Bob Lauderdale, like a number of other Speedmerchants, scaled his basic design to suit all of the AMA Speed classes. The published Dizzy Boy plan shows a chart for Class "A", Class "B", and Class "C" versions. He also did a Class "1/2A". They were all pretty small planes. The Harter kits were named Dizzy Boy for the Class "C", Dizzy Bee for the Class "B", and Dizzy Bug for the Class "A". There was also a published Dizzy Bug the was F.A.I. legal.
The Kansas Twister was kitted for Class "A", Class "B", and Class "C". All used the same wing but had increased tail areas as the engine size increased.