Great Planes P-51D Mustang 40 Kit - GPMA0175 - Manual (Page 4)

4. You must properly install all R/C and other components
so that the model operates properly on the ground and in the
air.
5. You must test the operation of the model before the first
and each successive flight to insure that all equipment is
operating, and you must make certain that the model has
remained structurally sound. Be sure to check the nylon
clevises often, and replace if they show signs of wear.
6. You must fly the model only with the competent help of
a well experienced R/C pilot if you are not already an
experienced and knowledgeable R/C pilot at this time.
Note: We, as the kit manufacturer, can provide you with
a top quality kit and great instructions, but ultimately the
quality and flyability of your finished model depends on
how you build it; therefore, we cannot in any way
guarantee the performance of your completed model, and
no representations are expressed or implied as to the
performance or safety of your completed model.
Remember: Take your time and follow directions to end
up with a well-built model that is straight and true.
DECISIONS YOU MUST MAKE NOW
ENGINE AND MOUNT SELECTION
The recommended engine size range is as follows:
.40* - .46 cubic inch displacement 2-cycle
.60** - .70 cubic inch displacement 4-cycle
*NOTE: Performance may be marginal if a non-sch-
neurle-ported .40 cu.in. 2-Cycle engine is used.
**NOTE: The O.S. Max 48 Surpass also provides
sufficient power to fly this airplane.
NOTE: If you choose to side mount a 2-Cycle engine,
we recommend using a muffler that can be almost
completely enclosed inside the cowl. The muffler used
in one of our prototypes is a Tatone #11413 Pitts Style
Muffler for .29 - .40 engines. The muffler may require
slight modification to fit your engine.
If you mount a 2-Cycle engine inverted or upright,
a standard muffler may be used. Complete enclosure of
the engine and exhaust requires inverted installation and
a custom-made exhaust manifold.
The engine you select will determine how you build
the fuselage, so it is important that you have the engine
close at hand while building.
This kit includes the new Great Planes
Adjustable Engine mount. This mount will work on
most .40-.60 2-Cycles and .40-.70 4-cycles. Cut or
break the "spreader bar" off each mount half.
Carefully trim any extra plastic off each mount half
left by the spreader bar. The surfaces where the
spreader bars were a t t a c h e d need to be very
smooth to allow the mount halves to fit together.
Snap the two mount halves together. Slide the
mount halves apart until the engine mounting lugs
will sit flat on the beams. Adjust the mount until
the firewall centerline (or offset line) is centered
between the "tick" marks on the mount.
NOTE: If you choose to power your P-51D with a 4-
cycle engine, keep in mind that the RPM of your engine
will be considerably less than that of a 2-Cycle engine;
therefore, you should select a higher pitch propeller to
keep the speed and overall performance roughly equiva-
lent to that of a 2-Cycle engine. For example, a 10x6 or
10x7 prop would be used with a .40 (2-Cycle) engine; but
a 12x8,11x9 or 10x10 prop may be the best choices for
a 4-cycle engine. The 4-blade prop shown on the
prototype is a mock-up for static display purposes only.
SELECTION OF WHEELS
To save weight, we recommend using lightweight
foam rubber wheels.
2-1/2" diameter main wheels are recommended for
retracts (but 2-3/4" wheels will fit, and may be needed for
satisfactory operation on grass fields).
2-3/4" diameter main wheels arc recommended for
normal sport flying with fixed landing gear (3" wheels
may be needed for satisfactory operation on rough grass
fields).
3-1/4" scale wheels may be installed for maximum
scale realism (such as Robart UX-325 diamond-tread
scale wheels).
A 1" diameter tailwheel is recommended.
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