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Fuel tank - bulges and leakage.
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arno-k(at)online.no
Guest

Posted: Tue Apr 29, 2008 11:54 am Post subject: Fuel tank - bulges and leakage.

Hi, 

  

Shortly before start of taxiing, it was discovered that fuel was  coming out of the fuselage on my Europa XS trigear (LN-ABM), through the access  holes below the tank. Draining of the tank was started and the leakage stopped  when 20 - 25 litres were remaining in the tank. 

  

Two days before I had drained the tank completely  since the aircraft had been stationary (in a heated hangar) since 1. july 2006  with app. 35 litres of mogas in the tank. The day of start up I filled 18  litres and checked all hose connections. Started the engine and runned it for 5  minutes to check hose connections to the recently installed oil thermostat. Then  filled another 36 litres of mogas and started the engine for the local  flight. 

  

Removing the wings, it was revealed that the tank front  facing the wing spars, had great bulges,  bulges inwards and outwards, and  the centre one touching the aileron cross tube, see attached picture. I have not  yet localized the crack, but I suspect the saddle section just ahead of the  fibreglass bracket. To me the in and out shape of the bulges indicate  compression stresses due to material expansion (caused by the fuel applied, 95  octane mogas?). And I think the crack is caused by shear stresses just forward  of the bracket mentioned. 

  

I will appreciate comments and advice. At present I do  not trust the material, polyethylene, used in the tank. Has anybody applied  metal tanks? 

  

Regards 

Arnold Kr. Hansen 

Europa XS trigear, Kit  No.381

FUEL_TANK_007.jpg

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Gary.Leinberger(at)miller
Guest

Posted: Tue Apr 29, 2008 1:05 pm Post subject: Fuel tank - bulges and leakage.

How old is your tank and how long have you had fuel in it?  I had to replace mine - it was my fault in the sense that I pressure tested it  with too much air pressure and ended up with stress cracks on the outer  edges where the wing comes in - but the real problem seems to be it is not a  very flexible material and over time I am afraid I will need to replace it again  - if I do I guess I will get an aluminium tank welded up - pictures of land  Rovers running over the tank may not be the best approach to judging the long  term ability of the tank to accept stress -

  

  

 Gary Leinberger

 A237



   From: owner-europa-list-server(at)matronics.com  [mailto:owner-europa-list-server(at)matronics.com] On Behalf Of Arnold Kr.  Hansen

Sent: Tuesday, April 29, 2008 1:52 PM

To:  europa-list(at)matronics.com

Subject: Fuel tank - bulges and  leakage.

 

  

  

Hi, 

  

Shortly before start of taxiing, it was discovered that fuel was  coming out of the fuselage on my Europa XS trigear (LN-ABM), through the access  holes below the tank. Draining of the tank was started and the leakage stopped  when 20 - 25 litres were remaining in the tank. 

  

Two days before I had drained the tank completely  since the aircraft had been stationary (in a heated hangar) since 1. july 2006  with app. 35 litres of mogas in the tank. The day of start up I filled 18  litres and checked all hose connections. Started the engine and runned it for 5  minutes to check hose connections to the recently installed oil thermostat. Then  filled another 36 litres of mogas and started the engine for the local  flight. 

  

Removing the wings, it was revealed that the tank front  facing the wing spars, had great bulges,  bulges inwards and outwards, and  the centre one touching the aileron cross tube, see attached picture. I have not  yet localized the crack, but I suspect the saddle section just ahead of the  fibreglass bracket. To me the in and out shape of the bulges indicate  compression stresses due to material expansion (caused by the fuel applied, 95  octane mogas?). And I think the crack is caused by shear stresses just forward  of the bracket mentioned. 

  

I will appreciate comments and advice. At present I do  not trust the material, polyethylene, used in the tank. Has anybody applied  metal tanks? 

  

Regards 

Arnold Kr. Hansen 

Europa XS trigear, Kit  No.381

  [quote][b]

steven.pitt2(at)ntlworld.
Guest

Posted: Tue Apr 29, 2008 1:16 pm Post subject: Fuel tank - bulges and leakage.

hagargs(at)earthlink.net
Guest

Posted: Tue Apr 29, 2008 4:55 pm Post subject: Fuel tank - bulges and leakage.

Arnold;

  

 A143 has been down for awhile while I am developing an aluminum tank for it.  I got the leaks after draining gasoline from the tank.  What happens is that the tank expands and I am told that if it is drained it shrinks back slightly.  My crack developed right alonside one of the layup straps in the saddle area.  Get a small mechanics mirror and start probing around.  The bulges you are seeing in the spar aperature are only an example  of what happens  to all of the surfaces of the tank.  When I cut my tank out of the cockpit seatback the top of the tank was all rippled where it had expanded and was constrained by the top of the seat back.  The back flat surface also exhibited  thesame phenomenon it was just constrained by the cockpit section.

  

 Steve Hagar

 N40 SH

 Mesa AZ

  

 

  

 [quote] ---

Pedro

Joined: 20 Apr 2008
Posts: 1
Location: Western Australia

Posted: Wed Apr 30, 2008 12:16 am Post subject: Fuel tank - bulges and leakage.

Hi guys, I am just about to start on a part built Europa XS #374 fuselarge is still 

in 2 pieces so I'm very interested 

to here these problems with the fuel tank (although the cockpit module is in). I have 

also heard of a similar case in

Western Australia where fuel (unleaded petrol)

had been sitting in the tank for about 8 - 12 months I think. The tank split on the 

fuel line.

Does any one know or heard of  the SMP system, link attached?

http://www.schuetz.net/schuetz/de/industry_services/service/downloads/brochure_smp_eng

lish.pdf



Regards

Peter H

WA



 	  Quote: 	
		  Melding



Arnold;

 

A143 has been down for awhile while I am developing an aluminum tank for it.  I got 

the leaks after draining gasoline from the tank.  What happens is that the tank 
	


expands and I am told that if it is drained it shrinks back slightly.  My crack 

developed right alonside one of the layup straps in the saddle area.  Get a small 

mechanics mirror and start probing around.  The bulges you are seeing in the spar 

aperature are only an example  of what happens  to all of the surfaces of the tank.  

When I cut my tank out of the cockpit seatback the top of the tank was all rippled 

where it had expanded and was constrained by the top of the seat back.  The back flat 

surface also exhibited  thesame phenomenon it was just constrained by the cockpit 

section.

[quote] 

Steve Hagar

N40 SH

Mesa AZ

 



 



---

Gary.Leinberger(at)miller
Guest

Posted: Wed Apr 30, 2008 5:12 am Post subject: Fuel tank - bulges and leakage.

Steve - if you get a tank developed I would like to get info on it  - and if you (or who you have fabricate them) are interested in selling  them please let me know. I am going to try this new tank I just installed but  have little faith in it -

  

  

 Gary Leinberger

 A237

 gleinberger(at)millersville.edu

  

  

  



   From: owner-europa-list-server(at)matronics.com  [mailto:owner-europa-list-server(at)matronics.com] On Behalf Of Steve  Hagar

Sent: Tuesday, April 29, 2008 8:52 PM

To:  europa-list(at)matronics.com

Subject: RE: Fuel tank - bulges  and leakage.

 

 Arnold;

  

 A143 has been down for awhile while I am developing an aluminum tank for  it.  I got the leaks after draining gasoline from the tank.  What  happens is that the tank expands and I am told that if it is drained it shrinks  back slightly.  My crack developed right alonside one of the layup straps  in the saddle area.  Get a small mechanics mirror and start probing  around.  The bulges you are seeing in the spar aperature are only an  example  of what happens  to all of the surfaces of the tank.   When I cut my tank out of the cockpit seatback the top of the tank was  all rippled where it had expanded and was constrained by the top of the seat  back.  The back flat surface also exhibited  thesame phenomenon it was  just constrained by the cockpit section.

  

 Steve Hagar

 N40 SH

 Mesa AZ

  

 

  

 [quote]   ---

alan(at)kestrel-insurance
Guest

Posted: Wed Apr 30, 2008 5:49 am Post subject: Fuel tank - bulges and leakage.

Hi Everyone  

   

As you may know from previous posts. I had a tank split on me last year after bringing my aircraft over to the USA from UK. The aircraft had been used for several years in UK without problem. The tank had sat empty for over two months before being refilled with unleaded fuel again (thanks to US customs). The split occurred on the inside of the tunnel and was very difficult to see even with the wings removed. Initially we tried to repair the damage by cutting off the top of the tank applying a sealant to the inside and refitting the top, which seemed easier than removing the whole thing. The repair lasted about a week and then started to leak again! So the only solution was to remove the tank and replace it. The reason I tell this story again is to hopefully avoid anyone else either leaving the tank empty after it having previously  been filled with fuel (I am convinced that was the cause of the split) or trying to effect a repair. The only solution in my opinion is to simply cut it out and replace the thing. The bulges seem to appear after a time on almost every Europa I have seen so I wouldn’t be too concerned about that  

Hope that helps.   

Kind regards from sunny Florida J  

   

Alan  

   [quote]  [b]

fklein(at)orcasonline.com
Guest

Posted: Wed Apr 30, 2008 9:43 am Post subject: Fuel tank - bulges and leakage.

"Troubling" is the kindest word I can utter on this topic.



Heretofore I have eased my mind with the notions that fuel tank 

failures have been the result of previously-filled tanks left empty for 

extended periods and subject to abnormally high ambient temperatures 

(say, an Arizona summer).



Now it appears in Arnold Hansen's case that a partially filled 

tank...left untouched for 20 months (with no leaks) but not subject to 

extreme temp. changes...then drained for two days and partially 

re-filled...is subject to failure.



And Jeff B has been flying the pants off of Baby Blue and finds bulges 

and distortion in tank shape sufficient to contact control rods.



Sounds to me that we have a very serious issue on our hands.



I have CM installed, top just clecoed, and will be checking on the 

feasibility of supplementing the plywood and aluminum angle 

spacers...with the intent of minimizing tank bulging and preventing 

interference w/ the control rods. I reason that maintaining the shape 

of the tank as much as possible should reduce crack-inducing stresses.



Fred

-- 

This message has been scanned for viruses and

dangerous content by MailScanner, and is

believed to be clean.

topglock(at)cox.net
Guest

Posted: Wed Apr 30, 2008 11:02 am Post subject: Fuel tank - bulges and leakage.

Fred and all,



That would be my approach, if I were to build again.  Support the front 

of the tank with ply, or some such and possibly spray foam all other 

areas, to add support.  Seems this would completely encase the tank and 

keep it relatively ridged.  Any other ideas?



As the fleet ages, there are bound to be unforeseen problems that pop 

up.  We just have to deal with them as they appear and hopefully, spare 

the new builders the pain... 



Jeff - Baby Blue

Exhaust fixed and ready to take to the air, once again...



Fred Klein wrote:

 	  Quote: 	
		   

 

 "Troubling" is the kindest word I can utter on this topic.

 

 Heretofore I have eased my mind with the notions that fuel tank failures 

 have been the result of previously-filled tanks left empty for extended 

 periods and subject to abnormally high ambient temperatures (say, an 

 Arizona summer).

 

 Now it appears in Arnold Hansen's case that a partially filled 

 tank...left untouched for 20 months (with no leaks) but not subject to 

 extreme temp. changes...then drained for two days and partially 

 re-filled...is subject to failure.

 

 And Jeff B has been flying the pants off of Baby Blue and finds bulges 

 and distortion in tank shape sufficient to contact control rods.

 

 Sounds to me that we have a very serious issue on our hands.

 

 I have CM installed, top just clecoed, and will be checking on the 

 feasibility of supplementing the plywood and aluminum angle 

 spacers...with the intent of minimizing tank bulging and preventing 

 interference w/ the control rods. I reason that maintaining the shape of 

 the tank as much as possible should reduce crack-inducing stresses.

 

 Fred

fklein(at)orcasonline.com
Guest

Posted: Wed Apr 30, 2008 12:34 pm Post subject: Fuel tank - bulges and leakage.

On Wednesday, Apr 30, 2008, at 12:00 US/Pacific, Jeff B wrote:



 	  Quote: 	
		   As the fleet ages, there are bound to be unforeseen problems that pop 

 up.  We just have to deal with them as they appear and hopefully, 

 spare the new builders the pain... 


	


Jeff...just love your "can do" attitude...helps me persevere!    Fred



do not archive

-- 

This message has been scanned for viruses and

dangerous content by MailScanner, and is

believed to be clean.

sidsel.svein(at)oslo.onli
Guest

Posted: Wed Apr 30, 2008 12:48 pm Post subject: Fuel tank - bulges and leakage.

All,



Preventing the tank from bulging too much forward will of course prevent it 

touching any of the controls or the wing spar (in which case the strap on 

the left spar might catch on the bulge during withdrawal/installation).



The inherent problem with high density polyetylene (HDPE) without any 

barrier layer (which automobile tanks have, and the newer Europa tanks may 

have - this is now being looked into) is that it is permeable and components 

of the fuel get into the material and causes it to swell (and some gets 

through the tak walls and gives the typical "Europa smell").  Where the 

material is thick, as in the edges between the bottom and sides, sides and 

top, and sides to sides, the swelling is apparently negligible.  This 

swelling cannot be stopped as such, so if the tank is prevented from 

buckling forward at all, it will bulge only inwards.  This will probably not 

be one single large bulge in each panel, but smaller "wrinkles" that another 

contributor reported yesterday from his findings along the top and the back 

(where outward bulging is restricted).



The best, given this undesired but unavoidable swelling, would be if the 

tank were of a simpler shape (say like a box without indentations and the 

saddle) and if we had no spacers to keep it away from the controls.  Typical 

hard points as the saddle and the outlets at the bottom appears to be where 

cracks are developing in some cases.  Even though the fuel components 

entering the permeable material also acts like softeners, local faults in 

the material may cause overstressing (e.g. thinner than intended material 

due to the fabrication process; maybe insufficient heating during the 

moulding).



The spacers installed according to the Builders Manual could be typical 

danger areas as far as cracks.  However, both on Arnold's tank and mine 

(which shows far less bulging - yet), the wave form of the bulging across 

the width of the tank is such that there is an inward bulge right behind the 

spacers and a forward bulge on either side.  It is easy to envisage the 

stress that would be introuced if a spacer were installed where the tank 

naturally wants to bulge forward.



So, based on what I have observed and learned about the tank material in 

these last few days, I would carefully evaluate where to stop the tank's 

bulging.  Newer tanks have a stiff rib or indentation running across the 

front, which should help (one such installation will be inspected shortly by 

another owner).



As for those still in the appropriate build stage, I would shape the BM 

spacers differently:  Build the plate of thicker material, oval instead of 

rectangular (with long axis horizontal) and shape its thickness markedly 

convex (thich in the center, thinning towards a well rounded circumference).



I am in contact with a polymer expert at a central Norwegian scientific 

institute.  His immediate comment is that HDPE does not "dry out" if the 

tank is left empty, but I am awaiting his further comments to a host of 

follow-up questions with relevance to our particular tanks and how we 

operate our airplanes.  Temperature definitely plays a part in the swelling. 

The hotter, the faster it swells, but I am still awaiting to hear from him 

whether HDPE swell more (higher maximum swell elongation) in hot weather 

than in cold.  He also mentioned that the particular fuel used may play a 

role.  When a major fuel supplier here introduced unleaded 98 octane mogas 

several years ago, it was found to "attack" polymers more aggressively than 

the previously used auto fuel did (we use unleaded 95 octane mogas in our 

Europas here in Norway).



What I really hate about this issue is not knowing whether I have spent 10% 

or 90% of my tank's safety margin with the present bulging, and what does 

say 5mm more bulging translate into as far as approaching a crack somewhere?



Regards,

Svein

LN-SKJ

topglock(at)cox.net
Guest

Posted: Wed Apr 30, 2008 1:08 pm Post subject: Fuel tank - bulges and leakage.

So, what you're saying is that the tank "grows" as it swells and will do 

so inwardly if not allowed to, outwardly.  Hmmmm, that's something I 

hadn't considered.  I'll have to rethink my solution.  Thanks for the 

information, Svein.  Please keep us up to speed on any additional 

information you should get...



Jeff - Baby Blue



Sidsel & Svein Johnsen wrote:

 	  Quote: 	
		   

 <sidsel.svein(at)oslo.online.no>

 

 All,

 

 Preventing the tank from bulging too much forward will of course prevent 

 it touching any of the controls or the wing spar (in which case the 

 strap on the left spar might catch on the bulge during 

 withdrawal/installation).

 

 The inherent problem with high density polyetylene (HDPE) without any 

 barrier layer (which automobile tanks have, and the newer Europa tanks 

 may have - this is now being looked into) is that it is permeable and 

 components of the fuel get into the material and causes it to swell (and 

 some gets through the tak walls and gives the typical "Europa smell").  

 Where the material is thick, as in the edges between the bottom and 

 sides, sides and top, and sides to sides, the swelling is apparently 

 negligible.  This swelling cannot be stopped as such, so if the tank is 

 prevented from buckling forward at all, it will bulge only inwards.  

 This will probably not be one single large bulge in each panel, but 

 smaller "wrinkles" that another contributor reported yesterday from his 

 findings along the top and the back (where outward bulging is restricted).

 

 The best, given this undesired but unavoidable swelling, would be if the 

 tank were of a simpler shape (say like a box without indentations and 

 the saddle) and if we had no spacers to keep it away from the controls.  

 Typical hard points as the saddle and the outlets at the bottom appears 

 to be where cracks are developing in some cases.  Even though the fuel 

 components entering the permeable material also acts like softeners, 

 local faults in the material may cause overstressing (e.g. thinner than 

 intended material due to the fabrication process; maybe insufficient 

 heating during the moulding).

 

 The spacers installed according to the Builders Manual could be typical 

 danger areas as far as cracks.  However, both on Arnold's tank and mine 

 (which shows far less bulging - yet), the wave form of the bulging 

 across the width of the tank is such that there is an inward bulge right 

 behind the spacers and a forward bulge on either side.  It is easy to 

 envisage the stress that would be introuced if a spacer were installed 

 where the tank naturally wants to bulge forward.

 

 So, based on what I have observed and learned about the tank material in 

 these last few days, I would carefully evaluate where to stop the tank's 

 bulging.  Newer tanks have a stiff rib or indentation running across the 

 front, which should help (one such installation will be inspected 

 shortly by another owner).

 

 As for those still in the appropriate build stage, I would shape the BM 

 spacers differently:  Build the plate of thicker material, oval instead 

 of rectangular (with long axis horizontal) and shape its thickness 

 markedly convex (thich in the center, thinning towards a well rounded 

 circumference).

 

 I am in contact with a polymer expert at a central Norwegian scientific 

 institute.  His immediate comment is that HDPE does not "dry out" if the 

 tank is left empty, but I am awaiting his further comments to a host of 

 follow-up questions with relevance to our particular tanks and how we 

 operate our airplanes.  Temperature definitely plays a part in the 

 swelling. The hotter, the faster it swells, but I am still awaiting to 

 hear from him whether HDPE swell more (higher maximum swell elongation) 

 in hot weather than in cold.  He also mentioned that the particular fuel 

 used may play a role.  When a major fuel supplier here introduced 

 unleaded 98 octane mogas several years ago, it was found to "attack" 

 polymers more aggressively than the previously used auto fuel did (we 

 use unleaded 95 octane mogas in our Europas here in Norway).

 

 What I really hate about this issue is not knowing whether I have spent 

 10% or 90% of my tank's safety margin with the present bulging, and what 

 does say 5mm more bulging translate into as far as approaching a crack 

 somewhere?

 

 Regards,

 Svein

 LN-SKJ

grahamsingleton(at)btinte
Guest

Posted: Wed Apr 30, 2008 2:48 pm Post subject: Fuel tank - bulges and leakage.

I tend to blame the oil companies for putting all sorts of stuff in the 

fuel without a word to anyone.

Could be wrong I suppose

Graham



Fred Klein wrote:

 	  Quote: 	
		   

 

 "Troubling" is the kindest word I can utter on this topic.

 

 Heretofore I have eased my mind with the notions that fuel tank failures 

 have been the result of previously-filled tanks left empty for extended 

 periods and subject to abnormally high ambient temperatures (say, an 

 Arizona summer).

 

 Now it appears in Arnold Hansen's case that a partially filled 

 tank...left untouched for 20 months (with no leaks) but not subject to 

 extreme temp. changes...then drained for two days and partially 

 re-filled...is subject to failure.

 

 And Jeff B has been flying the pants off of Baby Blue and finds bulges 

 and distortion in tank shape sufficient to contact control rods.

 

 Sounds to me that we have a very serious issue on our hands.

 

 I have CM installed, top just clecoed, and will be checking on the 

 feasibility of supplementing the plywood and aluminum angle 

 spacers...with the intent of minimizing tank bulging and preventing 

 interference w/ the control rods. I reason that maintaining the shape of 

 the tank as much as possible should reduce crack-inducing stresses.

 

 Fred

 

 


	


-- 

Graham Singleton



Tel: +441629820187

Mob: +447739582005

kheindl(at)msn.com
Guest

Posted: Wed Apr 30, 2008 3:41 pm Post subject: Fuel tank - bulges and leakage.

When I inspected my tank a couple of years ago I noticed that the back wall had buckled inward, probably reducing its capacity somewhat. This may well have happened on other Europas, but unless you have a large opening at the top you would never see it. I have an opening for the fuel level  probe,

 which allows me to get my whole arm into the tank. I was considering constructing some sort of internal framing, but couldn't come up with a good solution.



 Karl

  

 

<html><div></div></html>



 	  Quote: 	
		   

 --> Europa-List message posted by: Jeff B <topglock(at)cox.net>

 

 So, what you're saying is that the tank "grows" as it swells and will do 

 so inwardly if not allowed to, outwardly. Hmmmm, that's something I 

 hadn't considered. I'll have to rethink my solution. Thanks for the 

 information, Svein. Please keep us up to speed on any additional 

 information you should get...

 

 Jeff - Baby Blue

 

 Sidsel & Svein Johnsen wrote:

 > --> Europa-List message posted by: "Sidsel & Svein Johnsen" 

 > <sidsel.svein(at)oslo.online.no>

 > 

 > All,

 > 

 > Preventing the tank from bulging too much forward will of course prevent 

 > it touching any of the controls or the wing spar (in which case the 

 > strap on the left spar might catch on the bulge during 

 > withdrawal/installation).

 > 

 > The inherent problem with high density polyetylene (HDPE) without any 

 > barrier layer (which automobile tanks have, and the newer Europa tanks 

 > may have - this is now being looked into) is that it is permeable and 

 > components of the fuel get into the material and causes it to swell (and 

 > some gets through the tak walls and gives the typical "Europa smell"). 

 > Where the material is thick, as in the edges between the bottom and 

 > sides, sides and top, and sides to sides, the swelling is apparently 

 > negligible. This swelling cannot be stopped as such, so if the tank is 

 > prevented from buckling forward at all, it will bulge only inwards. 

 > This will probably not be one single large bulge in each panel, but 

 > smaller "wrinkles" that another contributor reported yesterday from his 

 > findings along the top and the back (where outward bulging is restricted).

 > 

 > The best, given this undesired but unavoidable swelling, would be if the 

 > tank were of a simpler shape (say like a box without indentations and 

 > the saddle) and if we had no spacers to keep it away from the controls. 

 > Typical hard points as the saddle and the outlets at the bottom appears 

 > to be where cracks are developing in some cases. Even though the fuel 

 > components entering the permeable material also acts like softeners, 

 > local faults in the material may cause overstressing (e.g. thinner than 

 > intended material due to the fabrication process; maybe insufficient 

 > heating during the moulding).

 > 

 > The spacers installed according to the Builders Manual could be typical 

 > danger areas as far as cracks. However, both on Arnold's tank and mine 

 > (which shows far less bulging - yet), the wave form of the bulging 

 > across the width of the tank is such that there is an inward bulge right 

 > behind the spacers and a forward bulge on either side. It is easy to 

 > envisage the stress that would be introuced if a spacer were installed 

 > where the tank naturally wants to bulge forward.

 > 

 > So, based on what I have observed and learned about the tank material in 

 > these last few days, I would carefully evaluate where to stop the tank's 

 > bulging. Newer tanks have a stiff rib or indentation running across the 

 > front, which should help (one such installation will be inspected 

 > shortly by another owner).

 > 

 > As for those still in the appropriate build stage, I would shape the BM 

 > spacers differently: Build the plate of thicker material, oval instead 

 > of rectangular (with long axis horizontal) and shape its thickness 

 > markedly convex (thich in the center, thinning towards a well rounded 

 > circumference).

 > 

 > I am in contact with a polymer expert at a central Norwegian scientific 

 > institute. His immediate comment is that HDPE does not "dry out" if the 

 > tank is left empty, but I am awaiting his further comments to a host of 

 > follow-up questions with relevance to our particular tanks and how we 

 > operate our airplanes. Temperature definitely plays a part in the 

 > swelling. The hotter, the faster it swells, but I am still awaiting to 

 > hear from him whether HDPE swell more (higher maximum swell elongation) 

 > in hot weather than in cold. He also mentioned that the particular fuel 

 > used may play a role. When a major fuel supplier here introduced 

 > unleaded 98 octane mogas several years ago, it was found to "attack" 

 > polymers more aggressively than the previously used auto fuel did (we 

 > use unleaded 95 octane mogas in our Europas here in Norway).

 > 

 > What I really hate about this issue is not knowing whether I have spent 

 > 10% or 90% of my tank's safety margin with the present bulging, and what 

 > does say 5mm more bulging translate into as far as approaching a crack 

 > somewhere?

 > 

 > Regards,

 > Svein

 > LN-SKJ

 > 

 > 

 > 

 > 

 > 

 > ======================

 ========================> 

 

 


	


  [quote][b]

rparigor(at)suffolk.lib.n
Guest

Posted: Wed Apr 30, 2008 5:14 pm Post subject: Fuel tank - bulges and leakage.

If anyone is interested, here is what we did to "Say "NO" to Crack (in

fuel tank)":

http://www.europaowners.org/modules.php?set_albumName=album233&op=modload&name=gallery&file=index&include=view_album.php



Our CPM was in but top was off, but with a little effort you could drop

the pushrod and do layup of tunnel from rear. Use plastic and BID, easy to

polk BID flat from bottom of aeroplane, 2 person job though. Foam very

dooable on completed plane.



Ron Parigoris

rlborger(at)mac.com
Guest

Posted: Wed Apr 30, 2008 6:06 pm Post subject: Fuel tank - bulges and leakage.

Graham,



There are so many ancillary ingredients added to MoGas it would be  

difficult to list them all on the side of the pump.  According to the  

Wisconsin State Government, there are over 150 separate chemical in  

gasoline.  There are detergents, solvents, oxidents, octane increasers  

and many other things beside C5 - C12 hydrocarbons.  And it varies  

from Regular to Super Premium.   Some of them are mandated by the  

government.  Others are there to keep your carb or fuel injectors,  

etc., neat and tidy.  Most of them change on a seasonal basis to  

provide fuel which meets Federal standards on emissions.  Here in the  

U.S.A., there are even regional formulations.  Fuels that provide the  

minimum emissions for the temperature/humidity ranges of the area.    

Fuels that are OK in Minnesota are verboten in Texas and vice-versa.



Though, I bet if you wrote to your favorite oil company you could get  

a listing of ingredients.  I doubt there are any "secret"  

ingredients.  Check their website for information and contacts.  You  

can also do a Google search on Gasoline Additives or start with the  

Wikipedia and ask about gasoline and/or gasoline additives.  All  

provide good starter information.



AvGas on the other hand is almost devoid of additives other than  

tetraethyl lead for antiknock.  This is why AvGas stores well and  

MoGas doesn't.  All those MoGas additives are volatile and will  

evaporate out of MoGas surprisingly quickly.



Certainly there are no insidious reasons for the oil companies to hide  

what goes in their gas.  It's just that most folks wouldn't know what   

2,4-dimethyl-6-tert-butylphenol or methylcyclopentadienyl manganese  

tricarbonyl are or what they do in any case.



Just some thoughts from a fellow who has been in "da o'l bidness" (as  

they used to say in Louisiana) for 30+ years.



Check six,

Bob Borger

Europa Kit #A221 N914XL, XS Mono, Intercooled 914, Airmaster C/S

http://www.europaowners.org/N914XL

(95% done 95% to go) tail kit done, wings closed, cockpit module  

installed, pitch system in, landing gear complete, rudder system in  

with Singleton Mod, outrigger mod in, Fuselage Top on, lift/drag/flap  

pins in, wing incidence set, tie bar in, flap drive in,  baggage bay  

in. Fuel system complete.  Rotax and Airmaster installed.  Mods 62,  

66, 70 & 72 done.  Completed the instrument panel install.   Europa  

interior kit being installed.  Installed windows.  Working in -  25  

Electrical, 28 Flaps, 30 Fuel System, 32 Tail, 34 Door Latches & 35  

Doors, 37 Finishing.   Mostly finishing these days.

3705 Lynchburg Dr.

Corinth, TX  76208

Home:  940-497-2123

Cel:  817-992-1117



On Apr 30, 2008, at 17:47, Graham Singleton wrote:



 	  Quote: 	
		   

 >



 I tend to blame the oil companies for putting all sorts of stuff in  

 the fuel without a word to anyone.

 Could be wrong I suppose

 Graham

keithhickling(at)clear.ne
Guest

Posted: Wed Apr 30, 2008 6:54 pm Post subject: Fuel tank - bulges and leakage.

Thanks for that Bob.



So is the problem of cracks and bulges limited to the use of mogas? Has 

anyone using Avgas had bulges or cracks in the tank? For those of us who 

have not yet had fuel in the tank, would avgas be better?



Keith Hickling,

New Zealand.

---

fklein(at)orcasonline.com
Guest

Posted: Wed Apr 30, 2008 7:22 pm Post subject: Fuel tank - bulges and leakage.

On Wednesday, Apr 30, 2008, at 13:46 US/Pacific, Sidsel & Svein Johnsen 

wrote:



 	  Quote: 	
		   

 <sidsel.svein(at)oslo.online.no>



 All,



 Preventing the tank from bulging too much forward will of course 

 prevent it touching any of the controls or the wing spar (in which 

 case the strap on the left spar might catch on the bulge during 

 withdrawal/installation).


	


Before getting Svein's thoughtful and informative post (thank you 

Svein!), I spent some time looking for a solution to potential bulging 

in my tank (which came w/ kit # A194, shipped from the factory in fall, 

2000).



In order to "contain" the (outward)  bulging, I reset my spacers (which 

have generous curves at the corners of the specified lay up) to ensure 

a gap between tank (dry and never filled w/ anything)  of between 1/8" 

and 1/4" and maintaining 1/4" clearance from the aileron control rod, I 

was planning to do the following:



Insert a piece of 1/8" thick plywood, 6.25" x 34",  w/ 1 layer of bid 

each side between the spacers and the front face of the tank, 

cushioning the plywood w/ 1/8" thick "sill sealer" (I believe it is a 

closed cell polypropylene foam available in 6" rolls at any building 

supply) between the plywood and the forward face of the tank. Prior to 

insertion, I would add a 3/4" x 2" x 34" foam stiffener w/ 2 layers bid 

on the forward face of the plywood. The plywood would be held in place 

w/ a 2 ply bid 2" wide tape which laps onto the underside of the FG 

"shelf" (previously installed as per manual). In doing this, my goal 

would be to resist "bulging" of the forward face of the tank.



Having reviewed Svein's post, I will not be doing anything until we 

have more information, hopefully in answer to Svein's questions on the 

nature of the HDPE used in our tanks.



I do appreciate so much the value of this forum as we attempt to 

address this insidious problem.



Fred

-- 

This message has been scanned for viruses and

dangerous content by MailScanner, and is

believed to be clean.

Venu Rao

Joined: 14 Oct 2007
Posts: 16
Location: Texas

Posted: Wed Apr 30, 2008 9:22 pm Post subject: Fuel tank - bulges and leakage.

I'm rather concerned about this too. Going to have a look at my tank  

for signs of bulging.



Almost certain I'm converting the mono to a conventional through Bob  

Berube. Just need to price it out.



Do you know if the tank can be replaced easily?



This forum is invaluable!

Hope all's well.

Cheers



Venu



Cell: (512) 771-3286



On Apr 30, 2008, at 22:18, Fred Klein <fklein(at)orcasonline.com> wrote:



 	  Quote: 	
		   



 On Wednesday, Apr 30, 2008, at 13:46 US/Pacific, Sidsel & Svein  

 Johnsen wrote:



> 

> >

>

> All,

>

> Preventing the tank from bulging too much forward will of course  

> prevent it touching any of the controls or the wing spar (in which  

> case the strap on the left spar might catch on the bulge during  

> withdrawal/installation).



 Before getting Svein's thoughtful and informative post (thank you  

 Svein!), I spent some time looking for a solution to potential  

 bulging in my tank (which came w/ kit # A194, shipped from the  

 factory in fall, 2000).



 In order to "contain" the (outward)  bulging, I reset my spacers  

 (which have generous curves at the corners of the specified lay up)  

 to ensure a gap between tank (dry and never filled w/ anything)  of  

 between 1/8" and 1/4" and maintaining 1/4" clearance from the  

 aileron control rod, I was planning to do the following:



 Insert a piece of 1/8" thick plywood, 6.25" x 34",  w/ 1 layer of  

 bid each side between the spacers and the front face of the tank,  

 cushioning the plywood w/ 1/8" thick "sill sealer" (I believe it is  

 a closed cell polypropylene foam available in 6" rolls at any  

 building supply) between the plywood and the forward face of the  

 tank. Prior to insertion, I would add a 3/4" x 2" x 34" foam  

 stiffener w/ 2 layers bid on the forward face of the plywood. The  

 plywood would be held in place w/ a 2 ply bid 2" wide tape which  

 laps onto the underside of the FG "shelf" (previously installed as  

 per manual). In doing this, my goal would be to resist "bulging" of  

 the forward face of the tank.



 Having reviewed Svein's post, I will not be doing anything until we  

 have more information, hopefully in answer to Svein's questions on  

 the nature of the HDPE used in our tanks.



 I do appreciate so much the value of this forum as we attempt to  

 address this insidious problem.



 Fred

 -- 

 This message has been scanned for viruses and

 dangerous content by MailScanner, and is

 believed to be clean.

_________________
Venu Rao
Austin, TX
Europa Mono
Builder: Jim Nelson
TTAE 119.1 hrs

grahamsingleton(at)btinte
Guest

Posted: Thu May 01, 2008 1:21 am Post subject: Fuel tank - bulges and leakage.

Hi Bob

apreciate your thoughtful reply.

I wish they wouldn't put alcohol in though, It isn't good for engines 

and it is even worse for the environment, takes too much energy to make 

it and it uses up too much food, (imho!)

Simple answer, there are already too many of us on this planet, we need 

to start colonising space!

Graham



Robert Borger wrote:

 	  Quote: 	
		   

 

 Graham,

   According to the Wisconsin State Government, there are over 150 
	


separate chemical in

 	  Quote: 	
		   gasoline.  There are detergents, solvents, oxidents, octane increasers  

 and many other things beside C5 - C12 hydrocarbons.  


	


 	  Quote: 	
		   Certainly there are no insidious reasons for the oil companies to hide  

 what goes in their gas.  It's just that most folks wouldn't know what   

 2,4-dimethyl-6-tert-butylphenol or methylcyclopentadienyl manganese  

 tricarbonyl are or what they do in any case.


	


 	  Quote: 	
		   Bob Borger

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