REFLECTOR: Site gage tube tore like wet cardboard, YIKES

Scott Derrick scott at tnstaafl.net
Wed May 21 07:27:43 CDT 2008


Tygon is hydrocarbon resistant  and perfectly  acceptable.  I'm 99% 
certain  alcohol won't effect it either/.

I'm not sure what you installed but it certainly wasn't fuel resistant! 

I have the tygon fuel site lines. 450 hours of flying and they have 
worked great.  It would be tough to puncture them, really tough. And its 
very easy to change them when they start to get that film on the 
inside.  Vance gauges are somewhat more resistant to puncture but they 
also could be broken with a sharp wack from something hard, something 
the tygon would resist.

There are good reasons for both sides...

Scott

Chuck Jensen wrote:
> WITH EDITING: I believe you want polyurethane tubing (ACS Page 120), not polyethylene or even tygon.  The polyurethane is liquid clear and resistant to fuels.  If you put plugs in the fitting on both ends of the fuel tube and insert Vance Atkins little-red-balls into the tube, you can see fuel level in an instant.  I stuffed stainless steel scrub pad into the fitting so the small red ball can't go in the tank, top or bottom.  A more elegant solution is to machine small plugs with a small hole drilled in the plug to let fuel in/out.  Fit the plug in the opening of the fittings and viola--sight gauge that dampens fuel sloshing.
>
> Chuck Jensen
>
> Thanks,
> Chuck Jensen
>
> Diversified Technologies
> 2680 Westcott Blvd
> Knoxville, TN  37931
> Phn:    865-539-9000 x100
> Cell:    865-406-9001
> Fax:     865-539-9001
> cjensen at dts9000.com
>
>
>
> -----Original Message-----
> From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org]On
> Behalf Of Chuck Jensen
> Sent: Wednesday, May 21, 2008 7:30 AM
> To: Velocity Aircraft Owners and Builders list
> Subject: Re: REFLECTOR: Site gage tube tore like wet cardboard, YIKES
>
>
> I believe you want polyurethane tubing (ACS Page 120), not polyethylene or even tygon.  The polyurethane is liquid clear and resistant to fuels.  If you put plugs in the fitting on both ends of the fuel tube and insert Vance Atkins little-red-balls, you can see fuel level in an instant.  I stuffed stainless steel scrub pad into the fitting so the small red ball can go in the tank.  A more elegant solution is to machine small plugs with a small hole drilled in the plug to let fuel in/out.  Fit the plug in the opening of the fittings and viola--sight gauge that dampens fuel sloshing.
>
> Chuck Jensen
>
>
>
>
> -----Original Message-----
> From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org]On
> Behalf Of jewen at comporium.net
> Sent: Wednesday, May 21, 2008 7:19 AM
> To: Velocity Aircraft Owners and Builders list
> Subject: Re: REFLECTOR: Site gage tube tore like wet cardboard, YIKES
>
>
> Chris,
> Did you use the tubing supplied with the kit?  The tubing that came with my kit was slightly yellow, I believe it is likely tygon.  Tygon should resist fuels OK, while others such as clear PVC will deteriorate.  I like many others have installed the atkins units.
> Joe
>
>
> ---- Original message ----
>   
>> Date: Tue, 20 May 2008 17:53:55 -0500
>> From: "Christopher Barber" <CBarber at texasattorney.net>  
>> Subject: REFLECTOR: Site gage tube tore like wet cardboard, YIKES  
>> To: "COZY Mailing List" <cozy_builders at mailman.qth.net>, "FlyRotary aircraft" <flyrotary at lancaironline.net>, "Velocity Aircraft Owners and Builders list" <reflector at tvbf.org>
>>
>>   This may be one of these "known issues" that I was
>>   just clueless about, but a couple of weeks ago I
>>   arrived at the hangar to the strong smell of fuel in
>>   the air.  Uh oh.  I went to the plane and found
>>   about a 1/4 inch of fuel in the fuselage.  What
>>   gives?  I had just removed the old engine (13b) to
>>   build a new one when I found coolant in the rotor
>>   housings.  I thought that perhaps moving the fuel
>>   lines around behind the firewall may have allowed
>>   fuel to flow in a wired way and it drained into the
>>   cabin.....not sure, but first things first, lets
>>   clean the fuel up......anyone got a cigarette????
>>   <g>
>>    
>>   After all was clean  and no more fuel was leaking I
>>   put the issue on the back burner to think about it
>>   and to check all the lines.  I am waiting for the
>>   PSRU to come back from Tracy so I am doing some
>>   major "clean up" of "proof of concept" wire runs
>>   etc. 
>>    
>>   As I was re-running the wire that goes to the strake
>>   (Velocity SE) fuel sender I had to move the wire
>>   around the "clear" tubing that is used as a site
>>   gage in the strake luggage area.  To my shock the
>>   tubing ripped with just a slight touch.  In my
>>   dismay I pressed it with my fingernail and my nail
>>   cut clean through it.  I looked and found a crack on
>>   the pilot side tubing.  Hmmmmmm, since I checked all
>>   my aluminum connections inside the cabin and all
>>   were secure and, the sump was still full of fuel I
>>   am guessin' I found my fuel leak.
>>    
>>   Is this common?  What did I do wrong?  My first
>>   thought is this clear tubing is NOT compatible with
>>   auto gas. I have been fuel with local auto gas from
>>   the local station.  I don't remember but it MAY have
>>   some ethanol included.  I do not have much concerns
>>   there is issue with the tanks themselves as they
>>   were coated with Jeffco way back when.
>>    
>>   What tubing would y'all recommend for this use, that
>>   is clear AND not subject to deteriorating?  Really,
>>   it tore like wet cardboard.  I must have completely
>>   missed earlier discussion on this problem.  But,
>>   alas, would much rather find it now.  I got some
>>   regular black fuel lines to use until I find a
>>   solution so I can continue my engine development as
>>   my PSRU arrived back today.
>>    
>>   Thanks all.
>>    
>>   All the best,
>>    
>>   Chris
>>   Houston
>>    
>>   Velocity SE/FG w/ rotary 13b
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