Avionics and Instrumentation

This page describes the avionics that I was looking at way back in the early stages of this project (2003).

Like most builders, looking into avionics and engines seems to occupy a lot of my time. I am planning on doing an all-digital / all-electric panel. Depending upon which engine monitor and which EFIS that I go with, there should be no analog gauges in the panel, whatsoever. In this section, I will be showing examples of the equipment that I am looking at. Of course, I am not even close to being ready to buy any instruments yet, so this will change over time. In the mean time, I can dream.

Currently, there is a good selection of afordable, or close to afordable, flight and engine instrumentation. This includes engine monitors, EFIS (Electronic Flight Information Systems), moving maps, and other things that fall under avionics and instrumentation. Who knows what will be available in two years when I hope to be seriously shopping.

Although I am not ready to install anything yet, I still need to be aware of what my choices might be, so I can prepare the airframe to accept things in the future. For example, one of the EFIS units likes you to install the magnetometer in the wing tips. Also, this is a good place for the comm antenna, so I need to provide routing for cables and such, when I build the wings.

Engine Instruments

The first thing to take care is all of the engine instruments. This includes Oil Pressure, Oil Temperature, Ammeter, Voltmeter, Exhaust Gas Temperature (EGT) for each cylinder, Cylinder Head Temperature for each cylinder, Outside Air Temperature (OAT), fuel levels, and possibly fuel flow gauges. This is a lot of gauges to monitor, and they take up a lot of panel space. I plan on replacing all of these gauges with an engine monitor.

An engine monitor takes the inputs from all of the sensors that would normally be attached to the individual gauges and connects them to a single board. The information is usually displayed on a single LCD display that has several pages to display all of the data. Instead of monitoring each gauge, you can monitor a single display. Less often monitored information can be relagated to another page, that you have to select occassionally.

Besides compressing all of these gauges into a single display, an engine monitor can also help out with the monitoring by providing alerts when specified conditions are detected. A nice feature is that you can usually program what special conditions to monitor, and what the ranges are.

So, what am I looking at? My first choice was, originally, the RMI Micro Monitor from Rocky Mountain Instruments, as well as their RMI Micro Encoder.

I still like this unit, since it is inexpensive and does most of what I need. The price of the MicroMonitor is about $1300, but you can build it as a kit for $1000. The price of the MicroEncoder is about $1200, with the kit around $900. I like the idea of a kit, more to build, less money. I probably would not buy the MicroEncoder, since all of its features are handled by other EFIS units that I am thinking about.

I said "originally" because the MicroMonitor has a few problems. It does not handle fuel level sensors, and it displays temperatures in Centigrade. One other thing is that the unit only monitors a single EGT and a single CHT sensor. You have to use an external switch to select each cylinder.

I emailed RMI about the fuel gauges and they said they have no plans to support fuel level sensors. Note, that they do show fuel quanity, but that is based upon the fuel being subtracted from the original quanity, which the pilot has to enter on each flight. I don't know about you, but I don't like to have to enter how much fuel is in the tanks before each flight. I don't know why they do not want to support fuel level sensors, since they are some of the simplest sensors to monitor. Even the new capacitive sensors are not that big a deal.

Other guys on the RV mail list have asked if they can get degrees F on the Micro Monitor, and they were told that there are no plans to upgrade the MM to Fahrenheit. Again, this is extremely simple to do. Plus, Fahrenheit is already supported on the RMI Micro Encoder. I am a little leary of a product that has such dubious support. Otherwise, I still kind of like the unit.

My next choice would be the EIS 4000 by Grand Rapids Technology.

The EIS 4000 does everything the Rocky Mountain Micro Monitor does, and more. It supports both resistive and capacitive fuel level sensors, it supports 4 EGTs and 4 CHTs without a switch. And it displays temperatures in Fahrenheit. Plus, it costs about $1000. Of course, you don't get to build it, but that's ok--I have plenty of building to keep me busy.

One thing that is really nice about the EIS 4000 is that it can also display its information on the EFIS Horizon Series I monitor, which I am also looking at. If I go with the EFIS Horizon Series I, then I will also use the EIS 4000. Note, that this unit is the one that has been selected by the Eggenfellner Suburu conversion.

There are a few other engine monitors that I have looked at, but most of them were for ultra-lights. The RMI and the GRI are the two that I like the best. Now, on to those EFIS systems that are really cool.

Electronic Flight Information Systems (EFIS)

There are several ways to go with the EFIS. I could simply buy one EFIS from Dynon Development,

Dynon Development, and not have any backup. This is a really neat and inexpensive instrument for about $2000, that I saw first-hand at an EAA meeting in August of 2003. It is small, but very nice.

Another option would be to purchase two of these units, and have one for the pilot and one for the co-pilot. Add an alternate battery system, and this would be a nice system with plenty of backup for about $4000 plus whatever the backup battery system costs. Of course, I would have to have a separate GPS system with moving map, since this is a flight instrument, only. Still, a very reasonable system.

Another system that is really nice, but a little more expensive is the Horizon EFIS Series-1 system from Grand Rapids Technology.

This system has several different configurations that are as simple as a single engine monitor, or a single flight instrument display with moving map, all the way up to multiple monitors with engine monitoring, flight instruments, and GPS moving-maps. You can either combine the engine monitor with the flight instruments, or put them on separate monitors.

The base Horizon EFIS Series-1 runs about $6000, and includes a monitor and an air data computer for flight instrumentation. Add the EIS 4000 from above, and you have engine and flight instruments all in one package for about $7000. A dual monitor setup is about $9000. This allows the engine monitor or moving map to be displayed on the second monitor, with flight instruments on the first. This would also allow flight instruments on both the pilot's and co-pilots side For $13000, you get two air data computers and two monitors which allows full backup of the flight instruments. This is starting to get a little steep, but I like the $9000 setup.

Next, we have the DigiFly FMS100 from Italy. This system is very similar to the GRT in capabilities and price.

Primary Flight Display "PFD"

Moving Map

Engine Instruments

The FMS100 is sold in the US by Composite Design, Inc. A single monitor system with flight instruments and engine monitor is about $7100. A dual monitor system is around $10000, with a triple monitor system coming in at $13000.

Radio Stack

My radio stack needs are simple. I would like to have a radio with a VOR, but they are relatively expensive, plus the VOR system is slated to be decomissioned in a few years (yeah, right). So, my current plan is to have a single Comm Radio, a GPS of some sort, and a transponder.

I could go with a Bendix-King KX-135A, which would give me Comm and GPS, but it costs $3000, and the GPS is pretty dated. They make the KX-125, which includes Nav and Comm, with a built-in Course Deviation Indicator (CDI). This goes for about $2600, and a Transponder would be around $1500.

What I think is a better solution is to cover the comm radio and transponder with something from MicroAir in Austrailia. These guys sell a 760 channel comm unit and a transponder. Both units are very small, and each fits in a standard 2 1/4" cutout. They have several packages. The Works Combo Kit includes both a M760 comm and a T2000 transponder, plus a 4-place intercomm, transponder antenna and two wiring harnesses for $4000 Australian (about $2800, depending upon the day of the week).

I would then need some sort of GPS moving map. There are several on the market that would be acceptable. I could use my portable GPSIII Pilot unit from Garmin, but I think I would really like something a little larger and with color. By the time I get this airplane built, the GPS III is going to be pretty dated.

There are also several companies selling GPS moving map software for a Compaq and other hand-helds, but I think there are better options. There is the Skymap IIIC from Bendix for about $2500. That's nice, but a bit much. I kind of like the EKP-IIIC from C-MAP. This unit is intended to be a portable knee-board, but it is huge. It would take up a lot of panel space, and look kind of funny, but it is relatively inexpensive at around $1700, but you do get a large display.

Of course, the best solution would be to go with the GRT or DigiFly EFIS and add a GPS receiver for moving-map.

As you can see, there is a lot to chose from, even now (2003). I can't wait to see what is available in 2005. More to come...