Van's Air Force
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Gascolator
- Thread starter Ron B.
- Start date
Tom Martin
Well Known Member
Ron
Not there yet but it will be firewall mounted, likely low on the the right side. In anticipation of this I omitted the supplied cabin fuel filter. It is an odd little assembly and it is not going to easy to service. Service will require removal from the aircraft. There is no way to inspect this filter for blockage without removal. If it plugs you lose both tanks!
As for gascolators, my preference is the Van's blue unit. I currently have an Andair unit in my rocket and have found it not worth the extra $.
Gascolators are used in almost all certified aircraft. Although they have some limitations in RVs, ie not the lowest spot in the system, they provide a method of sampling which inline filters do not.
Not there yet but it will be firewall mounted, likely low on the the right side. In anticipation of this I omitted the supplied cabin fuel filter. It is an odd little assembly and it is not going to easy to service. Service will require removal from the aircraft. There is no way to inspect this filter for blockage without removal. If it plugs you lose both tanks!
As for gascolators, my preference is the Van's blue unit. I currently have an Andair unit in my rocket and have found it not worth the extra $.
Gascolators are used in almost all certified aircraft. Although they have some limitations in RVs, ie not the lowest spot in the system, they provide a method of sampling which inline filters do not.
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The inline filter has more square inches of filter area than any of the gascolators do so any contamination issue that will be a problem for the in-line filter, will likely be an even bigger problem for the gascolator.
There are positives and negatives to both filtering methods...
A gascolator induces more heat exposure on the fuel system, and depending on the installation can induce more risk of system breach in a crash, but it is easier to service.
The inline method reduces heat exposure and provides filtration upstream of all pumps and flow sensors, but it is more challenging to service (though once you learn to shut the engine down by starving with the fuel valve it is no big deal).
There are positives and negatives to both filtering methods...
A gascolator induces more heat exposure on the fuel system, and depending on the installation can induce more risk of system breach in a crash, but it is easier to service.
The inline method reduces heat exposure and provides filtration upstream of all pumps and flow sensors, but it is more challenging to service (though once you learn to shut the engine down by starving with the fuel valve it is no big deal).
Tom Martin
Well Known Member
Scott
I totally agree with you regarding the heat exposure of having the gascolator firewall forward. In my current plane and other RVs and rockets I have mounted the unit aft of the firewall and in some cased provided a nice access door in the fuselage bottom. However the RV14 has that really nice stainless steel cooling air exhaust tunnel and it complicates a centreline gascolator installation. Putting it off to either side would just make a nice simple system too complicated.
Thus, for simplicity sake, firewall forward makes sense here and a cooling blast tube could be added if required.
I totally agree with you regarding the heat exposure of having the gascolator firewall forward. In my current plane and other RVs and rockets I have mounted the unit aft of the firewall and in some cased provided a nice access door in the fuselage bottom. However the RV14 has that really nice stainless steel cooling air exhaust tunnel and it complicates a centreline gascolator installation. Putting it off to either side would just make a nice simple system too complicated.
Thus, for simplicity sake, firewall forward makes sense here and a cooling blast tube could be added if required.
Tom Martin
Well Known Member
In over 20 years of RV types finding any water is a rare event. When it happens I typically find it in the wing sumps, which are the low point; at least in a tail dragger it is. The amounts I am talking about are a few small drops of water. I have also found a drops of water in the gascolator even though it is not the low point in the system. Finding anything is a bit of a surprise, and I think this demonstrates how good the quality of US and Canadian 100LL is.
The only time I have ever found significant water was in my Citabria 25 years ago when I was burning car gas. That ended the use of car gas in airplanes for me!!
The only time I have ever found significant water was in my Citabria 25 years ago when I was burning car gas. That ended the use of car gas in airplanes for me!!
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gascolator
glad to hear it's so rare.
I do remember, several years ago, gassing up from a fuel truck on a rainy, slushy winter day in Idaho. Later, when I pulled the sump drain on the gascolator in Missoula the water beaded up on the ground, and we must have taken a couple of cups of water from the wing and gascolator. Don't know how the engine stayed running, but for years after that I sumped the drain whenever I gassed up
glad to hear it's so rare.
I do remember, several years ago, gassing up from a fuel truck on a rainy, slushy winter day in Idaho. Later, when I pulled the sump drain on the gascolator in Missoula the water beaded up on the ground, and we must have taken a couple of cups of water from the wing and gascolator. Don't know how the engine stayed running, but for years after that I sumped the drain whenever I gassed up
Under the Wing Root Fairings
On some RV's the wing root, allows space for one andair gascolator per side, with the use of flex lines. This provides a cool location, with ease of sampling prior to flight. Also on the plus side is that either unit could block and allow you to feed from the other tank. Somebody more gifted than I with searching can find the threads and photos of some of the wing root gascolator installs.
On some RV's the wing root, allows space for one andair gascolator per side, with the use of flex lines. This provides a cool location, with ease of sampling prior to flight. Also on the plus side is that either unit could block and allow you to feed from the other tank. Somebody more gifted than I with searching can find the threads and photos of some of the wing root gascolator installs.
I do not think so but I wish they did as it's a requirement here in Canada.
A bit of heat
http://www.vansairforce.com/community/showthread.php?t=60961&highlight=Gascolator+Wing+Roots&page=2
Look for cloud dancers post about mid page on Page#2 ( post #15)
If you search the other specific RV models forums for "Gascolators in Wing Roots" you may find photos of finished installs. There have been some very neat and clean and serviceable installations posted.
Depending on where and how cold you plan on flying..... a bit of heat is not a bad thing. For example, ice crystals can form in LL100 if it is cold enough and those can block a fine enough mesh filter. A gascolator on the firewall can be a lifesaver if ever you did have this situation present itself vs blocked flow if in the wing roots. If a sumer only machine, I am all for the wing root location. You can sample the wing sump drains and the gascolator quick drains with one squat per side.
Some homebuilts have header tanks inside the firewall. The heat muff and cockpitt heat keeps the fuel nice and warm if flying in serious cold temps -20C and colder.
Best of Luck
http://www.vansairforce.com/community/showthread.php?t=60961&highlight=Gascolator+Wing+Roots&page=2
Look for cloud dancers post about mid page on Page#2 ( post #15)
If you search the other specific RV models forums for "Gascolators in Wing Roots" you may find photos of finished installs. There have been some very neat and clean and serviceable installations posted.
Depending on where and how cold you plan on flying..... a bit of heat is not a bad thing. For example, ice crystals can form in LL100 if it is cold enough and those can block a fine enough mesh filter. A gascolator on the firewall can be a lifesaver if ever you did have this situation present itself vs blocked flow if in the wing roots. If a sumer only machine, I am all for the wing root location. You can sample the wing sump drains and the gascolator quick drains with one squat per side.
Some homebuilts have header tanks inside the firewall. The heat muff and cockpitt heat keeps the fuel nice and warm if flying in serious cold temps -20C and colder.
Best of Luck
flyboy1963
Well Known Member
tech info welcome!
Nice of Scott to chime in....but it makes me wonder if the inline is considered a 'pre-filter' at x microns, and the gascolator would be the final filter? ( carb'd)
....or is the screen size not that relevant if we are only talking water?
( am I the only one reading this thread that really, really, is having trouble feeling sympathy for guys building -14's?)
Nice of Scott to chime in....but it makes me wonder if the inline is considered a 'pre-filter' at x microns, and the gascolator would be the final filter? ( carb'd)
....or is the screen size not that relevant if we are only talking water?
( am I the only one reading this thread that really, really, is having trouble feeling sympathy for guys building -14's?)
