RC John Deere 8360RT

tractors and accessoriesThis is one of the most difficult vehicles I have tried to convert to RC as this one requires you to squeeze two motors and gearboxes side by side in the vehicle. You might think this is simple as SIKU have done a Radio Controlled John Deere 8430T tracked tractor but take a good look at that model and you will see that they have built the chasis to house two large motors. You will notice that the wheels are pressed right up along the body of the tractor and the floor of the cab is raised to allow the battery to fit in above the tractor body. Unfortunately we do not have the luxury of designing our own chasis so we need to find motors that will fit which is not an easy task.

The JD 8360RT was the fourth tractor I attempted to build and while it took a long time to get the drive motors perfected, it is probably my most successful build. This tractor will pull ridiculous loads up ridiculous inclines, a brilliant conversion.



Cost Breakdown

Final Design Costs

Component Quantity Individual Price Comment
Siku John Deere 8360RT 1 €30.00  Siku No. 3274
5V Arduino Pro Mini  1  €2.35
3.3V Arduino Pro Mini  1  €1.81
NRF24L01 Radio Module  1  €0.91
TB6612FNG Motor Driver  1  €2.21
Hobby King HK-15178 Servo  1  €2.00  Used for lifting arms
Flipped Output N20 Motor, 30 rpm  2 €10.40  Used as drive Motors
LEDs, Transistors and Resistors €1.00 Bought in large quantities
250 mAh LiPo Battery 1 €2.26
Total €63.34

Development Costs

 Component Quantity Individual Price Comment
 Tamiya 70103 Motor Gearbox 2 €11.84  Good motor but not for this model
 Total   €23.68

Tractor Tracks and Gearmotors

The rubber tracks are perfect for RC conversion as they have teeth which mate to slots on the large rear gear wheel of the JD 8360RT. The wheel can also be easily connected to a Tamiya shaft with no more difficulty than any other RC tractor.

In a normal tractor model you have one axle which is the width of the tractor, supports just before the wheels and spreads the load evenly through the vehicle. In the case of the John Deere 8360RT each wheel has it own small axle which has the weight of the tractor pushing up and the tension of the track pulling forward. Add to that the lack of support at the wheel and you are going to have a lot of leverage resulting in a lot of friction at the motor end of the shaft. This means you need a very powerful motor to even turn the wheel without a load.

My first motor attempt used a pair of Tamiya 70103 motor gearbox kits and you can see in this video of me testing the motor that idea didn’t really work. The motor required a 2 or 3 amps to spin the track which just isn’t possible to handle in this scale because the electronics would be too big and require air flow for cooling.

The solution that worked for me in the end was to mount two 30 rpm flipped output N20 motors back to back in the model. I used two brass couplings to connect the motors to the Tamiya hex shaft which I had already mounted to the wheels. This resulted in a very powerful drive system which required only a couple of hundred mAs to pull relatively heavy loads.


LEDs

Most of my models are fitted with a lot of superbright LEDs and the John Deere 8306RT is no exception. The 8360RT cab has eight superbright white 5mm straw hat LEDs around the roof, 4 on the front and 4 on the back. The cab also has two more 5mm straw hat LEDs down beside the front indicators which are 1.8 mm orange LEDs. On the rear mud guards of the model are two more 5mm straw hat LEDs, another pair of 1.8 mm orange LED indicators  a pair of 1.8 mm red LEDs for brake lights. Finally inside the bonnet are some 3 mm superbright white LEDs which shine through the fake headlights at the front of the model.


RC John Deere 8360RT Circuit Diagram

Here is the schematic for my John Deere 8360RT in pdf form. This model uses a 3.3V Arduino Pro Mini in the cab with an NRF24L01 radio module providing the wireless link. In the body of the model a second Arduino pro mini controls a TB6612FNG motor driver to drive a Siku control 32 motor and normal hobby servos for steering and the lifting arms.

Click here to view the RC John Deere 8360RT Schematic


RC John Deere 8360RT YouTube Playlist

YouTube_logoThere are many videos following the RC John Deere 8360RT conversion on the RC Tractor Guy channel. There are also videos of the JD 8360RT dozing snow and pulling heavy loads up inclines to demonstrate its power. If you want to view the videos related to the RC Massey 8680, follow the link below to visit the playlist on the RC Tractor Guy YouTube channel.

Click here to view RC John Deere 8360RT Playlist


RC John Deere 8360RT Code

Arduino Blink Sketch

The RC John Deere 8360RT code can be found in the RC Tractor Guy Arduino library.

Click here to view the RC Tractor Guy Arduino Library