In 1969, I had just finished the molded Bearcat III and was thinking of putting together a simple stunt ship just to play with. There were many Orientals around here in Dallas. I had used one to win my first contests. That first Oriental also happened to be the first airplane used to experiment with an idea that I had about yaw control and movable rudders. I cut off the vertical tail surfaces and retrofitted the first movable rudder onto that Oriental.
Anyway, I decided to build a modified Oriental specifically designed around the movable rudder (Rabe rudder), a fatter airfoil, semi-scale features, sliding block adjustable leadouts (an original idea), upright engine, a full house of trimming adjustments including variable ratio flap/elevators, some molded components and simplified construction. It turned out to be an excellent little airplane. It was used for several contest wins and met its end at Shreveport when a judge walked into the circle. He wasn't hurt but the airplane was destroyed.
There were request for plans and a goodly number of Mustunts were built locally. That first Mustunt was later labeled a Mustunt II. In 1970 some local flyers began to fly profile Mustunts, so I legitimized the airplane by redesigning it for even simpler construction while retaining the semi-scale military character. This airplane retained the aerodynamics of the Mustunt II but omitted formed wingtips for simplicity and trimming ease. It also featured an upright or inverted engine with a molded cowl and plastic wheel covers to dress things up a bit. It was a popular design.
In late 1971, I decided to write an article about trimming and learning to stunt using the basic Mustunt design and offering progressive stages of improvements for developing stunt flyers. To complete the series, I designed and built the Mustunt III and sold the article to American aircraft Modeler for publication in the Feb 1973 issue.
The article was well received and in the next to last paragraph, I stated there was enclosed in the article a thinner rib template for Mustunts needing less lift than provided by the original thick section. Thinner wing Mustunts were refereed to Mustunt IIAs. The thinner wing rib template was somehow omitted from the published article. The wing rib existed as part of the original design, differing little from an Oriental rib. it should probably be considered legal for Classic Mustunts.
OK, so the Mustunt was a "bashed" Oriental. I guess I shouldn't have taken it so personally when Sig kitted the "Twister" shortly after the Mustunt article was published. Did anyone else noticed the resemblance of this profile stunt trainer with its fat constant chord wing and square tips? I think they missed the Mustunt I's best feature of having an upright engine for simple engine operation for beginners.
Al