Atwood .049 engine pics
I've been posting pictures of diesels on the diesel forum and was just told about this 1/2A section.
Here are some Bill Atwood designed engines.
The 1949 Atwood "Wasp" .049 was designed by Bill Atwood and Bob Holland. When they split up in the early '50's Bob Holland kept the Wasp name and later marketed as the Holland "Wasp." The Wasp was the first high-performance .049 engine.
The original Atwood .049 featured a heavier (stronger) crankshaft and larger porting. The tank was similar to the Wasp but picked up fuel from a hole in the left side of the tank rather than the low pickup tube as on theWasp.
The Atwood Shriek had improved performance over the original Atwood .049 with a glo-head instead of the previous separate head and glo-plug.
The 1954 Atwood .049 had a shortened case with a long prop driver. This setup used a prop screw rather than the threaded shaft on previous Atwoods. This was about the same time as Atwood started building outboard engines so it is my belief that Bill wanted to lower the flywheel on the boat engines and had to make the modifications to shorten the case and made up the length on the airplane engines with a longer prop driver. Note this engine also has a fuel tank and separate backplate, making a 2-piece tank instead of the previous 1-piece designs.