Curtiss O2C-1 Helldiver (oz1931)

About this Plan

Curtiss O2C-1 Helldiver ( Curtiss F8C-1 Helldiver). Scale biplane bomber for control line. MAN July 1950. Scale is 1/16.

Quote: "No modeler can deny that the prime advantage of controline flying is the ability to fly his favourite scale model successfully, without worrying about lateral stability, looping tendancies, etc. The author has built and flown many controline scale models and the model presented heer is one fo the best for sport flying. Engines from .099 cu in displacement can be used, but .19 cu in displacement engines have been found to be perfect for this model, and glow plug is recommended.

The full scale craft was one of the most famous planes employed in the service of the US Navy. Designated as the O2C-1 well over a decade ago, it was intended for observation and dive-bombing; after undergoing minor modifications, this design was reclassified as the F8C-1 series. To withstand vertical dives, the plane was built extra strong, and it earned the nickname Helldiver, thus becoming the first of this famous line of Navy dive bombers. Powered by a Pratt and Whit-ney Wasp engine of 550 hp, the 02C-1 served on shipboard as well as at land bases for many years.

When your model is completed, it will be to a scale of 3/4 inch and the plans are drawn one-half size, except for the front view. This makes it easy to enlarge them because all measurements are merely doubled.

The fuselage is of conventional longeron-crossbrace former construction, using very hard 1/8 sq longerons and 1/8 sheet balsa formers. After the 'box' frame has been completed, the bulkhead can be added and the 3/32 diameter wire landing gear bolted to it. The engine bearers are added next, using plenty of cement. This is followed by the addition of the formers, balsa nose block (which is made of soft 1/2 in sheet balsa) and filler pieces. The controls can now be installed. The bellcrank is mounted on a plywood platform which is attached se-curely to the upper fuselage longeron in the location shown. Cut the horizontal tail from 1/8 sheet balsa, and sand to a streamline cross section. Bolt the control horn to the elevator and cement well. The stabilizer is cemented to the fuselage and the elevator is hinged to it.

If you intend using electric ignition, install it now. Before covering the fuselage, test the ignition system to be sure of correct wiring. The switch can be located in the forward cockpit.

From the plywood bulkhead to the back of the rear cockpit, the fuselage is planked with 1/16 sheet balsa, The remainder is light Silkspan covered. If the builder so desires, he can cover the entire fuselage with sheet balsa. The author used Silk-span on the fuselage rear because the full size plane had fabric on this portion and true scale appearance was desired.

Laminated 1/4 in sheet balsa rings make up the ring type of cowl. Fin and rudder are added at this time. The wood landing gear struts (both front and rear) should be used for exhibition only and removed when flying, leaving the 3/32 and 1/16 wire to absorb the shocks..."

Update 22/07/2016: Replaced this plan with a clearer scan, scaled to correct wingspan at 24in, thanks to JoeFergusson, Poacher. Also added article pages, thanks to 50+AirYears.

Supplementary file notes

Article pages, text and pics. Also, previous scan version.

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