Desert Aircraft DA50 EFI User manual

DA50 EFI
Electronic Fuel Injected Engine
OWNER’S MANUAL

DA 50 EFI OWNER’S MANUAL HFEDCN0374 REV C
2
See HFE “Released Documents” folder for latest revision.
Document Revision Table
Rev
Description of change
Revised by
Revision
Date
Approved
By
Approved
Date
A
Initial Release
DMcClain
01/16/19
TWest
01/16/19
B
Update Spark Plug Callout
DMcClain
07/29/19
DRB
7/31/19
C
Format and part list update
R.Shoemaker
2/11/20
DRB
2/12/20

DA 50 EFI OWNER’S MANUAL HFEDCN0374 REV C
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See HFE “Released Documents” folder for latest revision.
Table of Contents
Section Page
1. General Safety 4
2. Un-Packing Your Engine 5
3. Getting Started 10
a. Hardware Installation 10
b. Transmitter/Receiver Set Up 11
c. Starting Engine 12
4. Maintenance 13
5. ECM Signal Data 14
a. Blink Patterns 15
6. Technical Specifications 16
a. Battery Recommendations 16
7. Warranty Information 17
8. Replacement Pats List 19

DA 50 EFI OWNER’S MANUAL HFEDCN0374 REV C
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See HFE “Released Documents” folder for latest revision.
1. General Safety
Read and understand this Owner’s Manual before operating your engine. You can help
prevent accidents by being familiar with the controls and observing safe operating
procedures.
Operator’s Responsibility:
1. The operator should know how to stop the engine quickly in case of an
emergency.
2. A safety zone around the propeller should be established in which no person
or object is allowed to enter. Install a guard around the propeller when
appropriate.
WARNING
1. Observe all safety precautions when working around the propeller.
2. Exhaust contains poisonous carbon monoxide, a colorless and odorless gas.
Breathing carbon monoxide can cause loss of consciousness and may lead to
death.
3. Never run your engine in an enclosed space. Always allow for appropriate
ventilation.
4. Observe precaution around the muffler. The exhaust system gets hot enough
to ignite some materials.
5. Keep flammable materials away from the engine.
6. Gasoline is extremely flammable and is explosive under certain conditions. Do
not smoke or allow flames or sparks where the engine is operating.

DA 50 EFI OWNER’S MANUAL HFEDCN0374 REV C
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2. Un-Packing Your Engine
Caution
Your Engine comes with wire harnesses attached to the intake assembly. Handle the
engine with care when removing the assembly from the box.
Package Contents
1. Engine with Throttle Body Assembly
2. Engine Control Module (ECM)
3. Engine Wire Harness
4. ECM Input Harness
5. Owner’s Manual
6. Mufflers (If Ordered)
7. Installation hardware
8. Fuel Pump
9. Air Filter
10. Ignition and ECM mounting kit
ATTENTION
Observe Precautions for Handling
Electrostatic Sensitive Devices (ESD).
The ECM and Throttle servo on this engine contain sensitive electronic hardware. As a
result, this engine is packaged in electrostatic dissipative foam and contained in
electrostatic dissipative bags. Any handling of these devices should be contained in an
ESD safe area.

DA 50 EFI OWNER’S MANUAL HFEDCN0374 REV C
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EFI Components and Descriptions
Figure 1: Engine Control Module (ECM)
Figure 2: ECM Input Harness from Receiver
14 Pin ECM
Receptacle
24 Pin ECM
Receptacle
MAP Inlet
14 Pin ECM Plug
Fuel Pump
CH 3 Servo
(Throttle)
Tach Output
Battery (12V)

DA 50 EFI OWNER’S MANUAL HFEDCN0374 REV C
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Figure 3: Main Engine Harness
Figure 4: Assembly Hardware
24 Pin ECM
Plug
13 Pin Engine
Plug
Ignition
Crank Sensor
Exhaust Gaskets
(square holes)
Fuel line between fuel
tank and fuel pump
Vacuum line
between ECM and
engine
Fuel line between
engine and fuel pump
Heat Shrink: used to
connect CHT sensor to
wire harness

DA 50 EFI OWNER’S MANUAL HFEDCN0374 REV C
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Figure 5: Fuel Pump
Figure 6: Engine and Crank Harness
Crank Sensor
Connector
13 Pin Engine
Receptacle
Fuel Out to Engine
Fuel In; from Fuel
Tank
Fuel Pump
Electrical
Connector

DA 50 EFI OWNER’S MANUAL HFEDCN0374 REV C
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Figure 7: Intake Components
Figure 8: Throttle Body Gasket Order
Throttle Servo
Injector
MAP Outlet
Fuel Fitting

DA 50 EFI OWNER’S MANUAL HFEDCN0374 REV C
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3. Getting Started
Engine Oil
This engine was calibrated using Red Line 2 Stroke Racing oil at a mix ratio of 40:1.
This oil type and mix ratio should be maintained to ensure that the fuel injection system
and engine operates as designed.
Oil Brand:
Red Line
Oil Type:
2 Stroke Racing Oil
Mix Ratio: 40:1
40 parts gasoline to one part oil.
Fuel Recommendations
The engine was calibrated with standard 87 octane gasoline.
a. Hardware Installation
1. Do not install the ECM to the engine or motor mount. The vibration will damage
the hardware. Route the ECM to a location inside the aircraft and mount it where
vibration is minimal. The ECM does not produce excessive heat and can be
encapsulated in foam to isolate it from vibration if needed.
2. Refer to the diagrams in section 2 for wire harness designations and
connections.
3. Install blue tube between the MAP inlet on the ECM and the MAP outlet on the
throttle body.

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4. Install the gray tube from the fuel pump push to connect to the injector port on
the throttle body. Make sure the blue fuel filter is in this line between the pump
and engine.
Figure 9: Push to Connect Diagram. Push tubing past
locking ring and O-ring to produce a proper seal. Push
locking ring to release.
5. Install the green fuel filter between the fuel pump inlet and the fuel tank.
6. Install the blue filter between the fuel pump and the engine.
FUEL SYSTEM WARNINGS
Do not connect the fuel port to the Manifold Air Pressure tube.
Do not exceed 15 PSI (1 bar) of fuel pressure.
3b. Transmitter/Receiver Set Up
1. Throttle commands use the standard output from Channel 3 of the receiver.
Expected pulse width range from 900µs for closed throttle and 2100µs for wide
open throttle. You may need to extend the end limits for channel 3 in your
transmitter to produce the appropriate range. Adjust the exponential rate to get
the desired throttle response.
2. (Throttle kill) Using the DA EFI system does not require an opto-kill switch for
proper operation. When the pulse width from the receiver falls below 960µs (5%

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throttle), the ECM will remove power to both the injector and ignition system,
thus stopping the operation of the engine.
3. (UAV option) Provide 5V to the enable line; when power is removed ECM will
remove power to both the injector and ignition system thus stopping the
operation of the engine.
4. Any 3 cell LiPo, 4 cell Lifepo4, or equivalent battery with a minimum of
2000mA/hr rating will run the engine for up to 2 continuous hours.
3c. Starting Your Engine for the First Time
1. Verify that the ECM is powered up (Blue Light on ECM).
2. Verify that the throttle setting is between 25%-30%.
3. Prime your system for the first time by removing the fuel line from the back of
the throttle body. Cycle the battery power to the ECM in 5 second intervals
until fuel is flowing from the fuel line, then re-install the fuel line. You should
not have to complete the priming process again unless the engine fuel system
is allowed to run dry or has been disconnected for any reason.
4. The engine should be started using an external spinner, or using a built-in
starting alternator. Flip starting is an additional option but is not
recommended due to possible injuries.
Note: The engine may struggle to run for the first few minutes as it is purging
all the air from the fuel system. This may not be evident until you go to wide
open throttle.
5. Allow the engine to run for a few minutes at idle; around 3000 RPM.
6. Hold at wide open throttle for 15 seconds to verify that the air in the fuel
system has been purged.
7. Reduce the engine speed to idle; around 3000 RPM. The engine is now ready
for flight.

DA 50 EFI OWNER’S MANUAL HFEDCN0374 REV C
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See HFE “Released Documents” folder for latest revision.
Starting Again After First Start
1. Verify that the ECM is powered on (Blue Light on ECM).
2. Verify that the throttle setting is between 25%-30%.
3. The engine should be started using an external spinner, or using a built-in
starting alternator. Flip starting as an additional option but is not
recommended due to possible injuries.
Note: The engine may struggle to run for the first few minutes as it is purging
all the air from the fuel system. This may not be evident until you go to wide
open throttle.
4. Allow the engine to run for a few minutes at idle; around 3000 RPM.
5. Verify all systems are functioning properly. The engine is now ready for flight.
Flood Clearing
If the engine is flooded, increase the throttle above 50% and turn the engine over for 5
seconds. Return the throttle to 25%-30% and proceed with start procedure.
4. Maintenance
Table I: Maintenance Schedule
Item
Before
Each
Flight
Every 50
Hours
Every 100
Hours
Every 300
Hours
Engine Oil Pre-Mix
X
Spark Plug
Check/Adjust
X
X
Spark Plug Replace
X
X
Air Filter Check/Clean
X
Air Filter Replace
X
Fuel Filter
X
HFE OEM Maintenance
X

DA 50 EFI OWNER’S MANUAL HFEDCN0374 REV C
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5. Signal Inputs/Outputs for ECM
Table II: ECM 24 Pin Output Connector
Pin
Signal
Description
1
NC
Not Connected
2
NC
Not Connected
3
NC
Not Connected
4
NC
Not Connected
5
NC
Not Connected
6
IGN PWR
+6V power supply output from the Engine Control Unit for
the ignition power.
7
NC
Not Connected
8
IGN GND
Ignition Ground
9
NC
Not Connected
10
IGN SIGNAL
Modified integrator filtered output.
11
SERVO POWER
+6V power supply output from the Engine Control Unit for
the throttle servo power.
12
CRANK PWR
+5V power supply output from the Engine Control Unit for
the crank sensor.
13
SERVO GND
Throttle servo ground.
14
CRANK GND
Crank sensor ground.
15
SERVO SIGNAL
Throttle position with logic-level output. A Pulse Width
Modulated (PWM) signal at nominally 100Hz with ON time
ranging from 900µs to 2100µs corresponding to throttle
position. This pin has an 8mA draw.
16
CRANK SIGNAL
+5V logic-level digital input. Bi-polar type.
17
CHT (+)
Cylinder head temperature sensor. Variable resistance
thermistor.
18
CHT (-)
Cylinder head temperature sensor reference.
19
MAT (+)
Manifold Air Temperature sensor. Variable resistance
thermistor.
20
MAT (-)
Manifold Air Temperature sensor reference.
21
NC
Not Connected
22
NC
Not Connected
23
INJECTOR GND
Injector Switching to Ground. Frequency matches engine
RPM.
24
INJECTOR
POWER
Battery voltage.

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Table III: ECM 14 pin Input Connector
Pin
Signal
Description
1
Tx
RS-232 Transmit
2
PUMP SIGNAL
Variable voltage output from fuel pump assembly.
3
Rx
RS-232 Receive
4
NC
Not Connected
5
GND
Crank signal output ground reference
6
PUMP (+)
Fuel System power (routed internally from system power
pin 14 and enabled by a high side driver (relay) from
ECM state commands).
7
TACH OUT
+5V logic-level digital output. This pin has a maximum
continuous load of ±20mA. Output signal has a 50% duty
cycle.
8
PUMP (-)
Fuel system ground reference.
9
THROTTLE SIGNAL
Throttle position with logic-level input. A Pulse Width
Modulated (PWM) signal at nominally 50Hz with ON time
ranging from 900µs to 2100µs corresponding to throttle
position (0% to 100%). This pin has an 8mA draw.
10
GND
Throttle input ground reference.
11
ENABLE
(Special feature
available on
request)
Engine enable signal from AP. A 5-volt signal present to
enable (UAV option only). This pin has an 8mA draw. 10k
pull down resistor.
12
GND
Enable ground reference
13
MAIN GND
Main Ground
14
POWER 12V
Main power input. 10 to 14 volts. Maximum power draw
is 12 W at wide open throttle. (11.1v 3 cell LiPo 2000ma
or bigger)
5a. ECM Blink Patterns
If the engine is not starting, checking the STATUS light on the top of the ECM can signal what
problem is seen by the ECM. The pattern repeats after 3 second pause, and blinks at 1 to 2 Hz.
Table IV: Blink Patterns
Number of Blinks
Fault
1
High battery disconnected
2
MAT disconnected/no signal
3
CHT disconnected/no signal
5
Pulse train (throttle) not active

DA 50 EFI OWNER’S MANUAL HFEDCN0374 REV C
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6. Technical Specifications
Only use NGK CM-6 spark plugs.
Plug gap is .018” to .020" (.38 to .50 mm)
Size Torque
Spark plug: CM-6, 10mm 90 in. lbs.
Steel prop bolts: M4x 40mm 65 in. lbs.
Aluminum crankcase bolts: M5x20mm 70 in. lbs.
Aluminum cylinder base bolts: M5x13mm 70 in. lbs.
Throttle Body mounting bolts: M5x40mm 20 in. lbs.
*Caution: Care must be taken to not over tighten the TBI mounting bolts. Over
tightening can distort and damage the injected molded reed valve parts, rubber
gaskets, and throttle body.
6a. Battery Recommendations:
Any 3 cell LiPO battery or equivalent battery pack with an amp hour capacity of
2000mA/hr or greater will run the engine for 2 hours continuously. A 4 cell LiFePO4
battery pack is also permitted.

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7. Warranty
Thank you for choosing an HFE International and Desert Aircraft Product.
Your Total satisfaction is our #1 priority.
If you have any questions on the installation and operation of this engine, please contact us
directly. Please have your engine serial number on hand when calling for service.
Desert Aircraft Engine Customer Service:
Phone: [phone]
Email: [email protected]
1815 South Research Loop
Tucson, Arizona 85710
U.S.A
Engine Core Warranty
Your DA50 motor and ignition system are covered with a 3-year warranty
by Desert Aircraft, starting from the date of purchase.
•This warranty covers defects in workmanship and materials only.
•Do not disassemble the motor or ignition system. Disassembly of the motor or
ignition system can void the warranty on that item.
•Any modifications to the motor, or the ignition system, other than those authorized
by Desert Aircraft, will void this warranty.
This warranty does not cover the following:
•Shipping expenses to and from Desert Aircraft for warranty service.
•Damage caused by improper handling, operation, or maintenance.
•Damage caused by a crash.
•Damage caused by using improper fuel or additives.
•Damage incurred during transit to Desert Aircraft. WRAP AND PACK ENGINE
CAREFULLY!!
NOTE: DESERT AIRCRAFT WILL NOT SHIP ANY WARRANTY
REPLACEMENT ITEMS UNTIL POSSIBLY DEFECTIVE ITEMS IN
QUESTION ARE RECEIVED BY DESERT AIRCRAFT.

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HFE International EFI System Customer Service:
Phone: [phone]
Email: [e-mail]
1646 S. Research Loop
Suite 170
Tucson, AZ 85710
EFI System Warranty
Your HFE International EFI system is covered with a 1-year warranty by HFE
International starting from the date of shipment from HFE International.
•This warranty covers defects in workmanship and materials only to include Fuel
Pump, wiring, ECM and throttle body.
•Do not disassemble the ECM or Throttle Body assembly. Disassembly of the ECM
or Throttle Body assembly will void the warranty on that item.
•Any modifications to the ECM, or Throttle Body assembly, other than those
authorized by HFE International, will void this warranty.
This warranty does not cover the following:
•Shipping expenses to and from HFE International for warranty service.
•Damage caused by improper handling, operation, or maintenance.
•Damage caused by a crash.
•Damage caused by using improper fuel or additives.
•Damage incurred during transit to HFE International.
NOTE: HFE INTERNATIONAL WILL NOT SHIP ANY WARRANTY
REPLACEMENT ITEMS UNTIL POSSIBLY DEFECTIVE ITEMS IN
QUESTION ARE RECEIVED BY HFE INTERNATIONAL.

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8. Replacement Parts List

DA 50 EFI OWNER’S MANUAL HFEDCN0374 REV C
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See HFE “Released Documents” folder for latest revision.
Table V: Part numbers and descriptions