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X

4

MR

250 

 

MexAir RC 

 

 

c.

 

When initially dry-fitting the motor in the following sections and on final tightening 
of the motors, verify that the motor shaft is centered in the arm shaft hole and that 
there is sufficient clearance from any shaft hardware.  Some motor shafts have a clip 
or setscrew that secures the shaft in the motor.  Visually verify that the clip/setscrew 
will not contact the edge of the hole.  Turn the motor rotor by hand and again verify 
sufficient clearance all the way around. 

d.

 

Embedded Wire Option (for typical 20 gauge motor wires – size for many high power 
2000KV motors) 

i.

 

It is possible to widen the three motor wire holes for wire sizes greater than 
20 gauge using a small, round needle file inserted at an angle toward the 
arms body end.  The hole is already predrilled at an angle to allow pushing 
the lead through and toward the body without binding.  The intent here is to 
ultimately thread the leads into the three holes and into the arms cavity and 
out to the body end leaving sufficient wire to reach the solder pads or 
connectors with some excess.   The excess allows the arm to pivot to its 
maximum angle without tightening or binding.   

 
 
 
 
 
 

 

ii.

 

Align the motor mount holes to the motor mounting slots of the arm with 
the motor wires facing the three motor wire holes in the arms.  Verify that 
there will be sufficient wire to reach your intended ESC solder pad locations 
or connector.  A minimum wire length of about 4 inches is necessary.  If not, 
use the “Surface Wire Option” described below.  A solder joint will not fit 
through the hole unless the hole is widened as described above. 

iii.

 

If your wires have pre-installed connectors, they must be removed.  If the 
wire insulation is not uniquely colored, note which wire is threaded into each 
hole by tagging or marking the bare end after each is pulled through.  This 
will aid in attaching to the correct pads on the ESCs for proper motor 
rotational direction.  This step may not be necessary should your ESCs have a 
reverse motor option and you plan on setting direction using this ESC feature. 

iv.

 

Avoid kinking the wire/insulation while snaking the motor wires into the 
holes and out the other end.  There is a curvature to the channel so it may be 
necessary to give the end of the wire a slight bend to follow the curve near 
the exit of the channel.  First insert the outermost motor wire into the 
corresponding hole.  Gently push the wire through the arm until you can pull 
it out at the body end.  The middle wire is next then the third.  It may take a 
couple of tries until you get the hang of it – and yes – it can be done!  You 
may need to manipulate the wires past the leg hole in the arm if it hangs up 
there.  You will be able to see the wire through the leg hole and manipulate it 

Needle File to Open Motor Wire 

Holes ONLY if Necessary 

 

Summary of Contents for X4MR 250

Page 1: ...Class Racing Quad airframe We specialize in the design and construction of the airframe Since the various electronic components and peripherals are widely available through many sources our focus is...

Page 2: ...me comes configured to mount the supplied Power Distribution Board with the included PDB standoffs and predrilled main frame mounting holes This PDB mount allows for piggy back mounting of a 30 5mm co...

Page 3: ...o metal screw contact surfaces especially motor mounting screws 4 Dry fit and test all electronics and FPV gear to the extent possible during the build so disassembly will not be required after you ha...

Page 4: ...ary to start tightening it back it out slightly repeating this process until the fastener is threaded to the proper depth This creates a threaded hole that should hold firmly without any other aid For...

Page 5: ...both the positive and negative wire ends at the main body hole the large elongated hole You can always trace the polarity later during the build if you forget to do it now If supplied with colored wir...

Page 6: ...ile holding the standoff in place Take care not to over tighten the standoff and shear off the screw For added assurance to prevent the screw from ever backing off a small dab of RTV Silicone Seal can...

Page 7: ...s Verify that there will be sufficient wire to reach your intended ESC solder pad locations or connector A minimum wire length of about 4 inches is necessary If not use the Surface Wire Option describ...

Page 8: ...o the arm using small tie wraps ii If using this option you may also consider surface mounting your motor ESCs directly on the arm surface Again this will additionally increase drag and turbulence and...

Page 9: ...r This will allow for soldering the motor wires later and THEN moving the heat shrink over the ESCs prior to final shrinking d TEMPORARILY place the ESCs onto the bottom plate so that the motor pads f...

Page 10: ...ole is clear of any obstruction When finally tightened this creates a very rigid frame Temporary and partial frame assembly may be desired as you progress through assembly CF Tube Standoff Configurati...

Page 11: ...piece If there is any noted slipping or twist verify that all standoff fasteners are properly tensioned f Landing Gear Installation Note Nylon landing gear can be cut to desired length i Embedded Mot...

Page 12: ...pivot with moderate force Tighten loosen the arms as necessary so that they are firmly seated but can pivot with moderate force Do not over tighten to cause excessive dimpling of the laminate or poss...

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