3D Printed Radio Box for 1/8 Scale Hobao VSE Buggy Free Download

Download this Printable File on Thingiverse: https://www.thingiverse.com/thing:4300018

3D Printed Radio Box for Hobao 1-8 scale VSE Buggy
3D Printed Radio Box for Hobao 1-8 scale VSE Buggy

The trigger for me to design and print this radio box came from a requirement that the physical internal size of the stock box was too small. I could not get the radio that I wanted to use in the stock box. What was required was a new box that maximized the available room inside. But the problem was the physical footprint where the radio box is installed on to the buggy was rather limiting. Also, this box must have an easier method of accessing the radio inside. Here we make use of a standard body clip to lock the cap in place. You can see this in the image above.

Just for reference RX refers to the receiver.

The stock radio box also includes the steering servo mount. The steering servo mount has been designed in such a way to maintain high strength as a number one priority.

There are 2 Printable Versions

One version has side flanges in side the box for a receiver. The internal distance between these flanges is 26.5mm. The other version of the box does not contain any flanges for installation of a more generic radio receiver. You may see these when you load the files in to your printing software.

3D Printed Hobao VSE Buggy Box with Flanges
3D Printed Hobao VSE Buggy Box with Flanges

The internal opening size of the box is 32.1mm long x 24.8mm wide x 40.8mm Deep. These dimension include the space that would be occupied in the cap.

Model of the 3D Printable Hobao Buggy Radio Box
Model of the 3D Printable Hobao Buggy Radio Box

3D Printer Settings

Printer brand: MakerBot
Printer: MakerBot Replicator (5th Generation)
Rafts: Yes
Supports: Yes
Resolution: 0.2mm
Infill: 35% (Recommended)
Filament Brand: MakerBot
Filament Color: White
Filament Material: PLA
Shells: Use a Minimum of 2 shells

Post Printing

The Radio Box must be Tapped for M3 Fasteners. Once the Radio Box is completed, your 3D printed may have shrunk the size of the holes required to be tapped. If this is true be certain to drill the hole back out to be suitable for a M3 tap. Once the hole is at the correct size tap the 4 holes for an M3 fastener.

Upon Installation of your RX box, there are two wire exits that you can use for the ESC. One is located at the bottom corner of the radio box. The other is located right under the cap. Choose which location you would prefer to use. As for the steering servo, use the wire entrance slot at the bottom of the box to pass the connector through.

Use a body clip to secure and lock the cap of the box in place. This allows quick and easy access.

Hiding Wire

The box has a convenient area where excess wire can be tucked away. This is located right under the lip where the cap locks in to place on the side where the steering servo wire exits the box. Use this area to hide excess wire.

Other Considerations:

The box is not waterproof and is never intended to be. Place your receiver in a balloon if you operate in wet condition.

Check Out more 3D Printed Projects

All About RC Car Gear Pitches – Why are there so many?

In brief, RC Cars utilize a transmission that contains a gear set. Different applications will require different “pitches”. A gear pitch given in imperial terms is related to the amount of teeth that would encircle a one inch diameter. This one inch diameter is known as the pitch diameter. The metric module is how pitches are defined in the metric system. The metric module is known as the ratio of the diameter of the pitch circle per tooth. Do not confuse the metric and imperial pitch sizes as they represent different sizes of pitch.

MOD1 and 32P Gears of Different Sizes
MOD1 and 32P Gears of Different Tooth Counts

What Gear Pitches Exist

In particular, there are both metric gear pitches and Imperial gear pitches used in RC cars. Below is a list of the common gear pitches used:

Imperial Gear Pitches:

  • 32 Pitch
  • 48 Pitch
  • 64 Pitch

Metric Gear Pitches:

  • 0.5 Module
  • 0.8 Module
  • 1.0 Module

If you are unsure of which pitch your specific RC car vehicle uses, look up the parts in your manual. In any event that you can’t find the pitch of your spur gear or pinion gear in the manual, try out the gear pitch calculator.

As the imperial gear pitch increases, the size of the teeth and gear actually decrease. They get smaller. Furthermore, as the Metric Module increases, the size of the teeth and gear increase. Hence, the gears and teeth get larger

Can you Use a Metric Pitch in Place of an Imperial Pitch?

A Metric Module of 1.0 converts to an imperial pitch of 25.4. Gears with a Metric pitch are not designed to match an imperial pitched gear.  I would recommend not using a metric pitch in place of an imperial pitch. In short, this does not mean that you will never find a combination that is close enough to substitute. One could argue and even use a 0.8M gear in place of a 32P gear and it may work well. Even so, I would not recommend using the pitches interchangeably unless you are OK with an increase in gear wear that could result.

Why Use Different Gear Pitches?

Not all applications are alike, this is why we must use different gear pitches in RC. Generally speaking there are two main reasons to use a different pitch. The first reason being physical size. If you are operating a smaller indoor 1/18 scale RC car, it is not ideal to use a large gear with a big pitch. The size of the gear would be far too big to place in to the RC car. It’s also worth it to point out that moving to smaller gears also allow for a decrease in friction allowing more power to make it to the wheel. This is also important for smaller RC cars in order to get the limited power they make, to the ground more efficiently.

LaTrax Prerunner Teton 3D Printed Drift Wheels Free Download

Download this Printable File on Thingiverse: https://www.thingiverse.com/thing:4235548

Here we have a 3D printed LaTrax Teton or Pre-runner (by Traxxas) Drift wheel. The idea was inspired by a friend talking about having an indoor RC car that can drift. I know how much I like the LaTrax line of RC cars and decided that adapting one that I already have should be very easy. That is with the help of 3D printing!

Latrax Prerunner 3D Printed Drift Wheels
Latrax Prerunner 3D Printed Drift Wheels

I jumped on the design software that I use and came up with a simple solution. Something that would be a good balance between print cost, print time, appearance and performance. The end result is a lot of fun.

These wheels work very well with the brushed (stock) setup. The 3D printed wheels have been optimized for use on carpet, and it is quite easy to hold a drift on short carpet. It is also quite easy to hold a drift when running on any hard surface.

The overall Diameter of the wheel is 50mm. (2.0in)
The overall Width of the wheel is 30mm (1.20in)

Latrax 3D Printed Drift Wheels
Latrax 3D Printed Drift Wheels

3D Printer Settings

Printer brand: MakerBot
Printer: MakerBot Replicator (5th Generation)
Rafts: Yes
Supports: Yes
Resolution: 0.2mm
Infill: 15%
Filament Brand: MakerBot
Filament Color: White
Filament Material: PLA
Shells: Use a Minimum of 3 shells

Latrax Teton 3D Printed Drift Wheels
Latrax Teton 3D Printed Drift Wheels

Post Printing Steps

Step One – Clean Up Part

After your wheel has been printed, remove any loose printed material from your wheel. The important point is to make certain the hex insert is free of any loose material. Loose material that has not been cleaned out of the hex area may allow the wheel to sit incorrectly.

Step 2 – Remove Existing Wheels

Remove the wheels on your LaTrax Teton or Prerunner by unfastening the single fastener in the center of the wheel. Use a 2.5mm Allen key.

Step 3 – Check center Wheel Hole Clearance

Use on of the fasteners that was removed from the existing wheels to check the size of the wheel fastener hole on the printed wheels. This may occur if there was shrinkage of the hole during printing. If so drill it out to 4mm (0.150in)

Step 4 – Installation

Use the fasteners to fasten the wheels to your RC Traxxas LaTrax Prerunner or Teton. Do not over tighten.How I Designed This

The hex drive has been oversized slightly to allow for a small amount of shrinkage during printing.

Download this Printable File on Thingiverse: https://www.thingiverse.com/thing:4235548

The RC Car Gear Ratio Explained and Calculated

For every mating pair of gears in an RC car, there exists a gear ratio. The gear ratio is simply the number of teeth of one gear divided by the number of teeth of a mating gear. Gear ratios are important as they allow us to better control speed and torque. We are able to sacrifice speed in order to benefit from increased torque.

This relationship allows us to achieve optimal output RPM by adjusting the gear ratio. Another point worth noting, it is much easier to extract power from a high RPM brushless motor vs a slower turning motor.  It is all made possible by utilizing the gear ratio.

How Gear Ratio is Calculated

The gear ratio is calculated using the number of teeth on a gear. The other option instead of using the number of teeth can be using the overall diameter of the gear. Either way will work, for simplicity and consistency, we will use the number of teeth as our preferred method. Watch the video for a more visual demonstration.

Determine the number of teeth on the two meshing gears that you are calculating the ratio between. Use the number of teeth on the spur gear  and divide by the number of teeth on the pinion gear.  The resulting value will more than likely be greater than 1.0. A good way to always remember this relationship is dividing the Output gear by the Input gear.

Multiple Gear Sets and Ratios

Gear ratios can be confusing when there are multiple sets being used. In the example below, the output shaft of gear set number one is connected to the input shaft of gear set number two. The gear ratio is determined in each set first. The above method is used to calculate the ratio in each set. Next, the calculated gear ratios for each set are then multiplied together. The resulting value is the gear ratio for the entire system.

2 Meshing Sets of Gears - Output of Set one Connected to Input of Set 2
2 Meshing Sets of Gears – Output of Set one Connected to Input of Set 2

You may also use the RCI gear ratio calculator.

Determine Torque Multiplication from a gear Ratio

Torque multiplication always occurs when there are two meshing gears of different number of teeth. The torque multiplication can be calculated directly based off of the gear ratio. As an example, we will use a gear ratio of 10:1. For every 10 turns of the input shaft, the output shaft turns once. We can use this exact number and multiply it by the amount of torque the motor produces. For example, if we say the brushless motor can deliver 0.05 ft-lbs of torque at the input shaft, we would expect 10 times this at the output shaft. The resulting value would be 0.50 ft-lbs of torque at the output shaft.

Putting it together – Application of Gear Ratio Sets in RC

In many RC vehicles, multiple sets of gears are used. Quite commonly, one set will almost always be found directly on the motor itself. The pinion gear on the motor is the first gear that is in a set. The next set of gears in a transmission is typically the differential on a shaft driven drive train. The output shaft going to either the front or rear differential contains a pinion gear. This pinion gear mates with the differentials ring gear, that ultimately drives the differential. In order to calculate the gear ratio, the Motor pinion gear mated to the spur gear must have the ratio calculate first. Next, calculate the gear ratio of the differential setup. Lastly, take the 2 resulting gear ratios and multiply them together.

The total value that you have as a result is what would be considered as your final drive ratio. For every one turn of the output shaft leading to a tire, the final drive ratio represents how many times the pinion gear on the motor shaft must turn. You could then use this value to determine the total amount of output torque produced as long as you know the total input torque.

Why use a Cap Pack on an RC Car? (Capacitor Pack)

A look at a cap pack.

A Capacitor pack is a fancy name for a bank of capacitors. That is a bunch of capacitors that are electrically wired together to form what we would know as a pack. Each capacitor is wired in parallel to each other. The idea is to place the cap pack as close as possible to the ESC on the battery to ESC wires. The purpose is to smooth out any voltage dips that occur during operation.

What a Cap Pack will NOT help / Capacitor Boost

You may have heard that a Capacitor bank helps with the performance of a Radio Controlled vehicle. This is one area that we will need to set straight right away. Capacitor Boost, ya, not really a thing. Cap packs are not installed to increase the top speed of our RC car. They will also not help to increase the acceleration we can achieve out of our car. Essentially, cap packs do not store nearly enough energy in order to discharge this to the motor increasing power potential. In fact they would not store enough energy to operate the Radio Controlled vehicle for even a split second. For this reason we should not expect any improvements to RC car performance.

Purpose of a Cap Pack (Capacitor Pack)

When an ESC is powering a brushless motor, the ESC must turn on and off power to each of the motors winding’s. The main purpose of a capacitor is to fill the void in voltage as the ESC is switching the motor on and off. An example of where the voltage void comes from would be when the battery is under load. As the battery is under load, the voltage tends to drop creating a voltage drop that could be read across the ESC. As the ESC turns a winding in the motor off, the battery unloads and causes a potential dip and spike in voltage. It is possible during this spike that the voltage can be higher than the source voltage. The capacitor bank is able to fill in the void in order to maintain a more constant or steady voltage across the ESC power input. Now let’s look at which RC car can most benefit from more capacitors!

Does my RC Car need a Capacitor Pack

RC Cars that pull a lot of power and are pushed very hard for short duration’s of time tend to be the offenders that are hard on ESC’s. It doesn’t matter if your ESC is rated for 200A and you are only using 100A of that current handling capacity. What is critical is as we noted above, the cyclic voltage drop that occurs across the input side of an ESC. Using a Cap pack in these high demand applications can only help your ESC by reducing the variance in voltage.

Examples of a few RC Car applications that would benefit the use of a cap pack include:

  • RC Drag Car
  • RC Speed Car (Car specifically designed and raced for achieving highest maximum speed)
  • A vehicle that has been geared for a high rate of speed similar to above

What Cap Bank do I Require? (Capacitor Pack)

There is no magic solution as to the exact specifications you require in your application. What we do know, is that a Cap pack, will not harm your RC vehicle in anyway other than to simply occupy space physically. Therefore, it is recommended to choose a Cap pack that has a minimum of 800μF.

When running your RC Car, keep an eye on the temperature that the capacitors are reaching. Higher temperatures indicate that the capacitors are being taxed more significantly. The cooler the temperatures are, the better off your components will be. The result would be prolonged lifespan of your ESC.

To look at the installation details of a Cap pack, visit the Cap Pack installation part of the extending ESC wires page.