12a Sportsman Pro Class
The Sportsman Class exists for propeller-driven aircraft designs and requires a minimum wingspan of 80 inches.
12a.2.1 Subjects need not have been entered in closed-course racing events, but must have been built and flown since the beginning of 1930.
12a.2.2 Aircraft that are eligible to race in other USRA classes may also be entered in the Sportsman Class. These aircraft must meet all Common Class Rules as well as Class specific rules.
12a.2.3 Aircraft are not limited to current USRA approved airframes, but must meet the minimum 80” wingspan requirement. Aircraft must meet all Common Class Rules with the following exceptions.
12a.2,3,1 Common Class Rule 4.14 – Race numbers.
12a.2.4 Racing Procedures
12a.2.4.1 A raw time of less than 100 seconds will result in zero (0) points for that heat race.
12a.2.4.2 Pilots must not deviate from the racing line or engage in time-stalling behavior during the race, unless in an emergency situation. Obvious time stalling will result in a warning from the CD. Issuance of a second warning during the same heat race will result in zero (0) points for that heat race.
12a.2.4.3 Use of any form of timing device during the race by pilot or caller is prohibited. Timing usage will result in zero (0) points for that heat race.
12a.2.4.4 Pylon cuts will be penalized by the addition of 15 seconds to the raw time. More than 2 cuts will result in a zero round.
12a.3.1 Minimum aircraft weight is 12 lbs. (dry). Maximum aircraft weight is 55 lbs. (wet).
12a.3.2 Aircraft weight may be verified at any time during a race.
12a.4 Wing Specifications
12a.4.1 Minimum wingspan of 80 inches, regardless of aspect ratio.
12a.5 Engine Specifications
12a.5.1 Maximum allowable engine displacement is 400 cubic centimeters.
12a.5.2 Aircraft must be propeller driven, electric, piston, or rotary engines.
12a.5.3 Engine weight on single engine aircraft may not exceed 14 lbs. Twin engine aircraft engines may not exceed 9.5 lbs. per engine. Engine weight is measured with the engine out of the aircraft in a "ready to race" mode, i.e. if you need the item to race, it must be included in the engine weight. Engine weight does not include ignition modules, batteries, wires, exhaust system, propeller, spinner, spinner back plate or prop nut. A propeller shaft extension is included, if used as part of the engine, is included in engine weight. Electric power systems will be allowed. Motor and battery combined weight shall not exceed 14 pounds. Battery capacity should be sufficient for 7 minutes of flight time.
12a.5.4 Engines must be neatly cowled where possible with no more than 50% of the cylinder head length projecting outside the cowl (measured from the centerline of the output shaft to the top of the cylinder head).
12a.6 Exhaust Systems
12a.6.1 Exhaust system components (headers, mufflers, tuned pipes, etc.) may not protrude from the airframe more than 30% of their total length. If the exhaust system is not greater than 8 inches, any or all of it may protrude or be exposed.
12a.7 Landing Gear
12a.7.1 All aircraft must use scale-like retractable or fixed main landing gear as appropriate to the aircraft modeled.
12a.7.2 Landing gear must be of sufficient size and strength to permit takeoff, landing and taxi in a reliable manner.
12a.7.3 Tail wheels must be installed and steerable, but do not have to be retractable.
12a.8 Airfoils and Planform
12a.8.1 Wing and tail group airfoils suitable for model aircraft may be used. Wing and tail group planforms should follow scale planform, chord, area, etc., of the full size subject.
12a.8.2 Tail area may be enlarged to insure stability as long as planform is preserved.
12a.8.3 Control surface dimension may vary as long as planform is preserved.