Porterfield Model 50 (oz7725)

About this Plan

Porterfield Model 50. Radio control semi-scale model.

Quote: "Ultimate in Sport R/C. A smooth, slow-flying scale model for any system - and any flyer. Porterfield, by Herb Clukey.

THE 1939 Porterfield Model 50 was one of the best known light planes of the era. A fully cowled 50-hp engine in the nose, wheel pants, plus parallel wing struts made this tandem stand out. Our thanks to the late EE Porterfield Jr the designer and president of Porterfield Aircraft Corp for making this article possible.

Our model was first designed as a 1/2A R/C beauty called the Porterfly (oz7139) in Sept 1967 American Aircraft Modeler, and was such a success that it was decided to build a larger model which could incorporate any of the radio gear on the market today. Hence the semi-scale Porterfield which American Aircraft Modeler displayed on the front cover of its June '67 issue.

Since the Porterfield is tagged as semi-scale, let's explain the phrase. Any time areas are added or subtracted, landing gear positions shifted, struts changed or any other deviation from absolute scale, you have a semi-scale airplane. The joy of all this is the fact that you have improved the ability of the model but have retained the original looks of the prototype. So semi-scale does not necessarily mean an ugly out-of-proportion airplane.

On our Porterfield the chord was increased by one inch, airfoil thickened by 2% and horizontal tail group increased by 20%. The landing gear location was advanced 1-1/4 inches which showed up on takeoffs, landings and touch-and-goes. V-type struts were used instead of parallel struts, thus making two groups to hook up instead of four which allows for easier alignment. With these minor changes the Porterfield is one of the best semi-scale sport trainers available.

The plans have been drawn as self-explanatory as possible. Before starting to build, bear in mind that good material is half the battle, so choose it wisely. The fuselage is a good place to start so obtain two sheets of 1/8 x 6 x 48 medium balsa and two sheets of 1/8 x 4 x 48 balsa of the same weight and texture, if in wide plank. Make two. Draw in fuselage sides, mark bulkheads and sections.

Cut out #10 and #11 from 1/4 sheet and glue in place. Install the 1/2 and 3/4 bass mounts and let dry. Meanwhile, cut out #1 (nose block) and #2, 3, 4, 5, and 6. Glue to fuselage sides, then add the 1/4 x 1/2 balsa cross members and uprights from section 6A on back to section 9. Add square cabin brace, then #12's on outside of cowl and all blocks on top and bottom of nose section. Next, bend the strut from 1/16 wire and epoxy to ply floor, then install as shown on side view. Follow up by installing remainder of ply cabin floor. Cover top and bottom of rear fuselage then add #14 and also the dowel wind-shield braces. At this time cut out cabin windows and trim all cowl blocks to conform with fuselage.

Using a razor saw or sharp knife, cut top nose cowl off as shown by cowl separation on the drawings. Shape #13 and drill for particular engine to be used and install as shown. Cut out engine cowl to suit. Also, all servos and receiver shown on plans are of no particular type and are shown for positioning purposes only. This is due to the wide variety on the market. For the tail group obtain medium light C-grain balsa and butt join for proper width. C-grain balsa has a flaky appear-ance. Insert bass inlays where shown for horn attachment. Two type hinges are shown but all hinges are optional to the builder.

The wing is of standard construction. Make a right and a left panel first. Do not add any sheeting at this time. Now cut two each of the spar reinforcement..."

Update 23/05/2016: Article added, thanks to RFJ.

Supplementary file notes

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