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X

4

MR

250 

 

MexAir RC 

 

 

X

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MR 

 Manual 

(See our website 

www.mexairrc.com

 for our upcoming video series on 

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4

MR

 Construction))

 

Introduction 

Congratulations on your purchase of the MexAir RC 

X

4

MR

 250 FPV Race Quadcopter.  This quad has 

some very unique design features that allow for advanced flight characteristics.  The built-in 
configurations enhance maneuverability, speed and load handling capability.  Some of these are 
described below and throughout the build sections of this manual.  Besides the advantages described 
below are the less obvious materials making up the airframe.  Most quality multirotors use some form of 
carbon fiber in their design.  We have chosen the more costly but highest quality aerospace 

quasi-

isotropic

 carbon fiber.  Rather than describe the benefits of this material, especially when used in 

conjunction with a light-weight core, you may wish to simply “Google” the terms to find the vast amount 
of technical data supporting the use of this grade of carbon fiber in light-weight rugged, rigid, and strong 
applications. 
 
MexAir RC, located in Central New York, is the designer and manufacturer of the 

X

4

MR

 250 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 on 
providing a unique platform for the already available devices.  The experienced builder will already know 
much of the information – but we decided to cover details not always found in build manuals – 
especially considering some of the unique features of the 

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MR

.

  

 
 
 

 
 
 
 
 
 
 
 
 
 
 
 

 
The 

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MR

 carbon fiber laminated airframe design, materials, and methods of construction create an 

assembly that allows for: 

 

Enhanced aerodynamics due to the ability to embed wiring within airframe structural 
components thus reducing turbulence and drag 

 

Elimination of the typical “lightening holes” in areas of the airframe to improve strength and 
rigidity, additionally reduce  turbulence, while at the same time reducing airframe weight  when 
compared to typical solid carbon fiber frame materials used in many other multirotor copters 

 

Reduced induced vibration through use of vibration damping body & arm core material – 
resulting in better video quality 

 

Electronic component placement flexibility due to: 

o

 

ease of mounting additional accessory items to the CF frame using simple self tapping 
screws 

Completed 

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4

MR Airframe 

Total Weight as 

Pictured:  111 Grams

 

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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