My Glass Cockpit
NOTE: Anybody with a Garmin x96, Flight Cheetah, AnywhereMap, or other modern device will recognize that the information below is hopelessly out of date.
I conceived of an EFIS device in the late 1980's, and had written all the software and produced a working model in the early 90's, when most glass cockpit products were in the $10,000-and-up range and out of the reach of most small aircraft owners. But I was not able to test my device, because I was spending most of my spare time building an experimental aircraft.
I'm leaving this historical page up for a short while longer, for the sake of posterity and to spark the creativity of anyone who has the inclination to play with this kind of stuff. But I am no longer making any attempts to catch up with the products that are already on the market, and at this time, include things like XM Weather and terrain avoidance.
Important News! The tablet computers I have researched radiate too much in the aircraft band.The Fujitsu 1200 has a very strong signal at 120MHz and a lot of birdies all around the band. I studied the Stylistic 2300 as an alternative, but it also has a radiation problem. Some of the photos on this page show the Stylistic 1200 or 2300, which have identical dimensions and accessories.
But the future may well lie in a new breed of "carputer" components that are becoming popular and can be adapted to aircraft:
This technology is so new, I am just beginning to accumulate information on it, but here are some photos of the display and computer board: Stay Tuned!OverviewThe Dragonfly I am building has a fairly small instrument panel. Its height is only marginally adequate to accomodate a pair of standard-sized flight instruments.This Glass Cockpit will replace 8 instruments (holes) - namely the ASI, altimeter, turn & bank, DG, VSI, artificial horizon, GPS, and OAT thermometer - with just 2 holes. Although I have designed some redundancies into the system, I do not intend to attempt to fly IFR with this arrangement, so even if the entire system dies, I can continue to fly.
On this page, we will primarily address the Glass Cockpit, which consists of the following software modules:
One of the primary design criteria for the system was that all components be reasonably cheap and be available off-the-shelf,
without requiring a lot of custom engineering.
There are no gyros involved in this system, which would add thousands of dollars to the pricetag.
I am planning to make this system available to other interested experimental aircraft builders.
The choices of computer and GPS are up to the builder, and you should test them carefully before committing to your choices.
The autopilot requires some work to mount servo motors and adjust them to the specific aircraft.
If no autopilot is desired, the system becomes even simpler to build.
If you are seriously interested, and you are able to use a soldering iron and not afraid to do some experimentation of your own,
please join our Yahoo eGroup.
If on the other hand, you want a complete turnkey package with gyros and everything, and you are willing to spend several thousand $$$ to get it, then by all means check out Grand Rapids Technology, Dynon Development, Blue Mountain Avionics, Becker, Sierra Flight Systems, or Archangel, which have some very slick packages for sale. NOTE: Throughout my life, I have always been much more interested in putting theory into action, turning designs into reality, and in practical application rather than advanced theory. That has allowed me to develop several software products and get them on the market in less than a year, while the theoreticians are still slaving away at Microsoft and Carnegie Mellon University TEN YEARS later, saying it can't be done. SO, if you are looking for the ULTIMATE in PERFECT glass cockpit and are willing to spend many thousands of dollars and wait an indefinite period for a solution that incorporates every aeronautical theory, you might take a look at some other glass cockpit projects that have been in progress for several years and still have years of work ahead of them.
 CPU and RMI MicroEncoder being bench-tested. Note the two 6V lantern batteries taped together sitting on top of the MicroEncoder behind the panel to produce a cheap 12V battery that is portable and light weight for short tests. Hardware ComponentsWhat looks like an LCD display is actually a full-blown computer: a Fujitsu Stylistic 2300. I chose it because:
Not even really discussed as part of this Glass Cockpit is the separate engine and fuel monitoring system, comprised in my case of a Grand Rapids Technologies EIS, which will replace the 12 holes required by most panels (oil temp, oil pressure, 4 CHT, 4 EGT, tachometer, carb air temp) with a single instrument. Since this is a standalone instrument that is not connected to the Glass Cockpit, it will not be covered here, but its space-saving advantages are obvious! The software is designed so that no full-size keyboard is needed to perform all control functions. The entire Glass Cockpit can be controlled from an external numeric keypad, including waypoint selection, autopilot control, etc. These functions can also be performed to a certain extent with the stylus and touch screen, which provides redundancy.
Testing the Parallel Port Relay board. It is connected to the printer port of the computer and a small external 12VDC power supply (to simulate the aircraft battery) and takes control inputs from the computer's autopilot, triggering various relays to activate the pitch and roll servos. (The computer is wearing its docking station in this photo, which will not be attached in the cockpit.) Another photo showing two of the test LEDs illuminated on the board Total cost breakdown and links to vendors:
AutopilotThe autopilot allows the following:
 Alex Strong pitch trim servo installed and connected to elevator pushrod in center console. (Don't worry, all those hoses will be routed out of the way later.) Glass Cockpit DisplayHere's what the Glass Cockpit display looks like. In the center is a moving map display, always upright to North, and always with the aircraft centered in the middle, but rotated in the proper direction. The purpose of the map is not to act as a replacement for a sectional chart, but rather for gross recognition of large-scale landmarks and such.
The maps can be downloaded on the web as "ChartChunks" from AeroPlanner.com for $4.95 for a map
of about 86nm by 86nm size (1600x1600 pixels).
By using the OziExplorer georeferencing files, the Glass Cockpit automatically adjusts to the proper scale factors
and properly displays the aircraft on the map. The task of georeferencing previously took about 10-15 minutes per map and
was a tedious process. If someone else has already done it, why re-invent the wheel?
A compass is shown at the top of the display. Below the moving map are the flight instruments. On the left side is what is commonly called a Primary Flight Display (PFD), consisting of an Artificial Horizon (AH) and tape displays on the left and right. The AH displays Rate of Climb and Rate of Turn, as opposed to AOA and Bank Angle. A tape-style Airspeed indicator is to the far left, with placards all critical airspeeds from values the pilot can store permanently in the computer. To the right of the AH is a tape-style Altimeter. To the far right is a Horizontal Situation Indicator (HSI), showing current track. If a Waypoint has been selected, the Course, Distance (DME), ETA (TTG) in minutes are shown. If the autopilot has been engaged to steer to a heading or waypoint, a bug is shown on both the HSI and AH (as shown). You can click on the AH or the HSI to minimize them both, if you need to look at a part of the map that is hidden underneath. When you minimize them, the airspeed and altimeter tapes disappear also, moving their digital displays up next to the compass. (example) Click again on either of the tiny minimized instruments, and they are moved back in place and maximized to normal size with the tapes. The Glass Cockpit can display the entire screen in normal color, or in Black and White as required by the Fujitsu, and the gray scale is optimized for display in that mode. I obtain Compass, Altimeter, Rate of Climb, and Airspeed data from the Rocky Mountain Instruments MicroEncoder. If you install the temperature probe on the RMI, I use True Airspeed and True Altitude, instead of the Indicated versions. Should the RMI fail, the computer will automatically switch to Ground Track and Ground Speed from the GPS as substitutes for Compass and Airspeed. The Servo Status Indicator shows graphically the position the computer thinks the "stick" is in, based on the servo motor positions. This will probably only be required during initial system debugging. If you add an external 10-key numeric pad, you can also call up Airport Information. Enter an airport/navaid identifier, and the Glass Cockpit shows distance, bearing, and time to arrival. The external Keypad allows you to place your hand on the keyboard and scroll up and down through AAA-ZZZ 3 character abbreviations without moving your hand from the keypad. Press Enter to select. The computer looks up the abbreviation in a database on the hard disk, computes distance, bearing, and ETA, and displays it in the Waypoint window. On October 9, 2001, I also added the ability to touch the screen with the stylus, and the Glass Cockpit will go look for the closest airport to the point you touched, and will use that as the new Waypoint selection. If the autopilot's Heading Hold is engaged, it will automatically start heading in that direction. You can also momentarily display Runway Information on the moving map adjacent to the airfield. After a waypoint (airport) is selected (see above), 2 keystrokes on the external keypad will cause the computer to look up info in the database on the hard disk, and display runway and field elevation on the moving map next to airport.
A configuration settings screen allows you to set the serial port numbers and baud rates, change from B&W to color display,
set the critical airspeed values for your particular aircraft, and indicate whether you have a servo relay board attached to the printer port.
These settings are saved to disk and are thus non-volatile.
User Manual for the current release(See the Yahoo eGroup mentioned above for free downloads of the program)Other Items for N75UP but not really part of the Glass Cockpit system itselfAnnunciator Panel
Switch Panels
These are the 2 switch panels I had fabricated from 1/8" acrylic with engraved lettering that allows backlighting. One will go on the left side, and the other one goes in the center. (The passenger has to bring his own toys!) This will be so much nicer looking than drilling holes all over the panel and pasting labels on by hand. Total cost for both panels, including all switches: less than $200! I am sticking as close to Bob Nuckolls' design philosophies, as he appears to make a lot of sense. One of these is to use fuse blocks and not put circuit breakers all over the place that will just tempt the pilot to keep resetting a circuit that has gone bad. I have seen many fires result from that method of troubleshooting. You will also notice that there is no avionics master switch for equally logical reasons. |
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