Inline 4 Layout
The Inline 4 Air Engine is basically identical in piston operation to the Radial Air engine. It's 4 pistons are same size, with same travel. It is a faster engine because it does not have the oversized flywheel the radial does.
It is more difficult to build because of the crankshaft. Getting connections lined up and secured in place is quite a challenge. In the end for me this engine ran easier and smoother then the radial, primarily because it was my 2nd air engine with the same pistons and I was better at making them.
Well, some people were making 8 cylinder versions of my inline 4 and I wanted to make a 8 cylinder engine too. Since I was getting far to many model engines laying around I decided to design a smaller one.
Because of the V8 arrangement and my continuing efforts to incorporate more of the air flow into the engine block the tube hook up is simpler on this engine. However because of its size and the number pistons it is very difficult to build.
When I first finished the engine it didn't work and that sinking feeling that it wouldn't set in. pistons bottomed out, the crankshaft twisted and a lot of air was coming out the engine the shouldn't be. I gave it a day or two and decide to try and fix it. I ground down every piston about 1/32" and fixed crank, amazingly it worked and it worked well.
To be continued. . .