KISS principal.



I am at a loss.

Larry, Oregon



Hi Larry:



I never had an airplane with this "screwy" system of pulling fuel from 

two tanks through one line.



If I did have two tanks, you can be assured I would be pulling from 

the bottom of both into a T.  I can assure you you will then be 

getting equal draw from each tank.



There is a neoprene grommet and elbow fitting available from Kolb or 

most any UL parts house for tapping a plastic or metal tank.  I have 

used them for many years and many hours with great success.



If you still want to pull fuel from the top of the tank, then tap the 

bottoms, tie them together so gravity can do its job for you.



Why switch back and forth between tanks with your fuel level sender 

when you are working with a flow system that doesn't work logically?



My thoughts for what they are worth.  2 cents.



john h

mkIII 




	


I don't know didly about Kolbs, but most high wing Cessnas with 2 wing 

tanks & the selector on 'both' feed unevenly.  Others have mentioned 

venting issues; that's usually the cause of uneven feeds. It's very 

difficult to set up the tank vents where both tanks pressurize evenly. 

Add in inadvertent slip angles in flight, slight differences in fuel 

line length, routing, etc & It would be more surprising if they *did* 

feed evenly. 



One technique in the homebuilt community (the Bede BD-4 is a good 

example) to work around the problem is to feed both tanks into the top 

of a small low mounted 'sump' tank & feed the engine from the bottom of 

that tank. Bear in mind that no homebuilt I'm aware of uses a syphon 

type feed out of the primary tanks; all draw from the bottom of the tanks.



FWIW,



Charlie

John Hauck

Joined: 09 Jan 2006
Posts: 4639
Location: Titus, Alabama (hauck's holler)

Posted: Mon Jan 29, 2007 6:39 pm Post subject: tank troubles

| Add in inadvertent slip angles in flight, slight differences in 

fuel

| line length, routing, etc & It would be more surprising if they 

*did*

| feed evenly. 

 |

| Charlie

Charlie:



Pull the fuel off the bottom of both tanks, siamese the vents to one 

line, and I bet the fuel will drain evenly from both tanks.



john h

mkIII

_________________
John Hauck
MKIII/912ULS
hauck's holler
Titus, Alabama

ceengland(at)bellsouth.ne
Guest

Posted: Mon Jan 29, 2007 7:09 pm Post subject: tank troubles

John Hauck wrote:



 	  Quote: 	
		  

 | Add in inadvertent slip angles in flight, slight differences in 

fuel

| line length, routing, etc & It would be more surprising if they 

*did*

| feed evenly. 

 |

| Charlie

Charlie:



Pull the fuel off the bottom of both tanks, siamese the vents to one 

line, and I bet the fuel will drain evenly from both tanks.



john h

mkIII




	


It might, but it might not. Some of the previously mentioned Cessnas 

have the tank vents siamesed together. They still don't feed evenly.



Charlie

John Hauck

Joined: 09 Jan 2006
Posts: 4639
Location: Titus, Alabama (hauck's holler)

Posted: Mon Jan 29, 2007 7:26 pm Post subject: tank troubles

together. They still don't feed evenly.

| 

| Charlie

 



Charlie:



Impossible to compare Cessnas and Kolbs.  



john h

mk III

DO NOT ARCHIVE

_________________
John Hauck
MKIII/912ULS
hauck's holler
Titus, Alabama

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