Swat (oz2859)

About this Plan

Swat (aka Privy Boy). Free flight power model. For .049 - .051 engines.

Quote: "SWAT! By Don Alberts. They combined the Civy Boy and the Hogan and racked up the highest gas time at the 1955 Nationals. Five years development in this Half A.

Immediately after the 1950 Nationals, when it was evident that the Half A class was becoming a serious competition category, some of the members of the South West Aero Team in Albuquerque decided to design a model of this size incorporating the best features observed at that meet.

Paul Gilliam's Civy Boy (oz5497) design was particularly impressive and the Swat started off having the same dimensions but with altered surface outlines to facilitate construction. During the following five years, the design was flown in contests throughout the Southwest with considerable success. We were also influenced by the Hogan (oz9266) philosophy and the tail-moment arm was shortened and the flat-bottom airfoil was adopted while an effort was made to clean up the external lines of the ship. The fuselage construction has evolved from a built-up truss construction, and corners have been cut everywhere possible in the interest of simplicity and light weight. The temptation to taper the wing tips has been resisted, not due to ignorance of the structural advantages, but to simplify rib cutting and tip construction. The result of this long range improvement program is this lightweight, rugged, high-performance competition machine which put up the highest gas time at the 1955 Nationals.

After building several models which varied only in detail, we reached the conclusion that this could be a boring process and that simplicity and ease of construction were necessary if many planes were to be built, and if good craftsmanship was to be a part of the process. Also the mortality rate for low-incidence models is higher than with the high angular difference or sport

type model. Few experienced competition fliers will deny that the way to get really high is by using as little angular difference as possible and, by using vertical take-off, this has become less dangerous than is generally thought. The engine improvements over the last five years have made necessary changes in the nose-moment arm due to weight and overhang differences, but I prefer the Atwood engines with a micro-tank fuel shut-off system and the plans show the proper dimensions for that system. Various warp resisting wing and stab constructions have been tried during the development period and the one shown on the plan has proven to be best with respect to simplicity and warp resistance both.

The pictures show geodetic wing construction, that is, with ribs crossed over X-fashion to resist warping. Conventional ribs may be easier to build, as shown on the plan. A detail shows how to assemble the geodetic ribs into the wing.

Even if this is your first competition free flight model, no difficulties should arise in the construction. An aluminum template of the wing and stab rib is well worth the time it takes to cut it out and will allow the ribs to be sharply cut and evenly notched. After the ribs have been cut from soft sheet, the right wing half can be built backwards on the plan, since spar locations are already into the ribs..."

Update 05/12/2017: added article, thanks to SimonBlake.

Supplementary file notes

Article.

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