A PHOTOGRAPHY: CHUCK FELTON T 50
he Ambrosini SAI.207 was a light- weight fighter interceptor built en- tirely from wood and developed in Italy during World War II. The con- cept called for an airframe of wooden con- struction that could be built rapidly in large numbers without interfering with existing fighter production lines. Armament consist- ed of two 12.7 mm (0.500 in) Breda-SAFAT machine guns in the nose. Powered by a sin- gle 750 hp Isotta-Fraschini Delta engine the SAI207 enjoyed limited success during eval- uation of the 12 pre-production aircraft. In level flight the performance of this air- craft was impressive, achieving a speed of 580 km/h (360 mph) and over 800 km/h (497 mph) in a dive. A production order for 2,000 machines was placed, plus a pre-production batch of 12 aircraft for operational testing. However, after mixed results of opera-
tional evaluation, including negative effects of rain and humidity, and the signing of the Armistice, no production aircraft were built. The 207 is distinctive in looks with its long
and deep nose section with side cheek fair- ings, large nose air intake and scoop and the pointed aft fuselage fairing typical of many Italian designs.
The control line Ambrosini 207 model pre- sented here is also simple in construction and inexpensive as it uses 1⁄8-inch corrugat- ed cardboard as the primary building mate- rial, which greatly reduces both building time and cost. The design makes use of card- board’s unique features in that it can be used in large sections and folded. For in- stance, each wing panel is built of a single piece of cardboard scored and folded at the leading edge with cardboard ribs and a sin- gle spar. The tail surfaces and fuselage are primarily
cardboard with little internal
bracing required. The result is a low cost fast building model that has good scale-like appearance and can take plenty of punish- ment at the flying field.
Cardboard varies in weight, but any 1⁄8- inch corrugated cardboard will do. Sources of this material include box manufacturers
mbrosini 207 By Chuck Felton
An Italian lightweight fighter of WWII makes for an outstanding sport scale C/L model!
AT A GLANCE Type:
Construction:
Wing span: Wing area: Length: Weight:
Wing loading: Line length/diameter: C/L sport scale
cardboard with some balsa and ply
60 inches 582 sq. in. 50 inches 80 ounces
19.8 oz./sq.ft. 60 ft/.018 in.
Engine Required: .40–.50 two-stroke
and local shopping centers where you can find stacks of discarded boxes. Look for card- board with brown paper on one side and a white finished Kraft paper on the other side. The white paper on the outside of the model results in a smoother finish and neater ap- pearance. The method of folding the card- board and the use of gummed paper tape to seal the joints and exposed corrugations is explained in the construction hints. The model has a wing span of 60 inches and a length of 50 inches. The bottom of the airfoil is flat with a curved upper surface, due to the scoring and folding technique em- ployed. Engines of .40 to .50 size can be used. My model is powered by a .40 engine and has a fully fueled flying weight of 80 ounces. This weight combined with the 582 square inch wing area results in a wing loading of 19.8 ounces/square foot.
FEBRUARY 2013
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