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Just a couple of questions

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backstagelive(at)gmail.co
Guest

Posted: Tue Aug 23, 2011 8:54 pm Post subject: Just a couple of questions

I have a couple of questions I hope you can help me with.



I just finished all of the changes for the B model change and now it's time 

to start on regular construction again! I ran into a few small snags I hope 

you can give me some advise on.



I have brass through the firewall threaded fittings for my 2 fuel lines 

going through the firewall. Someone at EAA told me to use aluminum fittings 

rather than the brass because they were lighter and safer. I can understand 

the lightness, but I don't understand why they would be safer. What are you 

guys using for through the firewall fittings for your fuel lines? I don't 

mind sacrificing weight for safety. I have seen rubber fuel lines with steel 

reinforcement on the outside in both a race car and in an RV6. What is the 

safest way to build a fuel system and what are the finest products I can buy 

made for safety?



Tonight I fit the stab to the fuselage for the very first time! It was a 

great feeling to see the stab sitting there on the fuselage. I knew there 

would be a sizable gap between the fuselage skins and the bottom of the 

stab, but I didn't think it would be big enough to put my finger in there! 

What are you guys doing with that big open hole? Would it be worth it to 

build a fairing of some sort on the bottom of the stab? Is there a reason 

for the big gap?



I am also ordering a new elevator for my plane from the factory, unless I 

can find a used or unbuilt one. There are 2 types. One with the trim tab cut 

into the elevator, and one with a full tab on the outside of the elevator. I 

saw both in Oshkosh and they both look OK for me, but which one is better? 

Which one is lighter?



I am preparing a web page this week where you will be able to go and 

download pictures of the banquet and award ceremonies. I filmed the entire 

banquet and I still can't get over the incredible speech Paul Poberezny 

gave. I will have this available shortly for everyone.



Thanks for any help you can give. It feels good to be working on something 

other than the retrofit!!!



Joe in Oshkosh

psm(at)att.net
Guest

Posted: Wed Aug 24, 2011 2:16 am Post subject: Just a couple of questions

Hi Joe,



I agree with you about Paul Poberezny's speech.  He stole the show.  The 

biggest part of my memory of the event is the notion that he is still 

building planes at age 90.  This must be a  hobby that is good for your 

health!



I don't remember what material I used for the fuel line going through 

the firewall.  I do know I have only one line going through.  I think I 

have the normal arrangement of fuel lines going from the two tanks to 

the fuel selector which is mounted on the center console.  From there 

one line goes to the gascolator which is mounted on the bottom of the 

cabin and from there through the firewall.  I can't imagine why you 

would have two lines going through the firewall.



I guess the ideal material for the tube going through the firewall would 

be steel.  it will stand up to the heat of a fire a lot better than 

either brass or aluminum.  Brass would hold up better than aluminum.  I 

have no idea how these materials act in the presence of fuel.  Perhaps 

there is a chance of interaction with the fuel, but brass fittings are 

quite normal in fuel systems.



I don't think you need to worry about the hole under the horizontal 

stabilizer.  The fuselage blocks airflow in this area.



Good luck with your project.



Paul

Camas, WA

XL - 10 hours flight test completed.



On 8/23/2011 9:52 PM, Joe wrote:

 	  Quote: 	
		   



 I have a couple of questions I hope you can help me with.



 I just finished all of the changes for the B model change and now it's 

 time to start on regular construction again! I ran into a few small 

 snags I hope you can give me some advise on.



 I have brass through the firewall threaded fittings for my 2 fuel 

 lines going through the firewall. Someone at EAA told me to use 

 aluminum fittings rather than the brass because they were lighter and 

 safer. I can understand the lightness, but I don't understand why they 

 would be safer. What are you guys using for through the firewall 

 fittings for your fuel lines? I don't mind sacrificing weight for 

 safety. I have seen rubber fuel lines with steel reinforcement on the 

 outside in both a race car and in an RV6. What is the safest way to 

 build a fuel system and what are the finest products I can buy made 

 for safety?



 Tonight I fit the stab to the fuselage for the very first time! It was 

 a great feeling to see the stab sitting there on the fuselage. I knew 

 there would be a sizable gap between the fuselage skins and the bottom 

 of the stab, but I didn't think it would be big enough to put my 

 finger in there! What are you guys doing with that big open hole? 

 Would it be worth it to build a fairing of some sort on the bottom of 

 the stab? Is there a reason for the big gap?



 I am also ordering a new elevator for my plane from the factory, 

 unless I can find a used or unbuilt one. There are 2 types. One with 

 the trim tab cut into the elevator, and one with a full tab on the 

 outside of the elevator. I saw both in Oshkosh and they both look OK 

 for me, but which one is better? Which one is lighter?



 I am preparing a web page this week where you will be able to go and 

 download pictures of the banquet and award ceremonies. I filmed the 

 entire banquet and I still can't get over the incredible speech Paul 

 Poberezny gave. I will have this available shortly for everyone.



 Thanks for any help you can give. It feels good to be working on 

 something other than the retrofit!!!



 Joe in Oshkosh

bryanmmartin

Joined: 10 Jan 2006
Posts: 1018

Posted: Wed Aug 24, 2011 1:12 pm Post subject: Just a couple of questions

It's called a firewall for a reason, it's supposed to provide some protection from a fire in the engine compartment. Fire resistance should be a factor for any penetrations through the firewall. They should provide at least as much protection as the material of the firewall itself. Brass will tolerate heat better than aluminum. Galvanized steel is even better.



I ran my rubber fuel line through the firewall inside a steel bulkhead cable fitting and covered it with fire-sleeve. I built steel baffles around my other firewall penetrations and filled them in with high temp RTV or other resistant material.

On Aug 24, 2011, at 12:52 AM, Joe wrote:



 	  Quote: 	
		   

 

 I have a couple of questions I hope you can help me with.

 

 I just finished all of the changes for the B model change and now it's time to start on regular construction again! I ran into a few small snags I hope you can give me some advise on.

 

 I have brass through the firewall threaded fittings for my 2 fuel lines going through the firewall. Someone at EAA told me to use aluminum fittings rather than the brass because they were lighter and safer. I can understand the lightness, but I don't understand why they would be safer. What are you guys using for through the firewall fittings for your fuel lines? I don't mind sacrificing weight for safety. I have seen rubber fuel lines with steel reinforcement on the outside in both a race car and in an RV6. What is the safest way to build a fuel system and what are the finest products I can buy made for safety?

 

 Tonight I fit the stab to the fuselage for the very first time! It was a great feeling to see the stab sitting there on the fuselage. I knew there would be a sizable gap between the fuselage skins and the bottom of the stab, but I didn't think it would be big enough to put my finger in there! What are you guys doing with that big open hole? Would it be worth it to build a fairing of some sort on the bottom of the stab? Is there a reason for the big gap?

 

 I am also ordering a new elevator for my plane from the factory, unless I can find a used or unbuilt one. There are 2 types. One with the trim tab cut into the elevator, and one with a full tab on the outside of the elevator. I saw both in Oshkosh and they both look OK for me, but which one is better? Which one is lighter?

 

 I am preparing a web page this week where you will be able to go and download pictures of the banquet and award ceremonies. I filmed the entire banquet and I still can't get over the incredible speech Paul Poberezny gave. I will have this available shortly for everyone.

 

 Thanks for any help you can give. It feels good to be working on something other than the retrofit!!!

 

 Joe in Oshkosh

 

 

 

 

 

 


	


-- 

Bryan Martin

N61BM, CH 601 XL, 

RAM Subaru, Stratus re-drive.

_________________
--
Bryan Martin
N61BM, CH 601 XL, Stratus Subaru.
do not archive.

jeffrey_davidson(at)earth
Guest

Posted: Wed Aug 24, 2011 3:44 pm Post subject: Just a couple of questions

I am certainly no expert, but here are a few things I did and learned along the way:

I have a leading edge fuel tanks only system.  No header tank.  I used the Zenith supplied 30R7 rubber fuel lines where the lines might move and aluminum tubing inside the fuselage and cabin where the lines were fixed in place.  The tanks overflows are not interconnected, so the selector AndAir valve has no "both" position.  I installed Facet pumps, 40105 I believe, next to both tanks.  After that per Chris Heintz' recommendation, are check valves to keep fuel from re-entering the tanks.  Lines from both tanks then run up to the selctor valve.  From there down to the Dynon fuel flow transducer down to the copper bulkhead fitting.  On the engine side the bulkhead fitting empties into the gascolator.  From there to the fuel pressure guage and then on to the engine driven pump on the 3300A.  

Here is what I think I learned putting this together:

1) Don't suck fuel, especially auto fuel!  Put the pumps where they will push the fuel.       

2) The 30R7 fuel lines are fine in areas that are subject to vibration.  Just use firesleeve over it in the engine compartment.

3) Putting the gascolator in the engine compartment makes it hard to get it away from the exhaust pipes should it drip fuel for some reason.

4) Yes, only one hole in the firewall is needed for fuel.

5) The pressure from the electric fuel pump and the engine fuel pump are not additive.  The pressure stays between the 1 and 3 PSI that the Bing float bowl likes.  So I run the electric pump on the active tank all the time.  

6) On the Zenith welded tanks, you still need to create the 45 degree angle into the relative wind on the tank overflow pipe.

I hope this helps. This setup got me to Oshkosh this year!

Jeff D. 

--

jeffrey_davidson(at)earth
Guest

Posted: Wed Aug 24, 2011 3:53 pm Post subject: Just a couple of questions

Joe,

For what it is worth, I choose the recessed trim tab on the elevator just so it wouldn't either catch someone as they walked by or get damaged somehow because it sticks out.  The recessed one works fine on my HD.  I have the non-recessed trim tab arrangement on the aileron.  If you are thinking of a trim tab there, I suggest you wait.  I don't use it at all.

Jeff D

--

mtherr(at)yahoo.com
Guest

Posted: Wed Aug 24, 2011 4:45 pm Post subject: Just a couple of questions

Jeff, when i tested check valves in line with fuel pumps, i found there would be much more back flow into the opposite tank with a check valve than without... So i decided to deinstall them.



Sent from my iPad



On Aug 24, 2011, at 7:40 PM, Jeff Davidson <jeffrey_davidson(at)earthlink.net> wrote:



 	  Quote: 	
		   

 

 ... installed Facet pumps, 40105 I believe, next to both tanks.  After that per Chris Heintz' recommendation, are check valves to keep fuel from re-entering the tanks.  ...

jeffrey_davidson(at)earth
Guest

Posted: Fri Aug 26, 2011 3:01 pm Post subject: Just a couple of questions

Michel,

I have check valves on both sides next to the tanks.  So the valve on the opposite tank stops the flow if the selector valve leaks a little.  The selector valve only allows flow from one side or the other at any one time as long as it is fully in the detent.  My Facet pumps are operated independently, usually one at a time as intended.  There is documentation that the Facet pumps do allow fuel flow in the backwards direction when not operating.  If anything, the check valves are overkill but Chris himself drew it up for me.  And Fred Hulen, or was it Hinde, anyway the fluid design engineer on this list agreed.  Anyway, it seems to work for me.

Jeff   

--

mtherr(at)yahoo.com
Guest

Posted: Sat Aug 27, 2011 3:31 am Post subject: Just a couple of questions

Jeff, i do not use a selector valve.   Iselect tanks by selecting the fuel pump to be activated.   My valves are for shutoff.    I found that the pump not in use will allow a bit of flow in the backward direction. However, i also found that with the ACS check valve, the backward flow will be more than twice as much with a check vqlve in place.   I think this might be because of the pulsating action of the pump and the sync of the check valve action with the one internal to the pump.



Sent from my iPad



On Aug 26, 2011, at 6:58 PM, Jeff Davidson <jeffrey_davidson(at)earthlink.net> wrote:



[quote] 

 

 Michel,

 I have check valves on both sides next to the tanks.  So the valve on the opposite tank stops the flow if the selector valve leaks a little.  The selector valve only allows flow from one side or the other at any one time as long as it is fully in the detent.  My Facet pumps are operated independently, usually one at a time as intended.  There is documentation that the Facet pumps do allow fuel flow in the backwards direction when not operating.  If anything, the check valves are overkill but Chris himself drew it up for me.  And Fred Hulen, or was it Hinde, anyway the fluid design engineer on this list agreed.  Anyway, it seems to work for me.

 Jeff   

 

 

 --

jeffrey_davidson(at)earth
Guest

Posted: Sat Aug 27, 2011 4:14 am Post subject: Just a couple of questions

Michel,

I understand.  I had already designed my system similar to that in the Piper Warrior that I learned to fly in before I learned about what is a simpler design without the selector valve.  I do still alternate the active pumps too but also must change the selector valve in coordination.  So the procedure for changing tanks is to check fuel pressure, turn on the opposite pump, move the selector, turn off the origonal pump, and check fuel pressure after the change.  I presume that your procedure involves shutting off the valve for the inactive tank.  That difference in design may account for the difference in the behavior of the check valve.  But yes, the Facet pumps do allow some flow back into the opposite tank.

Jeff

--

mtherr(at)yahoo.com
Guest

Posted: Sat Aug 27, 2011 5:02 am Post subject: Just a couple of questions

 

OK, I see...  I just found on my web site the information on the test I did back when I installed my fuel system: 

 

"Fuel pump check valve  test

I checked how much gas was flowing through the system in the  opposite tank.  Well, there is a leak.  The fuel pump has internal check valves,  but they are not perfect.  I tried putting a check valve in series with the fuel  pump and the result is worse!  Instead of about 0.5 to 0.8 liter per hour, I get  3 to 4 liter per hour of cross-transfer.  This may be explained by the fact that  two check valve in series somewhat cancel their capabilities (there is no flow  to push the ball or diaphragm in the check valve).  I removed the check valve I  put in there (and had to replace a segment of fuel line)."

 

On another note, I noticed it is tough to get to my web site as the Zenith Builder Ring link apparently highjack the web page.  I found that by cancelling the page load as soon as my page shows up allow it to be seen.  I would like to correct that, but I no longer have the software to update my site... when I have time, I'll try to resolve that.

 

----------------------------

Michel Therrien CH601-HD, C-GZGQ

  http://mthobby.pcperfect.com/ch601

  http://pages.infinit.net/mthobby

From: Jeff Davidson <jeffrey_davidson(at)earthlink.net>

To: zenith601-list(at)matronics.com

Sent: Saturday, August 27, 2011 8:11:49 AM

Subject: Re: Just a couple of questions



--> Zenith601-List message posted by: Jeff Davidson <jeffrey_davidson(at)earthlink.net (jeffrey_davidson(at)earthlink.net)>



Michel,

I understand.  I had already designed my system similar to that in the Piper Warrior that I learned to fly in before I learned about what is a simpler design without the  selector valve.  I do still alternate the active pumps too but also must change the selector valve in coordination.  So the procedure for changing tanks is to check fuel pressure, turn on the opposite pump, move the selector, turn off the origonal pump, and check fuel pressure after the change.  I presume that your procedure involves shutting off the valve for the inactive tank.  That difference in design may account for the difference in the behavior of the check valve.  But yes, the Facet pumps do allow some flow back into the opposite tank.

Jeff

--

bryanmmartin

Joined: 10 Jan 2006
Posts: 1018

Posted: Sat Aug 27, 2011 5:24 am Post subject: Just a couple of questions

Some Facet pumps have a built in check valve that still allows some back flow through them, this is by design. It is intended to allow the fuel lines downstream of the pump to depressurize after shut down. 



There are also Facet pumps that are designed to prevent any back flow at all. These are listed as having a built in anti-siphon valve or positive shut off.



Here is a link to the Facet- Purolator web page: http://tinyurl.com/252fhcb





-- 

Bryan Martin

N61BM, CH 601 XL, 

RAM Subaru, Stratus re-drive.

_________________
--
Bryan Martin
N61BM, CH 601 XL, Stratus Subaru.
do not archive.

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