Event 421: Formula 1 Sport (provisional)

I. AIRFRAME

A. WEIGHT

Minimum 7-1/2 pounds, maximum 10 pounds.

B. WINGS

1. Span: Maximum 64 inches.

2. Area: Minimum 750 square inches.

3. Thickness: Minimum 1-1/2 inches, measured at a point 10 inches outboard of wing centerline. Wing thickness shall progress uniformly in a straight line taper from root to within 6 inches of tip.

C. TAIL SURFACES

Thickness: Minimum 1/2 inch at junction with fuselage, not including fillets or fairings. Thickness shall progress uniformly in a straight line or convex taper from root to tip.

D. FUSELAGE

1. Depth: Minimum 9 inches at its deepest point, which shall occur within the wing chord.

2. Width: Minimum 4-1/2 inches at its widest point, which shall occur within the wing chord. Cheek cowls and wing fillets, if any, shall not be included in the width or cross-sectional area measurements.

3. Cross-sectional area: At some point within the wing chord, the fuselage shall have a cross-sectional area of at least 30 square inches.

4. Shape and features:

(a) Profile representations of any significant feature of the full-scale prototype are prohibited.

(b) Cheek cowls and canopy shall have at least a 1-inch radius at their widest point so that a hypothetical 2-inch-diameter ball would fit inside, tangent to the outer surface. The base of the canopy, where it intersects the fuselage, shall be at least 2-1/2 inches across, as measured perpendicular to the thrust line.

(c) Cross-sectional contours at the height and width measurements and at stations determining the likeness to the full-scale prototype shall maintain the integrity of the contours of the full-scale prototype. The only exception permitted shall be in the engine compartment.

(d) Cheek cowls shall be equal in size. The combined width of both cheek cowls (or of one cheek cowl and the engine cylinder or muffler, if the engine is mounted with the cylinder or muffler exposed), shall be at least 7 inches as measured across the fuselage perpendicular to the thrust line at a point 2-1/2 inches behind the spinner backplate. All or part of the engine cylinder or muffler may be enclosed within one of the cheek cowls.

4. Spinner: A rounded spinner with a diameter of at least 2-3/4 inches is required.

E. LANDING GEAR

1. Location: The landing gear shall be fixed and shall resemble that of the full-scale prototype aircraft as to location on the airframe and the number of wheels used; except that if the full-scale prototype used a tail skid, the model shall have a tail wheel. The main wheels shall be at least 10 inches apart, measured parallel to the wing span.

2. Size:

(a) Main wheels: At least 2 of the wheels shall have a diameter of at least 3-1/2 inches and a tire radius, measured at the outside edge, of at least 7/16 inch so that a hypothetical 7/8 inch diameter tube would be fully enclosed, tangent to the outer surface.

(b) Nose or tail wheel: The nose or tail wheel shall have a minimum diameter of 1-1/4 inch.

3. Streamlining: Wheel pants, wheel spats, or strut fairings are not required, and are permitted only if they were used on the full-scale prototype.

F. REPLICA RULE

1. General: Models entered in this event shall be recognizable replicas of full-scale, human-carrying, propeller-driven aircraft that either raced in or were built for the 190/200 cubic inch class of Formula I closed-course racing competition. Models of full-scale aircraft that do not meet the objective requirements of these rules (for example, a model of Wild Turkey whose wing thickness does not progress in a "straight line taper" as required by paragraph I.B.3., or a model of the monowheel version of Fast Lane Exit that does not meet the main wheel track requirement in paragraph I.E.1.) are prohibited.

2. Specific dimensions: Models are nominally 25 percent scale, subject to the following:

(a) The root and tip chord of the wing may vary from scale in order to achieve the required wing area within the specified wing span.

(b) Wing and tail outlines shall maintain the integrity of the outlines of the full-scale prototype aircraft, as shown by photographs or 3-views.

(c) The fuselage side view shall maintain the integrity of the outlines of the full-scale prototype aircraft, as shown by photographs or 3-views.

(d) Except as necessary to achieve the minimum width across both cheek cowls as stated in paragraph I.D.4.(d) above, the fuselage top view shall maintain the integrity of the outlines of the full-scale prototype aircraft, as shown by photographs or 3-views.

(e) The fuselage shall measure at least 50 inches from the front of the spinner to the trailing edge of the rearmost tail surface.

(f) Tail group linear dimensions shall be a uniform percentage of full scale, from a minimum of 25 percent to a maximum of 35 percent.

II. POWERPLANT

A. ENGINE

1. Maximum displacement: 0.9153 cubic inch (15.00 cubic centimeters).

2. Configuration: Single-cylinder, front-intake, side-exhaust, equipped with a remote needle valve placed at least 4 inches behind the spinner backplate.

3. Availability, modification: Engines shall be production units assembled from commercially available production parts.

4. Intake: A single carburetor with a single air inlet having a round opening with a maximum inner diameter, at its narrowest point, of 0.435 inch. The carburetor shall be fully functional and shall be stock, except for longevity-enhancing modifications as follows:

(a) Adjustment screws and idle needle valves may be held in place with commercially available thread locker, epoxy, or other adhesives and safetied with rubber bands, wire, or plastic ties.

(b) Barrel retaining screws or pins may be replaced with commercially available screws or pins of harder material and may be held in place with commercially available adhesives. Barrels may be deburred for smoother movement and may be safetied with rubber bands, wire, or plastic ties.

(c) Throttle arms may be modified or replaced.

5. Exhaust system: The engine shall be equipped with a commercially available muffler meeting the following specifications:

(a) Design. The muffler shall be an expansion chamber muffler, zero-boost muffler, or tuned muffler. Tuned pipes are prohibited.

(b) Configuration. The muffler shall be of the compact, "in-cowl" variety. This variety includes, but is not limited to, the styles commonly known as Pitts style and Turbo-Jett(TM) style mufflers.

(c) Dimensions: The muffler shall have one expansion chamber and either one exhaust outlet with a maximum outlet area of 0.08 square inches (equivalent to the area of a round hole measuring 0.32 inch in diameter) or two exhaust outlets with a combined maximum outlet area of 0.1 square inches (equivalent to the area of two round holes measuring 0.25 inch in diameter). The distance from the center of the piston to the far end of the expansion chamber, not including the exhaust outlet tube(s), shall not exceed 4 inches. Other than the exhaust outlet tube(s), no portion of the expansion chamber shall exceed 4 inches in any dimension or extend more than 2 inches behind the engine backplate. The outside diameter of the exhaust outlet tube(s) shall be constant and shall not exceed 9/16 inch.

(d) Modification: The muffler may be tapped for a pressure fitting to supply pressure to the fuel system. No other modifications are permitted.

6. Fuel feed: Other than muffler pressure, no fuel system pressurization is permitted.

B. PROPELLER

1. Material: APC composite or a similar nylon- or epoxy- based injection molding compound containing chopped fiber reinforcement. Wooden propellers are prohibited. Propellers that are handmade, compression-molded, or contain continuous strands of fiberglass, carbon, or aramid fiber are prohibited.

2. Dimensions: Minimum diameter 11 inches.

3. Availability, modification: Propellers shall be commercially available and stock, except as otherwise provided in paragraph 7.5.2. under "General Model Aircraft Requirements."

C. FUEL

The fuel shall be commercially available, containing not over 15 percent nitromethane. The CD or his or her designee may require any or all contestants, at any time, to use only fuel supplied and dispensed by the hosting organization.

III. SPECIAL PROVISIONS

1. Engine idle capability: The CD or his or her designee may require any or all contestants, at any time, to demonstrate an idle below 3,000 rpm without changing or readjusting any component. The time period for such idle demonstration shall be long enough to prove that the engine is capable of extended idling, but not longer than 30 seconds. Failing the idle demonstration shall result in a deduction of 2 points from the contestant's total score. The deduction shall be made at the end of a round and shall not affect the order of finish or points awarded to the contestants in any specific heat.

2. Radio system safety requirements: The aileron (roll) and elevator (pitch) functions shall each employ at least 2 standard-sized, 4-screw servos, one for each control surface. All control horns and pushrod or cable ends connected to the movable tail surfaces shall be external and shall not be covered by any hatches or fairings. The battery pack used to power the airborne radio system shall have a capacity of at least 0.6 ampere-hours (600 mAh).

3. "Grandfather" clause: The wing area, tail surface airfoil thickness, and main wheel diameter specifications stated above shall be waived for unmodified, factory-built Great Planes Shoestring 60 ARF and World Models Midget Mustang ARF airframes. All other designs shall comply fully with these rules.