Sunday, June 14, 2015

Sunday, June 14th, 2015 - fast stack, exhaust, control cables, Dynon hub mount, heat box

The last week or two I've been moving forward with general wiring tasks.

I also received my pre made cables from Approach Fast Stack.  I was very impressed with the level of detail of documentation, overall quality, labelling, etc.  Really nicely done.

At first my intention was to proceed with wiring everything.  Since I hadn't had my components until recently (VPX, fast stack, etc) I hadn't figured out the best way to lay everything out - where every piece would go and how I would route all the wiring.

*However* - once I started taping/clamping components in place, I realized I really needed to get some of the items installed that might interfere in some way with wiring (rudder pedals, control cables, etc).   At first I thought I'd just need to do a few things, but once I started going that direction I realized there was more stuff I'd delayed previously because I didn't want to box myself in or do something that would create a problem later (or because I hadn't decided yet).

Just a hindsight thought:  I've commented to a bunch of local builders that you really need to build your second plane first (can't be done obviously).  There are so many things I'd have managed better if I had known more about the process - wire as I went, etc.

I also updated the hobbs meter today since I haven't done that in ages.  The total build time at this point is 1641.3 hours - 946.3 on the fuselage and counting.  I started the project in April of 2011, so I'm at 4 years and 3 months.  Looking back over the last year especially, there were several big gaps where I was working on the project but the time didn't really move anything forward in a physical sense.  A lot of time (maybe 2 months???) spent deciding on avionics and wiring, nearly a month on the engine, 3 weeks working on panel layout and cutting, etc.  I also spent nearly a month learning how to do composites.  There is also a lot of what I would call "noodle time" - noodling/thinking about things, how to get past a problem.

Oh - when I started I thought I could be done in about 3 years.  At the time I felt like that was realistic and was based on a honest appraisal of how much time I thought I could put in as well as looking at estimates from folks I knew and a lot of reading.  :)  What I had no idea going in was how much time I'd spend doing things like modifying the garage, building jigs or making decisions, reading blogs figuring out how to do something, and just working with something enough that I understood it and knew how it should go together.

My new target is next summer (June 2016).  We'll see how that goes.

One note to someone starting out - the plans get less and less detailed as you go, and you pretty much drop off the map once you're done with the fuse.  Firewall forward and on you're pretty much on your own.  Just something to think about.

I started off just running a cable from the ADAHRS forward. As I looked at all the pieces (2 a/p servos, ADAHRS, and ADS/B) it became apparent that it would be much more efficient to have a Dynon hub somewhere in the mid fuselage area, just behind the baggage compartment.  I'd a seen a couple of folks that had installed stuff using either the Van's ELT/Stobe mount kit (which I will probably use for my ADS/B box, or something they'd fabbed up themselves.

I decided to put the hub on the left side between the lower J stringers.

Van's supplies a fair bit of scrap aluminum rectangles in various thicknesses - I just eyeballed a piece of .032 that was long enough to accommodate the hub and cut it to length.  If you make the piece correctly, you can just pop rivet it to the structure.

I cut it slightly oversize, then bent one side to the correct angle, then was able to lay it in place and figure out the second angle and how long the flange needed to be.

From Finish Kit 2

Here I'm working on the flange size and correct angles.  Pretty close at this point.

From Finish Kit 2

This is the end result.  I marked the holes for the nutplates using the hub as a template, then drilled the plate and installed nutplates.  Finally I just had to mark and drill for the pulled rivets - 3 top and bottom.

From Finish Kit 2

As I was doing this (and was yet again unable to use the nice pulled rivet tool you get with most tool kits) it occurred to me I have used this rivet puller very little.  They aren't horribly expensive, have a nice swivel head, and dies that will accept a bunch of different shank sizes, but due to their bulk, I haven't used it much at all.  The only place I did use it much was on the pulled rivets for the elevator, rudder, flaps and ailerons.

From Finish Kit 2

The puller I use nearly all the time (and which would have been perfectly adequate for the places I did use the expensive puller) is this ancient Arrow pop rivet tool that was originally my grandfather's.  This thing is at least 40 years old, probably more.  It doesn't take a lot of space, is easy to use, and works in way more places than my snazzy Stanley swivel head unit.  The business end also has dies for different size shanks as well.  Newer ain't always better - just sayin'.

From Finish Kit 2

Right after I got that done, I received my cables from the folks at Approach Fast Stack.  They do great work - excellent documentation and the build quality appears to be first rate.

Here are some pics.

This is a shot of all the cables I got from them.  Garmin 400W, Skyview, GMA 240, SL 40, A210, ARINC, flying lead for the D10A (provides GPS to D10A for backup nav)

From Finish Kit 2

Detail of the 400W cable.  Everything is well labelled, shells are provided, as well as a complete cable pinout and test sheet.  Leads for power/ground as well as any other necessary connections are coiled up and labelled so I can terminate as and where necessary.  Everything appears to be excellent quality.

From Finish Kit 2

This is the audio cable - easily the most complex of the lot.  Includes PTT leads as well as music/aux in and headset connections.

From Finish Kit 2

In my discussions with Tim I told him everything I had - they helpfully provided a full schematic of not only the cables they provided, but also including all the Skyview network stuff for the A/P servos, ADS/B, etc.

From Finish Kit 2

Finally the included docs of the hub and all the interconnects if you are inclined to make your own cables (I'm not).  Each D sub on the hub is labelled and each provided cable has a matching label - very easy to know what goes where.

From Finish Kit 2

I've been trying various ideas on where to put the hub and routing cables.  At the moment this seems to be the best config (pending changes once I'm done putting in bits that are non-moveable).

BTW- Approach Fast Stack has a standard length for everything, but can custom make any cable to any length you want.  I toyed with making them shorter based on my initial location thoughts (original plan was to use the bay to the right of this pic - right behind the radio stack to the back and left side of the bay).  However, I wasn't sure if there would be room for everything and if I had to move it I'd be stuck.  I guess in a perfect world you'd just move components around until you found the perfect home for everything and then carefully measure each wire, but I do want to finish, so I opted to stick with the stock length.  I can always take a service loop/coil if I need to.

From Finish Kit 2

At this point I decided to get a cheap lawn tractor battery to use during testing and so I could hook things up just to see some blinky lights/screens. :)

I just put everything on my bench (used my VPX with temporary crimps on some cables I'll have to trim anyway).  I dragged the bench over to the plane so I could hook up the Skyview.  I had my hub installed with connections for the ADAHRS and EMS.  It recognized both, so I guess I wired it correctly.

From Finish Kit 2

Once I got it configured, up came the HUD.  My project is oriented slightly north of east in the garage, so the heading looks pretty good to me.

From Finish Kit 2

Right after the fun with powering everything up, I started working in earnest on layout and config.  There are no pictures - I was just moving bit around inside the forward ribs and clamping things in place, and a lot of think time.  At some point during all that I realized wiring was a bad idea and I need to put fixed things in place so I would know where to run the EMS wiring and penetration, where the ground block (using B&C's "forest of grounds"), etc.

The most obvious non-negotiable location is the exhaust, so I started with that.

Note: this is my first attempt following the Vetterman plans, and I wasn 't happy with the result.  I changed it later, however I'm doing to give Clint & Van's a call to get their take.

From Finish Kit 2
Right side - trying to follow the instructions, which is basically get it as far aft as you can.  Also this is way too low - once you try to fit the cowl you realize you have to have everything just about as close to the lower fuse as you can get without actually hitting it.  You end up with maybe 3/4" all around.

From Finish Kit 2

Left size.  Again, way too low - didn't realize that til later.

From Finish Kit 2

This is the bit I really didn't like.  The instructions have a drawing showing the rubber laying on the nose gear mount and they say to put a dab of silicone there to hold it in place but allow for vibration.  This just doesn't seem like a good idea to me.

From Finish Kit 2

Since the throttle & mixture have to go in the same general area as the exhaust, and again have very little in the way of options regarding moving it, I went ahead and started on that.  Note: I missed the note on the plans - this bracket is backwards, and I should have put the carb heat to the far left with throttle and mixture in the middle.

From Finish Kit 2

Cable support on the sub panel.  This just gets riveted in, nut plates on the bottom for adel clamps.

From Finish Kit 2

Found a nice little steel firewall penetration to use instead of the nylon bushings.  This won't work on the bottom (mixture) hole due to the fuel pump doubler being in the way.

From Finish Kit 2

Throttle and mixture temporarily in place on the bracket.  I was kind of baffled at this point because the throttle cable was clearly too short by an inch or two.  I puzzled over this for the better part of a day and didn't really figure it out until I started working really hard to get it to work and woke up in the middle of the night realizing I could flip the mounting bracket around or mount it further forward (doh! - read the manual!!).

Only after I'd had this revelation did I find the note about the bracket orientation.

From Finish Kit 2

Bracket correctly installed and cables moved.  It fits! :) Much happier.

From Finish Kit 2

Cables are now long enough and can be secured with the adel clamps.

From Finish Kit 2

Take two on the exhaust mounting after a lot of fiddling.  I found a way to run the horizontal support under the nose gear support.  I think there is enough clearance all around, but will check before I settle on this.  Thankfully it can be moved around pretty easily.

From Finish Kit 2

Horizontal support is under (and clear of) the nose gear mount

From Finish Kit 2

At this point I decided to finish up one of those deferred items.  I had never safetied the bolts for the engine mount to the airframe or for the engine mounts themselves.  At the time I thought I might have to take it back off, but at this point I obviously don't, so I final torqued all the bolts and installed the cotter pins.

It's funny, I've done a ton of these since I used to work on a farm, but we always did them with the pin oriented sideways on the ends wrapped around the nut.  Looking at the AC advisory book, they recommend this method and way I learned as the alternate.  I do like this method better - much cleaner.  I've ripped up a lot of knuckles on the other way since you almost always had pins sticking out.

From Finish Kit 2

Next was to install the heat box control and the scat tubing since that can pretty much only go in one place as well.

Here's the firewall penetration - just used a plain old hole saw (Lennox carbide).  Worked pretty well.

From Finish Kit 2
Scat tube cut to length and installed temporarily.  Lousy picture, but it shows the essentials.