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Tips on Self-Fueling


NC Bill

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Am I right in assuming then that the putty holding the filler on the wing is also conductive?

I realize that if there is conductivity through to the tires static will drain from my plane as it sits. I always place my conductive plastic containers on the floor of the hangar before fueling. And make physical contact with the plane in the process of refueling. ( In case anyone gets uptight, they containers draw air from inside the wing tank to displace the fuel that comes from the container so fumes aren't vented externally.)

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Hi Tom,

 

I disagree. The spars do touch especially when you apply 200 in/lbs of torque on the pin retainers. The metal rings inside the spars where the pins go through touch when tightened down.

 

Like I said, it really won't make a difference since the whole aircraft is linked in some way shape or form. Put a power supply on the right wing fuel insert then take a reading on the other wing insert or put the power supply on the exhaust pipe and take a reading on the fuel insert. There is conductivity.

 

I think he meant they don't touch the fuselage in any place, that's the pins doing that.

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The spars do touch each other. The metal collard inserts in the spars touch when you torque down the retainer caps on the spar pins. The entire spar length may not touch, but they do touch on the metal pin collared insert. Then the metal spar pins are in contact with the fuselage and the two alignment pins on each wing are in their metal inserts embedded in the fuselage.

 

I think we are playing with semantics. The wings are in contact with the fuselage at some point.

 

The basis question is there conductivity between wings, engine and fuselage. The answer is yes.

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Roger, the spars do touch each other. The main pins go in the metal bushings in the spars, but none of this touches the fuselage. You could pin the wings together on a pair of saw horses and it would be the same. There are no metal inserts in the fuselage for the main pins. The alignment pins do touch the sides of the fuselage, this is where the conductive path is.

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I guess I am wondering why question if Roger has tested the plane and says he shows a full circuit. Does it matter what all the glue, bolt, washer, rubber parts, hoses, links, lines, cables, tubes, carbon fiber shell, leather in the seats, glass in the panel, rubber in the tires do if there is conductivity end to end?

 

No.

 

What does matter is that you can indeed put a static ground on the tailpipe and fuel the plane without concern for static discharge and fire, UNLESS, you somehow managed to goof up putting the clamp on the tailpipe.

 

We have continuity but at what level of resistance? Is it a reliable path that exists in all CTs including mine?

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I used my multi-tester and found that I do have continuity from my gas fill to my gas nozzle when my bonding cable is attached from my fuel trailer to the exhaust. :) I guess I have no need to contact the fill with my nozzle.

 

I have continuity from my gas fill to my hangar frame which is my ground. :)

 

The airframe does does have continuity from metal part to metal part like exhaust to wheel pant fastener but there is none to painted surfaces. If you think you are discharging just by touching the painted wing when filling from cans I don't think so.

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Am I right in assuming then that the putty holding the filler on the wing is also conductive?

I realize that if there is conductivity through to the tires static will drain from my plane as it sits. I always place my conductive plastic containers on the floor of the hangar before fueling. And make physical contact with the plane in the process of refueling. ( In case anyone gets uptight, they containers draw air from inside the wing tank to displace the fuel that comes from the container so fumes aren't vented externally.)

 

Doug - are you fueling inside your hangar? I always push my plane outside. Maybe that's not really necessary and I have only seen one fire which was during a de-fueling. I don't know of any others. Wiped out the hangar and 3 airplanes. That was enough to convince me to go outside especially since my hangar is attached to my house.

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Yes, I usually do, but to clarify, the possibility of spilling is extremely small since it is only when the nozzle of the "can" is in the filler that the weight of the can opens the end of the nozzle which is already inside the wing, then a tube running from the top of the nozzle ( inside the wing) draws a volume of air/fumes equal to the volume of fuel back into the can. this also eliminates the possibility of over fill since once the fuel reaches the end of the nozzle the air line is cut off and the fuel stops. I never smell fumes from refueling. I suspect there is more danger from sticking my tanks.

I always fuel before I go which means the plane has been sitting at least overnight.

I am not allowed to store fuel containers (full or empty) in my hangar. I do at home and refill my mower and snow blower with less safe containers. That has not been an issue for my 64 years of life.

The two incidents of similar fires I am aware of involved people working on motorcycles who were smoking.

 

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The spars do touch each other. The metal collard inserts in the spars touch when you torque down the retainer caps on the spar pins. The entire spar length may not touch, but they do touch on the metal pin collared insert. Then the metal spar pins are in contact with the fuselage and the two alignment pins on each wing are in their metal inserts embedded in the fuselage.

 

I think we are playing with semantics. The wings are in contact with the fuselage at some point.

 

The basis question is there conductivity between wings, engine and fuselage. The answer is yes.

 

No no, i meant the spars don't touch the fuselage. They do touch each other. It is the alignment pins that have the most relaible ground path. :)

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How many ohms is it from the exhaust pipe to the filter neck, Roger? (Sorry, I missed your reply above.) This it's what I have been trying to find out. I appreciate someone having the capability to do this.

 

I measured this years ago, and probably posted the value on the old ctflyer forum. I seem to recall it was around 100k ohms. Enough to bleed off any static charge in a few seconds.

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post-456-0-87430400-1388637930_thumb.jpg

 

Yeah how many!

 

Let's set the groundrules before I start my exhaustive count...

 

1) Does each individual battery in my ELT count separately? Makes a big difference.

 

2) Do I count the batteries in portable devices? In my headsets?

 

3) Is my AirGizmo mounted 496 a "portable device" once it's snapped into place?

 

Let me know. For now, my answer has to be "a whole bunch"!

 

 

 

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Here's a question about ELT's

 

You depart from your local airport fly an uneventful flight to your next stop which is a high density airport, taxi to your FBO shut down and while securing the plane are greeted by a FRIENDLY member of the local FSDO. He is curious about your funny looking plane and would like to educate himself about it...You show him all the goodies explain about the range, useful load etc..You pop open the baggage door and as he looks in the space he asks how you pack everything in without damage to the ELT? You explain that you are careful packing the plane...FRIENDLY response, can you demonstrate to me that it is working? Now there is a sticker clearly showing that the battery replacement isn't due for another month.

Question: Do you demonstrate that it is operational?

Question: What is your response?

 

We may want to move this to a more appropriate forum..

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