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Gascolators between wing and fuselage

C

Clouddancer

Well Known Member
Has anyone tried to install gascolators between wing and fuselage, as some have done on RV-8's (Fernando Abasolo for ex.) or on RV-7's (Lorne Green, see http://picasaweb.google.com/lorne7a/NewAlbum091101711PM#)?

The point is, that the gap between the wing and the fuselage is narrower on the RV-4. An Andair gascolator should fit http://www.andair.co.uk/pdfs/GAS01.pdf , but the point will be, if I have enough place to check and clean the gascolator? Are there any gascolators around that are smaller, especially in diameter?

As a background information: I don't want to start a debate about gascolators or filters. Fact is that this placement would make the most sense for me. I want to use mogas, so I don't like the gascolator on the firewall (vapour lock). I don't like the gascolator to be in the cockpit (fuel smell) and I like the filtering system to be in front of the tank selector valve, which makes more sense to me in the case of a congestion.
 
tight fit

To install an andair gascolater in the gap would be a real tight fit,,,I'm not sure it could be done...that said, a firewall mount and a blast tube to cool it might be a better fit but you will still be vunerble to vaporlock when stopped for fuel on a hot day,,,,open the oil dipstick door and hot air escapes up and is replaced by cooler air from below..this is worth 2 cents
 
Moving my gascolators

I have seen this done before on a RV6 and this winter will be moving my gascolator from the firewall to wing root. Been using mogas in the left tank and when outside temperature over 90 I been getting vapor lock after landing taxiing to the ramp and suspect it coming from the gascolators being on the firewall. Now I switch to right tank about 5 miles out to run Avgas, which has been solving the vapor lock problem.
Squeak
 
Yes

I'm working on this now and feel it is do-able. I don't have all the answers but have seen it done before by someone on VAF.

I bought miniature shut off valves from Summit racing so that the gascolator bowl can be removed without having to drain the tank first. These will also go under the gap fairings.

Bevan
 
Gascolator

Andreas:
The minimum distance from exterior side wall (with bracket) to outside of the standard Andair gascolator is 72mm.
The distances in my pics show 90mm. I don't know what the 4 specs are but this should give you some perspective.
Regards.
 
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Thank you for your inputs. It looks as 72mm would be approx. the max. distance I have between the rib and the fuselage skin.

Bevan, which type of gascolater do you use? I would be very much interested to see a picture of the installation, once you have one at hand. Do you have to cut out a bit of the fuel tank skin that overlaps the rib?
 
I'm using an Andair in each wing root. I don't have a picture (yet), and it's not done yet. Only mock-ups so far. I've not been to the shop for a week or more but I'm pretty sure there's much more than 72 mm between the fuselage and the tank rib.

I don't anticipate having to cut any skin. Why and where?

Bevan
 
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My bad. I now see that you're building an RV4. There may well be less room there. I don't know. I'm building a 7. Send me a pm to keep in touch and I will try to get some measurements of the exact amount of space required.

Bevan
 
Will it fit? It will!

Last week, we mounted one wing to the fuselage, to take final measurements and to decide what kind of fuel filter we are going to install between the fuselage and the wing.
The inline filters would have been easy and straightforward to install, but we did not like the idea of taking apart the fuel lines each time we want to inspect and clean the filter.

What you see on the picture is a dummy for an Andair GAS375 gascolator (don?t laugh, even if it does not look exactly as the original, all the important dimensions are correct, and it?s much easier to imagine how everything comes in place). As you can see it?s really tight, but it will work! So we order two of them.
The left fitting you see in the picture is for the pitot air pressure. We might change the position of this one.

I will post a picture, once we finished the installation.

5547328374_51027c145e.jpg
 
Heresy

Leave it out. Use in-line filters. Unlikely to be in the lowest point in the fuel system anyway. (flame suit on)

LarryT
 
Gascolator needs a good grip to unscrew the retaining ring

I love the process of planning the systems on our airplane projects. Cool jig Andreas, and nice job getting to a solution. I considered your plan also, but the black plastic retaining ring on my Andair gascolator takes a full grip with the whole hand wrapped around it to unscrew. Once the retainer ring starts turning, it takes very little force to rotate. It's that first one-eighth of a turn that is stiff. I'm not sure if my unit is just a little tighter than average, but check it out and play around with it before you go permanent on it.

Thanks for sharing your thinking and planning process.
 
Andreas

Brian Vickers said:
I considered your plan also, but the black plastic retaining ring on my Andair gascolator takes a full grip with the whole hand wrapped around it to unscrew. Once the retainer ring starts turning, it takes very little force to rotate. It's that first one-eighth of a turn that is stiff. I'm not sure if my unit is just a little tighter than average, but check it out and play around with it before you go permanent on it.
Click to expand...

I think you can work around the threaded locking ring initial breakout force issue with a fabric strap wrench of some design. But, a potential problem lays waiting to be solved and that is this. On the top of the locking ring there are three locations where the ring is drilled to recieve at least one safetie wire. With limited access, do you have the room to apply the wire? One solution could be, (although not desirable) at your annuals, assuming you can get a wrench in there, simply remove the gascolator fittings and the gascolator itself from its attach bracket. Then you could inspect/clean the filter and reinstall.
Part of the fun of building is meeting the challenge and finding reasonable, intelligent and safe solutions to different problems....build on!
Regards
 
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Thanks for your inputs. I thought about the black locking ring. An idea was to manufacture a tool to unscrew the ring. But today I don't know how hard it is to break it loose. I will see in a few days when I get the gascolators... I think, I should be able to run the safety wire through the ring.
 
Andreas,

You might be able to get a mini oil filter wrench on the gascolator to remove it if its too tight to do by hand. I think my motorbike oil filter wrench would fit my andair gascolator.

Bevan
 
This is what I have done on my RV6.

http://s456.photobucket.com/albums/qq282/whittfic/?action=view&current=DSC02753a.jpg

Not quite the same set-up as yours but might provide you with some inspiration?? Fuel feed goes from the tanks back to the fuel selector, then to the fuel pump, gascolator, back inside to the firewall, then to the engine pump. Extension to be added to the drain for easier access through a hole in the wing root cover.

It's tight but workable. Aircraft isn't flying yet so not suggesting it is the perfect answer

Clive Whittfield
 
Servicing gascolators in wing root

To you guys who installed 2 gascolators in the wing roots, how do you shut off the gas to service them? Did you install another valve between the gascolator and the tank?
 
Ron RV8 said:
To you guys who installed 2 gascolators in the wing roots, how do you shut off the gas to service them? Did you install another valve between the gascolator and the tank?
Click to expand...

Ron, unless the goal is to increase leaks, weight and cost why would you do that? What are you trying to achieve?
 
Gascolators in wing roots

I am trying to comply with Canada's MDRA requirement to install a "gascolator located at the lowest point in the fuel system". Yes I know the tank drains are lower but I am trying to comply as much as I can firewall forward...

In the RV-8 the lower engine mounts interfere with mounting the gascolator towards the sides of the firewall. This leaves an area between the exhaust pipes and behind the mufflers which may not be the best choice from a fire or vapour lock perspective.

I'd rather not use two gascolators, but thought it was worth looking at what others had done... If I go that way, since they would be ahead of my Andair fuel valve, I would need some sort of small valves to allow servicing.

Thanks for any advice

IMG_4841.jpg


IMG_4843.jpg


IMG_4863.jpg
 
Are Gvt regulation...........

Why not put the gascolator forward of the fuel valve inside the fuselage, and if you want the springy thing easily accesible just put an extender pipe between the gascolator and the springy thing on the outside of the fuse?
 
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