Sunday, January 20, 2013

BUZZ COIL SPARKER

During one of the first couple days in January I went to Cutler Cycle and Mower and bought a new snow blower to replace the one that has that been in use for the past 27 years. It still worked OK, but I wanted to treat myself to something new.
While I was there, I was able to acquire some magneto coils from lawn mower type engines. They can be converted to make ignitions systems for model gas engines, and even full size ones for that matter.
 The first step is to check it out to make sure it is good. It was.
Then a small wooden box is constructed and everything stuffed inside. Also a set of buzz points and some terminal screws.
After all that, it is time for testing so an old battery that has been sitting around for ages was pulled out. The meter indicated 6 Volts, but it only produced a puny weak spark and then quit altogether. How disappointing.This is the 4th system I've built so I knew it should do better than that. A trip to the hardware store for a new battery proved it. Look at the video.
video
These little buzz coils are a facsimile of the buzz coils used in Model T Ford cars and Fordson tractors. They produce an almost continuous arc rather than a snap spark supposedly providing more positive ignition.
 If desired these coils can be hooked up to provide a single snap spark too. The model Atkinson in the previous posting is wired that way.





Tuesday, January 1, 2013

ATKINSON CYCLE ENGINE

Somewhere around August or September while browsing the HEME website, I happened to see a picture of Jan Ridders version of an Atkinson Cycle engine that intrigued me. Although it uses the Atkinson Cycle, it is not a scale model such an engine. This one has a timing belt driven overhead cam shaft. Not vintage at all, but still interesting. I happened to mention seeing the picture to correspondent friend Reg Ingold of Australia, and would you believe by return email he sent a PDF of the plans for the model. I happened to be out of a project at that time and thought what the heck, it is as good a candidate as any, so I started gathering materials.
Just happened that materials to build it were already on hand, so it was a matter of cutting them out and start making chips. Progress was slowed by the fall cleanup (leaves etc.) and care taking responsibilities, but never less it proceeded at a rate about as fast as a snail tied to a stump, and parts slowly started to emerge.
                        Here are just a few of them.
The ignition is powered by flashlight batteries using a coil from the magneto of a Lawn mower type engine. The breaker points, not shown, are a Micro switch operated by a cam on the crank shaft. The spark plug is also home made. It is a spare left over when I built the 4 cylinder Panther Pup engine.
This engine is equipped with a Vapor Carburetor, where the intake air is drawn through the fuel tank, where it picks up vapors to run the engine. While this concept dates back to some of the very first gas engines ever built, it is new to me. I'm not sure how good it works. At the time of this posting I have not yet had the engine running, so I'll have to do a bit more fine tuning, but I feel confident that it will work. Videos of them show them working very well.
      During construction I took a short video while turning the engine by hand. It can be seen much easier how the mechanism works turning at that speed than running anyway.
video