Desert Aircraft DA-215 User manual

T TM M
D DA A2 21 15 5
Owners Manual 10/19

Safety Instructions
READ THIS!
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 misuse of its products.
You alone are responsible for the safe operation of your motor.
This motor can stop at any time, for a variety of reasons. Do not fly your plane in such
a way that damage or harm will result if the motor stops running. If you cannot fly your
plane safely if the motor stops running for any reason, do not fly the plane.
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.
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 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.
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.
Never use a damaged or repaired prop, or a prop that has struck the ground or any other object.
Damage that can be hard to see, could turn into disaster when the prop is turning at thousands of
RPM.
1

Motor Installation
Mount the motor using high grade 1/4" or 6mm dia. bolts with washers and locking nuts on the rear
of the firewall. Make sure your firewall is structurally sound. The crankshaft centerline is in the exact
center of the rear mounting plate bolt pattern.
Make sure the carburetor's idle set screw is removed or set so that the carb can be fully closed by
the servo at low trim. Use a high quality servo for the throttle. A poor quality servo or linkage will not
provide accurate and repeatable throttle settings. Don't use metal to metal linkages.
You can un-hook, but don't remove, the throttle return spring if the motor is not going to be bench
run. The spring helps to limit shaft wear due to vibration.
Do not try to rotate the carburetor 180 deg. on the mounting block, or remove the butterfly shaft
assembly.
The carburetor should have at least 1”(25mm) of clearance between the intake and the bottom of the
cowl. If there is less than 1", make an opening in the cowl below the carb at least as large as the
carb intake diameter.
Since the carburetor must often be adjusted differently with the cowl on as compared to off, we
recommend small access holes be made in the cowl for adjusting the needle valves with a long,
narrow, screw driver. Sometimes the needles can be reached through the cowl's openings for the
exhaust system.
A 50 oz. fuel tank (Approx 10 minute flight time) is the minimum size recommended. The tank must
be vented. The carb has a strong pump, so the tank can be mounted almost anywhere in the
airframe. The fuel line and tank stopper must be gas compatible. Do not use any silicone sealers on
the fuel system. Gas can break it down and carry it into the carb.
The inner diameter of the fuel tubing should be the same or larger than the carburetor's fuel inlet
fitting's inner diameter. 1/8” I.D. is recommended. Make sure all fuel line connections are secure.
Small nylon zip ties work well to keep the fuel line on the metal fittings. Make sure the fuel line is
secure and not touching the exhaust or cylinder fins. An inline fuel filter can be used, but we prefer
filter the fuel entering the fuel tank from your field container.
Cooling is critical to motor performance and longevity. Allow as much cooling air as
possible in through the front inlets of the cowl. Provide an outlet opening approximately 2
1/2 times larger than the intake at the bottom rear of the cowl for the hot air to escape. Most
factory outlet openings are not large enough! A lip or air dam protruding down and rearward
from the leading edge of the air out let will create negative air pressure (suction) to help pull
hot air out of the cowl.
Air must flow through the cylinder fins, not just inside the cowl, to properly cool the motor.
Don't let the air take the easy way out! Use ducting to make it go through the fins. Round
cowls with large frontal openings still need ducting to direct the air through the cylinder fins
Air ducts can be made from thin plywood, balsa, fiberglass, or aluminum sheet to guide and force air
from the front inlets to and through the cylinder fins.
Depending on the location of the exhaust system, and cowl airflow, the carburetor may need some
air cooling also. A hot carb can be erratic in flight or make the motor hard to restart. Sometimes
placing heat shielding material between the exhaust and carburetor can help.
Keep components like the ignition system, fuel tank, fuel lines, receivers, etc, shielded from heat
generated by canister and tuned pipe exhaust systems. Hot fuel tanks and fuel lines can cause
frustrating tuning issues, and over heated electronic components can have intermittent problems or
total failures.
2

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 length to a minimum. Heavy-duty plugs, as supplied on the ignition, or as used on electric cars
and planes, are recommended.
Use a high quality switch such as a heavy duty R/C receiver switch.
Make sure the charge current does not reach the ignition module. In other words don’t “charge” the
ignition module.
Keep ignition components and wiring separated, as much as possible, from your receiver, receiver
battery, servos, wiring and switches.
Don’t use metal-to-metal linkages to operate the throttle.
Always perform a radio range check before flying. Range should be at least 300 Ft. with the plane
on the ground and the motor running. If there are “glitches”, DON’T FLY! Check for holes in the
braided shielding, loose connections, etc.
The ignition can be powered directly by 4 cell (4.8 volt) or 5 cell (6 volt) NiCd orNiMH batteries. You
can also use 6.6 volt A123/LiFe batteries. If using batteries rated at more than 6.6 volts, a 5.5 or 6
volt regulator must be used. Higher voltage will damage the ignition system and will void the
warranty.
We recommend an 1800 mAh or larger capacity pack. With this size pack, the ignition should last
longer than your receiver pack will. If meter test shows 5.0 volts or less at the ignition module, don’t
fly, re-charge.
When connecting the red pick-up sensor to the ignition module, make sure that the polarity of
the wires entering the connectors is correct (Brown to brown, orange to orange)
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 a sufficient "starting" speed, the ignition will not
produce a spark. This helps to prevent the motor from firing accidentally. The ignition coils can store
energy for a short period of time after shut off. A few firm flips of the prop with the ignition off will
expend any energy held in the coils by firing for one revolution.
When removing the spark plug caps, PULL STRAIGHT out on the caps. Do not pull on the
shielded ignition wires!
To prevent radio interference, the spark plug caps must have the split retainer ring around the base
to insure a tight fit. –DON’T FLY WITHOUT THEM! If the spark plug caps seem loose and are not
making a solid metal to metal contact with the spark plug base, use a small hose clamp around the
base of the cap to keep them firmly attached to the base of the plug.
Protect the shielded plug wires from rubbing against fiberglass or sharp edges of wood or
metal. Rubber grommets and plastic “spiral wrap” insulation from automotive or electronic supply
stores work well. Holes in the braided shielding can emit R/F noise or loose connections (spark plug
caps, connectors and switches).
Timing is set at the factory and should not need adjustment. Contact Desert Aircraft if you have any
questions regarding timing.
Only use NGK CM-6 spark plugs. Other plugs may not fit the plug caps firmly.
Plug gap is .018” to .020" (.38 to .50 mm)
Never operate the ignition without a spark plug in the plug caps! This can permanently damage the
ignition coil.
3

Fuel and Oil Mix
For the DA215, use Premium pump gas, such as 91 to 93 octane.
We recommend purchasing your fuel from “name brand” gas stations. We often see problems with
cheaper gas from some discount type outlets.
We recommend filtering your fuel between your fuel container and your plane’s fuel tank when
fueling your plane.
Make sure the plane’s tank is well vented and the fuel clunk moves freely.
Use of any other fuel or additives such as nitro formulas, aviation gas, white gas, etc., can
harm the motor and void the warranty.
Do not use silicone sealers on the fuel system. Gas can break it down and carry it into the carb.
Use a high quality synthetic oil. Red-line Two Stroke Racing Oil, mixed at 40 to 1, is strongly
recommended. We have not tested a better oil for our engines than Red Line Two Stoke Racing Oil
(We do not recommend the Red Line Smokeless Oil). If Redline Two Stroke Racing Oil is not
available, Motul 800 (50 to 1) is a short term option. Use these oils during and after break-in. Do not
use a lower quality oil to speed the break-in process.
Break-in
We do not recommend breaking the engine in on a test stand. The stationary load and lack of air
ducting can lead to severe engine overheating.
Special break in props are not required. Just don't start with something beyond the recommended
sizes. Over loading the engine creates excessive heat. Peak rpm should be over 5,400 during the
break-in process.
Adjust the needles as needed and give the engine a few easy flights. Maneuvers like
“Hammerheads” help to cycle the engine temperatures during break-in. The needles may need
adjustment as the engine settles in or when other things change such as different props, exhaust,
weather, and altitude.
The engine should run well from the beginning and improve as flight hours accumulate.
Engine temperatures
Temperatures can vary greatly at different locations on the engine and can change quickly at
different throttle settings. Near the spark plug, max temp at full throttle is approx. 325 F (162 C). All
other locations should be cooler.
Recommended Props
Always check and tighten prop bolts before each flight! Loose prop bolts allow prop movement,
which will shear the bolts.
Always use the correct length prop bolts. If a spinner back plate is not used, the prop bolts may be
too long and can bottom out in the hub before they fully tighten against the prop washer.
While special/small break-in props are not required, avoid over loading/heating the motor with large
props that limit RPM to 5,400 or less. The recommended max operating rpm during break-in is
approx. 5,800.
Some recommended props during and after break-in are:
Wood: 34x12, 32x14
Carbon: 32x14, 33x13, 34x12
Smaller diameter props with more pitch, especially 3 blades, can reduce tip speed and noise.
Always use a drill guide to drill your props.
Always check the balance of your prop.
For safety, we recommend painting the tips of your props (front and back) with a bright color,
especially on black props.
4

Starting
1. Check that the prop bolts are tight and spinner is secure.
2. Make sure the starting area is free of dirt, sand, gravel, or other loose debris
3. Turn on the radio system and check the throttle operation and position.
4. Have someone (with eye protection) firmly hold the plane.
5. Close the choke completely.
6. Open the throttle to approximately 1/4 position.
7. Turn on the ignition. ALWAYS BE PREPARED FOR THE MOTOR TO START ON ANY FLIP OF
THE PROP, whether the ignition switch is on or off!
8. Always wear a heavy leather glove when starting the motor.
9. This is a large engine that requires significant force to flip the prop. Give the prop a quick, firm, flip
counter clockwise. Follow through quickly as you flip the prop so your hand swings out of the
propeller's path. Repeat until the motor fires or “pops”.
10. Open the choke.
11. Set throttle to idle position. (carb butterfly plate slightly open)
12. Flip the prop again until the motor runs.
13. Let the motor warm up for 15 or 20 seconds before advancing the throttle.
Needle Adjustments
The needle farthest from the motor is the “High RPM” needle. The needle closest to motor is the
“Low RPM” needle. Turning the needles clockwise “leans” the fuel mixture. Turning the needles
counter-clockwise “richens” the fuel mixture.
A starting point for the DA215 carb adjustment needle settings is:
Low needle 5/8’s turns open, High needle 1 and 7/8’s turns open
Your settings might vary slightly (Usually less than 1/8 of a turn) with various exhaust systems,
altitude, temperature, humidity, fuel, carb variances, etc.
Adjusting either needle can have a slight effect on the other. Example: leaning the low needle can
"slightly" lean the high range.
Adjust the High RPM needle to peak rpm. A tachometer is a great help, but remember that the RPM
may drop a little bit after every start due to residual heat build up. Don’t lean the mixture any more
than necessary. If the engine does not gain rpm and/or run smoother by closing/leaning the high
needle, open it more. If the rpm steadily drops at full throttle or fades on long vertical maneuvers, the
motor is too lean and is overheating. Open the needle more.
Adjust the Low RPM needle until you achieve a smooth idle and a reliable transition to high throttle.
Generally if the motor “stutters” or “coughs” in the mid range or when the throttle is advanced, the
low end needle is too rich and possibly even the high end needle. If the motor dies quickly, the low
end is probably lean.
Don't set the needles overly rich. Operating the motor overly rich not only reduces power, it creates
other problems such as poor transition, fouled plugs, excessive exhaust residue, excessive vibration,
and overall rough running.
Trouble Shooting
Motor won't start
Check battery voltage ( should be 5.0+ volts) and all ignition connections, wiring and switches. Wires
can break from vibration near connectors. Check and/or swap out regulators and optical kill
switches.
Check tank venting, clunk position, and fuel flow.
Does fuel move towards the carb when the prop is flipped?
(Cont'd)

5
If carb isn’t priming, is the choke plate closing completely? Are the carb mounting bolts loose
causing an air leak? Look for fuel seepage.
Is throttle set at idle or slightly higher after motor “pops” and choke is opened?
Make sure prop is flipped over with authority. The ignition won’t fire at low speed.
If a lot of fuel drips from carb, the motor might be flooded. If so, remove and dry, or replace, the
spark plugs. Try starting again without using the choke.
Other issues
Fuel drips continually from carb: Check that the pin on the center of the diaphragm is inserted in the
metering lever “fork”. Make sure there is no debris in the needle seat. Remove needles and blow
air into the holes. A carb rebuild may be required.
RPM won’t go over 3,500 to 4,000: Check that the polarity of the connection between sensor and
ignition is correct (not plugged in backwards).
Broken prop bolts: In order for bolts to shear, some type of side loading (shear) movement is
usually present. If the bolts are tightened correctly, nothing moves and prop bolts will rarely break.
It’s a good idea to replace prop bolts routinely. Check prop bolts before each flight!
Excessive vibration: Check that low rpm needle setting is not too rich. Check prop and spinner
balance. Make sure ignition timing is correct.
Pink or purple colored cylinders: These colors indicate engine temperature has been too high.
Check that needle settings are not too lean, air flow for cooling is sufficient, oil/gas mixture is
correct.
Engine starts backwards: Make sure prop is flipped forcefully through the compression stroke.
Without enough force, the prop may "bounce" off compression and run backwards.
IF ANY PROBLEM PERSISTS, PLEASE CONTACT
DESERT AIRCRAFT FIRST!
We designed and manufactured your engine and have built, serviced, and analyzed thousands more.
We cover your engine’s warranty, not someone at the field or a stranger on the internet. Please give us
the opportunity to help first!
Maintenance
Being a high performance 2 stroke engine, certain parts can wear quickly. Under normal operation,
pistons, piston rings, needle bearings, spark plugs, etc. may need occasional non-warranty
replacement to ensure peak performance.
Screws can come loose! After a few flights check that all screws are secure. Periodically check that
all screws are tightened to the correct torque rating. It's recommended to replace, rather than re-use
the red aluminum screws.
Size Torque specifications
Spark plug: CM-6, 10mm 90 in. lbs.
Steel prop bolts: M6x55mm 90 in. lbs./wood props, 110 in. lbs./carbon props.
Crankcase bolts: M5x25mm 90 in. lbs.
Steel cylinder base bolts: M6x20mm 110 in. lbs.
Carb mount bolts: M5x85mm 70 in. lbs.*
Steel motor mount bolts: M6x16mm 120 in. lbs.
*Caution: Care must be taken to not over tighten the carb mounting bolts. Over tightening can
distort and damage the injected molded reed valve parts and rubber gaskets.
(Cont'd)
6

Use a 4m hex wrench for all M5 cap screws, and a 5mm hex wrench for all M6 cap screws.
For spinner mounting, the crankshaft extension is threaded for M5 screws. In this application
(steel to steel) the 10-32 SAE screws supplied with many spinners will work fine in the M5
threaded hole. Do not substitute 10-32 screws for any other screws on the engine!
Inspect the engine periodically for any signs of fuel seepage. This can indicate an air leak which
can create a lean fuel/air ratio, which in turn can cause erratic running and engine damage. If
tightening the appropriate screws does not cure the problem, contact Desert Aircraft.
After prolonged use, carbon deposits can build up on top of the piston and on the combustion
dome of the cylinder. Great care must be taken when trying to remove these carbon deposits to
avoid damaging the parts. Once an attempt to remove carbon has been made, the task must be
completed, as any remaining carbon may be loosened and can dislodge while the engine is
running. This can damage the engine and/or bridge the spark plug.
Manuals may be updated with additional tips and trouble-shooting info from time to time. Please
check our web site, www.desertaircraft.com , for current downloadable manuals and updates.
Remember! This motor can stop at any time, for a variety of reasons. Do not fly
your plane in a way that damage or harm will result if the motor stops running. If
you cannot safely fly your plane if the engine stops for any reason, do not fly the
plane.
Desert Aircraft will not be responsible for damage caused in engine–out situations.
DA215 WARRANTY
Your DA215 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 ITEMS IN QUESTION ARE RECEIVED AND DEEMED
DEFECTIVE BY DESERT AIRCRAFT.
DESERT AIRCRAFT
1815 S. Research Loop
Tucson, AZ 85710 USA
Ph 520 722 0607 Fax [phone]
Email [e-mail]
Web www.desertaircraft.com
7

Repair/Return Form (Please keep a copy)
Please fill out and enclose this form when shipping items for service
Customer Name_________________________________ Date___________
Address________________________________________________________
City______________________ State______ Zip_________ Country________
Phone #_________________ Cell #__________________
Email _________________________
For most engine service, we only need the engine and/or ignition. Exhaust, prop bolts, and washer are not
required.
Items in Box:
DA35 Serial #__________ DA50 Serial #__________ DA60 Serial #__________
DA70 Serial #_________ DA85 Serial #__________ DA100 Serial #_________
DA100 Inline Serial #_______ DA120 Serial #________ DA150 serial #_________
DA170 Serial #_________ DA200 Serial # ________ DA215 Serial # __________
Single Ignition Serial # ________ Twin Ignition Serial # ________
Prop Bolts? ___________
Prop washer? _________
Muffler(s)? ____________ Muffler screws_____________
Standoffs? ____________
Other Items? __________
REASON FOR RETURN?
Crash: Yes___ No____ Other_________________________________________
_______________________________________________________________________
_______________________________________________________________________
_______________________________________________________________________
_______________________________________________________________________
_______________________________________________________________________
Oil used? _____________ Are you the original owner?___________
Gas type? _____________
Exhaust system type? __________________
Has the engine been sent in for service before? _______Why?________________
______________________________________________________________________
______________________________________________________________________
DESERT AIRCRAFT
1815 S. Research Loop
Tucson, AZ 85710
520 722 0607
[email protected]
www.desertaircraft.com