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David Kerzel, Pompano Beach, Florida david@FloridaAME.org
Just Miss, 1 Cylinder, 0 cycle, .438 bore X 0.531 stroke First posted 2/8/2003 finished 2/23/2004
In the summer of 2002 when I was struggling with getting my horizontal hit and miss to start I began to realize how it never had a problem with miss cycles. As I thought about it, it became obvious that had the hit and miss era had ended before the designs were perfected and the just miss engine was the only logical progression for these engines.
A properly designed Just-Miss would not have any of those hit and Miss problems, no valve leakage, no bad rings, no ignition problems, no carburetor adjustments, just pure simple operation.
The basic idea has come together and construction was been started in January 2003. The engine will have modern features like ball bearings and a hall effect sensor.
It
was a fun engine to build and interesting to watch it run. It runs at 62
RPM and looks like it will not make it to the next revolution. It has a sound
like a hit and miss during miss cycles. It runs for over 2 days on a set
of AA batteries. A wonderful living room engine.
This should be a simple quick project. I will post in progress pictures. (when I started)
It took nearly a year, but most of the time was spent on other projects like
those little CO2 engines.
Construction pictures:
2/8/2004
2/8/2003
4/6/2003 Finally back to the shop. Since this is a modern engine it gets ball bearings. It low speed and low power so brass is the material of choice. The connecting rod is actually soldered together. the crank shaft will be assembled with LocTite 640.
Together for the first time. Low friction, and the flywheel inertia keeps
it moving for a long time.
7/1/2003 I got back to this project and added the hall sensor, built a transistor drive circuit. The engine runs quite well. Now I need to find some small batteries to fit in a small base and finish all the detail parts.
8/10/2003 I finally have gotten back to this. The
batteries and electronics work great now.
The engine actually runs too fast and I need to add a speed regulator.
It is an amazingly low friction engine and takes nearly a minute to coast to a stop.
It needs some details along with paint and polish.
2/23/2004 If is finally done, polished and ,mounted
The coil assembly
The electronic speed regulation. It works just like the fly weights in principle.
Copyright 2004 Florida Association of Model Engineers and engine builder as noted above, All rights reserved.