The nervous system arrives

Back from Thanksgiving with family at Bear Ass Cove on Newfound Lake, New Hampshire and guess what UPS delivered? That’s right – the avionics harness!

Unboxing the avionics harness

I’m almost ready to install the harness – just a couple of empennage things left to finish – but I couldn’t resist stretching it out. This is, essentially, the Mighty RV’s nervous system and having it fabricated by the neurosurgeons at Approach Fast Stack is saving me a *ton* of build time. Cool!

The whole nervous system

Random tasks…

Finally getting a lot of little cleanup tasks done while the avionics harness is percolating at Approach FastStack.

First, I installed this…

Mystery device

First person to guess what it is gets a ThermosWorks sticker or a free beer at Oshkosh 2019.

Second, I dug out the cockpit lights from Oplite and fabricated a small bracket to mount them on the roll bar support.

Oplite 6sOplite wires

These lights are extremely well-made by my friend and fellow RV builder Rich Mileika. In addition to Oplite, Rich owns and operates Machine, Inc, a precision machining company in the greater Boston area. If you need quality cockpit lighting, try Oplite…you’ll like ’em.

And lastly, I replaced the stock Van’s flap motor with an upgraded version made by Pat Hatch at PH Aviation Services.

This motor has several advantages over the stock unit. The motor and jackscrew are separate so grease can’t migrate into the motor windings, a common problem with the Vans motor. It also has limit switches to stop the motor at full extension on either end, and also has a position sensor to report flap position to whatever device needs it.

The only downside is that the flap support bracket must be modified to accommodate the new motor. Rather than trying to rework the existing bracket, I bought new parts from Vans and started from scratch…only took a couple of hours, and Pat’s motor will save some wiring work later on.

Panel population progress

I think it’s time to start mounting stuff in the panel. Being an electronics/avionics geek, I’ve waited for this for a long, long time.

Panel population progressThe white labels are mockups of the panel labels I’m having engraved by Aircraft Engravers in Granby, CT.

The G3x GSU 25 ADAHRS is mounted on the subpanel behind the PFD/MFD – makes plumbing the pitot-static lines to the GSU and G5 a little easier. It was hard to get in there with a ruler to lay out hole positions so I made a drill template out of thin Al.

One minor hiccup…the ignition switch locking tab isn’t clocked correctly, causing interference between the switch body and panel support rib. I’ll probably have to grind off the tab and rivet on a new one at the right orientation. The switch label will cover the rivets nicely.

Switch interference

The light at the end of the tunnel…

…is getting brighter – it’s time to start installing and wiring avionics. I’ve been plotting and planning how to mount the Garmin G3x Touch system, radios and transponders and I’ve settled on building a tray which will hold all the remote-mounted LRUs, Comm 2 and transponder.

Here’s a cardboard mockup.

Avionics tray mockup…and the tray with avionics temporarily attached.

Avionics tray fitting 1The GAD 27 and GAD 29 are on the right side. Most of the airframe power interfaces will be through the right firewall passthrough so having these boxes on the right should make wiring a little more straightforward.

GAD 27 and GAD 29The GEA 24 engine interface is on the left side as most of the engine sensor wires will come through the left firewall passthrough. Guess where the AoA CPU is going?

GEA 24More pics? Sure, I’m glad you asked.

The avionics tray from overhead

The tool that got away

Sometimes you see a really cool tool that you think about buying, but you don’t need it at the time – and when you do need it, it’s no longer available. Such is the case with the Terminal Tool.

The Terminal Tool

I had originally bought a hydraulic crimping tool from Harbor Freight, but the dies that came with it weren’t compatible with quality Amp terminals.

HF crimper result

Fortunately, a friend and fellow RV builder at KASH had a Terminal Tool. It’s easy to use, and makes first-rate crimps on large cables.

Terminal Tool

Terminal Tool crimp

Racking and stacking

Getting a little frustrated with tweaking engine stuff, so in preparation for permanently installing the subpanel I started working on fitting the avionics racks.

2016-09-18-16-42-21

The GMC-307 autopilot controller was easy.

A trimmed subpanel

Wasn’t so easy to get a correctly-aligned hole in the subpanel to accommodate the GTN-650 rack (the comm/WAAS GPS/VOR/localizer/ILS does-everything box).

Aligning the radio racks together

Also had to make sure the GTN-650 and GMA-245 (that’s the audio panel) racks were correctly spaced from each other.

A lot of filing and fitting to get to this point

Took a lot of filing and fitting to get to this point. The rear rack mount “ears” are actually riveted to two 0.063″ angles that will be held in place by nutplates. I would’ve preferred just to attach them to the front side of the subpanel, but the rack attachment fasteners are too close to the subpanel to allow that.

Another bit of visual progress - the radio stack fitted

A nice bit of visual progress, don’t you think?

The last really big check

…I hope.

I wrote it to Tim Hass and the folks at Approach Fast Stack for a Garmin 10.3″ G3X Touch EFIS system with Sirius XM, GTN-650 GPS/Nav/Comm, GTX-45R ADS-B In/Out transponder, GMA-245 audio panel, GMC-307 autopilot mode controller, two GSU-28 autopilot servos, and all the associated Garmin boxes that go into a G3X installation.

All these gadgets will be connected to one of Tim’s Fast Stack Pro-X hubs, which will make wiring significantly easier and neater.

ProX hub

It’s worth the (relatively) few extra dollars to speed up avionics installation, and the resulting product will be a lot easier to upgrade should I ever want to.

Two really expensive boxes…

Two really expensive boxes

…and their contents.

The contents of two really expensive boxes