MLB Bat Version 3 User manual

MLB
Bat Version 3
User Manual
WARRANTY
The MLB Company guarantees this uncrewed aerial vehicle (UAV) to be free from defects in both material
and workmanship at the date of purchase. The warranty does not cover any component parts damaged by use
or modification. In no case shall MLB’s liability exceed the purchase cost of this system. Further, MLB
reserves the right to change or modify this warranty without notice.
In that MLB has no control over the final assembly or material used for final assembly, no liability shall be
assumed or accepted for any damage resulting from the use by the user of the final user-assembled product. By
the act of operating the user-assembled product, the user accepts all resulting liability.
If the buyer is not prepared to accept the liability associated with the use of this product, the buyer is advised
to return this system immediately in new and unused condition to MLB.

TABLE OF CONTENTS
INTRODUCTION......................................................................................................................1
SYSTEM COMPONENTS.........................................................................................................2
SYSTEM OVERVIEW...............................................................................................................3
HARDWARE IN-DEPTH PROCEDURES ................................................................................4
Fuselage..................................................................................................................................4
1) Nose Assembly............................................................................................................4
2) Airspeed Probe............................................................................................................5
3) Power Switch ..............................................................................................................6
4) Serial Port ...................................................................................................................6
5) Access Hatch...............................................................................................................6
Tail Section.............................................................................................................................7
1) Tail Surfaces Removal & Attachment..........................................................................7
2) Tail Boom Removal & Attachment..............................................................................8
3) Tail Inspection.............................................................................................................9
Wings .....................................................................................................................................9
1) To Attach Wings .........................................................................................................9
2) To Detach Wings.......................................................................................................10
3) Wing inspection.........................................................................................................10
Propulsion.............................................................................................................................11
1) Propeller....................................................................................................................11
2) Fuel System...............................................................................................................11
3) Engine.......................................................................................................................12
Tuning......................................................................................................................................13
Flight Computer....................................................................................................................13
1) Aircraft Control.........................................................................................................14
2) Data Link ..................................................................................................................14
3) R/C Receiver.............................................................................................................14
4) GPS...........................................................................................................................14
Video System........................................................................................................................15
1) Video Cameras & Transmitter...................................................................................15
2) Tracking Antenna......................................................................................................15
3) Video Receiver..........................................................................................................17
4) Video Deck ...............................................................................................................18
5) USB Video Adapter...................................................................................................18
Data Modem .........................................................................................................................19
Radio Control Transmitter.....................................................................................................19
Payload.................................................................................................................................20
Batteries & Power Regulator.................................................................................................22
1) Aircraft......................................................................................................................22
2) Ground Station ..........................................................................................................23
Declination Corrections.........................................................................................................24
SOFTWARE IN-DEPTH PROCEDURES................................................................................25
Overview ..............................................................................................................................25
1) Description of aircraft state information.....................................................................26
2) Description of map display........................................................................................27

Getting Started......................................................................................................................27
Adding & Calibrating Maps..................................................................................................27
1) To Add and Calibrate a Map......................................................................................28
2) To Recalibrate a Map ................................................................................................28
3) To Remove A Map From the Database......................................................................29
4) To Display a Different Map.......................................................................................29
Creating a Flight Plan............................................................................................................29
1) Map...........................................................................................................................30
2) Adding Waypoints.....................................................................................................30
3) Return To Home Mode..............................................................................................31
Editing Waypoints ................................................................................................................32
1) Waypoint Action .......................................................................................................32
2) Camera Action...........................................................................................................33
3) Altitude .....................................................................................................................34
4) Airspeed....................................................................................................................34
5) Waypoint Location....................................................................................................34
Using and Editing Existing Flight Plans................................................................................35
Image Mosaic Flight Plan......................................................................................................36
Initializing the Aircraft..........................................................................................................37
Re-tasking Aircraft................................................................................................................40
Reviewing the Aircraft’s Course ...........................................................................................41
Shut down Aircraft................................................................................................................41
Saving and Loading Flight Data............................................................................................42
Flight data format..................................................................................................................42
Flight Plan Format ................................................................................................................43
Configuration file format.......................................................................................................44
Autonomous takeoff procedures............................................................................................45
Autonomous landing procedures...........................................................................................45
Voice Error Messages ...........................................................................................................46
Tutorial 1 (Creating a flight plan)..........................................................................................46
1) Getting started...........................................................................................................46
2) Add a Map.................................................................................................................46
3) Create a Flight Plan ...................................................................................................46
OPERATING INSTRUCTIONS...............................................................................................49
Advanced Preparation...........................................................................................................49
Flight Operations ..................................................................................................................49
1) Airplane Setup...........................................................................................................50
2) Ground Station ..........................................................................................................50
3) Takeoff......................................................................................................................51
4) Landing.....................................................................................................................53
5) Post-flight Operations................................................................................................53
SPECIFICATIONS...................................................................................................................54
CHECK LISTS.........................................................................................................................55
Advanced Preparation...........................................................................................................55
Flight Operations ..................................................................................................................56
FLIGHT TRAINING................................................................................................................58

Ground Station Operator.......................................................................................................59
Aircraft & R/C Operator .......................................................................................................60
Catapult Operator..................................................................................................................62

INTRODUCTION
The MLB Bat UAV is a low cost aerial sensor platform that is convenient to deploy and operate.
It can be launched by hand or with a catapult, and the groundstation provides an intuitive
interface for defining a flight plan or airborne re-tasking with a series of waypoints. In flight, the
aircraft transmits telemetry and video to the ground station allowing a single operator to monitor
the flight and identify points of interest. A stabilized, 3-axis, geo-referenced camera provides
real time video surveillance, which is also recorded on the ground station for post-flight analysis.
While the aircraft is capable of fully autonomous launch and recovery, a competent radio control
pilot is essential for safe operations.
While every effort has been made to ensure safe and reliable operation, there are potential
dangers associated with operating the Bat UAV. On the ground, the propeller and catapult can
cause injury to operators, and loss of control while flying can lead to injury and damage to
persons and property. Bystanders should be kept well clear of the airplane while it is running.
Use the system with due care!
A statistical survey of current UAV operations has shown that they have a significantly greater
chance of crashing than manned aircraft. MLB has attempted to make the Bat as reliable and
easy to operate as possible, but it is the operator’s responsibility to operate the system properly.
Exercising caution, using sound judgment, and adhering to the procedures outlined in this
manual will give the best chance of extending the life of the Bat.

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SYSTEM COMPONENTS
Bat Version 3 aircraft
The groundstation components are stowed in the black Pelican case, and consist of the following
items: Laptop computer
Video deck (Digital 8 format)
Video receiver
Video to USB device with cabling
Video Antenna
Tracking antenna system with tripod
Modem
Radio control transmitter
Power cables for video receiver and modem
Serial cable for modem
Data/Power cable for tracking antenna with serial/USB adapter
Coaxial video cable
12V Battery
A field box contains components to assist with fueling the aircraft and starting the engine. Items
include:
Electric starter
Fuel pump
Fuel container

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SYSTEM OVERVIEW
The drawing in Figure 1gives a basic overview of the system’s communication structure.
1) The Bat UAV, with a self-contained flight
computer capable of flying aircraft with only
a GPS signal
2) 72 MHz R/C transmitter used for manual
modes only; can be disabled with 900 MHz
data system
3) 900 MHz 2-way modem for flight data
and in-flight re-tasking; 10 km range with
omnidirectional antenna
4) PC laptop computer with flight data,
moving map display of UAV, and graphic
user interface for mission planning and
updating
5) 2.4 GHz real-time video downlink; 10 km
range with 12 dBi directional antenna
Figure 1. System diagram
R/C PCM
8-Channel Uplink
72 MHZ
Video
Receiver
Real-time
Video
MLB
Ground
Station
Wireless
Modem
900 MHz
Flight
Planning
Real-time Data
GPS
5)
3)
1)
2)
4)

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HARDWARE IN-DEPTH PROCEDURES
This section provides detailed information on how to perform specific tasks related to the Bat
UAV hardware. Detailed procedures for using the MLB Groundstation software are provided in
the next section. These sections are not a set of operating instructions. A specific set of
sequential procedures for operating the Bat is provided in the OPERATING INSTRUCTIONS
section.
Fuselage
This subsection contains information on the nose assembly, airspeed probe, flight computer,
power switch, serial port, and access hatch. The lightweight airframe is rigid and very durable
due to its fiberglass, carbon fiber, and Kevlar composite construction. Fuselage repairs or
modifications should be done by MLB.
1) Nose Assembly
The nose assembly is a removable pod that can be changed to meet a variety of payload needs.
Figure 2shows the nose with a gimbaled, 3-axis turret that contains wide and narrow angle color
video cameras. An infrared camera can also be included with the video cameras. Alternatively,
the nose assembly can carry a fixed video camera and a special agricultural imaging system.
Along with the cameras, the video transmitter and its antenna are part of the nose assembly.
Other custom payloads can be integrated into the nose.
To inspect the turret for proper operation, apply a gentle torque by hand to slowly rotate the
turret ball. Check freedom and range of motion about all axes. There should be small, even
resistance from the servos, but no binding or blockage. If movement is restricted, do not attempt
to force it; rather, find the cause of the problem before proceeding. As with any servo-actuated
surface, care must be taken when moving. Moving a servo by hand is OK if done slowly and the
servo does not bind, but rapid movement of the servo’s output shaft or use of excessive force can
damage the internal gears. Inspection of the turret for proper operation must be conducted prior
to turning on the aircraft. Once the system has been turned on and initialized, the servos cannot
be moved.
Prior to each flight:
•Check that the nose assembly is securely
mounted to the fuselage.
•Check the turret for proper function.
oA visual inspection and movement
over a small range of motion should
suffice in most cases.
oA full check of the turret’s range of
motion only needs to be conducted if
there is a possibility it was damaged
on a prior flight or in transport.
•Check that all camera lenses are clean.
Figure 2. Nose assembly and airspeed probe

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2) Airspeed Probe
The airspeed probe is mounted just aft of the nose cone on the left side of the fuselage and
extends forward to the front of the nose. To obtain proper airspeed readings the probe needs to
be clear of obstruction and properly fitted to the mount, as depicted in Figure 2. Any blockage in
the probe can have serious consequences for autonomous flight.
Blockage can cause an erroneous measurement of the airspeed. In almost all cases, the airspeed
will read much lower than the true airspeed and the aircraft will dive into the ground trying to
increase the airspeed reading. In normal autonomous flight, the flight computer will compensate
for a low airspeed by pitching the nose down and then increasing the throttle to compensate for
the loss of altitude. If corrective action is not taken immediately, the aircraft will quickly enter a
full-power dive, with disastrous consequences
In an autonomous launch, this would occur a couple seconds after launch. In a manual launch,
the aircraft would begin to dive when the R/C transmitter is set to autonomous mode. To avoid
crashing in either case, revert to manual mode immediately and land the plane.
•Mount the airspeed probe by sliding it into its mounting bracket.
oThe shorter portion of the airspeed probe slides into the mounting bracket.
oEnsure that about half of the small rubber tubing slides over the larger tube of the
mounting bracket.
ALWAYS check that the airspeed probe is clear before flying.
•Inspection with probe mounted on aircraft
oLook into the probe and check that the rubber tubing at the back of the probe is visible.
•Inspection with probe removed from aircraft
oRemove the probe by pulling it forward while holding the mounting bracket. The front
portion of the tube will slide out where it is attached with the small piece of rubber
tubing.
oLook through the probe to ensure it is clear.
If blockage is evident:
•Remove the probe from its mount, clear any debris, and remount the probe.
•Check that the airspeed system is working properly.
oTurn on the aircraft and execute the start-up procedure.
oWhen the aircraft is ready for launch, gently blow into the airspeed probe and check that
the airspeed increases on the groundstation display.
Tip: On the ground station, select “Airspeed” on the plot display drop-down box. A
history of the airspeed will then be displayed, so the changes over time can be seen.
oIf the test does not show an increased airspeed on the ground station, there may be
additional blockage, or the airspeed sensor may have been damaged at the time the probe
was plugged.

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A more comprehensive ground test of the airspeed measuring system is also feasible:
•Turn on the flight computer, load a flight plan, select manual launch and complete the
Prepare for Launch sequence (up to but not including engine start).
•Turn on the R/C transmitter, switch to autonomous mode, and gently blow into the airspeed
probe.
•If everything is working properly, the elevators should deflect upward and a moderate
airspeed should be displayed on the ground station.
•Immediately switch back to manual mode. If continuing with the launch sequence, be sure
that the transmitter is set back to manual mode.
3) Power Switch
The power switch, shown in Figure 3, is
located behind the nose assembly on the left
side of the fuselage. It activates the flight
computer, video system, data modem, and
ignition system.
•For Power On, the switch is toward the
back of the plane (direction of the launch
g forces and airstream).
•For Power Off, the switch is forward.
•The locking safety latch is rotated into
position to ensure the power switch
cannot be accidentally turned on.
Figure 3.Power switch and serial port
4) Serial Port
The serial port, located on the left side of the fuselage next to the power switch, can be used for
two-way communication between the aircraft and the ground station without the 900 MHz RF
modems.
•When the serial cable is connected to the aircraft, the other end should be connected directly
to the groundstation laptop computer’s serial port.
•The groundstation-aircraft data link will function exactly as it does with the wireless modems
when using a serial cable connection.
5) Access Hatch
The access hatch is located on the top of the fuselage. The hatch provides access to the battery
lead for recharging and a view of the fuel tank to inspect its level. This is also how the flight
computer and associated electronics are accessed. However, except for battery charging and fuel
level inspection, this area should only be accessed by MLB
To Open Hatch:
•Remove screw at rear of hatch (shown in Figure 4).
•Raise the back of the hatch while sliding it back until tab at front end is free (Figure 5).
To Close Hatch:
•Hold back end of hatch slightly elevated and slide tab under opening at front of hatch.
•Lower back end of hatch so that the screw hole aligns with the fixed nut.
•Insert screw snugly, but do not over tighten and strip screw.

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Figure 4.Access hatch screw Figure 5.Access hatch open
Tail Section
The Bat’s tail is a composite structure with aluminum booms connecting it to the fuselage. The
inverted V tail configuration combines the horizontal stabilizer and elevator functions with the
vertical stabilizer and rudder. As an elevator, the control surfaces move synchronously, both
moving up or down together. As a rudder, the control surfaces move asynchronously. Right
rudder command causes the left tail surface to move down and the right surface to move up. The
tail section, with or without the booms, can be removed for shipping. This takes a few minutes
and requires tools, so the tail is not normally removed for day to day operations
1) Tail Surfaces Removal & Attachment
•Detach the R/C antenna (long thin wire)
from the tail surface.
•Unscrew and remove the bolts that are
located along the tail booms near the tail
surface (see Figure 6).
•Disconnect the servo leads along the tail
booms.
•Pulling evenly on both booms, slide the
rear section of the booms out of the
forward sections. Be sure that both side
move equally to keep the slide joints from
binding.
•To keep from losing any hardware, insert
the bolts back into their holes and loosely
attach the nuts.
Figure 6.Tail boom & servo connections

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•Reattachment of the tail surfaces is simply the reverse process of removing the tail.
oBe careful to ensure that the servo connectors are properly and securely connected.
oRemember to reattach the R/C antenna (Figure 8).
2) Tail Boom Removal & Attachment
•Detach the R/C antenna (long thin wire)
from the tail surface.
•The tail surfaces can be removed or left
attached for this process.
•Support the tail surface so that it cannot
fall as the attaching bolts are removed.
•Remove the bolts that affix the tail booms
to the fuselage (2 bolts per side) .
•Carefully move the tail boom assembly a
few inches out and back from the fuselage
to expose the servo wires where they exit
the fuselage (see Figure 7).
•Pull the servo wires from the fuselage so
that the connectors are accessible.
•Unplug the servo connectors.
•Remove the tail boom assembly.
•Reattach the tail boom assembly by first
connecting the servo wires.
oBe careful to ensure that the servo
connectors are properly and securely
connected.
oPush the servo connectors back into
the fuselage.
oPlace the servo boom assembly into
place, ensuring the servo wires are
properly routed and not pinched.
•Bolt the assembly onto the fuselage (snug
the bolts but do not over-tighten).
•Reattach the R/C antenna to the rubber
band and string with a simple knot.
•The rubber band is used to tension the
antenna and it should be slightly shorter
than the string when fully stretched.
•The string is a backup. If the rubber band
fails, the antenna will not enter the
propeller.
Figure 7.Tail pylon & servo lead
Figure 8.R/C antenna tail attachment

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3) Tail Inspection
•Gently move the elevators/rudders (with the power off) to check that the control surfaces,
servo, and linkage move freely. If the control surface is at full deflection, the angle between
the linkage and the servo might make it difficult to move the servo via the control surface. If
this is the case, do not force it to move. Instead, grasp the servo lever and gently rotate the
servo toward its center position.
•Inspect the servo, linkage, and associated attachments for any loose or damaged parts.
•Check the elevator/rudder hinge lines for tears.
•Check the servo wire connections along the tail boom.
•Check the tail boom connection near the tail surface.
•Check the tail boom to the fuselage connection.
Wings
For ease of transportation and storage, the Bat’s wings are simple to remove and reattach.
Constructed of composite materials including Kevlar, carbon fiber, and fiberglass, the wings are
very light yet rigid, strong and durable.
1) To Attach Wings
•First, note the position of the snap button
on the bottom of the aluminum wing spar
that extends from the fuselage (Figure 9).
•With one hand, hold the wing by its
leading edge near the wing root (thumb on
top and fingers underneath), and use the
other hand to support the wing tip.
•Align the aluminum spar on the fuselage
with the spar tube at the wing root and
slide the wing onto the spar up to the snap
button.
•Using a finger on the hand that is holding
the wing’s leading edge, depress the snap
button (Figure 10) and slide the wing a
few inches farther onto the spar, but stop
before the trailing edge alignment pin hits
the wing.
•Attach the servo wire connectors for the
flaps and ailerons.
oRead the wiring labels and be sure to
attach the appropriate connectors.
oA wrong connection will cause the
plane to crash.
•Slide the servo connectors into the wing
and be sure all wiring goes into the
fuselage or the wing once the wing is fully
attached. Figure 11 shows the servo
Figure 9. Wing spar and snap button
Figure 10.Attaching wing

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connectors and wiring being inserted into
the wing root.
oPoorly routed wires can keep the wing
from properly attaching and a pinched
wire could be damaged and cause a
failure.
•Adjust the wing so that the trailing edge
alignment pin inserts into its hole in the
wing root.
•Continue sliding the wing onto the spar
until the wing root touches the fuselage.
oListen for the sound of the snap button
locking into place and check with a
finger that it is locked. Figure 12
shows the snap button locked in place.
The procedure is identical for both wing
halves.
2) To Detach Wings
•With one hand hold the wing by its
leading edge near the wing root (thumb on
top and fingers underneath), and use the
other hand to hold the fuselage.
•Depress the snap button on the underside
of the wing with a finger on the hand that
is holding the wing.
•Pulling outward from the fuselage in the
direction of the wing tip, slide wing out a
few inches.
•Detach the servo connectors.
•Remove the wing the rest of the way from
the aluminum spar.
Figure 11.Servo connectors partially inserted into
wing
Figure 12.Wing spar snap-button locked in place
3) Wing inspection
There are a few key points that should be checked prior to every flight. A more thorough
inspection should be performed at regular intervals.
Prior to every flight & for each wing:
•Ailerons are the outboard movable surface.
•Flaps are the inboard movable surface.
•Gently move the aileron (with the power off) to check that the aileron, servo, and linkage
move freely. If the aileron is at full deflection, the angle between the linkage and the servo
might make it difficult to move the servo with the aileron. If this is the case, do not force the

11
aileron to move. Instead grasp the servo lever and gently rotate the servo toward its center
position.
•Inspect the servo, linkage, and associated attachments for any loose or damaged parts.
•Check the aileron hinge line for tears.
•Repeat this process for the flap, but note that it only moves from neutral to down.
•Inspect the upper and lower surfaces for skin damage.
•Grasp the wing near the tip at about ¼ cord, gently lift upward and check that the wing does
not bend or kink.
Propulsion
The propulsion system includes the propeller, fuel system, and engine.
1) Propeller
The propeller is an APC 14x10 regular propeller. Although the aircraft is a pusher configuration,
the engine runs in reverse so that a regular propeller, rather than a pusher propeller, can be used.
While the aircraft will operate with a slightly worn propeller, this practice is not recommended
by manufacturers as a worn or damaged propeller increases the potential of serious injury to
operators and bystanders. A damaged propeller can cause excessive vibration and may fly apart
during use.
•Check the propeller for damage prior to each flight.
•Check that the propeller is tightly mounted.
2) Fuel System
The fuel system consists of a tank, fuel lines,
vent line, and fuel filling port. Figure 13
shows the vent and fuel lines exiting the rear
of the fuselage. The vent line is on the right
side of the image. The fuel line attaches to the
filling port and to the bottom of the carburetor.
Attached to the top of the filling port is a
refueling line.
Figure 13.Fuel, vent, and filler lines
A full tank of fuel yields a duration of approximately 6 hours when flown at 35 mph at sea level.
For shorter duration flights the aircraft can be flown with less than a full tank, which will save
weight and increase performance. Fuel starvation is an avoidable and foolish reason to lose and
aircraft, so be sure to have enough fuel for the mission and monitor the fuel level during flight.
Furthermore, use good judgment to evaluate the fuel level (e.g. if the aircraft was launched with
a half tank and 2 hours later the gauge is still reading above ¼ there may be an error in the
gauge).
•Fuel tank capacity is 52 fl oz.
•Fuel is unleaded gasoline (87 or higher octane) mixed with high quality 2-stroke motor oil
using a 40:1 gas:oil ratio.

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oMLB uses oils from motorcycle dealers (i.e. Honda HP-2, Klotz, etc.), but any 2-stroke
oil is acceptable.
•To fuel the aircraft:
oAttach fuel filler probe to filler port.
oPump fuel and observe fuel line to verify that fuel is going into the aircraft.
oFor a full tank, continue pumping until a small amount of fuel spills from vent line,
indicating the fuel tank is full.
oIf less than a full tank is desired, remove the access hatch and observe the fuel level in the
tank. Also, confirm the fuel level on the ground station once the system is up and
running.
•To de-fuel the aircraft:
oAttach fuel filler probe to filler port.
oKeep the aircraft level (as it sits on its landing gear).
oReverse the pump and draw fuel from the aircraft until the pump sucks air.
•Prior to flight inspect the fuel lines
oCheck the fuel lines for any damage.
Check that the fuel lines are properly attached to the carburetor and both sides of the filler port.
3) Engine
The Bat uses a modified 2-stroke engine originally designed for weed trimmers. The carburetor,
muffler, and ignition system are considered part of the engine. It requires little maintenance and
is easy to operate. All components should be kept clean and the spark plug should be replaced at
regular intervals. The engine and carburetor have been adjusted by the factory, and should not
need changing.
•Replace spark plug every 100 flight hours.
•Replace the engine every 500 flight hours.
Starting
•The R/C transmitter is required for running the engine.
•Ensure that the propeller is clear of the ground.
•Turn the R/C transmitter on, and set the throttle stick to idle and the trim to full.
•Check that the starter is rotating in the proper direction (clockwise as viewed from the rear of
the plane).
oReversed leads on the starter battery will cause the starter to turn backwards.
•Hold the plane firmly with one hand and apply electric starter until the engine starts.
oIf the plane is on the catapult and it is cocked, the plane is secure and does not need to be
held with a hand.
•Allow the engine to warm up for about 1 minute.
•Check engine performance.
oSecure the aircraft.
oSlowly increase and decrease the throttle a few times to ensure that the engine is warm.
oFrom idle, quickly advance the throttle to full. The engine should spool up to full throttle
without hesitating and emit a high-pitched tone.
oPeak RPM should reach at least 7,700, which can be checked on the ground station.
oIdle RPM should be no lower than 4000.
•If any of these tests fail, the carburetor needs to be tuned.

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Tuning
•Carburetor tuning is most effectively done
with the engine running. For greater
safety, adjustments can be made with the
engine off and then restarted to test for
proper tuning.
•If the engine is running, approach the
aircraft from the front and stand
straddling the fuselage so that the wing
leading edges are pressing against the
operators legs, as shown in Figure 14.
•The carburetor has two needle valves.
The needle closest to the engine
crankcase is the low speed needle. It
affects the mixture for throttle settings
below 6000 RPM.
Figure 14.Needle valve adjustment
•The outer needle is the high-speed mixture and affects operation above 6000 RPM.
•Use a small flat-bladed screwdriver to adjust the needle valves.
•A change of 1/8 turn is significant for each of the needle valves, so adjustments should
be made carefully.
•Turning the needle counterclockwise richens the mixture; turning clockwise will lean it.
•Tune the high-speed needle by setting the throttle to full and adjusting the needle for
maximum RPM. Do not set the needle any leaner after achieving max RPM.
•Tune the low speed needle for smooth idling, and a quick transition to full RPM when the
throttle is opened.
•Good initial setting for the needles are:
oLow Needle 1 1/8 turns open
oHigh Needle 1 1/2 turns open
•If the low speed needle is not set properly, the engine may die during long periods of idling
(e.g. descents).
•If the high-speed needle is not set properly, the engine will not produce full power and will
reduce the aircraft’s climb performance.
MLB recommends that you do not change these settings without first consulting MLB.
Flight Computer
The FC-2 flight computer is the heart of the autonomous system. It communicates with the
GroundStation operator software, receives signals from the R/C transmitter, stores waypoint
information, and monitors GPS signals and internal sensors to maintain aircraft stability and to
navigate. The FC-2 is located in a black, carbon-fiber box in the forward section of the fuselage.
The flight computer and its associated internal electronics and wiring should not be accessed or
inspected by the operator. Moving any of the internal components could damage them,
disconnect wires, or cause other problems that may result in a failure.

14
Turning on the main power switch on the left side of the plane turns on the flight computer along
with all of the other aircraft systems.
Caution: Turning on the FC-2 power enables the ignition system, and the engine can be started.
1) Aircraft Control
The most crucial role of the flight computer is to fly the plane. Sensors in the FC-2 provide data
to determine the aircraft’s inertial state and position. In conjunction with control algorithms, the
flight computer uses this information to manipulate the servos for aircraft stability, to execute
maneuvers, and to navigate. Even when the aircraft is operated in manual mode, the flight
computer is still active. All of the up-linked R/C commands are first processed by the flight
computer before they are fed to the servos. This provides stability augmentation and makes the
Bat easier to fly than most non-stabilized R/C aircraft.
2) Data Link
Two-way communication between the FC-2 and the ground station is over the 900 MHz modem.
After the initial start up sequence has been completed, this communication link is not essential to
maintain flight. The aircraft can operate independent of the groundstation, so there is no
immediate problem if communication is lost or the ground station fails. However, the two-way
link is required to re-task the aircraft and receive flight status updates.
3) R/C Receiver
Signals from the pilot’s R/C transmitter are decoded by the R/C receiver and passed to the flight
computer. The receiver is the small foam-wrapped box attached to the FC-2 via a gray cable.
The receiver’s antenna is the thin black wire that extends out the left side of the aircraft and back
to the tip of the tail. If this antenna is damaged, the range of the R/C system is reduced; this may
result in loss of control of the aircraft. The FC-2 provides power for the R/C receiver, so the
receiver is on when the flight computer is on. If the 72 MHz R/C link is lost in manual mode,
the aircraft will revert to autonomous mode and begin flying the currently stored flight plan
(starting with waypoint 0).
•The R/C antenna cable should be checked for damage (such as kinked or worn wires) prior to
every flight.
•The antenna should never be subject to strain, and the external portion should be inspected
for damage prior to every flight.
oLook for nicks, color changes, or thinning of the plastic coating, especially where it exits
the fuselage.
4) GPS
A reliable GPS signal is essential to the aircraft’s navigation and autonomous operation. The
flight computer uses GPS positioning to maintain its track between waypoints and to establish
when it has reached a waypoint. In the event of a brief loss of the GPS signal, the Bat will
continue flying its course. If the GPS signal is lost for more than 10 seconds, the aircraft heads
directly for the home location. If the GPS signal is reacquired, the aircraft will resume waypoint
navigation heading to the same waypoint it was heading to prior to the loss of GPS. Without
GPS guidance, the aircraft has limited navigational accuracy.
•GPS is used only for autonomous navigation, so the plane can still be flown manually in the
event of a loss of GPS.

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Occasionally the GPS receiver requires an inordinately long time to acquire its position during
startup. This occurs when the receiver fails to initialize properly and must restart its acquisition
process.
•If the GPS is slow to acquire, the operator can wait for it to eventually acquire, or
•Turn off the aircraft avionics and ground station modem, wait a minute, and redo the aircraft
startup procedure from the beginning.
•If the GPS still fails to acquire it may be damaged, or there may be some external cause for
poor GPS signal.
Since the GPS antenna is mounted externally, the antenna and its cable are susceptible to
damage. Strong electrical shocks, impacts, or strain on the cable can cause damage. Problems of
this nature will normally be detected during start up, and a NO SAT or other GPS warning will
indefinitely be displayed on the Groundstation. However, intermittent problems due to a
damaged antenna or wiring may not be apparent until the aircraft is airborne.
•If damage is suspected or the GPS fails to acquire DO NOT FLY autonomously until the
problem is rectified. Contact MLB immediately to troubleshoot GPS problems of this nature.
Video System
Live video is provided by a one-way link from the aircraft to the ground station. The system
consists of cameras and a transmitter on the aircraft, while the ground station has a tracking
antenna, a digital video tape deck video receiver, and a USB video adapter.
1) Video Cameras & Transmitter
The airborne video system is housed in the nose section of the aircraft. Two color CCD cameras
(charged-couple-device) provide wide angle and telephoto images. A video switch, controlled
by the flight computer, selects the image that is transmitted to the ground station. The
transmitter operates in the 2.4 GHz band with a power output of 800 mWatt and broadcasts via
the stubby dipole antenna mounted on the aircraft’s nose section. The main power switch on the
left side of the plane turns on the aircraft’s video system along with all of the other systems.
Caution: The Video transmitter should never be powered without an antenna attached.
2) Tracking Antenna
At the ground station, the tracking antenna is used to capture the video signal. This system
consists of a flat plate antenna, tracking mechanism, tripod, and associated cables – all of which
are stowed in the ground station case below the tray.
•As with the servo-controlled components of the aircraft, the tracking antenna gimbals should
be moved slowly and cautiously. Do not force them beyond their range of motion.
The tracking system points the antenna relative to a known orientation; therefore, proper initial
alignment is essential for accurate tracking. The flat panel antenna has a 34-degree beam width,
which translates to only 17 degrees on either side of center. It is therefore imperative that the
antenna be oriented as accurately as possible. This is especially important at maximum range.

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To set up the antenna:
•Erect the tracking antenna tripod.
•Orient the tripod so that the arrow on the
tracking assembly (see Figure 15) is
pointed to GEOGRAPHIC North.
oIf using a magnetic compass to find
north, declination must be accounted
for. See the section on declination
correction for additional information.
•Next, attach the flat plate antenna to the
tripod head (see Figure 16).
•Viewed from behind, the release lever is on
the right hand side and points forward
when clamped. The release lever locking
pin is located beneath the lever and points
forward when locked.
•Check that the release lever is in the open
position (pointed to right).
oIf the release lever is in the clamped
position and will not move, check that
the locking pin is unlocked
•As depicted in Figure 16, hold the antenna
in a slightly tilted position and butt the left
edge of the attaching bracket up against the
left edge of tracking head’s top surface.
•Push the right side of the attaching bracket
down to snap the release lever closed.
•Press the release lever forward to ensure
that it is snuggly clamped.
Figure 15.Arrow for orienting the tripod
Figure 16.Attaching the antenna to the head of the
tracking system.
After the antenna has been set up, the communication/power and coaxial cables need to be
connected. While the antenna system has reverse polarity protection, it may still be damaged by
an inappropriate connection. Be sure that positive and negative leads of the ground station
battery are properly attached prior to connecting or turning on the antenna, modem or receiver.
At the antenna:
•Connect the coaxial cable to the antenna. The larger connector fits on the antenna and the
smaller end attaches to the video receiver.
oManually rotate the antenna to face south and then attach the antenna cable, at its marked
point, to the Velcro strap on the tripod leg. This will minimize wrapping the antenna
cable around the tripod while the antenna is tracking so that the servos do not become
overloaded.
Attaching
Bracket
Release Lever
(open)
Locking Pin
(open)
North
Arrow