MGL Avionics Stratomaster Enigma User manual

Stratomaster Enigma
Preliminary installation documentation

General
This document describes the installation requirements for a single Enigma panel.
This document is work in progress and still very incomplete. Please check on our website
for any updates to the Enigma installation documentation.
Electrical installation
This image shows typical wiring for an Enigma panel.
In this case a small backup battery is used. Note that two power switches are required.
One power switch for the main incoming 2 or 24 V feed (switch in positive supply lead),
another for the backup battery.
In flight, both switches would be “on” allowing the charging of the backup battery.
Preflight check would involve switching main power on, then battery power on. Check of
battery power would involve switching main power off and verifying that Enigma continues
to operate. Voltage on the backup battery should be measured by means of the backup
voltage readouts which can be placed on any display.
In this case the secured supply output is used to power a SP-3 or SP-2 horizon sensor
and/or compass. This supply will draw from the backup battery in case of main power fail.
Please note that it is not permissible to connect other high current users to this supply

output. Maximum permitted current draw from these terminals is 0.5A. Under no
circumstances connect transceivers or lighting to these terminals.
Recommended backup battery types are 2V sealed lead acid with capacities ranging
from Ah to 2.5Ah.
In case of a dual panel installation, it is permissible to connect both panels to a single
backup battery.
Please note that inline fuses or over-current sensing interrupters must be installed as
shown. It is wise to install these in such as way that it is possible to replace fuses in flight
or reset a circuit breaker.
This image shows a photo of a typical, principle installation wiring. Note the use of ferrite
beads on ALL wires leaving the instrument. Four ferrite beads are included with each
instrument as standard. These ferrite beads are vital to eliminate any RF interfering signals
that may cause radio interference particularly on VHF radios.
Beads may or may not be required, this will depend highly on installation and routing of
wiring in the aircraft. As a rule, follow these guidelines:
•Antenna cables must never be routed alongside other wiring.
•Place antennas as far away from any digital instrumentation as possible.
•Avoid ground loops which can act as powerful, short range transmitting aerials for
weak signals. Ensure that your aerial has a good and correct ground plane.
•Never share power or ground cables between RF equipment and digital equipment.
Each requires their own routing of power to the battery.
Notes on the use of ferrite beads:

Install ferrite beads close to the source of interference. It does not help much if there is two
meters of cable between source and ferrite bead. Distances as shown in the photo are
correct.
Multiple wires may share a single ferrite bead with the exception of the GPS aerial antenna
which requires a ferrite on its own.
In case of the GPS aerial, loop the cable twice through the ferrite. Notice the size of the
loops. Never loop this cable tightly, you will greatly reduce the sensitivity and performance
of the GPS system if you do. The size of the loops in the photo is correct.
Other wiring should be looped tightly as shown in the photo.
The more loops you can place around a ferrite, the better the effect.
Please note again that ALL wires leaving the instrument should have a ferrite bead if you
have problems with RF interference.
Identifying RF interference sources:
Enigma creates a signal that is highly dependent on the contents of the display and may
sound like an “angry grrrrrr”. If you have radio noise, change the screens to see if the
noise pattern changes as well. If it does, start identifying which cables are used to transmit
the noise to your radio. Enigma itself does not transmit a significant signal due to strict EMI
design techniques however, small signals may readily leak and use any attached wires as
convenient antenna for transmission. Thus, remove the wires one by one. Start with the
GPS – this is a long wire and may contribute significantly. You can remove this wire with
the instrument switched on. Then try the audio and airtalk cables which can be unplugged
easily, This way you will quickly find the source. Place ferrites as needed or reroute the
cable to improve the situation.
A good installation should not generate any noticeable RF interference on your VHF radio
with the squelch fully opened, you should hear only static noise.
Note that inside metal hangers noise interference may be considerably worse in some
cases. Always check outside a hanger and move at least 00 ft away from any hanger
structure.

AOA port types
Photo of an experimental single port AOA
probe mounted next to the pitot tube on the
wing strut of our Jora aircraft. This probe,
made from wood, works very well indeed.

Ergonomical considerations
Enigma contains a very advanced LCD display that is able to perform well in direct sunlight
conditions. In order to achieve this and further ensure low power consumption, the display
contains a “light director”. This focuses the major part of available light towards the viewer,
creating a brighter image but also reducing the effect of ambient light falling at an angle
onto the display surface.
In order to take optimum advantage of this, the panel should be installed such that the
pilots eye will look onto the panel in a vertical -30 to +20 degree angle maximum. The
negative angle would be applicable for a steeply sloped panel where you would be looking
onto the panel from below.
This can be achieved in two ways: Mount the instrument as high as possible onto the
panel. This also aids the pilot as the image is closer to the windscreen avoiding eye fatigue
while constantly changing view from the panel to outside the aircraft.
If this is not possible or can only be done in a limited way, consider tilting the instrument up
slightly in order to aim the picture towards the pilot.
Idealized view of a sloped panel to optimize viewing quality. This image overdoes this
somewhat, in practice the panel does not have to be angled this much and if it is possible
to install the instrument relatively high on the panel, it is not normally required to mount the
instrument angled.
Preferred horizontal viewing angles are within left 50 degrees to right 50 degrees. If a
single instrument is to be shared between two pilots seated side by side, consider
installation of the instrument towards the center of the panel or alternatively angle it
towards the disadvantaged side somewhat. The panel can be read as angles greater than
+/-50 degrees but with reduced brightness.

Transponder interface wiring
The transponder interface produces Gillman (Gray) coded altitude information suitable for
connection to a mode C transponder.
Connections using the standard code identifiers are shown here. If your transponder does
not support signals D4 and D2, leave them unconnected. At least one of the ground wires
should be connected to the corresponding ground terminal of your transponder.

Transponder connections for popular models

Transponder interface wiring for Microair T2000 (ignore pin numbers on DB 5 connector).
Also line “Encoder power” is not used with Enigma.