Galileo - A Sophisticated Glass Cockpit for Experimental Aircraft

All of the information provided here is for educational purposes only, and no warranty is made, expressed or implied, regarding its accuracy. Any use of this information is at your own risk. All avionics installations must follow FAR regulations and other applicable rules. These instruments are intended for use in experimental aircraft only.

While constructing a Cozy MKIV (see Orion link above), I investigated many avionics options, but found most of them distasteful. Avionics and engine subsystems are the two areas where current aviation market conditions (lack of competition, difficulty in certifying products, etc.) have the most visible impact. A simple radio stack cooling fan might sell for $60, despite the fact that it is identical to a device used in a computer that sells for $3.

I was also unhappy with traditional "steam" gauges. For various reasons, I had already made the decision to go all-electric (see the Aeroelectric Connection for details). The next step beyond this is the so-called "glass panel," a device that provides an electronic display of the same data as a traditional instrument panel but in a single device. Glass panels have a number of benefits:

1. They provide an integrated, single-glance view of the current flight profile, reducing scan time and pilot workload.
2. They provide additional features that traditional gauges cannot. For example, they can show altitude trends, such as where the airplane will be in 10 seconds. They can also provide data logging, GPS moving map, and other useful services.
3. They use less power than all-electric panels while providing the same benefits. While the alternator is running this is hardly a concern, but during an outage a glass panel could significantly extend flight times, allowing the pilot to land at a suitable airport rather than risk an emergency landing on a short runway (or road).
4. They are much lighter than either steam or electric gauges. Even with four displays in the system the weight savings can be impressive.
5. They provide significantly more functionality for significantly less money.

On the other hand, if you are adventurous, you can also roll your own. I've included a few links that have information you may find useful, and you should also take a look at the Glass Cockpit groups on Yahoo!.:
Al Wick's Glass Cockpit Site
myglasscockpit.com
Jeff and Barbara Wilson's Design

Galileo is my effort at making a glass cockpit system. In a twist compared to other options, I will be distributing this information Open Source, under the Common Public License. You are thus free to use this information for your own purposes, even commercial, although if you do so the terms of the CPL require you to make this original code and information available to the recipients. Upon request, I will also make kits and components available, prebuilt and tested. However, my fees will only go to cover my time and materials making the components. The intent of this site is to provide the information freely to all visitors.

Overall Architecture
Galileo is composed of a distributed network of sensors and display panels. Each display will typically show a different type of information, such as engine instruments or GPS moving map, but they are also interchangeable; if one panel fails another may be switched to display the former's data. Devices communicate via a Controller Area Network (CAN) bus, a highly reliable communications bus that tolerates a number of failure modes (such as short circuits) without bringing the system down.

The most important feature in the design is modularity. It is not necessary to install the entire system for it to function properly. Budget-conscious builders could start with a single function, such as one display and one or two engine sensors, and then grow the system as budget and feature desires allow.Read more...

Sensors
A sensor is a data collector, periodically transmitting that data on the CAN bus where display modules may collect and use it. However, sensors may also receive data. For example, the pitch and roll trim control module is both a data transmitter (indicating the current position of each trim servo) as well as a data receiver (accepting trim movement commands from the autopilot). It is easy to conceive of a complete fly-by-wire system using this architecture, although Galileo is not this ambitious. Read more...

Displays
Display panels are moderately-sized sunlight-readable PDAs. All of the displays run the same software, and can be switched to a different display mode at the touch of a button. Because they are PDAs, they can also be brought into the FBO for flight or weather planning, or brought home for data analysis (they record the data they see). The data recording facility is invaluable during flight testing, as it allows the pilot to "replay" each flight, looking for anomalies (such as brief temperature spikes) that might not have been noticed otherwise. Read more...

Software
Both sensors and display panels run various software modules that allow them to do their work. Sensor modules are microcontroller-based (where required), and thus use very small and efficient single-task programs. These are not portable, but because they are so small rewriting them would be straightforward. Display panels use Java-based applications, which not only allows them to be ported to different displays but also allows the builder to install new functionality by downloading and installing additional Java applications. Read more...

Installation in Cozy MKIV #1147
As mentioned above, Galileo is modular, and may be scaled from a single display and sensor providing a single function, to a network of sensors and display panels providing a complete replacement for traditional instruments. All information about the system is on the pages above. The information listed below is specific to my installation in my Cozy MKIV, for builders who wish to follow in my footsteps.Read more...

Module Summary:

Description	Build Cost	Weight
GPS Sensor	$100	9 oz.
Magnetometer Sensor	$100	5 oz.
Attitude Sensor	$200	8 oz.
Engine Sensor 1	$50	4 oz.
Engine Sensor 2	$50	4 oz.
Air Data Sensor	$50	4 oz.
Environmental Sensor	$50	4 oz.
Trim Sensor (excludes servos)	$75	6 oz.
Four displays	$1,800	36 oz.
Total:	$2,475	5 lbs.

Items Replaced: (Prices based on Aircraft Spruce, non-TSO'd if available)

Description	Price	Weight
Garmin GPSMAP 195	$895	22 oz.
Blind Encoder	$150	6 oz.
Vertical Speed Indicator	$110	0.9
Heading Indicator	$900	2.6
Turn Coordinator	$300	1.9
Voltmeter	$30	0.2
Ammeter	$30	0.2
Clock	$50	0.2
Oil Temperature	$40	0.4
Oil Pressure	$40	0.2
Coolant Temperature	$40	0.4
Engine RPM	$40	0.4
Outside Air Temperature	$80	0.2
Tachometer	$80	0.2
Total:	$2,785.00	10.45 lb.

The list above is extremely generous. For example, my configuration will provide a high-resolution color GPS moving map with a host of features, like the possibility for terrain display. The GPSMAP 195 is black and white, and fairly basic (although it does a good job). Also, my setup provides equal or greater functionality to a VM1000 engine monitor, which costs $3,145, a Dynon EFIS, which costs $2,200 with a backup battery (I included this since the PDAs all have them), a 2-axis autopilot (at least $4000), etc., all of which I excluded.