Paul,
I make sure my drain for the cobra neck is a ways down the tube so the
first time I know my tank is full (other than my sight gauge) is fuel
runs out the vent / drain. This keeps the bugs out and the tube clean I
guess. I put the vent inboard just enough to miss my toes on an
overfill.
Airplanes are 20,000 compromises flying in close formation. So we all
have to put up with something. I have never had a problem with my vent
tube or drain. But then again I have a trigear and operate off of
asphalt. I too do not like fumes in the plane, so I make a metal elbows
for the filler, use lined fuel tube, (R9 style), put drains under the
tank bottom reinforcements, under my cockpit module where my pumps are,
under my seats where the filters are so I know if I have a leak
anywhere, and it all stays clean.
My wheel pants are quite low for speed and so I avoid soggy grass
strips.
Those who complain about upper vent vs lower vent are living with other
compromises. I just don't like them up there and because I tend to do a
bit of spirited flying, fuel comes out of my upper drains if installed
and fuel stains. They are tough to finish nice also, and the sight
gauge vent tends to change the fuel level at different speeds. They are
also tougher for the upholster to finish on the inside.
It is all about compromises and preferences.
Best Regards,
bud
----- Original Message -----
From: Paul McAllister<mailto:paul.the.aviator@gmail.com>
To: europa-list@matronics.com<mailto:europa-list@matronics.com>
Sent: Sunday, January 06, 2013 12:09 AM
Subject: Re: Europa-List: Power loss and Inspecting comments
Bud,
Thank you for your comments. Well thought out and valuable as always.
I was one of the earlier pioneers of the system to route my filling
vent and into the top of the cobra inlet. For the fuel tank / system
vent I did something different again.
I adopted the idea that Robin use and placed my vent in the backside
of the wing root. At the time I thought this was a great idea, but over
time perhaps its only a good idea, maybe not even that. The upside is
that it is unlikely to be plugged by mud, but there are a number of
downsides:
- Once in a great while, if I over fill the tank, it will run out of
this vent and out of the wing root over the flap. I inspect the flap
regularly to make sure fuel has not got inside the core and dissolved
the foam.
- If I over fill the tank the fumes make there way into the flap drive
slot during flight.
- I have to take the wing off to inspect the vent which doesn't happen
regularly. There is a slight risk on my area that an insect called a
"Mud Dauber" can get in there.
So, in conclusion, while these departures from the original design
seem like a good idea there are often hidden consequences.
Over the years I have become involved in inspecting and technical
counselling for the EAA, and the experience of this community has taught
me that fuel systems and modifications to them feature high on the list
of accident causes.
Cheers, Paul
On Sat, Jan 5, 2013 at 10:40 PM, Bud Yerly
<budyerly@msn.com<mailto:budyerly@msn.com>> wrote:
Jim, and tibits for the rest of us:
After the tire failure and the subsequent off roading mud and dirt
experience while cross country, I commend you for your pursuit of the
problem which cost you much time, and money. You knew you had a mud
plugged vent, but an experienced guy like you missed the kinked vent
line cause. So what's a normal guy to do?
I had to ponder that we (really me), are always quick to assume an
engine related problem is causing the power loss. You told me about
finding the kink but I still assumed that you had a carb problem. You
cleared the clogged vent, but who would have thought about the rest of
the vent system and a possible kinked line when the plane has been
flying for years. I am anal about fuel system install and operation,
but once installed, I rarely look beyond making sure there is not
chaffing or leaks.
Added for all of us:
Recently I just finished an extended annual and another fuel tank
replacement / annual in a couple aircraft that I helped customers build
back in 2002 and 2004. Interesting to note that on both aircraft, that
they were past the 5 year hose replacement timeframe (we all dread
that). In both aircraft I found that the vent line was kinked or
compromised. In one of the aircraft when the upholsterer forced the
fabric around the fuel cover he had forced the fuel cover over one of
the polyurethane vent lines and over time the cover pushed on it nearly
flat so it barely vented properly, and on the other, the vent line was
perfect looking, but the hose was horribly brittle because the vent tube
was made from clear Tygon tubing. Tygon is supposed to be completely
impervious to fuel related problems. Duh, maybe not...
In my old Europa Operators Manual there was the requirement to pull
the fuel bosses off and flush the tank annually, which is quite tough,
but never to check our vent system, and in the new ops manual, it only
indicates to check and inspect for leaks. The 5 year recommendation for
changing hoses is still there, but not the vent lines. Vent lines never
get checked.
As far as I know, you are the first with an underside vent that ever
got plugged, however, you are the only mono I know of with the vent on
the bottom and operate off of grass a lot. In the trigear the vent on
the bottom is always clean, but your point of the oil overflow on the
right side of the cowl exit and a centrally located vent will be a
potential problem for oil, grime and dirt. I'll have to admit I will
make sure my annual checklist is changed to check the vents.
I prefer not to vent out of the top because with the motor glider in
turns when trying to soar, the fuel sprays out of the vent in right
turns. It also will vent fuel out if overfilled on a hot day in Florida
and let set in the sun (especially a mono), which of course can ruining
the paint.
Inspecting an aircraft is not an exact science. Manufacturers and
regulating agencies give only vague guidance. We are the manufacturer
as the builder, so we set the guidelines for inspections of our
aircraft, and if the kit manufacturer gives guidance, we the
manufacturer of the aircraft should be more specific, not less to
include info on our added systems, changes, modifications, and
additional wear areas or time change items due to all the above. I'm in
the US, and have my A&P use the FAA FAR 43 Appendix D as well as the
engine 100 hour checklist and I insist on him using the Kit
Manufacturers guidelines such as the Appendix E of the build manual and
Section 8 of the Ops manual when inspecting an experimental aircraft.
Now, I have been accused of doing a complete rebuild instead of an
annual inspection, but I am anal so that is my excuse, but on an
experimental aircraft (especially one I didn't help build or maintain) I
have found that there are many non standard items, routing conflicts
between wiring, fuel lines, brake lines and control cables, as well as
poor installation of equipment and structural construction mistakes that
the builder and final FAA inspector missed on the initial Airworthiness
Inspection. The FAA actually requires us, as US Experimental Aircraft
Manufacturers, to have established maintenance and operations
procedures.
I am attaching my personal annual inspection checklist out in the
open to show what we the builder can do to improve the inspections on
our aircraft. I only just added an item to inspect the fuel vents since
you called me about the problem weeks ago. I developed this checklist
long ago, before becoming a Europa owner and just tailored it to include
items in the Europa Section 8 inspection, the FAA and LAA recommended
guidelines etc. I am preparing to submit some of this info in a
condensed fashion in an updated Tech Support section of Europa's Website
as well as some other notes we all should know when maintaining the
Europa. Now this is my personal checklist, not for general
dissemination as a Europa Directive, but provided for others to see that
an annual inspection is not a walk around. But then again, it is not an
IRAN (Inspect and Repair as Necessary) like the military does by
completely disassembling every panel, inside and out, instruments,
wings, engine, etc. and inspect, refurbish, service and repair all the
above, it is however, more than a quick check for wrinkles in the skin,
change the oil and sign it off.
Great job of troubleshooting and thanks for the report Jim. Your
findings and my recent observations have changed my annual checklist for
sure...
Regards,
Bud Yerly
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avigator?Europa-List>
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