Power output measurement of the PE 2 Stirling engine

Calibration for motor load

This article covers power measurements for the PE 2 3D printed Stirling engine. The net output power (the useful power) plus the frictional losses measured earlier are combined with other test data and simulation results to more fully understand this engine’s performance. The techniques and data should be useful for others designing Stirling engines, especially […]

How to measure engine friction using flywheel deceleration

Flywheel kinetic energy vs speed

This article describes the method used to determine the engine component friction in the 3D printed Stirling engine. This technique can be used on rotating machines of any size. The ordinary purpose for a flywheel is to store kinetic energy to smooth the rotation of an engine or machine tool. For our purposes we will […]

Engine friction measurements using flywheel deceleration

complete engine with and without compression

Flywheels are used to store kinetic energy. Once a flywheel is accelerated to some rotational speed, it will only slow down because it is transferring energy to a load. By accurately measuring the flywheel’s rate of rotation versus time, we can determine the rate at which the flywheel’s energy is being transferred to the the […]

Speed & temperature measurements of the 3D printed Stirling engine

Stirling engine speed vs temperature ratio

Using the automated testing system for the 3D printed Stirling engine I described in my last article, I’m now presenting some of the results of using the test system. On the chart below I’ve plotted all the data I collected versus time. It’s a little busy so I’ll explain it in detail before I go […]

Automated testing of the PE 2 Stirling engine

test setup1

As you can see from the photo, I’ve switched over from manually taking data from sensors to semi-automated testing of the 3D printed Stirling engine. I’m still manually controlling the heat input so I wouldn’t call this fully automated testing. This article will cover the test setup details including a schematic and a listing of […]

A regenerator for the 3D printed PE 2 Stirling engine

Diagram of the regenertor in the PE 2 engine

This post will examine some of the practical and theoretical aspects of a regenerator as it applies to the 3D printed PE 2 Stirling engine. Those who just want to build a regenerator for the engine and get good performance, will find what they need here too. The above data show my tests of the […]

1 Watt Stirling engine driving high-power LED


First let me say I will display this engine and generator at the Maker Faire in San Mateo, CA on May 21, 22 so you can see it running if you are there. The above video shows a one-watt Stirling engine driving a one-watt LED. Conversion efficiency is not too high so I’m only driving […]

Engine 3F Efficiency Analysis part 4

Rev 1: See details at bottom. Let me summarize what has been covered and what remains in this efficiency analysis: Component Power percentage of total power Efficiency analysis Heat lost directly to the environment 40.3w 58.4% Part 1 Thermal shorting: heat conduction directly from the hot end to the cold end 5.9w 8.6% Part 2 […]

Engine 3F Efficiency Analysis part 1


In an earlier post I measured 1.05 watts output from my engine 3F using a 69 watt input. This computes to 1.5% efficiency. So where did the other 68 watts go? The following is my analysis of where all the energy went. It won’t be as rigorous as I would like, partly due to lack […]

Measuring a Stirling engine with 1 watt power output and 1.5% efficiency


The following is a transcript with still photos of the previous video on the same subject. I’ve included a few more notes about the engine, my model 3F. This is a gamma configuration Stirling engine. I’m powering it with the heat from a 70 watt light bulb so that I can accurately measure the heat […]