Recent content by lohring

I race model boats. We run weedeater type engines from 26 cc to 36 cc. They are tuned pipe twostrokes. The market is very small, but one company produces custom race engines that compete with the mass produced industrial style engines. Take a look at these sites...

There are some plans as well of design advice at https://web.archive.org/web/20181118222707/http://www.modelenginenews.org/. I've written a series of articles on design and construction of high performance engines that may be of interest. Below is one. Lohring Miller

You can make a much simpler eddy current brake. Below is one a friend uses on his inertial dyno. However, eddy current brakes work the best at high rpm. Lohring Miller

Aircraft and large boat engines develop power in a steady state. Endurance testing requires a steady state dyno. Most race engines never run in a steady state. There are places for each type of dyno. it's hard to build large inertial dynos for high power engines. Froude makes brake dynos...

Inertial dynos are much better for racing engines. We ran one for years. You get a full power curve in a few seconds; reducing wear on expensive engines. They are the standard for everything from karts to snowmobiles. See: https://www.performancetrends.com/tdkmotorsports/index.html...

You can make a brake from old computer drives. Below is one I made. Lohring Miller

Check https://web.archive.org/web/20181118222707/http://www.modelenginenews.org/ Lohring Miller

If you actually have an engine, a simple Prony brake with a scale will work fine. If heat disipation is an issue, spray water on it. Lohring Miller https://en.wikipedia.org/wiki/Prony_brake

The smaller Sunnen gauges are expanding ball style. All need to be set. Sunnen has special fixtures, but I used a micrometer. My main interest was checking cylinder bores for roundness and taper. The larger gauges were great for this. Lohring Miller

What is the minimum bore size for this tool? Thanks, ZJohn Sunnen has made a lot of different bore gauges. The picture shows the type I had. It comes with various tips and can measure around 1/2" to 3/4" bores in the small size and up to 2" in larger sizes. Even used they are around $600...

This was my favorite. By rotating and moving it up and down in a cylinder it is possible to see out of round and tapers very accurately. Lohring Miller https://diauctions.hibid.com/lot/82161-113357-2998/sunnen-dial-bore-gage

There is a lot of information on this old web site. https://web.archive.org/web/20181118222707/http://www.modelenginenews.org/ Lohring Miller

You can set variable heights in PrusaSlicer. Lohring Miller

My first engine that I designed and built in highschool is below. It was designed to compete with existing high performance 10 cc model race engines of the time (1960). I don't recommend that it be anyone's build. Lohring Miller

The smallest commercially available engine was the Cox with .010 cubic inch (.16 cc) displacement. My favorite books on engine design are Sir Harry Ricardo's The High Speed Internal Combustion Engine. Paperback reprints should be available at a reasonable cost. The others are Gordon Blair's...