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Safety Instructions

WARNING!
This motor can cause severe harm to you, and/or others, if misused or if
these safety precautions and instructions are not observed. Desert Aircraft is not
responsible for any loss, injury or damage resulting from the miss-use of its products.


You alone are responsible for the safe operation of your motor.

Do not operate the motor if you do not want to be completely responsible for any damage
or injury incurred or caused during its operation.

Read all instructions before operating your motor.

If you have any questions about any aspect of operating this motor, do not attempt to
start or operate it.

Never operate the motor, or fly, alone.

Keep away from the prop while operating the motor. Do not wear loose clothing near the
motor or prop. Do not run the motor near loose material such as dirt, gravel, power
cords, ropes, sand, etc. Loose material can be drawn into the turning prop causing injury
or damage.

Always operate the motor in an open area. Do not operate indoors.

This motor can develop tremendous thrust. Make sure the aircraft is properly secured
when starting or operating the motor.

Inspect motor mount bolts and firewall integrity before operating the motor.

Anyone in the immediate area of the motor should use eye protection during operation of
the motor.

When operating the motor, never stand, or allow anyone else to stand, in front of, or to
the side of the propeller. Always stand behind the propeller.

Keep spectators at least 30 feet away when operating the motor.

Turn off the motor before making any adjustments.

Always use the proper size propeller. Never use a damaged, modified or repaired
propeller.

Always use the correct length propeller bolts. Do not use spacers behind the propeller.
Spinner cones must not touch the propeller.

Thinner props may require using shorter prop bolts, especially if not using a spinner back
plate. Make sure your prop bolts do not bottom out in the propeller hub.

Check that the propeller bolts are tight before every flight.

Always install an ignition kill switch to stop the motor.

Adjust the carburetor linkage so that the motor will stop when the carburetor is
completely closed.

Gasoline is extremely flammable. Be careful of any sparks from electrical contacts such
as fuel pumps, battery chargers, etc. Do not allow smoking in the area of your fuel
supply or motor. Store fuel in approved containers and in well ventilated areas.

Allow the motor to cool before touching or fueling.

Always turn the prop a few revolutions after running the motor to discharge the ignition
system.

The ignition system develops extremely high voltage. Do not touch it during operation
.

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Mounting the Engine

The DA 50R features a rear induction carburetor that is intended to protrude or breath through
the fire wall. This carburetor location provides a stable air environment for consistent high
performance, while carburetor noise is greatly reduced. The width of the motor is also reduced
for tighter cowl installations.

The DA 50R can be mounted with or without the included stand-off spacer mounts.
The spacers are mounted to the motor mount flange tabs with steel M5 metric screws
(supplied). The rear of the stand-off mounts are threaded for ¼-20 SAE mounting
bolts (not supplied). The engine is mounted to the firewall with ¼-20 mounting bolts
that pass through the stand-offs from the rear of the firewall. Note: Export (Metric)
versions of the stand-off mounts are red color, and are threaded for M6 metric screws
at the rear.

We recommend blue Loctite on all engine mounting screws. Check the mounting
bolts regularly to insure they are tight.

Be very careful using shims or spacers behind the supplied stand-off mounts. The
rear face of each stand-off must be in the same plane. If they are not in the same
plane, the mounts and crankcase will be under stress. This can cause damage to the
engine, such as cracked/broken mounting tabs.

Make sure the carburetor has adequate clearance near the inlet to allow an
unobstructed airflow into the carburetor. If the carburetor is located in front of the
firewall, be sure there is at least 1 (25mm) of clearance from the carburetor inlet. If
there is less than 1 clearance, make a hole larger than the carburetor inlet diameter
in the firewall.

The throttle arm is tapped for a 2-56 SAE ball link. The spring tension on the DA 50R
carburetor is fairly light and most users will leave it as is. If you wish, the throttle
return spring can be released (not removed) off the end that hooks on the throttle
spring return arm. (Opposite side of the carburetor from the throttle arm)
NOTE: Removing the throttle spring will allow the shaft to move and wear due to
vibration. This wear/damage will allow air and fuel to enter the engine when in the
closed position.

The throttle is attached firmly to the carb linkage with red Loctite. Removing it may
cause damage.

The choke lever can be actuated by finger or by a small servo behind the firewall.
Another option is to remove the choke arm and replace it with a nose wheel steering
arm (Goldberg or equivalent) this allows adjustment for linkage access from the
bottom or rear. Do not remove the detent ball and spring on the choke shaft.

Soft mounts can be used, but movement of the engine can cause problems with
exhaust systems and carburetor linkages.

Make sure firewall and/or motor box are secure.
4


Ignition System


When making electrical connections to the ignition system, use the same gauge wire (or
larger) as used on the red and black power leads on the ignition module, all the way to the
battery pack. Keep wire lengths to a minimum. Please use the heavy-duty connector plugs
supplied with the ignition.

Use a high quality switch such as a Futaba or JR heavy-duty switch. Small size R/C receiver
switches are not recommended.

Mount the ignition module on a foam pad with plastic zip ties. DO NOT HARD MOUNT OR
USE DOUBLE SIDED TAPE!

Isolate the charge circuit from the ignition while charging the batteries. In other words, dont
charge the ignition module while charging the battery.

Use 4.8 or 6.0 volt batteries only. (We see no significant difference in engine performance
between the two.) The ignition will tolerate the peak charge voltage on these packs. Higher
voltage batteries will damage the ignition system and will void the warranty. We recommend
a 1500 mAh or larger pack. With this size pack, the ignition pack should last longer than your
receiver pack will. If a meter shows 5.0 volts or less, dont fly. Re-charge. Use a 5.2 to 6.0
volt regulator on packs rated above 6.0 volts.

Unlike some ignitions, the Desert Aircraft ignition is designed to spark only when the prop is
flipped at a high speed. If the prop is not turned over at starting speed, the ignition will not
fire. This helps to prevent the motor from firing accidentally. Unless you are having
problems starting the motor, dont bother testing the ignition with the plug removed from the
cylinder.

When removing the spark plug caps, PULL STRAIGHT out on the caps, not the shielded
ignition wires! If the cap seems loose, and is not making a solid metal-to-metal contact with
the spark plug base, contact Desert Aircraft for a replacement. To prevent radio interference,
the spark plug caps must have the split retainer ring around their base DONT FLY
WITHOUT THEM!

Protect the shielded plug wires from rubbing against fiberglass or sharp edged of
wood or metal! Rubber grommets and plastic spiral wrap insulation from automotive or
electronic supply stores work well to protect your braided shielding. Holes in the braided
shielding can emit R/F noise (i.e: RADIO INTERFERENCE!) Damaged plug wires are not
replaceable and may require the ignition to be replaced! Protect them!

Keep ignition components and wiring separated as much as possible from your receiver,
receiver battery, servos, wiring and switches.

Dont use metal-to-metal linkages to operate the throttle.

Always perform a radio range check before flying. Range with one section of the
antenna extended should be at least 80 to 100 ft. with the plane on the ground and the motor
running. If there are glitches, DONT FLY! Check for holes in the braided shielding or
loose connections (spark plug caps, connectors, and switches). If that doesnt solve the
problem, re-locate your ignition and receiver components farther apart. If the problem
persists, return the ignition to Desert Aircraft for inspection.

Timing is set at the factory and should not need adju