Offenhaser Model Engine Plans Development – Top End

I have started looking at the top of the engine, the head, cambox, and camshaft. But I got sidetracked working some of the subtle shapes of the crankcase that bothered me. I did not like the way that SolidWorks generated the fillets circled below. I spent a fair amount of time adjusting the control points and did not like this trial and error approach.

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So I decided to use surfaces instead of solid bodies. I have not used surfaces for a couple of years so I spent some time researching and practicing. Below the surfaces are being laid in:

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And once the surfaces are created, they are knitted together to create a solid body. I am much happier with the result. Below is the result of my test crankcase using surfaces instead of fillets.

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Below is the beginning of my study for the head and the cambox. These are complicated parts. Both coolant and oil travel through the head.

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Below is the underside of the head.

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I have spent a fair amount of time today reading through Terry Mayhugh’s Offy build log; what an absolute mother lode of information. I have a lot of studying to do before I can begin to add the next level of detail the Might Midget 97 cu in. model engine. The model engine will be about 24cc.