Plumbing at the Root

drone_pilot · #1 10-24-2015, 08:46 PM

Hi Everyone,

First, sorry for the wordiness.

I've looked through the forums etc, but cannot seem to find what I'm looking for.

I am danger close to putting the wings on to stay. I'm using the Dynon heated pitot and AoA and the SafeAir1 plastic tubing for all of the plumbing. As the left wing sits right now, it is completely wired and plumbed with about 2-3 feet of plastic tubing for both the AoA and Pitot hanging out of the root rib. I ran the tubing pretty much to the plans with the plastic tubing exiting out just behind the front spar.

My Dynon Skyview ADAHRS is mounted at the top of the fuselage about 1 foot behind the baggage bulkhead. Pitot and AoA tubing are routed from the ADAHRS down through the center tunnel to the front spar center section and through the forward wiring holes in the seat ribs. I have about 3-4 feet of tubing hanging off of the side of the fuselage just a few inches behind the main spar entry. Where the tubing currently exits the fuselage is too close to where the tubing exits the root rib, if that makes sense. In other words, there is no good way to connect the tubes where they currently exit the the fuselage to the tubes exiting the root wing rib in that confined area.

I'm thinking of running the tubes exiting the root rib aft past the large lightening hole that contains the main Aileron push rod. Do they make a bulkhead AN style elbow to exit out of the fuselage that would accept a 1/8" NPT male thread to 1/4" plastic tubing adapter?

What exactly is the best way to do the plumbing interface between the fuselage and the left wing? Is there a magic part? I'm at a head scratching moment.

HFS · #2 10-24-2015, 09:20 PM

You might look at Cleveland Aircraft Tool's P/N FPTH - Bulkhead Passthrough Fitting. You can put whatever you want on either side of a 1/8 NPT female thread.

HFS

az_gila · #3 10-24-2015, 11:26 PM

Or just use a plastic bushing/grommet in the fuselage side and a push-on fitting inside -

http://www.cleavelandtool.com/Push-O.../#.VixnQv9dGUk

Taildrgr · #4 10-25-2015, 06:25 AM

My tubing extends about 2 feet from the end of the wing. When I mounted the wings, I put the tubing through a couple plastic grommets I installed in the root area of the fuselage. Then I just T'd into the tubing to my ADAHRS with Safeair T connectors. They are under my removable seat pan.
I originally planned on a bulkhead fitting but there was not really enough room between the wing and fuselage to make it work.

Since you have the tubing routed through the center section, you could run the wing tubing forward through the spar and make the connection on the left side in front of the spar.

Smilin' Jack · #5 10-25-2015, 07:02 AM

I ran my tubing very close to what you stated. Since the Aileron push rod does not take up the whole lightening hole in it's movement I brought the Safe T Air tubing into the fuselage. Mounted an adel clamp on the lightening hole to hold the tubes and ran them up under the arm rest an to the back.
It has worked well. I did put an inline straight disconnect so if I ever have to remove the wings again I can just disconnect the safeTair lines.

Jack

N941WR · #6 10-25-2015, 07:21 AM

My tubing enters the cockpit in about the same place as yours.

With the first panel, I ran the tubing all the way from the pitot through the spar, forward to the firewall, and up to the panel. When I installed the SkyView, I pulled the tubing back and ran it aft of the baggage compartment to the ADHRS, again with no connectors.

drone_pilot · #7 10-25-2015, 11:24 PM

Does anyone know the distance between the root rib and the fuselage side? I was curious of how much clearance from an elbow from the fuselage will have from the root rib.

Okay, I'm going to ask.....but just send me a royalty check if you go out and manufacture on my idea. The technology is already there. Why doesn't anyone build the pitot tube with the sensors built in so we builders with glass instruments can run wires instead of this tubing which doesn't cooperate as well? I'm not sure why the circuits could not sit with the pitot/AoA out in the wing rather than in the actual ADAHRS box. I know it would change up some data communications but that's a software thing. I'd much rather do wiring than plumbing. As small as the Dynons ADHRS box is, I'd bet the circuitry/sensors for pitot and AoA doesn't take up much real-estate. Power, ground, Rx, Tx. Simple as pie! Doesn't seem like much design work for a company like Dynon who already has it on paper. I'd buy it! Especially right now. Anything to avoid plumbing! Electronic fuel lines are next!!

longranger · #8 10-28-2015, 12:07 PM

Quote:

Originally Posted by drone_pilot

Does anyone know the distance between the root rib and the fuselage side? I was curious of how much clearance from an elbow from the fuselage will have from the root rib.

Okay, I'm going to ask.....but just send me a royalty check if you go out and manufacture on my idea. The technology is already there. Why doesn't anyone build the pitot tube with the sensors built in so we builders with glass instruments can run wires instead of this tubing which doesn't cooperate as well? I'm not sure why the circuits could not sit with the pitot/AoA out in the wing rather than in the actual ADAHRS box. I know it would change up some data communications but that's a software thing. I'd much rather do wiring than plumbing. As small as the Dynons ADHRS box is, I'd bet the circuitry/sensors for pitot and AoA doesn't take up much real-estate. Power, ground, Rx, Tx. Simple as pie! Doesn't seem like much design work for a company like Dynon who already has it on paper. I'd buy it! Especially right now. Anything to avoid plumbing! Electronic fuel lines are next!!

In my 36 years of experience as an instrumentation engineer I didn't run across a single pressure transducer with a calibration that wasn't sensitive to temperature changes. On the ones we couldn't locate in a temperature controlled location, we calibrated before every use. I don't know for sure, but I suspect that the pitot and static pressure transducers in most ADHARS boxes are located in a temperature controlled "oven" in the box. I'm thinking that is much easier to accomplish in the fuselage rather that in the leading edge of a wing.