Krampe Half-Pipe Dump Trailer

I chose the SIKU Krampe Half-Pipe Trailer for conversion simply because of the location of the cylinder. The location at the front of the model leaves a lot of room to add a screw mechanism and still leaves space under the model to hide the electronics.

The model is quite simple electronically, it just has a micro controller which operates the motor with control purely in the hands of the operator i.e. no limit switches. This model was intended to be the test bed for a generic trailer code which I will use from now on every model I make in order to keep things simple.

Cost Breakdown

SIKU Krampe Hife-Pipe Trailer1€20.00
890 rpm N20 Gear Motor1€5.93
50 mm M3 Brass Standoff1€0.59Ebay (10 @ €5.85)
10 mm M3 Brass Standoff1€0.13Ebay (25 @ €3.20)
2.8 mm Mild Steel Nail2€0.10Hardware Store (40 @ €1.99)
PIC 16F6271€3.66
TB6612FNG Dual Motor Driver1€0.77
Turnigy 3.7 Volt 750mAh Battery1€2.32
Total Spend€33.60


Screw Meachanism

The screw mechanism required a little bit of extra work as a single screw wouldn’t give the required height so a double screw design was needed. The motor is connected to a threaded bar which I made from a mild steel nail. This threaded bar threads into a brass M3 stand off which provides the first screw level. This didn’t extend far enough so I threaded the outside of the brass stand off with an M6 tap and threaded this into an M6 nut to give the second screw level.

It has works well but the motor does wobble which makes the whole trailer wobble when the screw is turning. Also the trailer would dump better if the screw could get a little more height but it is pretty good as is.


The trailer has a simple electronic design with a PIC 16F624 microcontroller controlling the entire model however the code is very simple and very dumb. The controller simply takes serial commands from the tractor and reacts accordingly, it has no sensors and gives no feed back.

The model has a hitch for a second trailer at the rear so I added electrical connections so that serial commands and power could be forwarded to a following trailer.

LED Lights

This model has simple lights, just brakes and indicators. The tractor controls the lights on the trailer, when the tractor turns on its left indicator it also sends a command to the trailer to do the same and the same for every other light. This ensures perfect synchronisation of the tractor and trailer lights.

Krampe Half-Pipe Circuit Diagram

Krampe Half-Pipe Dump Trailer Videos

There are a few videos following the building of the Krampe Half-Pipe Dump Trailer on the RC Tractor Guy channel and a few videos of it being used with some RC Tractors. If you want to view the videos related to the Krampe Half-Pipe Dump Trailer, follow the link below to visit the playlist on the RC Tractor Guy YouTube channel.

Click here to view the Krampe Half-Pipe Playlist

RC Tractor Guy on YouTube

Krampe Half-Pipe Dump Trailer Code

The most up to date code for the Krampe Half-Pipe Dump Trailer build can be found in the forum. I post the code here so that I can update it easily and discuss any problems people are running into when trying to use or modify the code.

Click here to view the Krampe Half-Pipe Trailer Code