Rhombic drive Stirling engines are held in high regard in the Stirling engine community. It is a mechanism of choice for a number of reasons. Firstly the mechanism is symmetrical, minimising any imbalances. Secondly unlike most con-rod arrangements pressure to and from the piston is never at an angle. With a conventional con-rod for a large part of the time the con-rod is at an angle. However with this engine the two con-rods ensure no twisting forces are applied to the piston which ensures low wear and low friction.
The displacer con-rod passes through the power piston providing a long gland which reduces wear. Again, forces the on displacer are straight and those lack of lateral forces reduce wear/friction. The through piston design makes this a Beta Style stirling engine.
Although technically a remarkable mechanism, it is also astoundingly attractive, probably because of the symmetry and the pulsating rhombic shape of the con-rods when it is running. It is undoubtedly a very attractive mechanism both static and running.
As with all the nano range it comes with a special burner, you just light the burner, let the engine heat up and then give the flywheel a small flick to start. The engine has borosilicate glass cylinders which can withstand high temperatures enabling you to glimpse inside the engine.
A low-friction graphite piston was utilised which is self-lubricating and requires no maintenance. A brass heat sink disperses heat from the cold side, while the rest of the engine is made from anodized aluminium.
This beautiful engine will run at over 1800 rpm on a tiny methylated spirit flame.