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Fuel tank installation without bonding it in

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jan_de_jong(at)casema.nl
Guest

Posted: Sun Dec 20, 2009 3:56 pm Post subject: Fuel tank installation without bonding it in

Dear all,



Unless somebody has a bright idea I think I have come to the end of 

planning to install the fuel tank without bonding it in.

I now have a tightly fitting bed of 2 layers of bid and a quantity of 

1/16" wool felt to line it with. Also epp padding for locking in to 

restrict movement up and forward.

Yesterday I remembered belatedly that plastic moving on wool (and 

plastic on plastic) can lead to static charge buildup and sparks.

I decided to investigate antistatic measures and ordered Graphit 33 by 

CRC Kontakt Chemie. Covering rubbing parts of the tank with this (after 

test) might solve the problem (if it is).

Today I remembered, also belatedly, that sloshing fuel on the inside and 

a conductive layer on the outside is also not good - potential for 

sparks right through the tank wall.

I am not contemplating spraying the inside of the tank with graphite...

So I am at a standstill with this plan.



The alternative will be bonding in according to the manual but with 

staggered bid layers, 3 layers of bid on the whole tunnel and low 

expansion urethane foam supporting the front bottom - as described by 

Ron Parigoris. (the front bottom support was also part of the bed and 

lock-in plan).



What shall I do.



Jan de Jong

flyingphil2

Joined: 04 Dec 2009
Posts: 117

Posted: Mon Dec 21, 2009 2:22 am Post subject: Re: Fuel tank installation without bonding it in

Hi Jan,



You are ahead of me on your build and so I have this to come.  I was also advised by Roger not to bond the tank in and just have it supported by the brackets.



Could you not line the brackets with PTFE release tape or something?  I don't think that is a conductor.  Alternatively (and having recently had a large delivery of RAM memory at work), could you not use the non-static bag material that memory boards are delivered in?  I'm not sure what that is but some internet research may come up with a material spec.



Hope that helps and let me know if you find a solution.



Regards,



Phil

frans(at)paardnatuurlijk.
Guest

Posted: Mon Dec 21, 2009 3:38 am Post subject: Fuel tank installation without bonding it in

Jan de Jong wrote:



 	  Quote: 	
		   Yesterday I remembered belatedly that plastic moving on wool (and

 plastic on plastic) can lead to static charge buildup and sparks.


	


1) Restrict the movement. Ideally, you want to make the tank fit

precisely, so it won't shift during turbulence or scarobatic

manoeuvrings. It will then only move a bit because of thermal changes,

or when the fuel level (and hence weight) changes. This is not enough to

produce a significant amount of static electricity.



2) I wouldn't use a conductive layer on any side of the tank. This will

create a conductive path for anything that has a potential to spark. If

there is no conductor, it is difficult to get a spark. Localizes spots

of static charge won't spark, UNLESS there is a conductor that allows

these charges to collect together, create a massive force, and make them

jump to... something else where they can continue their travel.

Actually, the worst thing you can do is to make both the inside and

outside of the tank conductive, as then you have created a very large

capacitor, very able to build up a large charge, and with the potential

to spark through its dielectricum, that is, the wall of your tank. The

charge will then, due to the conductive layer, search for the weakest

spot, and the entire charge of the tank will spark through this weakest

spot.



3) Don't fix what ain't broken. There are no reports or even suspicions

that any Europa exploded due to static charge buildup of the tank and

ignition of the fuel.



Consider this: if you rub a balloon (these things used for party

decoration) over some plastic, these things will build up huge amounts

of static electricity. They will raise your hair easily from quite a

distance, or stick to a window or ceiling just by their static electricity.

Although they are building up huge amounts of static electricity, never,

never, will this electricity spark to the inside of the balloon (and

thus destroying itself by piercing the latex).

I believe balloons can be forced into building up more static

electricity than you will ever encounter in your Europa tank. And I also

believe that the skin of the tank is much thicker than the skin of the

balloon. 



I wouldn't worry about it, as long as you don't make the tank

conductive. Keep it as is, don't bond it it, but restrict its movement.



Frans

jan_de_jong(at)casema.nl
Guest

Posted: Mon Dec 21, 2009 7:30 am Post subject: Fuel tank installation without bonding it in

New day, new courage. Thank you.

I agree, Frans, no movement allowed and no antistatic (conducting) 

materials - that was a wrong turn I took.

There exists a "triboelectric series" (for instance: 

http://www.trifield.com/triboelectric.htm) . Distance in this series 

indicates propensity for charge buildup when materials are rubbed 

together. Close enough and no discharge in air can be induced. Epoxy and 

PE are not too far apart, closer than wool and PE (Phil, I see that PTFE 

is at an extreme end of the scale). PE and PP are in the same place.

I am now inclined to go ahead with my bed either lined with very thin 

HD-PE packing foam - to avoid all likelyhood of electrostatic discharge 

- or not lined at all. Mechanically the second option looks most certain 

- and simple.

Movement prevention using EPP padding where the tank has edges: at top 

front (front and top faces), at top rear (top face) and bottom front 

(front face of the bed).

The padding is not supposed to carry weight  Thin layer of Araldite 420 

(from a 2003 batch) bonds the stuff very well.



Any more thoughts welcome.



Cheers,

Jan de Jong

rampil

Joined: 04 May 2007
Posts: 870

Posted: Mon Dec 21, 2009 7:40 am Post subject: Re: Fuel tank installation without bonding it in

Happy Holidays!



Before going outside the build manual instructions for the fuel

tank, it might be worthwhile to recheck with the factory. No

offense to Roger, but the company is now owned by an actual

aviation engineer.



The presence of a conductive patch in the tank is meaningless, the

only thing that matters is the possibility to close a path to ground 

from a voltage source(like a static, or in engineering-speak, tribolelectric

charge) through a fuel-air cloud.



Unless the tank is electrically connected to the engine block or other

ground there is no ignition circuit.



BTW, the best fuel hose available is Aeroquip 666 with a carbon stripe

on the teflon inner liner to move fuel-flow induced charge to a controlled

ground site (not through gasoline-air vapor)



Best of Luck,

_________________
Ira N224XS

rparigoris

Joined: 24 Nov 2009
Posts: 804

Posted: Mon Dec 21, 2009 10:47 am Post subject: Fuel tank installation without bonding it in

Hi GroupI posted this site before, but here it is again that speaks why you want carbon lined teflon fuel line: http://www.sacskyranch.com/statichose.htm . I like Aeroquip 666 hose FWF, not only for long service life but it has a smaller OD for a given ID of many hoses. It allowed me to sneak between UCMF and tunnel. I fabricated SS banjo ends : [url=http://www.europaowners.org/forums/gallery2.php?g2_itemId 8355]http://www.europaowners.org/forums/gallery2.php?g2_itemId 8355[/url] . You can purchase with custom crimped ends instead of screw together compression ends. My banjo end uses parts from the later. Jan I don't think I would worry too much about static. I did a search a while back and only thing i found was explosin in a helicopter or two from inside of fuel system. I agree conductive both inside and outside is not a good idea. Unless tank is near empty the mixture inside will be way too rich to explode. Not much statis is going to be built up with minimal sloshing going on in tank. Another stroy sending 30 to 40GPH or more through 914 fuel lines. The tank is so thick I don't know if you would ever puncture it with a discharge. Now refueling is another story! I plan to make a swipe with a damp cottom cloth of cap before removal. there has been at least one Europa lost to discharge upon refueling. I don't see much benefit to wool? There is not much movement of tank, did you want this for cushion, anti chafe or?? Checking with factory is a good idea. If I were to mount tank at this time, would probably just put a piece of saran wrap on tank and lay up nice support. You don't want a cantelever from back trying to hold tank up in front. Tunnel layup is good idea, staggering layers for most part is always a good idea and is such here. Foam after all is said and done still a good idea. All said that is unless you want to install an aluminium tank at this point.Ron Parigoris   [quote][b]

frans(at)paardnatuurlijk.
Guest

Posted: Mon Dec 21, 2009 11:12 am Post subject: Fuel tank installation without bonding it in

rparigor(at)suffolk.lib.ny.us wrote:

 	  Quote: 	
		   there has been at

 least one Europa lost to discharge upon refueling.


	


Any more information about this?



Thanks,

Frans

rparigoris

Joined: 24 Nov 2009
Posts: 804

Posted: Mon Dec 21, 2009 2:54 pm Post subject: Fuel tank installation without bonding it in

Hi Frans"there has been at least one Europa lost to discharge upon refueling."" Any more information about this?"I remember when installing my cockpit module ~2004 I researched static discharges and fuel in plastic aeroplanes. I forget if it was a formal report or mention but I am pretty certain it happened and caused a total loss of a Europa caused by static discharge when refueling. I have a folder with static info in it that is in my engine crate. Next time I access engine will see if I made a copy, will scan and post if I did. After my research instead of putting discharge mesh down cobra and into tank and connect that to outlets of fuel tank I am going Nevs route, damp cotton cloth onto filler before removing cap. One bad thing you can avoid is filling a container that is not placed on ground but held off, then pouring it into right away into your plane.Ron Parigoris   [quote][b]

rparigoris

Joined: 24 Nov 2009
Posts: 804

Posted: Mon Dec 21, 2009 3:03 pm Post subject: Re: Fuel tank installation without bonding it in

Hi Frans



I searched static fire on Andrews search engine and got plenty of hits. Here is one:

http://www.sarangan.org/www/mhonarc/mharc/html//europa-list/2000-07/msg00018.html

Ron Parigoris

jan_de_jong(at)casema.nl
Guest

Posted: Mon Dec 21, 2009 3:03 pm Post subject: Fuel tank installation without bonding it in

Frans Veldman wrote:

 	  Quote: 	

 rparigor(at)suffolk.lib.ny.us wrote:

> there has been at

> least one Europa lost to discharge upon refueling.

>     

 Any more information about this?

 Thanks,

 Frans

Concerns G-BWDP / Harold Linke in the year 2000. There are pictures of 

the aircraft taken in 2006 so it was repaired.

Not much information searching in archives or googleing.

There has been a lot of discussion on best practices.

A nice searchable archive is at http://www.sarangan.org/aviation/

Re fuel tank installation - I will refer to factory tomorrow. They may 

have shut down for Xmas ofcourse.

Cheers,

Jan de Jong

jan_de_jong(at)casema.nl
Guest

Posted: Wed Dec 23, 2009 4:10 am Post subject: Fuel tank installation without bonding it in

Checking with John and Roger at the factory re tank installation.



1.

The last of the original (2004) Ltd crew is retiring and having its last 

day at the office today. The end of a period - again.

Roger will be available by e-mail for a while for technical questions. 

He monitors this forum. If I say a lie he will correct I'm sure.



2.

The gaseous tank treatment introduced to prevent swelling causes epoxy 

to bond to the tank material.

Thermal expansion rate difference is the most likely cause for tearing 

tanks.

Prescription:

Install in accordance with the manual but with a permanent release film 

between layup and tank.

No other measures are necessary and triboelectrics are not an issue.



(

Googling gives a linear thermal expansion coefficient difference between 

glass reinforced epoxy and polyethylene in the order of 1 in 10000 per 

degree C.

That would be 1 mm per 20 cm for 50 degree C.

)



Cheers,

Jan de Jong

wdaniell(at)etb.net.co
Guest

Posted: Wed Dec 23, 2009 5:06 am Post subject: Fuel tank installation without bonding it in

Jan



is there any suggestion for those of us who have already bonded in as 

per the manual?



..And to take the opportunity also to say Happy Christmas to all and 

thanks for all the help in 2009.



Will



Jan de Jong wrote:

 	  Quote: 	
		   2.

 The gaseous tank treatment introduced to prevent swelling causes epoxy

 to bond to the tank material.

 Thermal expansion rate difference is the most likely cause for tearing

 tanks.

 Prescription:

 Install in accordance with the manual but with a permanent release film

 between layup and tank.

 No other measures are necessary and triboelectrics are not an issue.



 (

 Googling gives a linear thermal expansion coefficient difference between

 glass reinforced epoxy and polyethylene in the order of 1 in 10000 per

 degree C.

 That would be 1 mm per 20 cm for 50 degree C.

 )



 Cheers,

 Jan de Jong

 _

richard.churchill-coleman
Guest

Posted: Wed Dec 23, 2009 5:34 am Post subject: Fuel tank installation without bonding it in

William,



I asked Roger about this yesterday (on his almost last day) because the

factory built my cockpit module and bonded in the tank as per the

instructions.  His comforting words were that the shear stress issues were

being experienced by extreme temperature ranges and would not cause problems

for "normal" (ie UK and mainland western Europe) temperatures.....



Not sure how much that helps for your circumstances...

RCC 



--

peterz(at)zutrasoft.com
Guest

Posted: Wed Dec 23, 2009 6:35 am Post subject: Fuel tank installation without bonding it in

This is the first I have heard of thermal expansion being attributed as a contributor to cracking.



It was my understanding that even the flourinated tanks swell, and it was the swelling + adhesion of the epoxy (restricting the swelling locally, creating point-stresses) which was the cause of some cracking. - Or have I mis-understood the previous reports and email threads?

 

Thx,

Pete

A239



-tank not yet installed, and contemplating the design and construction of an all-composite tank (...the Cozy and LongEze builders have geen doing it for years...no?).



 On Wed, Dec 23, 2009 at 7:06 AM, Jan de Jong <jan_de_jong(at)casema.nl (jan_de_jong(at)casema.nl)> wrote:

[quote] --> Europa-List message posted by: Jan de Jong <jan_de_jong(at)casema.nl (jan_de_jong(at)casema.nl)>

 

 Checking with John and Roger at the factory re tank installation.

 

 1.

 The last of the original (2004) Ltd crew is retiring and having its last day at the office today. The end of a period - again.

 Roger will be available by e-mail for a while for technical questions. He monitors this forum. If I say a lie he will correct I'm sure.

 

 2.

 The gaseous tank treatment introduced to prevent swelling causes epoxy to bond to the tank material.

 Thermal expansion rate difference is the most likely cause for tearing tanks.

 Prescription:

 Install in accordance with the manual but with a permanent release film between layup and tank.

 No other measures are necessary and triboelectrics are not an issue.

 

 (

 Googling gives a linear thermal expansion coefficient difference between glass reinforced epoxy and polyethylene in the order of 1 in 10000 per degree C.

 That would be 1 mm per 20 cm for 50 degree C.

 )

 

 Cheers,

 Jan de Jong

 

 

 

 

 

 

 ===========

 ="_blank">www.aeroelectric.com

 ooks.com" target="_blank">www.buildersbooks.com

 et="_blank">www.homebuilthelp.com

 "_blank">www.howtocrimp.com

 ="_blank">http://www.matronics.com/contribution

 le, List Admin.

 ===========

  target="_blank">http://www.matronics.com/Navigator?Europa-List

 ===========

 http://forums.matronics.com

 ===========

 

 

 

 [b]

wdaniell(at)etb.net.co
Guest

Posted: Wed Dec 23, 2009 6:43 am Post subject: Fuel tank installation without bonding it in

Richard



thanks,  it is a little disquieting because although BOG is pretty much 

like English Summer all year round due to altitude (8500´); fly 30 mins 

and you land at 1000´ and it is absolutely baking!



I suspect that some of the US builders/flyers probably have more 

experience of temp differentials.



Yours



Will



Richard Churchill-Coleman wrote:

 	  Quote: 	
		   



 William,



 I asked Roger about this yesterday (on his almost last day) because the

 factory built my cockpit module and bonded in the tank as per the

 instructions.  His comforting words were that the shear stress issues were

 being experienced by extreme temperature ranges and would not cause problems

 for "normal" (ie UK and mainland western Europe) temperatures.....



 Not sure how much that helps for your circumstances...

 RCC

rlborger(at)mac.com
Guest

Posted: Wed Dec 23, 2009 6:47 am Post subject: Fuel tank installation without bonding it in

 	  Quote: 	
		  Pete,



My thoughts as well.  And I have a factory assembled CM with bonded tank.



And because I had the same understanding as you, I keep the tank full and won't empty it for an extended time if at all possible.



Where do we go from here?



*** Merry Christmas and Happy New Year to all ***  



Bob Borger



On Wednesday, December 23, 2009, at 08:13AM, "Peter Zutrauen" <peterz(at)zutrasoft.com> wrote:

 	  Quote: 	
		  	
  This is the first I have heard of thermal expansion being attributed as a contributor to cracking.

 
	


It was my understanding that even the flourinated tanks swell, and it was the swelling + adhesion of the epoxy (restricting the swelling locally, creating point-stresses) which was the cause of some cracking. - Or have I mis-understood the previous reports and email threads?

  

Thx,

Pete

A239

 

-tank not yet installed, and contemplating the design and construction of an all-composite tank (...the Cozy and LongEze builders have geen doing it for years...no?).

 

  On Wed, Dec 23, 2009 at 7:06 AM, Jan de Jong <jan_de_jong(at)casema.nl (jan_de_jong(at)casema.nl)> wrote:

  	  Quote: 	
		   --> Europa-List message posted by: Jan de Jong <jan_de_jong(at)casema.nl (jan_de_jong(at)casema.nl)>

  

 Checking with John and Roger at the factory re tank installation.

  

 1.

 The last of the original (2004) Ltd crew is retiring and having its last day at the office today. The end of a period - again.

 Roger will be available by e-mail for a while for technical questions. He monitors this forum. If I say a lie he will correct I'm sure.

  

 2.

 The gaseous tank treatment introduced to prevent swelling causes epoxy to bond to the tank material.

 Thermal expansion rate difference is the most likely cause for tearing tanks.

 Prescription:

 Install in accordance with the manual but with a permanent release film between layup and tank.

 No other measures are necessary and triboelectrics are not an issue.

  

 (

 Googling gives a linear thermal expansion coefficient difference between glass reinforced epoxy and polyethylene in the order of 1 in 10000 per degree C.

 That would be 1 mm per 20 cm for 50 degree C.

 )

  

 Cheers,

 Jan de Jong

  

  

  

  

  

  

 ===========

 ="_blank">www.aeroelectric.com

 ooks.com" target="_blank">www.buildersbooks.com

 et="_blank">www.homebuilthelp.com

 "_blank">www.howtocrimp.com

 ="_blank">http://www.matronics.com/contribution

 le, List Admin.

 ===========

  target="_blank">http://www.matronics.com/Navigator?Europa-List

 ===========

 http://forums.matronics.com

 ===========

fklein(at)orcasonline.com
Guest

Posted: Wed Dec 23, 2009 10:53 am Post subject: Fuel tank installation without bonding it in

Though I recall seriously questioning the bonding called for in the manual, I blithely went ahead and laid up the glass on the tank...much to my chagrin. Because of the isolated reports of swelling, I did install a padded FG "shield", intended to enhance the apparent function of EURO 25 spacers shown on pg. 16-5, Fig. 7.



At this point, I intend to place a release film between underside of tank and the inside surface of the bottom of the fuselage and squirt some non-expanding foam through the twin access ports to fill the gap between tank and fuselage. I'll use a long straw on the foam can in order to raise the possibility of ending up with a full bed of foam...the intention being to provide uniform support for the fuel tank and to minimize any stresses on the tank caused by it being cantilevered from the FG "straps" previously bonded to the tank. This is a procedure described in Ron Pagoris's build-log. To my knowledge, this is a theoretical band-aide with no operational experience which might speak to its effectiveness.

...my 2 cents...comments & wisdom welcome,

Fred

A194 



On Dec 23, 2009, at 6:46 AM, Bob Borger wrote:

 	  Quote: 	
		    	  Quote: 	
		  Pete,



My thoughts as well.  And I have a factory assembled CM with bonded tank.



And because I had the same understanding as you, I keep the tank full and won't empty it for an extended time if at all possible.



Where do we go from here?



*** Merry Christmas and Happy New Year to all ***  



Bob Borger



On Wednesday, December 23, 2009, at 08:13AM, "Peter Zutrauen" <peterz(at)zutrasoft.com (peterz(at)zutrasoft.com)> wrote:

 	  Quote: 	
		  	
  This is the first I have heard of thermal expansion being attributed as a contributor to cracking.

 
	


It was my understanding that even the flourinated tanks swell, and it was the swelling + adhesion of the epoxy (restricting the swelling locally, creating point-stresses) which was the cause of some cracking. - Or have I mis-understood the previous reports and email threads?



	




 [quote][b]

jan_de_jong(at)casema.nl
Guest

Posted: Thu Dec 24, 2009 5:12 am Post subject: Fuel tank installation without bonding it in

Hi William,



No - not mentioned.

But assuming that stresses add up I would personally try to apply some 

relief as Ron Parigoris did.

And maybe avoid opportunities for parking on hot asphalt when there is a 

choice.



Regards,

Jan de Jong



William Daniell wrote:

 	  Quote: 	
		   is there any suggestion for those of us who have already bonded in as 

 per the manual?

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