Installing pipes and wires when it's easy

[John Slade]

OK, Mike... here's one that comes to mind right now.

I wish I'd installed pipes either embedded in, or against the fuselage sides during chapter 6. I now have five pipes I need to get from the cowling to the panel through all the bulkheads, seatback, firewall etc. etc.

 

1/4 OD AL AC feed line

5/8 OD AL AC return line

5/8 OD AL Vacuum line

5/8 OD heater hose

5/8 OD heater hose

 

OK, maybe everyone doesnt want a water cooled engine with a heater core and air conditioning, but the vacuum pipe will be important to many.

 

The plans "heat duct" would be a perfect place to run some of these pipes... if I could just get the damn things up there (and out of the way of the wheel at the front - see chap 13). Life would be so much easier now if I'd installed all five pipes when I constructed the heat duct and fuse sides. I could also have insulated the AC feed and the heater hoses during installation. I might even have run the pipes down the duct, then filled the entire heat duct with pour foam.

 

Another item to consider at this point is wires. The plans wire conduits are tricky to work with, especially if they're not entirely smooth inside. (i.e. where they go through the seatback). If I were working on Chapter 6 again I'd make provision for smooth, easy wire feeds. I'd also provide a path for wires to allthe places that need them. e.g. Lots of wires need to come along the fuselage side wall from the panel and end up above the spar on the forward side of the firewall. How do you do that? You need a way for wires (some fairly thick) to get from the rear electrical conduits on each side (the ones that goes through the two gear bulkheads) to the "hell hole". Then you need a way to get those wires uo to the area above the spar.

Quite a few wires need to go down the center console through the seatback. It's amazing how thick some of these wire bundles can get. Some of my bundles are one inch in diameter.

 

It's probably a bad idea to install any actual wires at this point, but making early provision for them cant hurt.

[dust]

well, before we taped the fuselage together, my holes were clean and smooth, not since then.

 

I plane on eithor gromets, plastic pipe or something else similar to solve the problem

 

Mike

[ekisbey]

Okay, so for someone who hasn't actually begun building yet (I plan to start very soon, perhaps late this month), what provisions can I make early on that might smooth the wiring process? I would think that now (while the plane is still imaginary and therefore flexible) is the best time to plan such things.

[dust]

I think my solution is the most elegant.

 

My partner will figure it out

 

Mike

[John Slade]

You might consider embedding the pipes you'll need, the thick ground and power wires and maybe a bundle of 22awg, 20awg and 18awg wires in the fuselage sides before glassing the inside. Alternatively you could consider installing this stuff during chapter 8, after the bulkheads are in.

 

The wires should probably go in just forward of the panel (excess coil equal to the width + height of the panel) and come out below the spar, about half way up the firewall. The thick wires need to come out where you're battery will be, probably above the spar on the forward side of firewall.

 

Note: This is just an idea. There may be gotcha's in it.

[ekisbey]

I'm not comfortable with the idea of embedding wires. That smacks of a "permanent" installation that's hard to inspect and harder to remove/repair. Embedded pipes on the other hand make more sense. An embedded Al line for vaccuum, for instance, might make things easier down the road, but I'll want to be more familiar with the plans before I consider actually "embedding" anything.

 

I was thinking more along the lines of a dedicated wiring "duct," similar to John's idea of using his heating duct for running pipes and wires. Perhaps something that runs a similar route to the provisions offered in the plans. Is it feasible to install a dedicated wiring conduit that accomodates the bulkheads and obstacles you mention? I realize that this also can make for difficulty in inspecting or repairing wires but it's considerably friendlier than something that is physically embedded into the airframe.

[John Slade]

Yea. You're probably right about not embedding wires.

 

The plans call for a wire duct on each side of the fuselage. Problem is that it's in multiple sections and made of fiberglass. Typically its not smooth inside. We use shower curtain rail covers in the wings. They might be a good idea in the fuse too.

[dust]

John, I think your problem with the plans construction method stems more from your engine installation than from a shortcoming in the plans, I too hope to be doing what you are doing, installing a liquid cooled engine that is new to the cozy and to be honest about it, i am not looking forward to it.

 

Every minor change we have made to the plans has taken an inordinate amount of time, as we had to figure it out, not just do it.

 

Installing all of the stuff you are doing is not a small undertaking and takes a tremendous amount of time. I fear it will also take quite a bit of tweeking once you are flying.

 

I am not saying this to insult you, only to point out to non builders that your problem in this area is one of experimentation (designing complete systems for liquid cooled engine, air conditioning etc.) not of building a standard lycoming powered non air conditioned plane.

 

We decided to make a landing gear cover under the inspection cover to tightly seal the nose gear, very simple, very time consuming. Aluminum brackets,split cover in the middle to allow taking it out with nose on plane, wooden forms to lay up cover over etc., way more time than it would appear to take for a simple item, let alone on a complex installation that you are completing.

 

Enjoy the build, dread the design hehehe

[John Slade]

your problem in this area is one of experimentation (designing complete systems for liquid cooled engine, air conditioning etc.) not of building a standard lycoming powered non air conditioned plane.

 

No argument there. Every time I do something outside the plans I bury myself in a series of gotchyas. For example, I built an annunciator out of LEDs. Later I ordered a voice annunciator and found that it used switched ground rather than switched power. I just rebuilt the LED panel to match. The voice annunciator has 8 messages. Each needs 2 wires. Some of the messages need a sensor module. So far I've added a total of 36 new wires, not counting the LED lights.

 

My point on the pipes was that, if you're going to depart from the plans, you might be able to make early provision for the changes. Getting all these pipes from the engine to the front is NOT easy after the airframe is built.

[ekisbey]

Although I'm planning to build the aircraft with few or no changes to the overall design, I can't say with absolute certainty that I won't decide otherwise at some point down the road. What I was looking for were possible "catch-all" simple changes that have little impact on the overall layout of the fuselage and bulkheads which would allow for easier changes or modifications later down the line. Although, now that I think about it, I can see John's comment on the time consuming effects of even small cahnges coming back to haunt me. Guess I'm going to have to just wait and see what I come up with while building.

[John Slade]

OK, I found the solution to my problem...

There's more than enough room in the heat duct for all the pipes. Getting them in there after the fact is a bit of a bear - I cut a hole in the nose wheel cover. Once the pipes are in, I'll fill the heat duct with pour foam for insulation.

 

Anyone who's definately going with an automotive engine might consider installing the heater, ac and vacuum pipes in the heat duct during construction of this item.