Sure Fire (oz4846)

About this Plan

Sure Fire. Free flight gas model.

Quote: "The high performance of this free flight has been proved in contests. Detailed plans for the AA version, construction data for C job. Sure Fire, by Frank Ehling.

The original D version of the Sure Fire won its share of contests so the basic design seemed a good bet for 1951, both as an AA ship and as a Class C job, the D class having been killed before the 1950 season started. A lot has been said about the bad points of scaling a design up or down to adapt it to other classes but the Sure Fire performs well in any size. Our tests bear that out.

Full detailed plans are presented for the AA version, but the more skilled builder will have no trouble in working up the C giant from the semi-detailed three-view which gives wing and tail construction. You will note data on the three-view for both AA and C. For the C model, a big Dooling, McCoy, Spitfire, and so on, will give top results. Ours was fitted with a 12 in Aero Prop. It will hold its own with any contest free flight.

The original D model was covered with Silkspan. However, after it was flown for one season, it was recovered with nylon. Nylon covering is the best possible protection to stand up in contest flying. Be sure that the model is well doped and fuel proofed. You should fly it in both calm and windy weather to learn all its peculiarities. If you can fly in calm or in the wind, you will be sure to take home prizes - there are many model builders who think that they cannot fly in wind, and therefore, hesitate to do so in a contest. Try 'wind' flying. It's easy.

Directions for the AA model. The wing is not high aspect ratio, nor is it low. The fuselage is not short coupled nor does it have long moment arm. The model seems to strike a happy medium, turning in one good flight after another. The fuselage cross section, while a little large, does not seem to alter the performance of the model whatsoever. The AA version uses a thin flat section, both in the wing and in the stabilizer. The fuselage has sheet balsa sides and bottom, and sheet covered front section. This means good handling qualities.

Start the AA by drawing the plan to proper size. making sure that you have all the material on hand. A little patience will pay off a model you will be proud to fly, and you will be up there with the rest of the winners throughout the season, if you don't forget the dethermalizer fuse when you launch your model.

Making the fuselage. Cut the two sides out of 1/16 in balsa sheet. If you can obtain quarter-grained balsa (speckled appearance), by all means use it. It produces the best possible fuselage for a given weight. Now cut the required bulkheads..."

Direct submission to Outerzone.

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