Bulkhead Fitting

[pfhoeycfi]

I'm putting together the fuel system to the firewall and looking at bulkhead fittings. I'll have 5052 on the cockpit side. I'm curious to know what type of fittings builders used through the firewall. Also curious about what type of fuel lines have been used on the engine side. Still on the fence about engine choice. It will likely be the aerovee turbo or jab. I'd be interested in seeing completed firewall pics if avail.

peter

[Bryan Cotton]

My thread, page 102+.
viewtopic.php?f=39&t=578&start=1010

[pfhoeycfi]

[quote="Bryan Cotton"]My thread, page 102+.

Perfect. No gascolator required with the aerocarb? I like the firewall offset blocks too...
Thanks Bryan...extremely helpful.

HNY
Peter

[Bryan Cotton]

Peter,
Info from the old yahoo group, posted by Sonex. I bolded the gascolator statement.

Sonex fuel
Hello again Sonextalk, AeroVee, and JabiruEngines eGroups-

There has been some discussion lately on these lists about a hesitation,
burp, or hiccup that a few pilots have experienced with the AeroCarb or
AeroInjector installation. This note has some tips from the Sonex Factory on
how this can be eliminated. Sonex does not experience this with any of our 8
factory AeroCarb/AeroInjector installations. As always, we highly recommend
following the Installation Manuals as closely as possible to achieve our
same level of success and reliability.

The AeroInjector (or AeroCarb) is a simple machine. All it does is mix the
fuel delivered by the fuel system with the air that is drawn by the engine's
intake strokes. It cannot direct fuel to a specific cylinder to control EGTs
and it cannot change the quality or content of the fuel it receives by
sifting out debris or vapor.

The "burp" some installations are experiencing is without question a vapor
bubble passing through the AeroInjector, resulting in a momentary lean
mixture for a single cylinder. If you are experiencing anything more than a
momentary hesitation you likely have a tuning issue that needs to be
addressed: adjust the valves, inspect the fuel system, verify ignition
system is functioning, check fuel pressure regulator setting if so equipped,
revisit the AeroInjector's tuning, confirm the quality of the fuel being
used, etc. We recommend all engine troubleshooting be done using 100LL in
the fuel tank as this eliminates poor fuel quality as a possible cause and
provides the highest vapor pressure.

Anything that can introduce vapor into the fuel supply is a possible source
for the hesitation. This may be the routing of the fuel lines, a low vapor
temperature fuel (autogas), or a heat source raising the fuel's temperature
to and above its vapor temperature. However, as the AeroInjector does not
have a float, instead of the vapor stopping your engine altogether it will
pass through the AeroInjector and cause the miss some of you are
experiencing but will not cause a full engine stoppage.

The more complicated your fuel system is the higher the likelihood of fuel
vapors forming. We continue to work with one customer that has a highly
complex fuel system which includes multiple pumps, many, many feet of fuel
line under the cowl, high spots in the fuel line, and an AeroInjector
mounted fractions of an inch above a muffler. If the AeroInjector gets too
hot it can be the source of the fuel turning to vapor.

So what can you do to reduce or eliminate vapor?
1. Keep your fuel flowing downhill as much as possible. The tank vent should
be the highest point of your fuel system and ideally the fuel system will be
all down hill from there, allowing the inevitable air bubbles to back up the
fuel line and exit through the tank vent. Rises in your fuel line anywhere
between the fuel tank and the AeroInjector are nothing more than traps for
vapor, vapor which will likely get entrained in the fuel and carried to the
AeroInjector.
2. Simplify your fuel system (most of our factory aircraft are flying
without a gascolator, though you still need a filter and low spot to collect
and drain water)
3. Use 100LL
4. Keep heat-generating ground running to a minimum
5. Insulate your fuel lines
6. Wrap your exhaust

In short, keep your fuel cool and the line as direct as possible.

One proposed fix we feel is bad idea is the "burp tube", in which a tube is
added to the fuel line to provide an escape path for air bubbles. This may
introduce even more air to the system as the fuel traveling through the fuel
line acts like a suction and draws more air in.

With the unusually hot summer the whole country has been experiencing we are
not surprised that reports have increased. Heat and high density altitudes
(low atmospheric pressure) are the primary causes of fuel turning to vapor.

As always, please feel free to contact Betty, John, Jeremy, Kerry, Mark,
Heather, Jacki, Steve, or Jackie at the numbers or e-mail below
with any questions or Comments.

Regards,
-Sonex Aircraft, LLC
--
http://www.sonexaircraft.com
Tel (Info/Orders): 920.231.8297
Tel (Tech Line): 920.230.8324
Fax: 920.426.8333
E-mail: jeremy@...

Sonex Aircraft, LLC's Mission is to provide the recreational aviation
community innovative, cost-effective and efficient aircraft kits,
powerplants, and accessories and support them with industry-leading customer
service.

[pfhoeycfi]

[quote="Bryan Cotton"]Peter,
Info from the old yahoo group, posted by Sonex. I bolded the gascolator statement.
....

Great...I didn't see that before. I'll have to dig thru the forum a little harder to see what else I'm missing. Did you add a quick drain at some point in the system?

Thanks again for your help,

peter

[Bryan Cotton]

Peter,
My lowest point is the aeroinjector. I consider it as the drain.

[builderflyer]

On the other hand, in the interest of "fuel system standard practice" and peace of mind, perhaps, it's not absolutely necessary to eliminate the gascolator in order to eliminate the "burps". Just make sure the gascolator is an "Usher", not an ACS, blow some fresh air on the gascolator bowl, insulate all fuel lines inside of the cowling, shield the AeroInjector from nearby exhaust pipe heat, don't use a Floscan sender unit for fuel flow info, and do use 100LL fuel.

Just my opinion and what I do having tested other options,

Art,,,,,,,,,,,,Sonex taildragger #95,,,,,,,,,,,,Jabiru 3300 #261

[Rynoth]

Hi Peter, here are some pics of my fuel through the firewall using the gascolator. The mounted gascolator is effectively the bulkhead fitting. This is pretty much how the plans call for the install IIRC.

http://www.rynoth.com/wordpress/waiex/2 ... -mounting/

http://www.rynoth.com/wordpress/waiex/2 ... -cleaning/

I have yet to experience any burping issues after 14 hours of flying. The run from my gascolator to aeroinjector is steel-braided rubber hose wrapped in a firesleeve further wrapped in HVAC aluminum foil tape.

[dirkverdonck]

Hi All,
Just my thoughts after 120 hrs on my Onex: no burping so far and using Mogas RON98 all the time.
I have no fuel filter and no gascolator and the fuel line runs straight into the Aeroinjector.
There is a drain valve in the tank bottom and the flexible line from the firewall to the Aeroinjector is firesleeved and alu wrapped.
To clear the fuel line of any water or debris, I flush the fuel line before every start by opening the fuel valve, fuel rich and full power setting for about 3 seconds. Thereafter the engine starts right away as it is primed in the process.

In the mean time, I fixed the problem with the K&N RC1980 air filter coming loose from the Aeroinjector by using the top half of the original Aeroconversions air filter set-up and attaching it to the top of the K&N filter after cutting away the rubber neck of it.

Happy New Year to all and enjoy the building and flying,

[pfhoeycfi]

To clear the fuel line of any water or debris, I flush the fuel line before every start by opening the fuel valve, fuel rich and full power setting for about 3 seconds. Thereafter the engine starts right away as it is primed in the process.

You're flushing through the aeroinjector? Where does the fuel go?

Thanks for the replies everyone...

peter