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Wing Root Filter Mod

JDA_BTR

Well Known Member
I have the Aircraft Specialty wing root filter mod kit in my hands and the quality is excellent. I have some questions and am looking for feedback from anyone who has it installed already.

The Holley filter supplied is a 40micron unit, and on the package it says it is suitable for after-pump use. Their package says there is a 100micron unit suitable for before the pump. Perhaps in our application it isn't a factor.

There are posts on here about reduction in head pressure to the fuel pump inlet as a result of the 90 degree pieces in the setup (3 of them).

If the inlet would vapor lock in the heat of summer due to the bends is discussed elsewhere on here as well.

So if you have installed it, what tests have you run and how is it working for you?
I really want to get the filter out of the tunnel because then I could just scope the tunnel/pump for problems and not pull apart my lower panel without a pump failure.
 
I have been flying this setup for a few weeks now. I know they did an in house flow test and found negligible reduction from the bends in the flow, I'm sure Steve or Tom can answer that more accurately. I replaced my pump as well with the AFP and did a flow test with fuel and got 60+ GPM rate measured just prior to the red cube firewall fwd.
 
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If you're using gerotor type EFI pumps, 100 microns is too large to protect it.

Too many 90 degree fitting prior to the pump can induce vapor lock under hot and high conditions, especially with mogas. More gentle 90 deg tubing bends are usually a better idea.
 
When we were thinking about the root filter install, we were also working on the SDS injection conversion for the RV14. Ross supplies Holley filters with his kits #'s 162-562 and 162-563 that just happen to be 40 micron each. The 563 was intended to be the pre filter in his install, but for the root install, they were just physically too big. BUT the 562 filters would work and they had the same micron rating. After discussing it with Ross, we decided to go with that.

Oh--and we did our own flow test. Not as elaborate as Don's flow tester (!) but pretty accurate. Thats not why we bought the testers, but it worked for the purpose.

Tom
 
Please post some pictures. Thank you!

Greg Novotny
RV-14a N14ZP
Tacoma Narrows, WA:
320 hours
Dues paid graciously:D
 
I did it to get the fuel filter out of the tunnel. I won’t have to take apart my center console and breakers again unless my fuel pump dies.
 
There is also a redundancy benefit in that you are not sending all of your fuel feed through a single tiny filter should it get clogged somehow. The 2 filters add complexity but also redundancy.


Is there a reason to convert to this kit if I am not doing EFI?
 
Wing Root Fuel Hook-up

I just test fit everything from TS Flightlines in my wing root for the pre-filter to the SDS EFII. Couldn't be happier with the fit up and the support from both Tom and Steve. You will note one screw that will be part of the lower wing root cover is used to hold the Adel clamp. I just used a longer screw and am adding a lock nut to it. I have not ran the engine yet but have a high confidence in what I see and in what I am hearing from other tests. I'll add to the post when I run the fuel flow test.
 

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I just test fit everything from TS Flightlines in my wing root for the pre-filter to the SDS EFII. Couldn't be happier with the fit up and the support from both Tom and Steve. You will note one screw that will be part of the lower wing root cover is used to hold the Adel clamp. I just used a longer screw and am adding a lock nut to it. I have not ran the engine yet but have a high confidence in what I see and in what I am hearing from other tests. I'll add to the post when I run the fuel flow test.

Thanks!!!! This has become one of our more popular packages for the RV-14. Glad you like it!!!! It's standard on all of our SDS and EFII installations and it is optional with our standard cabin fuel plumbing kits.

With this package, builders can delete the Andair Filter with their kit order, and they won't need the two rigid tubes that go from the fuselage to the wings. The credits for these two items bring the overall exchange cost down and you gain dual filter redundancy as well as an easier system to service.

Happy Building,
Steve
 
Great kit

Just finished the install of the root kit. Like all of the products I’ve gotten from AS, the kit is very high quality and went in easily and cleanly. Support from Steve was outstanding.

I hope Van’s considers making these wing root filters standard equipment. Given the mess that will certainly result from changing out a fuel filter full of Avgas while located in the stock center tunnel location, I’m concerned that pilots will avoid the task. The wing root location makes filter change out very clean and straightforward.
 
This is a nice installation. I wonder if a couple of bent hard lines might eliminate the three 90 degree elbows in the installation.
Also, on my 14, I cut the wing root faring off under the wing, about 10 to 12” forward of the aft bottom edge adding a tab to the forward edge of the cut faring and adding some extra plate nuts, meant that you could easily service this area without removing the whole faring. Not only faster to service, but greatly reduces the chance of scratching paint removing the whole faring.
Any time you can make something easier to service increases the odds that it actually gets looked at.
 
re Chattanooga upfit

I also installed the wing root filter kits an took out the fuel filter at the pump. It is a nice upgrade option.

From the pic, it appears that you added a bushing spacer to heighten the C-clamp attachment at the filter to 'straighten' out its alignment to the fuselage fairing mounting angle; I did the same thing.

I also did that on the shutoff valve side because the fuel hose loop appeared to be getting too close to the inside face of the bottom wing root fairing.

I made/cut the bushing spacers from some aluminum tubing, the filter side was slightly longer than the filter side (filter side about 3/16" long, shutoff side about 1/4" long), with a washer on the top end of the spacer bushing - no washer on the bottom end because it is a counter sunk nutplate.

Consider if you have not attached the wings to the fuselage - wait until you have the wings installed. I installed the filters on the wings before I had attached wings to the fuselage. When I was attaching the wings I found that I had to remove the fuselage filter side to provide clearance for the insertion of the fuselage side lower spar attach bolts.
 
Tom---We 'could' make some rigid tubes for this, by moving the filter aft and shortening the hose. While it seems easier, it is actually harder because of the tight flare to bend centerline from the fuselage to the filter. Yes we could extend it, but that would also close the bend radius of the hose. We did our own flow test on the 90* fittings versus straights and found a negligable difference. (Granted our flow test equipment isnt as good as Don's , but it served the purpose!). And it just so happened that with off the shelf fittings, things aligned themselves nicely.

Glen---we looked at doing the Aerolabs in the tunnel area like you did. I wasnt fond of exhaust blowing in the area of the drain. Maybe it would, maybe not. Also, as we found in doing our other kits, precisely locating the gascolator is imperative since you have either short hoses or rigid tubes, and its critical for the rigid tubes. So a precise locating template would be needed. Not that its any more trouble, but is does take time. WE are/have been playing with a Aerolabs install in the roots, but other things have had my attention lately. (Osh 2021)

Tom
 
Thanks!!!! This has become one of our more popular packages for the RV-14. Glad you like it!!!! It's standard on all of our SDS and EFII installations and it is optional with our standard cabin fuel plumbing kits.

With this package, builders can delete the Andair Filter with their kit order, and they won't need the two rigid tubes that go from the fuselage to the wings. The credits for these two items bring the overall exchange cost down and you gain dual filter redundancy as well as an easier system to service.

Happy Building,
Steve


Hi Steve - I just installed the Retrofit version of your wing root fuel filter kit in a -flying RV-14A. Very straightforward install, and it feels rock-solid (no movement once adel clamps are tightened).

I have one question: these filters don't appear to be serviceable; are you recommending that we replace the Holley 162-562 filters at each condition inspection? Or, is there an easy way to clean the filters?

Thanks,
Alex
 
Alex this is Tom. The Holley filters ARE serviceable, just unscrew the end, and the filter comes out.
Tom
 
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