Rethinking my gascolator

JimWoo50 · #1 07-08-2006, 05:47 PM

I have read various postings on the pros and cons of a gascolator and I am seriously thinking of omitting it. I can check for water through the wing drains and my fuel pickups have screens on them. It just seems like more of a hassle and extra weight than its worth. Besides I have owned a 172 for a long time and have never found anything in the bowl which leads me to believe that it is unnecessary. Opinions anyone?

OneTwoSierra · #2 07-08-2006, 06:02 PM

Just finished my first annual and had a a film/wad of lint in mine. I think they're a net plus, but others have omitted with no problem.

Captain_John · #3 07-08-2006, 06:27 PM

Brian, what was the lint and where did it come from? Also, what are you running for fuel filters?

I too am considering omitting the gascolator and was wondering if so, what filters to use in place of them.

Anyone???

CJ

sf3543 · #4 07-08-2006, 06:37 PM

My last planes, a Grumman TR2, RV6 and now RV8 did not have gascolators. I have never had a problem in about 1500 hours among them.
There are lots of opinions on whether or not you need one, but in my opinion, if you can't install it in a low point in the fuel system, where water would naturally settle in, they don't really provide anything except another failure point. If you have to have a filter, then put one in line, but even then, I have heard of several people who have had clogged or burst filters, causing additional problems. (I think the filter media was probably too fine in the clogged filter scenario.) On my fuel injected installation, I have a fuel filter placed just prior to the pump, so fuel gets filtered from both tanks. This is VAN's basic set up for FI set ups.
Install a gascolator if you feel you need to, or a filter if you want, but I would recommend that you stick with the recommendations from proven fuel systems. This is one place where I would not want to experiment.

gmcjetpilot · #5 07-09-2006, 02:02 AM

Quote:

Originally Posted by JimWoo50

I have read various postings on the pros and cons of a gascolator and I am seriously thinking of omitting it. Opinions anyone?

I vote for following the plans (I know call me crazy).

I have heard it all and think the firewall gascolator provides the largest catch basin for water and best chance to save the day, IF the day would ever need saving. The TRUTH is if no water or other contaminates are introduced into the fuel system than you don't need a filter of any kind.

The down side with just in-line filters is the volume of the SUMP or ability to hold larger amounts of water.

SO the winner is.... (drum roll)...... envelope please............ my opinion is the good old big fat gascolator on the fire wall provides the most ROBUST system for some serious contamination problem.

It is also STANDARD, common, universal, known, conventional, tried and true, blaaa blaaa blaaa. However all this conformity has MANY benefits. Any pilot will know how to pre-flight it. Almost every Piper and Cessna I flew has a FW gas bucket gunk catcher.

If you ever sell it and the airplane has a fuel related crash and you did not follow the "common wisdom" of the ages than you might open up a small liability door. Hey, you are not paranoid if they really are out to get you.

As you said you are going to check / sump the tanks every time, check the fuel caps don't leak, keep it out of the rain, assure good fuel it uploaded and so on. Hey it is experimental do what floats your boat. What are you saving? Cost, Weight, more better...

I played around with idea of deleting the gascolator with small gascolator's / sump's in the wing root, in-line filters and so on. I decided.........(drum roll)....... to go with the good OLD method of protecting the fuel supply, from water and other contaminates, the gascolator. I know, it's boring. I know it works. That is the best argument if you will.

I am opinionated and think the creativity should be left to your panel layout and paint scheme. Major systems like fuel should be kept simple and per plans.

Also consider maintenance of these in-line hidden filters. The firewall gascolator is there to see, touch and smell, not out of sight, out of mind.

IF YOU TAKE ON A ONE OF A KIND UNIQUE FUEL SYSTEM OF YOU OWN DESIGN, YOU BETTER KNOW WHAT YOU ARE DOING, TEST IT AND THINK OF EVERYTHING THAT MIGHT GO WRONG WITH IT, BECAUSE IT JUST MIGHT.

(I am not saying the FW GAS-CO is perfect, nothing is, but we know what we are dealing with.)

Serioulsy there are some rules of fuel system design you may want to research. I recall one is filters should need be course at first, and the fine filter'(s) are located down stream or last. Also the plane is ground tested by placing it in an extream climb attitude (which is hard to do since RV's climb steeply) and max flow rate is varified. I am no expert, but that is why I follow the plans.

That is why one BIG centrally located gascolator has stood the test of time, simple, robust and sized for the application. Start messing with small filters and small remote gascolators, you might be hurting your self? If you are smarter than do your thing.

The above are my opinions and do not necessarily express the views of this station, management or it's affiliates. I don't care what anyone else does BTW, and I try not to convince anyone, just stating my rational.

rv8ch · #6 07-09-2006, 02:27 AM

Quote:

Originally Posted by JimWoo50

I have read various postings on the pros and cons of a gascolator and I am seriously thinking of omitting it. I can check for water through the wing drains and my fuel pickups have screens on them. It just seems like more of a hassle and extra weight than its worth. ... Opinions anyone?

Opinions are easily found here, that's for sure!

You didn't mention if you are installing fuel injection or a carburator.

If you are building a tail dragger, the low point of the system will be your wing tanks, that's for sure.

Some (all?) FI suppliers do not recommend a gascolator. I'd check with them to get their opinion.

Here's a great article on fuel systems: http://www.rv8.ch/staticpages/index....30914230507849

gmcjetpilot · #7 07-09-2006, 05:18 AM

Quote:

Originally Posted by rv8ch

If you are building a tail dragger, the low point of the system will be your wing tanks, that's for sure.

I don't think it matters if it's tail dragger or not. The wing tank sumps tend to be the low spot regardless.

Here is the logic:

Clearly for pref-light the wing tanks are where water will most likely enter after you park it. However the gascolator check is basically from the last time you flew it. It is not likely water will get into the gascolator parked, unless fuel is running thru the system. Make sense?

It is about the things and stuff that gets caught AFTER it gets sucked out the tank. In a climb or descent the gascolator is high or low relative to the wing. The gascolator is just a large filter and a place to hold water.

This logic above is what makes the gascolator on the firewall, fairly close to the engine idea. It does not have to be the absolute bottom of the fuel system but close is good enough.

Also size does matter. A large bowl with some height allows water and sediment room to settle before trying to pass a screen or filter element. A little round in-line aluminum billet filter laying on its side may look cool but has little room to collect water or sediment.

Captain_John · #8 07-09-2006, 07:31 AM

According to Ken on Page 220 of the RVATOR, the gasco SHOULD be at the low point in the system and he goes on to say that this is difficult in a taildragger.

Also he hgoes on to say that vapor lock can be a problem as well. I am gleaning that this stems from the fact that we have tightly cowled ships and Ken says that a cooling tube leading to it should be considered.

I am still on the fence about this one.

Now, what about ceramic element filters? Should we use them in lieu of paper ones? You know, like the ones sold at hot rod shops...

CJ

rv8ch · #9 07-09-2006, 07:49 AM

Quote:

Originally Posted by Captain_John

Now, what about ceramic element filters? Should we use them in lieu of paper ones? You know, like the ones sold at hot rod shops...

I've never heard of ceramic filters. Do you have any pointers? I'm using a stainless steel 100 micron Aeromotive pre-filter, and a 10 micron cellulose (paper) filter after the fuel pumps. If I were doing it again, I'd look at the flowezy filters. http://www.FlowEzyFilters.com/

Dgamble · #10 07-09-2006, 08:03 AM

I just had what must be the six or seventh condition inspection on this airplane and found a small piece of aluminum caught in the gascolator filter, probably left over from the build.

I suppose it would have been caught at the final fuel filter too, but my GasCo is located such that it is far easier to get to, and has a more generously sized filter which would presumably be more resistant to blocking the fuel flow in the event of catching a relatively large piece of debris.