Relocate Fuel Valve

I am planning to have a center console in my 7a.

If I were to be using SS fuel lines and an Andair Fuel Valve, Can anyone see any foreseeable issues with purchasing lines a little longer and mounting the Fuel Valve higher, instead of using the grossly overpriced extension parts and mounting the valve in the stock location?

The new location will only be about 4-5 inches higher.

Personally, it seems there would be a higher risk with the multiple joints and angles of the extension then the simply longer fuel lines.

either way, thanks for the thoughts

I'm not exactly sure what you mean when you talk about mounting the valve higher, but I will suggest you consider the impact relocating the valve will have on your ability to climb down into the footwell for maintenance without needing chiropractic help afterwards.

Rick,

I have the center console in my RV-7. I built my own extension and used the stock Van's fuel selector in it's original location. All it takes to make your own extension is a bandsaw, a drill, an 8-32 tap, and about an hour. Here's the parts to order from McMaster-Carr...

6445K1
Low-Speed Pin-and-Block Universal Joint 1/4" Bore Diameter, 9/16" Bore Depth
In stock at $12.30 Each

6412K11
Steel One-Piece Set-Screw Coupling 1/4" Bore, 3/4" Length, 1/2" OD, without Keyway
In stock at $5.58 Each

1327K66
Miniature 12L14 Drive Steel Shaft 1/4" OD, 12" Length
In stock at $6.58 Each

I also got the pretty fuel valve selector and backplate - I think from Avery???

One thing to consider is that the higher you mount the valve, the more of a "trap" you create in the fuel system - not a great thing when sucking fuel with a motor-mounted pump.

Ironflight said:

One thing to consider is that the higher you mount the valve, the more of a "trap" you create in th fuel system - not a great thing when sucking fuel with a motor-mounted pump.

Click to expand...

Trap? Is this caused by air? Not quite sure what that is.

Sorry, my engine knowledge, at least at this point is limited

If by center console you mean a vertical structure at the front of the seats and between them...I wish I did not have one. Sometimes I want to move my legs to the right to stretch on long trips.

What you are proposing is similar to mine "I think"



I do not know precisely what you are thinking of doing. I took this photo while I was working on modifying the panel but it does show the center console and the two regular Van's fuel valves mounted on a plane level with the highese level of the seat structure/wing spar. Works fine for me. The fwd valve is for the tip tanks and the aft valve is the master. Inside the console are four fuel filters, the aux. fuel pump, the primer solenoid, the two fuel valves, the aux. fuel pump toggle switch, the primer push button momentary switch, all wiring routing aft of the spar including the coaxes, a "cigarette ligher" power outlet and the pitch trim control cable.

Bob Axsom

I had the same console as Grumpy in my -7 and like him made my own extension. It has been a few years and my plane is long sold but from what I remember I used two universal joints, spring pins, and a short length of steel dowel. I ordered the joints and spring pins from McMaster Carr and the dowel came from the aviation isle at H.Depot. I looked for pictures but for some reason I don't have any of the extension.

The valve is mounted in its original planned spot. The first joint mounts directly to the fuel valve using a spring pin. Then the shaft connected to that joint and one at the top, again using spring pins to attach them. From the top joint a short shaft, one end in the joint the other end sticks up through the console and the valve lever is attached to that. If I recall there was something with the angles needed which required two joints instead of one but one is certainly better if it works for you.

I was thinking of something similar to Scott Stewart's there.

But instead of the extension, the entire fuel valve is bolted to the console. With using flexible lines, in the rare event needed, you should be able to disconnect the valve from the console with ease.

Rick,
If you are interested I will be selling the exact same Center console Dakota Hawk has but with a Andair Fuel Selector with extension in a few months. I Have the console partially assembled and the hole for the Fuel selector is already drilled, I have not cut the extension at all yet. I decided to go a different route, The only reason it is not for sale right now is I am about 10,000 miles away from my hanger and won't be back till the beginning of July. If you are interested let me know and I will get it to you as soon as I get back, If not I'm hoping there is someone else out there who will want it since Aircraftextras.com is no longer making them. Let me know and I can get you some pictures if you are interested.

-david

FresnoR said:

But instead of the extension, the entire fuel valve is bolted to the console. With using flexible lines, in the rare event needed, you should be able to disconnect the valve from the console with ease.

Click to expand...

First off, there is not enough space inside the console itself to mount the fuel selector. The wide top you see is much larger than the actual width of the sides under it. The top overhangs the sides for a larger surface area. Second, the fuel valve really should be mounted low. The engineers among the group could probably give the most accurate answer as to why.

I can see why you would be looking at the simplicity of mounting the fuel valve directly to the center console, but there are a couple of downsides that I would be concerned about...

First, as you said, you would have to disconnect the flexible fuel lines to move the center console. Every time you open the fuel system, you're open to the possibility of fuel leaking into the cockpit. Making sure that the system is completely fuel-tight after reinstallation would be a MAJOR concern, since you're talking about fuel lines in the cockpit.

Second, as IronFlight mentioned, you're creating an air trap in the suction side of the fuel pump system. If there's any air sucked into the system (ie you run a tank dry prior to swapping tanks) you now have an air bubble that the fuel pump will have to overcome to get fuel moving again!

On the other hand, if you install the fuel valve per design and add the handle extension, then all it takes to move the center console is loosening a simple set-screw on the extension. No need to crack the fuel lines for routine work.

Just so you understand - it's easier to work under the panel if the center console is out of the way, but the throttle/prop/mixture cables are fairly difficult to remove, so usually I just move the center console off to the side with cables still attached when I'm under the panel.

Fuel valve

I built a center console in my 9A and I would suggest staying with the standard fuel valve location and using an extension shaft. Having just finished my condition inspection I had to remove my center console to do some work and look at everything, I also replaced the U joint that I was using for the extension shaft with a better one. If I had the fuel valve up there I would have had to open the fuel system lines to remove the console, during the inspection, which is not a good idea if you don't have to. Also in my case I have the Throttle and mix levers in the console behind the fuel valve selector, and the cables go on each side of the extension shaft. I am not sure they would clear the valve if it were up there plus you are adding extra line possible flex and movement into a item that for saftey you want to be very solid and not leak. I would stay with the Vans suggested location and use the extension shaft, mine has worked great like that for the 4 years since first flight. Thats my two cents, for what its worth.. good luck with it what ever you decide

WatkinsT1 said:

I have the Throttle and mix levers in the console behind the fuel valve selector, and the cables go on each side of the extension shaft.

Click to expand...

^I didn't think about the throttle cables, that is a good point.^


However, with flexible lines and the Andair valve, I do not think I would have to disconnect any fuel lines, as the valve mounts with three screws and then can be moved out of the way with the lines still attached, especially if the lines have the slack from the extra length.

The possibility of air in the line is concerning, does anyone know if the Piper Tomahawk does something special to alleviate this? The fuel selector valve on that aircraft is located between the throttle and mixture.


Now, I do not want this set up, just referencing the elevated selector valve.


I could be wrong here though, obviously I have not installed anything yet so do not know from experience.

Rick, I question the benefit of having the fuel valve mounted directly to the center console. Although you can remove the fuel valve fairly easily, you still have the problem of the ***very crowded*** area under the console - a minimum of three fuel lines and throttle/prop/mixture cables all trying to use the same space.

Since the control cables are difficult to remove, the center console isn't going to be removed very often (if ever!) and there's really no benefit that I can discern for putting the fuel valve up high.

You could air lock your fuel pump.

I.e the slug of air could could get drawn into the electric pump and thence it will likely stop pumping.

Keep it low and keep it flooded.

Frank

I can't believe I had these pictures but hopefully they give you an idea of how little space there is inside the console to mount the valve. The first shot looks up and forward. The second shot looks in from the front. The clecos should give you some perspective on the width of the console. I seriously doubt you could fit the fuel valve in there without bumping out the sides and with the console already killing your leg space that would not be a good idea.