Dyne's MSE-4

[Dyne]

As mentioned, I'm using the same car that the 3d printable MSE droid was designed for.  

The car in question is the "Blomiky 4WD 9MPH High Speed Racing RC Car 1:43 Scale 2.4G 4WD Electric Small Remote Control Vehicle", which is $25 on Amazon.  Here it is with Sphero BB-8 and a dirty keyboard for scale.



There are three color schemes for the body, but I think that's the only difference.  I'm trying to decide if the double "4WD" is additive or multiplicative ... is it eight-wheel drive (Sleipnir?), or sixteen-wheel drive?

I debated using a 1:32 scale car instead, the Cheerwing Phantom (aka Crazon Phantom, among various other brand names).  It is a bit faster than the Blomiky, but that's a bit of a drawback ... it's so fast it can be a bit hard to control.

A more promising car along the lines of the Cheerwing is the JJRC LT832, which is apparently a Losi Micro-T clone.  The main advantage it has over the other cars is that it has proportional steering, which would make it easier to control than either the Blomiky or the Cheerwing.  I've seen it typically go for $35 (only $10 more than the Blomiky), but it's possible to find it below $30.  Unfortunately, I'd already ordered the Blomiky before I knew about it.  You might have to cook up your own method of attaching an MSE body, as the existing body is held on with clips, not screws.

Regardless, I'm doing my own thing for the shell, and still have ideas on some cute things to do to differentiate my build.  Because of course I do.  I can't do anything completely by the book.

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My car arrived yesterday.  It was reasonably packed, but they used broken off bits of styrofoam to do it.

I hate broken styrofoam. It's coarse and clingy and gets everywhere.

The Blomiky comes with a pair of three cell 3.6v 700mAh NiCd batteries for the car (plus two charging cables, a pair of AA for the transmitter, and a screwdriver). These give about 20 minutes runtime at full speed (not tested yet). I saw a comment by Blomiky on the orange car's Amazon Q&A page that said you can use a 1s LIPO instead (it'd only be only 0.1v higher at the standard cell charge). That would open up some possibilities for larger capacity, but I'm a bit wary. LIPO is 4.2v at full charge and 3v at minimum, whereas I gather that NiCd doesn't change much from rated voltage over a discharge cycle.  I'm sure the motor could handle it, but I'm not so certain about the speed controller or LEDs.

I decided to take some measurements of the car, in case anyone needs them.

• Overall Length - 145 mm
  
• Chassis Length (no bumpers) - 133 mm
  
• Wheelbase - ~83 mm on center
  
• Tire Diameter - 30 mm
  
• Tire Width - ~11.5 mm
  
• Track Width, Front - 75 mm
  
• Track Width, Rear - 79 mm
  

The wheelbase and front track width dimensions are more or less 30% of the Traxxas Bandit's equivalents. That's the scale factor I'll be using to plan the shell.

Each wheel is held on with a screw at the axis. The axles are all hexagonal with a minimal diameter of 4 mm, and the wheels use this to prevent slipping.  The tires do slip on their rims, though, especially when removing the screw.



The body is held on with four screws.  Front to Rear, these four screws are 110 mm on center.  Left to Right, the front screws are 28 mm on center, while the rear screws are 40 mm on center.

After removing the four body screws, you can lift the body off the chassis.  There is a pair of LED headlights attached to the body with hot glue.  



You can remove the hot glue and keep these, or you can unplug the LEDs from the board if you don't want your MSE-4 Droid to be illuminated.  I'll probably keep them on mine.