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Radio controlled road vehicles on Upper Benllech

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Just to show I can do 'railways' and not just roads.

I recently completed this little set for the planned layout.



This isnt entirely off topic.

The wagons are to enable development of road to rail transfer. 

The concept for the layout is the "goods in" area of a housing construction site. Served by an internal contractors railway. 

Something I have seen in a number of pictures, most significantly Selsdon where I grew up and Letchworth garden city. Which between them are providing the inspiration. 

For this to achieve the operation I require. I need to unload from road vehicles to storage bays and directly to the wagons. Hence needing some wagons. 

The next stage is a side tipping trailer. I am trying to replicate a mechanism used in pre hydraulic tipping vehicles. The trailer bed is winched sideways until the centre of gravity gets far enough off centre and the load tips downwards.


The idea is to use a set of infra red transmitter and reciever to transmit a servo signal from the main vehicle. I have a motor drive pcb which will then convert this signal to motor speed rather than servo position. When the signal is disconnected, it stays at the last setting until the signal is re established. (servos work the same way)


The wagons will be helping test this tipper and define key geometries of the layout.


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Extremely nice work!


Looking forward to the trailer.

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Progress has been slow but steady, but the results have not been very photogenic, with the details not really being visible. But its now starting to come together.


I have focused on the tipping mechanism before worrying about the wheels and undercarriage. The body is built from plastikard, there is still lots of detailing like strapping etc to add. The tipper body features a set of transverse L section rails, which in turn rest on beams that form part of the lower chassis.

Underneath, a windlass hauls the body sideways until gravity causes it to tip. Stay chains at each corner restrain the movement.


On the prototype, the windlass would be wound by the driver (or his mate) using a 3ft long ratchet wrench. On the model I am using a 4mm planetary gear motor from sol-expert. It has to fit between the frames, which is very limited space, so I had to dismantle the gearbox, which is modular and separates into 3 rings, each with an epicyclic gear-set inside. So I reduced these from 3 down to 2. (125:1 reduced to 25:1) and swapped the motor for a shorter 4mm motor.  


The standard motor gearbox is held together by a tube of heat shrink. Having modified the contents, I re-assembled them into a pair of brass tubes to keep everything rigid and concentric. Everything except the output gear is 4mm diameter.


These then fit into one end of the chassis, driving the windlass via parallel worm gear.


At the opposite end, there is a pair of latches, these hold the 'top hinged' doors closed. The weight of the body resting on the slide rails of the chassis keeps the latches closed until the body is winched off centre. These work nicely now, I am hoping these will still release when there is a load inside pushing against the doors.


The control system is still under development, the motor is driven by a bi directional ESC which uses the servo signal from the tow vehicle's receiver. An Infra Red LED is connected to the RC receiver and was intended to control the ESC via a photo-diode. However, the best range I could achieve was 5mm between LED and photo-diode. Which is not enough to be useful, so I now have now ordered some phototransistors to hopefully increase the sensitivity. However, the basic principle did work, the motor could be controlled smoothly with an air gap between the 2 vehicles and it coped with them being moved out of range, without the motor running away due to lack of signal.

So far all the above has been tested independently, but next needs to be fully assembled and tested. If it works, I can then take it apart to start painting and build the running gear, turntable, etc.

This last picture shows the new wagon (without doors) alongside my existing wagon for the Atkinson for perspective.


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Your micro engineering is unequalled is this field!

I've have the 8mm gearboxes in pieces - but the 4mm ones!!!!


As always - superb!

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That's awesome work. I had never thought of taking one of the 4mm planetary gearboxes apart!

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