Scale rules

« Craftsmanship Events

50.1 Scope

Scale Competition comprises a single event open to any model rocket that is a true scale model of an existing or historical guided missile, rocket vehicle, or space vehicle, that has flown under rocket power. The purpose of this competition is to produce an accurate, flying replica of a real rocket vehicle that exhibits maximum craftsmanship in construction, finish, and flight performance.

50.2 Exclusions

Scale models of amateur rockets or missiles are specifically excluded from this competition, except when the prototype is of obvious historical significance.

50.3 Non-Flying Prototypes

Entries in Scale Competition may model a non-flying or inert vehicle if its configuration is reasonably representative of a historical vehicle configuration.

50.4 Plastic Models

Entries that qualify for Plastic Model Conversion Competition under Rule 55 are specifically excluded from this event. Parts from commercial plastic kits may be used on scale models provided this is pointed out in the data presented with the model for judging.

50.5 Kits

Commercially available flying scale model rocket kits are acceptable for entry only if accompanied by additional substantiating data other than that contained in the kit. The contestant shall be responsible for ascertaining the correct scale qualities of the kit, and must present satisfactory evidence that the kit model is to correct scale.

50.6 Serial-Numbered Prototype

The contestant should model one particular serial-numbered prototype (or round), except in the case where the prototype is in such extensive mass production that no single individual vehicle can be singled out for scaling. However, the contestant shall make every reasonable attempt to model a specific prototype, since any generalization may detract from his/her score.

50.7 Data

The contestant must supply data to substantiate their model’s adherence to scale in dimension, shape, color, and paint pattern.

50.8 Stages

If the prototype is a multi-staged vehicle, the scale model may be designed so that some or all of the upper stages are inoperable dummies. However, a scale model of only the upper stages of a multi-staged vehicle may not be entered without the operable lower stage(s) unless specific data is furnished to prove to the judges that the upper stage configuration has flown separately, alone, and as a vehicle itself.

50.9 Transparent Fins

If the prototype is not stabilized by means of fins, or if the scaled fins are not of sufficient size to ensure the stable flight of the model, the scale model may be fitted with transparent plastic fins to make it stable in flight. However, the transparent fins and their attachment shall be judged for craftsmanship along with the model.

50.10 Flight

Each entry must make a safe, stable flight. If the entry does not make a safe, stable flight, it shall be disqualified.

50.11 Judging

Each entrant shall be judged using the standard form Scale Model Judging Sheet that is available from the NAR Contest Board.

50.12 Static Points

Static points shall be awarded according to the following schedule:

50.12.1 Scale Data: 50 points

Points shall be awarded for data that exceeds the minimum requirements; however, data will be judged on quality, not quantity. All data presented should apply to the particular prototype that is being modeled. Minimum allowable data consists of:

  • Scale factor
  • Overall length
  • Significant body diameter(s)
  • Nose cone length
  • Fin length and width (if applicable to the prototype)
  • Length of transition pieces (if applicable)
  • Color pattern (documented either in writing or by photographs)
  • One clear photograph, halftone, or photo-reproduction
  • For at least all required dimensions listed above, both the actual (prototype) dimensions and the scaled (model) dimensions presented in a table or on a drawing

Dimensional data must be from an accurate source, such as magazines, books, the prototype manufacturer’s specifications or data sheets, and so on. Dimensions for which explicit data cannot be found may be calculated by proportioning drawings or photos; dimensions obtained in this manner must be so identified in the data. Drawings prepared by the modeler to facilitate judging must be accompanied by substantiating data or drawings. Photographs from any source are acceptable. The photograph requirement may be satisfied by reproductions of pictures from books and other printed material only if the reproduction is equal in clarity to the original. Any entry not accompanied by the minimum allowable data as listed above shall be disqualified. In addition, the modeler should make an effort to include in the table (or drawing) any additional dimensions (both prototype and scaled) that he/she has tried to accurately scale. Points may be deducted if the scale packet contains data not pertinent to the prototype model, or is presented in such a manner as to complicate judging. The entry shall be judged by the data presented in the scale packet.

50.12.2 Accuracy of Major Dimensions: 200 points

Major dimensions include dimensions required under Rule 50.12.1, as well as dimensions of subassemblies, location of details, location of paint pattern, and so on. At least 5 dimensions shall be checked for accuracy. It is recommended that calipers be used to check small scale dimensions and that Judges attempt to measure the main model dimensions to at least 0.5 millimeters. Points shall be deducted according to the percentage of deviation from the scale dimensions. Model dimensions so small that they cannot be measured to better than a 1% tolerance should not be measured by the judges, but should appear scale-like.

50.12.3 Accuracy of Color and Markings: 100 points

The color and texture (e.g., flat, glossy) of the paint should conform to the data and photographs. Lettering and insignia, if applicable, should be scaled and properly reproduced. Paint patterns should be properly proportioned.

50.12.4 Accuracy of Details: 50 points

Details such as antennas, rivets, cover plates, bolts, prototype imperfections, and so on that appear in the data should be present and properly scaled.

50.12.5 Craftsmanship: 300 points

Points will be awarded for neatness, care in construction, craftsmanship of details, and quality of finish. Consideration should be given to the invisibility of body seams and wood grain, the proper curving of curved lines, and edges made properly sharp or rounded as shown in the substantiating data. The finish should be free of fingerprints, brush strokes, runs, or other unintentional blemishes, and the paint pattern should be well defined. The details should be precise, and neither more nor less obvious than on the prototype.

50.12.6 Degree of Difficulty: 200 points

Points shall be awarded according to the difficulty experienced by the modeler in building the model and adapting it for flight. Consideration should be given to whether the model was built from a kit. Points should be awarded for parts and details that were individually constructed by the modeler. (To facilitate judging, the contestant should point out difficult assemblies or construction problems in his/her scale packet.)

50.13 Flight Characteristics: 300 points

Points for Flight Characteristics shall be awarded as follows:

50.13.1 Mission: 200 points

Mission points are awarded for appropriate and scale-like operation of the model during flight. Examples of such operations are staging, simulated cloud seeding, operation of electronic payload, and smoke ejection. Any such operation must comply fully with the safety standards set forth in this NAR Sporting Code. If it does not, the entry shall be disqualified. The RSO is the only official who may judge the safety qualities of the operation.

50.13.2 General Flight: 100 points

General flight points are awarded for proper operation of the model during flight, including launch, lack of misfires, stability, recovery, and lack of damage on landing. No consideration should be given to staging or scale-like flight characteristics, as these are covered under Mission points. However, if the general flight performance of the model is adversely affected by the failure of one or more of these aspects, points may be deducted from General Flight.

50.14 Scoring

Scale Competition shall be scored as follows: the points awarded to the entry in static judging shall be added to the points awarded to the entry in flight. The contestant receiving the highest score is the winner.

50.15 Damage

Damage shall be judged cumulatively with each flight, assessed from the judged condition of the model to the condition presented to the judge post-flight. The only exception to this is damage caused in the course of a catastrophic failure under Rule 11.5, in which case such damage shall not be counted against the flight points.

Weighting Factor 32