Gascolator and filter

[Dravenelle]

Hi

I need info with this...

I have a gascoltator on my plane..and do you use a filter if you have a gascolator ?

Dave

[rogerh12]

I myself have several fuel filters in my system, one of which is just before the carb in case something gets past the gassolator screen.
Roger

[jtpitkin06]

Dave,

Just a personal quirk... but when I have a question about how to put together an aircraft system I look to the certified aircraft manufacturers and how they have done it. I don't try to reinvent the Wright Flyer.

My fuel system has but a single filter. The gascolator. That's how they do it in most certified aircraft so it's good for me. The gascolator internal screen traps the junk and every time you pull the drain release on pre-flight it flushes the filter screen. Gascolators work and they have sufficient surface area on the internal screen to prevent fuel starvation if you get a tiny bit of dirt. You would have to encounter serious fuel contamination before one of these will get clogged.

It's my personal opinion that the small automotive inline filters have no place on an aircraft. I've had them stop the fuel flow on my cars, trucks, lawn mower, tractors, golf cart and a Miller Bobcat welder/generator. With that kind of tack record there's no way I'll put one on an airplane.

I think a good design is one with a low sump tank to trap any sediment. The Kitfox has just such a tank with the header mounted behind the seat. The quick drain valve on the bottom of the header is at the low part of the system to check for debris. The fuel to the engine comes from a slightly higher pick up point to prevent contaminates from going to the engine.

Gascolators are certainly more expensive than the cheap automotive inline filters, however, that's one area I will not try to save money.

One other thing about installation. Pace your gascolator where it is a bit higher than the bottom of the firewall. Use the type with a pull handle and a tube extension on the drain. Do not install any quick drain valve or fuel component protruding lower than the airframe. In the event of a forced landing in rough terrain the gear is likely to shear off and so will any exposed fuel drains. There's no sense in adding gasoline to the wreck site.

Hope this gives you some food for thought.

John Pitkin
Greenville, Texas

[kitfox2009]

Hi Dave
I have no filters in my system. Only the fine screen in the gascolator. In 200 hours I have had no issues. Actually, the inspector would not approve an "in line" filter anywhere in the system. Apparently problems have occurred with moisture swelling the membranes and restricting flow. I buy my fuel at a bulk dealer and store in a 45 gallon drum. I have a very fine filter cartridge and water separator on my hand pump. I also hanger the a/c.
Cheers
Don Model 5 Vixen 912UL.

[rogerh12]

FYI: If you have one of the Ellison Throttle Body Injector carbs, they have super small holes for the fuel (in order to atomize the fuel) and require a fuel filter with 70 micron or finer filtration (I use a large paper auto filter myself, if it expands, it still has good fuel flow in my experience.).
Hope this helps
Roger

[rogerh12]

I noticed Aeromotive makes a sweet replaceable FABRIC element fuel filter, with 10 microns of filtraton, but it's not cheap:

http://paceperformance.com/i-6486174...el-filter.html

[kitfox2009]

I also notice it states not for use with E85 or alcohol.

Cheers
Don

[t j]

Hi

I need info with this...

I have a gascoltator on my plane..and do you use a filter if you have a gascolator ?

Dave

Dave, make sure the screen in your gascolator meets the specifications needed for your engine and carb.

My two stroke Rotax installation manual says a 0.15 mm (150 microns) fuel filter is needed. I used the aircraft spruce gascolator with the 120 micron screen and no other filters in the fuel system. http://www.aircraftspruce.com/catalo...gascolator.php

[HighWing]

Wow, John, I don't know where you buy or store your gas, but none of these have ever happened to me and I am as old as dirt. I would be willing to wager that 80 to 90 percent of flying Kitfoxes have inline filters. Then keep in mind that the certified aircraft you refer to have either aluminum tanks or rubber bladders. I know of at least one reported instance when glass fibers from the wing tanks clogged a gascollator screen. And it was a s tricky diagnosis as, as you suggest, the fibers dropped from the screen, but were too long to exit the quick drain and were invisible on the bottom of the bowl. Then reassemble and over and over again.
For the sake of argument, I put 900 you're on a Model IV with the purelator glass filters and have them on my current project. Good thing they call these puppies experimental, I guess.

[szicree]

I know of at least one reported instance when glass fibers from the wing tanks clogged a gascollator screen. And it was a s tricky diagnosis as, as you suggest, the fibers dropped from the screen, but were too long to exit the quick drain and were invisible on the bottom of the bowl. Then reassemble and over and over again.

With no gascolator and just small inline filters wouldn't this have stopped things up just as well?