Savoia S12 (oz14000)

About this Plan

Savoia S12. Free flight scale model for rubber power.

Quote: "Savoia S.12 bis, by Bill Noonan. A truly rare scale modeling subject of a 1920 flying boat.

The Savoia S.12 is one of a number of interesting aircraft designs that was entered in seaplane races popularly known as the Schneider Cup races. These races started in 1913 and bore the title of 'La Coupe d'Aviation Maritime Jacques Schneider'. Their purpose was to advance the state of hydro-aeroplane racing and a perpetual trophy was offered, valued at 1,000 English pounds.

The races spanned 18 years and saw speeds climb from a modest 60 mph to over 340 mph. France, England, Italy, and the United States were represented at various times, and the trophy changed hands frequently over the years.

Our subject, the Savoia S.12, represents an approach to hydro-aeroplane design that prevailed in Italy and France in 1919 and 1920. Both Savoia and Macchi produced a number of single-hull flying boats that were modifications of planes used during WWI, but altered for the purpose of increasing their speed. This explains the use of the designation bis (translated: 'again, repeat'), which accompanies the S.12. This suffix is found frequently in foreign aircraft nomenclature when there has been a conspicuous alteration to engine installation or wing configuration.

The most striking thing about the S.12 is its coloring and marking scheme. Most manufacturers of racing aircraft realized that it was advantageous to have their name appear on the winning aircraft, and Savoia went at it with a vengence, their name occupying most of the sides of the hull. The handsome numerals and diagonal green, white, and red national tail markings contribute to a spectacular looking airplane.

The layout and proportions of the S.12 lend themselves to CO2 power. The engine/strut unit, is the heart of the model and forms the structural nucleus, the upper and lower wings being affixed to the unit. The Brown CO2 motor fits easily in the nacelle, but requires the fuel bottle to be accommodated in the forward part of the hull.

Construction: Take a few moments to look over the plans and photos. Note that the forward portion of the handsome hull is cut from soft block balsa and hollowed out. Carefully trace the side view onto the block and cut to shape. A jig saw will facilitate this operation. Do the same with the top view. Contour the hull exterior with a sharp knife and/or an electric sander.

The bottom of the hull is rather unusual and should be done slowly to make the transition between the typical keel, bow shape and the concave aft portion work smoothly. Keep the chine (the part of the hull where the sides and bottom intersect) as sharp as possible. This is hydrodynamically desirable. Check the hull cross-sections on the plans.

When you're satisfied that the exterior shape is okay, cut the top of the hull away at the 'beltline,' where the top decking curves over to form the sides. This will allow you to take a power router and remove the unwanted balsa inside the hull. Try to get the walls down to about I/4 inch. Hold the hull up to a strong light every once in a while to check for thin spots. Finish off this operation with sandpaper. particularly in the cockpit area. Cement the top portion back in place and sand off any cement or burrs that disturb the fairness of the contour. The top of the hull is open from the forward cockpit coa mine to the aft end of the block, under the wing.

The portion of the hull aft of the carved block is built up in a conventional manner. The main longerons are 3/32 square balsa. All uprights are 1/16 square..."

Savoia S12, MAN, June 1985.

Direct submission to Outerzone.

Supplementary file notes

Article pages, thanks to RFJ.

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