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Gascolator placement

hcccs

Well Known Member
A guy in Germany, Dirk Schlichtenhorst (RV8R.DE), has placed his gascolator inside the cockpit beneath the floorboard as seen in the picture. Being an RV-4 builder I found this solution very appealing since room on the firewall is somewhat problematic. I have mailed him and asked him how he drains it but I haven't had any reply so far. Is it OK to place it like this?
 
Hans, I did the same as Hans though not knowingly. See it here.

I view it as a filter, not a gascolator (if you view the difference as being a water trap.)

I talked to Ken at VANS wayback about filters, and he said that in an RV you would find any water at the main wing drains, not in the gascolator. That made complete sense to me. So once you accept that point, you are only really trying to filter the fuel. The Andair unit does a good job at that also.

What I did not want was a fuel cooking pot on the firewall. This approach simplified everything.

I only drain it very occasionally in all honesty and I just use a wide glass jar and a finger. I have never had a problem. I do the wing drains every time I pull it out of the hanger and have once or twice found a bead of water there after washing it.

After about 70 hours I took it to bits but there was almost no dirt in it either. I guess I get supplied with clean fuel.
 
I also did something quite similar in my RV4 without knowing it. I placed two gascolators in the outer floorboard compartments (one for each tank). They are located such that the drain protrudes through the floorboard and can be drained preflight. As noted, I rarely find anything in them, more often a few drops of water in the wing tank drains. I have taken them apart once to clean - it is difficult to not make a mess and that is the downside of this placement!

Best regards,
Steve H.
N144SH
 
In line filter

You can also try an in-line filter. Aircraft Spruce sells them, as well as most of the auto parts supply stores. They often come with the AN fittings already installed. I agree with Steve - it's working more as a filter anyway!.

Rick
 
My -4 also has the gascolator mounted inside of the firewall. There is a small piece of tubing that goes through a small hole in the bottom skin so that it can be drained from outside during preflight (as long as the fuel pump is on to supply pressure.)
 
Nomex in place. Flame away!

I have found that the best location for a gascolator is on a dusty shelf at the back of my hangar right next to the magnetos, vacuum pump and mechanical gyros, far, far away from my airplane. There is no way to mount a gascolator lower than the fuel tank drains on taildragging RV, so they are useless for collecting water. A filter is all you need.

Can't say the same for a tricycle gear RV. Maybe the bottom of the firewall is lower than the fuel drains. But then my nosewheel is also on a dusty shelf at the back of the hangar with the magnetos, vacuum pump, etc. ;)
 
But the point of the gascolator isn't that it catches water while it's sitting on the ground. It catches water as it fuel flows, and traps it while still allowing fuel to flow. 99.99% of the time this is transparent, but a filter is completely useless for this.
 
But the point of the gascolator isn't that it catches water while it's sitting on the ground. It catches water as it fuel flows, and traps it while still allowing fuel to flow. 99.99% of the time this is transparent, but a filter is completely useless for this.

That may be true, however I have never found water in a gascolator after a flight (and I have checked). Fuel injected engines handle water much better than carburetors so gasclators are not recommended. (Oh, did I mention that my carburetor is also sitting on that dusty shelf at the back of the hangar!) ;)
 
In Canada we have to use a gascolator. On all my airplanes I have mounted it in the stick bay, just aft of the #2 bulkhead and below the fuel selector. My airplanes are not left outside and in 1500 hours I have only rarely seen drops of water, from the tanks or the gascolator.
I believe that gascolators have been given a bad rap due to how crude and "garden tractor like" they used to be. The Andair unit, and the blue model offered by ACS and Van's are quality units. I sump not only for water but to see if there are any other contaminates in the fuel system. How do you sump an inline filter? How do you know if there is material building up in the inline filter? A gascolator lets you "look" at the cleanliness of your fuel supply before every flight. Have I found much in 14 years of RV/rocket flight? No, but that is more a function of how clean aviation fuel is at the locations where I have stopped for fuel. Years ago when flying a Citabria, which was burning auto fuel, I one time sumped the tanks and gascolator and was amazed at how much water I found. A year of flying, nothing every time, and then samples that had more rusty water then fuel! The auto fuel was purchased at the same location every time.
The inline filters that have come with some of my fuel systems are not sitting on the shelf, they have been sold!
 
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Today I just plumbed my gascolator in the stick bay. Very easy and straightforward however I did not complete the installation because the eight little allen screws (4 a side) did not come with the Andair gascolator I bought from A/C Spruce. Can those you that bought an Andair confirm that those allen screws should have been present?
Also, what size grommet did you guys use to stick the drains through the belly skin?
 
Keep it to proven designs

When it comes to fuel systems, I think it's wise to keep it as close as possible to Van's drawings and to proven designs - because of the reasons some of you have described.
I wanted to have the gasculator in front of the firewall, in a place where it is easy to drain and as far as possible from the exhaust pipes – and it is not easy to do on an RV-4. After much thought I came to this design. It has the advantage that the AN-fittings to the tube is sitting on the same piece and it can not be any vibrations between them.

I made two pieces so I have one for sale. it is sawn into shape, but needs to be processed and drilled...

Gasculator_1.jpg


Gasculator_2.jpg


Gasculator_3.jpg


Gasculator_4.jpg
 
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That may be true, however I have never found water in a gascolator after a flight (and I have checked). Fuel injected engines handle water much better than carburetors so gasclators are not recommended. (Oh, did I mention that my carburetor is also sitting on that dusty shelf at the back of the hangar!) ;)


I have.

The only certfied airplane I know of that doesn't have a gascolator is the Grumman AA5, which is carb'd. I don't know where you get that gascolators are not recommended for FI systems. Heck, even twin cessnas and stuff have them!
 
I have.

The only certfied airplane I know of that doesn't have a gascolator is the Grumman AA5, which is carb'd. I don't know where you get that gascolators are not recommended for FI systems. Heck, even twin cessnas and stuff have them!

Let me be more specific. Don Rivera of Airflow Performance recommends the use of a filter vice a gascolator with their FI systems. I can't speak for the rest of the industry and it was wrong of me to generalize. Sorry. :(
 
Took it off my RV-4. Utterly useless. Firewall mount NOT the low point in the fuel system. Replaced with a filter...
 
Filter is my choice

Took it off my RV-4. Utterly useless. Firewall mount NOT the low point in the fuel system. Replaced with a filter...

I've now decided to use a filter instead of a gascolator. If anyone is interested in a brand new VANs gascolator - I have one for sale.
 
Interferes with Vetterman Exaust

I tried to do mine the same as Thomas J and others that position the unit directly forward of the lower transverse engine mount member.

The Vetterman 4 pipe install has a strap between the pipes that is parallel with the lower member of the fire wall and would be smack bang right where the middle of the gascolator is in this configuration. Moving it forward and clipping it to the engine mount seems messy and ponderous. It would require a flexible hose to get from the fire wall to the gascolator.

Also I am not sure it is permissible to have aluminum fuel line forward of the fire wall - maybe it is ok if you use fire sleeve ?

Maybe the best option is to place it behind the firewall. Not another redesign!!

Has anyone put a gascolator forward of the firewall AND installed the exhaust as per Vetterman plans ? :confused:

UPDATE: I have cobbled together a firewall forward install and am not happy with it at all.

I have written it up in detail on http://rv-4builder.blogspot.com.au/2013/01/gascolator-where-to-moiunt-it.html Here are the two most informative pictures.

moregascolator+001.JPG


gascolator+003.JPG
 
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Solved !

Have gone the same way as other guys here and installed it in the battery bay. A far better solution and I am delighted with the results.

gascolatorfinal.jpg
 
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