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New Header tank for the Avid


35 posts in this topic

Posted

Hello Group,

 

I bought a header tank with a little bit more capacity to increase my range, this one has about 15 liters (almost 4 gallons); and I will take the opportunity to replace all the fuel lines, as per inspector recommendation to teflon hose and/or aluminium pipe, I know it more expensive this way, however  I won´t have to deal with fuel lines anymore. Out of sight out of mind! (hopefully).

 

I bought all the fittings on ebay, from racing cars fuel lines, AN-6 and so forth. HOWEVER I came across a problem I had and solved in a very CRUDE way, I Don´t know what type of thread the female WING tank fitting is, I bought it from Brett 3 years ago, and forgot to ask, I placed a NPT 3/8 fitting and it always leaked; but I covered it all up with fuel/oil resistance silicone and work ok.

 

anybody know what type of thread this whole is?? is a 3/8 but BSP, UNF, ?????

 

Thanks in advance. 

dimi3

 

 

 

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Posted (edited)

All of the fittings for finger screens that I have seen are 3/8 male NPT, with a 1/4 female NPT hole in them.

However, I believe I have seen some Avid fittings which look smaller.

The 3/8 NPT is much larger than any of the other 3/8 fittings - probably about 3/4 inch diameter.  It is now listed as 3/8 MIT, or Male International (Thread, or Taper?) but I think it is the same as the old NPT.

Kitfox uses a Permatex 9AR sealant, and I think Leni posted the other sealant which works good, or maybe the other numbers for this same sealant. 

Sometimes the threads in the tanks need to be refreshed with an NPT tap, but use caution not to get them too large.

Hope this helps.

EDMO

Edited by Ed In Missouri

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Posted

Hey ED;

 

I will run a tab on it carefully, it must be debrief from fabrication that caused the problem in the first place,  i´m not using finger strainer, but I ordered one to install.

 

 

Regards

Dimi3

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Posted

I think the general attitude here is to use the finger strainer, and check it at least at condition inspection, or when needed.

EDMO

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Posted

Anyone know where to buy brass screen? I want to build some finger screens but all I can find online is bulk. Wonder if my local Ace Hardware would carry it.

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Posted

Hey guys,

We definitely want to use the finger strainer as they prevent the resin bits that our fiberglass fuel tanks make over time from entering the fuel lines and stopping the air conditioner! My finger strainers for sure saved my A$$! Bryce

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Posted (edited)

Joey,

     Where is it written that the screens have to be brass?  What is wrong with aluminum?  fuel lines are aluminum - sometimes.  Oh, I know - fittings are brass - screen is brass......aluminum fittings are lighter....

check Grainger?  BUT, is it really worth the time and effort when they don't cost much from Spruce?

Compared to your smartphone and other gadgets costs, they are almost like getting a free Obamaphone!  :lol:

EDMO

Edited by Ed In Missouri

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Posted

Dimi3 I would like to know where you bought the new tank, and the H x W x D of it in inches.  Would like to have one. Thanks Russ.

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Posted

Joey,

     Where is it written that the screens have to be brass?  What is wrong with aluminum?  fuel lines are aluminum - sometimes.  Oh, I know - fittings are brass - screen is brass......aluminum fittings are lighter....

check Grainger?  BUT, is it really worth the time and effort when they don't cost much from Spruce?

Compared to your smartphone and other gadgets costs, they are almost like getting a free Obamaphone!  :lol:

EDMO

 

The original screens were brass so they could be soldered to the fitting.. Aluminum dont solder into the brass fitting very well.

 

It was only a couple years ago that the conventional wisdom was to pull the screens and let the filters before the header tank that you can see trap the crap so you dont end up with a plugged screen and no way to check it or bypass it... cause when that happens, your options for landing get really limited depending on the phase of flight your in.

 

:BC:

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Posted

What filters before header tank?  I thought the fingerscreen was the only one.  Doug posted something some time ago that the fg fibers couldn't be seen in some other filter, and clogged his up.  Maybe fingerscreens should be made twice as long, to lower chances of clogging by 50%?  Maybe pull them more often?

Good subject for discussion.

EDMO

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Posted

I have a glass filter with changeable plastic screens in them before the header tank, then one after the header tank.  And a valve right above the filters.  I can shut the valve, pull the filter apart and clean the screens in a minute or two.  I clean them about every 20 hrs but only once have I found any fibers in them.  

 

:BC:

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Posted (edited)

Leni,

      Can you give the part number or where to get the kind of filters you use?  Some filters have paper in them and I understand that they are not the kind to use.

Got a photo?

Thanks,

EDMO

Edited by Ed In Missouri

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Posted

Ed,  I am using the same ones.  I believe they are Spectra.  I got them at the local Shucks Auto Parts but should be available at any similar auto parts store.

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Posted

Thanks Randy - Will check out the local auto stores for them.

EDMO

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Posted (edited)

Hey Guys;

 

I kind up screwed up in the tank measures, I`m struggling to fit it on the desired place, I should have make it narrower in one side by 2" or more and compensate in the other side. But I think I can manage, I one guy in England made it for me for about 200$;

 

I bought many AN-6 fittings on a racing store, MAN I went crazy here, like a kid in a candy store I couldn´t help it.... I just couldn´t stop buying things there... all fuel lines will be replaced either by aluminium or Teflon, so I don´t have to worry about fuel lines anymore (knock on wood).

 

other thing I found, after I ordered the finger I was installing  Paul´s new modified F7A in the controls I need it to replace a little bolt and digging in my boxes I found a brand new  fuel finger strainer from my old Volksplane project (DAM) I hate when this happens, I´ve been waiting for this tiny little piece more than a week to proceed with the fuel fixtures and I had it all along.

 

turned out the finger will screw nicely in the tank female 3/8 NPT hole, however I have a aluminium piece for the Teflon hoses (AN-4), same thing 3/8 npt 18tpi that doesn´t fit on the tank, thus the question earlier.... hmmmm.... see the pictures, they both check out with the thread gauge... anodized perhaps???

 

if you want to use the header tank drawing I suggest you check measures in your plane, don´t know what you guys have behind the passenger seat exactly, and take into consideration the rudder cable as well, which is a easy fix....

 

Regards

Dimi3

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Edited by Wolverine

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Posted

Thanks Leni,

     Going to put 3 of these on my Christmas wish list.  Appreciate the Summit site - copied it.

GF,

EDMO

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Posted

Wolverine,

      I would have to refer to my machinists manual - I thought NPT threads were odd numbered - like 1/4 - 27.

If the thread numbers are correct on the 3/8 NPT, then is it really tapered thread?  Can you use a micrometer or dial caliper to compare the two fittings?  That's all I can think of for now.

EDMO

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Posted

Dimi3, thanks for the measurements.  Russ.

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Posted

I took my finger strainer out and have a filter in the main line and a filter on each line before it goes into the carbs.

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Posted

Bandit,

       did you have stoppage with the finger strainer?

ED

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Posted

tank looks nice but on a different note, is there any provision for venting it back to one of the wing tanks, I didn't see a fitting for this in your picture.

 

-Robert-

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Posted

I was looking and the plans anywhere, with the original header, there are no vents, but I guess is not necessary to vent the header when is only 2 liter or so; this one is almost 15Lt, that´s why I have 2 connections on top, one for fuel flow AN6 and a smaller AN4 for vent. I thought about route it back to the tank, but I think is more complicated, I will make a independent vent, somehow routed it to the top of the fuselage.

 

I will post pictures once the installation is done... right now I´m having a Chritsmas RUSH!!

 

Regards

Dimi3

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Posted

I do not have vents on my header tank.  Only the two lines coming into the top of the tank from the wings.  When the system is empty, I will fill one tank first and it will vent to the empty tank.  When its full, the header will vent to which ever tank is lowest on fuel.  I have not had any issues in almost 400 hours on it.  I do fly with one tank shut off at times, and the fuel flow meter will tell me if I am starting to loose flow.  So far, I have never lost flow due to a tank venting issue.  I have clear (blue) lines on both tanks to the header so I can see if they are full of gas or if I have air on one line.  If I have air in a line, I just open the valve and fly a circle with the high wing being the side with air in the line.  It clears in a matter of seconds and all is good to go.

 

The only time I have had an issue with flue flow was when I had a paper screen filter get water logged and she didn't want to let gas through.  I kicked on the electric boost pump and it got me to a safe landing so I could swap out filters.

 

:BC:

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Posted

Hey Leni,

 

How big is your header tank and where do you have it located it? pics will be nice; the blue lines are not a choice for me, in somehow, my inspector don´t like it, and he demanded to replace them all...  I used to have them between the pump to the carb, and he wasn´t please with it.

 

Well is that is the case, I will put a plug in the AN4 then!!! no need to reinvent the wheel.....

 

regards

dimi3

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