South Pointing Chariot.
A Chinese chariot with a figure mounted on top, forever pointing towards the south, irrespective of which way the chariot is heading. A series of gears driving a differential driven by the 2 wheels creates the movement of the figure relative to the chariot.
Actually not too accurate because of the need for the extreme dimensional accuracy of the gears and wheels but good for impressing the people on grand public occasions.
It was thought to have been developed first in 2600 BC the first historically confirmed version was created by Ma Jun around 200. It’s secret was lost and reinvented many time through history but in 1947 George Lanchester designed a model that used a differential to drive the pointing figure. It is that design upon which this model is based.
The design uses a 1:1 ratio between the wheels and the differential and a wheel base equal to the wheel diameter. All the calculations for the design can be found here.
More information can be found here. http://www.odts.de/southptr/
Printer: Zortrax M200
You will need 1 of each STL part except for the following:-
Long Column 2
30 Tooth gear 4
Bevel gear 15 Tooth 6
Diff Cap 2
Chariot wheel 2
Chariot wheel Cap 2
You will need some extra components to complete the build :-
2 piece Ø 4 mm steel rod 76 mm long
2 piece Ø 4 mm steel rod 60 mm long
2 piece Ø 4 mm steel rod 58 mm long
1 piece Ø 4 mm steel rod 35 mm long
2 piece Ø 4 mm steel rod 21 mm long
Acetone to solvent bond some of the parts together.
South Pointing Chariot
STL files for download are in 3 groups Blue, Red, and Orange, Use the drawing opposite as a guide for where the components fit into the assembly.