Delta-Too (oz6151)

About this Plan

Delta-Too. RC pylon delta, from MAN January 1966 by AW Leftwich.

Quote: "The Delta-Too continues MAN's policy of presenting AMA pylon record holders and Nats winners. Third in a line of good winners. Delta Too, by Austin Leftwich.

The name imiplies a sameness with other delta designss which actually doesn't exist. Delta-Too has the conventional plan form, of course, but its similarity to other deltas ends there. To begin with it was designed and built to the minimum area and weight for .15 site engines in the AMA Pylon class. In the author's opinion, the long existence and popularity of the 2.5 cc. competition classes in Europe has given the European engine manufacturers a slight edge in the .15 size engines. If all other factors such as wing loading, scale effect, etc can be held comparably equal (and they can) then this engine superiority dictates that the .15 is the ideal size for the AMA Pylon event.

Other then the slight advantage derived from engine selection, the superior performance of Delta-Too is directly attributable to two major factors. The first is its extreme light weight. The 32 oz total weight figure is difficult to achieve and requires constant attention to materials selection during construction, but results in a large increase in straight flight speed. Delta-Too has been clocked in straight flight in excess of 110 mph.

The second factor concerns the airfoil. Most delta designs, including some full scale aircraft, emploiy a double reflexed section. That is, the bottom curvature is convex and sweeps upward near the trailing edge, and the upper contour is concave or depressed at the trailing edge..."

Direct submission to Outerzone.

Supplementary file notes

Article, thanks to theshadow.

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