Gulfhawk (oz16164)

About this Plan

Gulfhawk. Control line scale model biplane. Wingspan 30 in.

Quote: "Build a 30 inch scale replica of the most famous of air show performers. Power with .29 to .65 gas or diesel engines. Al Williams Gulfhawk, by Walter A Musciano.

A brilliantly colored biplane sped at top speed only fifteen feet above the ground and suddenly zoomed up into a tight loop, then another and another until it had completed about a dozen or more! At times it seemed the plane would surely crash into the ground. The crowd of spectators were silenced with suspense, then let out a mighty cheer as the ship leveled off. On its return trip the neat little biplane whizzed along the entire 6,000 foot runway in a 90 degree vertical bank with the wingtips a bare ten feet above the concrete! No person in the crowd could deny that both plane and pilot were tops!

You guessed it. It was Major AI Williams at the controls of his famous Gulfhawk. Major Williams, of Pulitzer Trophy Race fame, has thrilled millions for over ten years with his daring and skillful maneuvers. The plane was selected by Al Williams, sponsored by the Gulf Oil Company of which he is an executive and built by the Grumman Engineering Company. Known as model G-22, the design is an adoption of the Marine Corps' F3F-2 fighter. A 1000 hp Wright Cyclone G-1 drives the plane at a speed of 290 mph and the rate of climb is 3,500 ft per min. The craft is rigidly braced to withstand power dives and violent maneuvers. It was the last of the US Navy's biplane fighters.

The colorful all orange paint job with white and blue striping and sunbeam design produces an attractive sport model potential beauty event winner. The symmetrical airfoil and concentrated wing area result in a fine stunt plane when fitted with a stunt tank.

Construction could not be simpler. The fuselage is carved from a balsa block and the wings employ a heavy leading and trailing edge with no spars. The tail is solid balsa sheet. The scale is one inch to the foot which brings the wing area to 230 sq in.

Select two straight grained medium balsa blocks sizes 3x4x20 in. and cement lightly along the horizontal center line. Trace the fuselage p!an view and cut the outlines to shape with a coping saw. Consult the sketches on fuselage construction. Repeat this procedure for the side view. Now, using a sharp carving knife or plane, shape the fuselage to the cross-sections shown on the plans. Sand until smooth and apply two coats of clear dope.

Pry the two halves apart and hollow to the thickness indicated, using an X-acto or similar gouge. Cut the plywood bulkheads and cement in place on the lower fuselage shell. Bend the landing gear struts and attach to the bulkheads with metal clips and bolts as shown. The engine mounts are now installed, using a casein glue as an adhesive. The location of the mounts will depend on the engine used.

A diesel or a glow-plug installation is recommended because it not only saves weight but eliminates ignition worries as well. Engines from .29 to .60 cu. in. displacement can be used effectively. Install the bellcrank support between the mounts and then bolt the bellcrank in place.

The wings are made in four separate panels. The upper panels are made by pinning the leading and trailing edges directly over the plans and then inserting the rib stock on which the airfoil should be traced. Remember, if you desire stunting (loops, inverted flying, etc) use the NACA .0012 airfoil. If ordinary leveling flying and zooming will satisfy you, then use the Clark Y airfoil.

Pin the ribs in place between the leading and trailing edges and after the cement has dried, remove the panel and carve both the edges, ribs and tip to shape. Since only one half of the wing is shown trace the outline through the plan and use the back side for making the remaining panel. This same procedure is used when building the lower wing panels..."

Direct submission to Outerzone.

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