Nano Rhombic Stirling Engine

Rhombic drive with beta configuration

The Kontax Nano Rhombic high temperature Stirling engine is a beta configuration engine with a rhombic drive. Two gear wheels mesh together and drive the piston and displacer coaxially. It has an anodised aluminium construction with precision machined brass gear wheels. The solid brass flywheel rim has integral balancing, allowing the engine to run up to 1800 rpm on a tiny candle-sized flame.

How does it work?

Stirling engines work by cyclically heating and cooling the air inside the main chamber. As the air heats up it expands, and as it cools down it contracts. This expansion and contraction drives a small power piston which in turn drives the flywheel. The clever thing about Stirling engines is that the mechanism for cycling the heating and cooling of the air is built into the engine in the form of the displacer, which is driven by the flywheel and crank arrangement and moves the air from the warm side to the cool side and back again over and over.

Stirling engines come in three main configurations, alpha, beta and gamma. This Nano Rhombic engine is a beta configuration, with a displacer inside the main chamber and a parallel power cylinder housing the power piston. The power cylinder is connected to the main chamber by a small tube.Four short connecting rods and two drive rods are connected together in a rhombus shape, with the relative lengths of the connecting rods giving the required 90° phase between the displacer and piston.

Main features:Beta configuration

• Beta configuration
• Rhombic drive mechanism
• 1800 rpm
• Runs on a tiny methylated spirits or denatured alcohol flame
• Extremely low friction self-lubricating graphite piston
• Oilite bushing between piston and displacer rod
• Built in flywheel balancing

Materials

• Aluminium connecting rods
• Stainless steel ball-race bearings
• Micron precision borosilicate glass cylinder
• Micron precision graphite power piston
• Aluminium base, foot, and brackets
• Aluminium flywheel spokes
• Brass flywheel rim

Dimensions

• Base - 115mm x 50mm x 5mm thick (4.5" x 1.9" x 0.2")
• Flywheel - 35mm diameter x 6mm thick (1.4" x 0.23")
• Power piston - 9.5mm diameter (0.375")
• Overall height - 115mm (4.52")
• Burner - 25mm diameter x 40mm high (1" x 1.6")

Assembled

The engine is despatched fully assembled and ready to go.

Instructions

Click the image below for PDF assembly, operation and maintenance instructions for this engine.