Removing wrinkles from the covering
While not an actual
?step? in the instruction manual, they do make a note that
the user may want to tighten up the covering to remove any
wrinkles that may have occurred during shipping. I prefer to
do this on any ARF that I have, just to be sure. A good point
to follow is to make sure that all the edges are sealed down
tightly. The plane had a few wrinkles in the covering, but a
heat gun and sealing iron made quick work of getting them
out.
Installing control hinges
The Mach Racer uses standard
CA hinges for its control surfaces. Since we only have 2
control surfaces to deal with, installing them with CA hinges
is pretty quick. Start by marking the center of each CA
hinge, and then insert one or two T-pins in the hinge at
that centerline. All 3 of the hinges are inserted into the
control surface and then into the wing of the plane. Push
the control surface in until there is little or no gap
between the surface and the wing. Then flex the control
surface downward and put 5-6 drops of CA on each hinge. Do this to each hinge on the control
surface and allow the
CA to cure for a few minutes before proceeding.
Turn the wing over and flex the control surface in the other
direction, then repeat the application of CA to the other side
of the hinges. Once again allow a few minutes for the CA to
cure. Once the CA has cured, flex the control surface fully
in both directions several times to free up the hinges and ensure you have full motion from the surface. Lastly, give
each control surface a good tug to make sure that it is
firmly glued to the wing.
Main Landing Gear
The main gear consist of two wire landing gear that are
inserted in the fuselage and secured with nylon straps. The
slot for the landing gear is already cut into the fuselage
and just needs to have the covering cut away in order to install
the landing gear. Once the covering is cut away, insert the landing gear
into the fuselage. Then mark the location for the screws to
secure the nylon straps and drill the holes for the screws.
After running a screw into each hole to cut the threads
into the wood, use thin CA to harden the wood. Install and
secure the nylon straps using the supplied wood screws. To
install the wheels, first place a wheel collar on the inside
of the landing gear. Then place the wheel on the gear and,
finally, put a wheel collar on the outside to hold the wheel
in place. Make sure that the wheel turns freely on the wire,
but doesn?t have any ?wobble? to it.
Nose Gear
As the nose gear is being installed it?s important to
notice that there are two flat spots already cut into the
nose gear. It?s important that these be used because they
place the nose of the plane at the correct height. If you
look at the video for this plane
you will notice that the nose of the plane sits higher than
the body of the plane. This was done to allow clearance for
the prop so that it doesn?t hit the ground. Install the
steering arm on the lower flat spot and tighten the screw so
that it is on the flat spot. Then slip a nylon spacer on the
nose gear and insert it into the nose gear bracket (the
included instructions said to install the bracket, but it
was already in place when I received the plane).
From underneath, place a wheel collar on the top of the
nose gear and tighten it down on the upper flat spot. When
installing the nose wheel use the remaining nylon spacer on
the inside of the wheel. Secure the wheel in place using
a wheel collar on the outside of the wheel. Once again make
sure the wheel spins freely without any wobble in them.
Installing the engine
The Mach Racer uses wood
rails that are part of the frame for the motor mounts.
When I placed the Magnum 46 on the mounts they were a
little bit too narrow for the engine to sit down on the
mount.
I used a Dremel rotary tool
with a small sanding drum to sand down the sides of the
mount a little bit. Take care when sanding the mounts
down that you don't change the thrust angle that is set
in the mount.
Since the engine compartment
comes pre-sealed with epoxy I needed to reseal the wood
that I just sanded down. A little bit of 5-minute epoxy
and an epoxy brush made quick work of this.
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Notice:
Before moving on I want
to take a moment to discuss a change in the
instructions for mounting the engine. On page 14
(section 10, step 1) the instructions tell you to
mount the engine with the spinner backplate
3-13/16" from the firewall. If this measurement is
used the engine will not fit into the mount, and the cowl will not fit. I contacted Global
Hobby about this and they agreed. There was a
change in the plane since the instructions were
written.
The proper
measurement is 4-1/8" from firewall to backplate.
Model Tech and
Global Hobbies have rewritten this step and will
be including an addendum in all planes sold in the
future. If you already have a copy of this plane
you can download a copy of the addendum here
Mach
Racer Instruction addendum in PDF format
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Magnum XLS 46A Closer Look |
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Magnum XLS 46A
Bringing you high
performance at an affordable price for more
than 20 years! |
Specifications:
- Bore: 22mm
- Stroke: 19.6mm
- Displacement: 7.45cc
- Practical RPM: 2,000 - 17,500
- Weight (w/ Muffler): 16 oz
- Weight (w/o Muffler): 13.1oz
The XLS .46 is a single
cylinder, two-cycle engine incorporating ABC
(Aluminum piston, Chrome-plated Brass sleeve)
technology for long life, high power output and
easy break-in. This engine features dual needle
valve carburetors for precise fuel/airflow
metering, cast aluminum rear needle valve
assemblies, dual ball bearing supported
crankshafts, high-strength connecting rods and
high-volume mufflers.
Recommended Prop Sizes
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9x5 |
9x6 |
9x7 |
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10x6 |
10x7 |
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11x6 |
11x7 |
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12x4 |
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Magnum recommends using a 10x6
prop for break-in
I used an APC 10x6 propeller for
both break-in and for the first flights on this
plane. I was pleased with the performance of the
plane using this prop so I left it on for normal
flying use.
I used Cool Power 15% for both
break-in and normal flying. This motor started up
on the 3rd flip on the break-in stand and ran
smoothly right off of the bat. Break-in was
performed in accordance with the instructions from
the manufacturer. With the motor broken-in it starts
quickly using a chicken stick to flip start it,
and runs reliably for the entire flight. With
approximately 20 flights on the plane so far I
have yet to have a flame out while in flight.
Download the manual in PDF
Format -
Click here |
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The distance for mounting the engine has changed, as noted
above. Install the spinner backplate on the engine and place
it on the motor mount. Move the engine until the distance
from the firewall to the spinner backplate is 4-1/8?. Once
the engine is in place mark the mount where the mounting
holes need to drilled. The mounting holes are drilled out to
1/8?. Then use the included hardware to mount the engine.
The next step is to install the throttle servo and the
throttle pushrod. After installing the throttle servo in the
fuselage I cut down the 8-arm servo horn to just one arm to
us in mounting the pushrod. The pushrod for the throttle is
pre-bent with a Z-bend at the throttle end. For the servo
end of the pushrod I used the included easy connector to
attach the pushrod to the control arm. To connect the
pushrod at the engine I had to remove the throttle control
arm from the carburetor.
Fuel Tank Installation
The fuel tank supplied with the Mach
Racer is set up like most fuel tanks available and is
190cc, which converts to 6.2 ounces. There is enough
included hardware to set it up as either a 2 line or 3 line
setup. I chose to set up the tank as a 2 line tank. The tank
is sized perfectly to fit in the fuselage, which is a nice
touch. With engines that have a rear needle valve it can
sometimes be a bit tricky to get the fuel line on and
off. Therefore, in these cases I put a small piece of fuel tubing on
the fuel inlet and join that with the fuel line from the
fuel tank with a small piece of tubing.
Elevon Control System
The servos for the elevons are located to the rear of the
fuselage, behind the landing gear. The mounts for the servos
are already cut and merely need to have the covering cut
away. Mount a servo in each mount on either side of the
fuselage. The control horns are mounted on the elevon
directly behind the servo, with the holes in the control
horn mounted directly above the hinge line of the elevon.
After marking and drilling the holes for the control horn
use CA to harden the wood underneath the control horn. The
pushrods for the elevons come pre-bent in an ?L? shape.
Use nylon keepers to install them at the servo horn. A nylon
clevis is used at the elevon end to connect the pushrod to
the control horn.
Steering Servo and Pushrod
Since the Mach Racer doesn?t
have a rudder, we use a servo by itself to steer the plane
on the ground. If you are building your plane for hand
launch you can skip this step of the assembly. The cut for
the steering servo is located just forward of the main
landing gear. Simply cut away the covering to open up the
mount. The servo is mounted in the fuselage using normal
servo mounting procedures. The included pushrod has a Z-bend
already in it, and this end mounts on the steering
arm of the nose gear. At the steering servo I used the
included pushrod connector to attach the pushrod to the
servo arm.
Cowl Installation
To install the fiberglass cowl I had
to make a small cutout to clear the nose gear. The area is
pre-marked to cut. I used a small cutoff wheel on my Dremel
to cut out this area, and used a small sanding drum on slow
speed to keep the paint from chipping. After cutting the
cowl I positioned it on the fuselage and used masking tape
to hold it in position to drill the mounting holes.
The instructions call for 6 holes to
be drilled to hold the cowl in place. Once the mounting
holes are drilled small screws are used to hold the cowl in
position.
Vertical Stabilizer
The slots for the
vertical stabilizers are already cut and only need to have
the covering cut away to expose them. Place the stabilizers
in the slots and mark on the stabilizers where the covering
needs to be cut away. While the instructions call for cutting
away the covering using a hobby knife I prefer not to do it
that way. This is due to the fact that it?s too easy
to cut into the wood, which can weaken it. Instead I prefer
to use a soldering iron to melt the covering on the line I
marked earlier.
After ?melting? the line, simply peel
away the covering to expose the wood on the lower part of
the stabilizer. I used 30 minute epoxy to install the
stabilizer so that I would have enough time to ensure that
they were square with the fuselage before the epoxy set. Use
a square in to make sure they are straight and use a strip
of masking tape to hold them in position while the epoxy
sets.
Hatch Cover & Canopy
To install the canopy of the
Mach Racer it needs to be cut out and trimmed before gluing
it in place. After trimming the canopy I used Formula 560
canopy glue to glue it in place. After applying the glue the
canopy needs to be secured in place. Let it sit overnight
to ensure that the glue has fully dried.
The radio
switch location is one of my ?misses? for this plane. The
instructions call for installing the radio switch at the
rear of the hatch cover, behind the canopy. The reason why I
don?t like this location is because it puts the switch
directly in line with the engine muffler, which allows fuel
residue and exhaust to flow directly over the switch. If a
standard switch is installed it?s possible for fuel residue
and exhaust to seep into the switch in flight. This can
cause the switch to fail and lead to a crash. Unfortunately
there really isn't a better location to place it because the
fuselage is pretty full as it is. There are a couple of
steps that can help reduce any problems. The first is to use a switch/charging jack mounting set. I used the
Great Planes mounting set (Tower Hobbies part #
LXJ778)
for this application. This gets the switch inside of the
fuselage and out of the exhaust flow. It also has a cover
for the charging jack to keep out any residue. The second
thing that can be done to reduce this problem is to
use an
exhaust deflector to move the exhaust flow away from the
hatch cover. I would have gone this route with this plane
but, unfortunately, I didn't have one available at the time I
did this review.
Final Radio Installation and Balancing
When I first saw the Mach
Racer I thought that installing the radio would be difficult
because the plane is on the smaller size. However, I was
pleasantly surprised at just how much room there is for the
radio inside of the fuselage. At the very rear of the
fuselage there is a large open area that is perfect for the
4.8v flat battery pack that I am using. I wrapped the
receiver in thin foam (I use mouse pads for this) and placed
the receiver next to the throttle servo. I then used
the area directly behind the servo for all of the servo
wires. There is a pre-installed exit for the antenna wire in
the left side of the fuselage. This exits onto the underside
of the left wing. Run the antenna wire through the exit and
out to the tip of the left wing and secure it with a piece
of tape. This will keep the wire from interfering with the
elevon controls.
The recommended CG for the
Mach Racer is a point 8? back from where the leading edge of
the wing meets the fuselage. The placement of the battery
and receiver that I used set the CG spot where it was
supposed to be. I was able to balance the plane without
adding any additional weight. |
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