Retro Class Rules

Revision: 1.00

NOTE:   Text in Blue represents a change from the AMA published Nostalgia rules. All text in black is the exact text from the AMA published Nostalgia 461 rules.

  1. For Event RET: Retro Class Unlimited Thermal Duration
    1. Class “A”, “B”, or “C” sailplanes are permitted (As a note of clarification for RET, aircraft or aircraft parts substitutions will not be allowed as in other TD events. Field repairs are allowed if the CD considers them safe for flight.)
    2. Date of Release
      1. The latest accepted magazine or book, cover date for the “published design,” or the manufacturer’s “construction plans date” of a kit will be prior to 1/1/YY. Where YY is a sliding year scale of 35 years, or older, from 1/1/<of the current year>. Example 1: If the date were 3/15/2015, then all designs meeting the RET criteria published before 1/1/1980 would be legal. Example 2: If the date were 3/15/2018, then all designs meeting the RET criteria published before 1/1/1983 would be legal.
      2. Models that have been kitted, but where there is no date on the plans or on the instructions, an advertisement in a dated magazine or book can be used for dating of the design.
      3. Models must be built from a kit, short kit, or scratch built.
      4. If the contestant has a plane design that meets the date requirements detailed above but is a design that was not published or kitted and the contestant can provide sufficient proof of design, build and being flown within that time frame, then that plane would still be considered eligible for competition. It is up to the contestant to provide this proof. The contestant must also provide proof of airfoil and the other requirements spelled out in Section Airframe Requirements Items that Must Duplicate the Original.
      5. If the plan used for construction and documentation was published in a book or magazine, all of the parts of the plane must be scalable and buildable from the plan. The aircraft construction and materials must be detailed, and not just a three view. This is especially important for the shape of the airfoil if it is not from a published set of coordinates.
      6. If the kit or published design had several construction plan dates that include modifications to the original design, only those changes made prior to 1/1/YY will be accepted. Where YY is a sliding year scale of 35 years, or older, from 1/1/<of the current year>.
    3. Airframe Requirements; Construction Restrictions:
      1. The construction shall be of balsa, ply, spruce, except where specified in section 1.5. Fully composite fuselages, wings, and empennages, are excluded (aka Moldies and foam-core wings are excluded).
    4. Airframe Requirements; Items That Must Duplicate the Original:
      1. The plane must replicate the original styling and appearance and comply with the vision of the Retro event (vision is stated under Special Items).
      2. Airfoil
      3. Planform, moments, and surface areas of all components of the flying surfaces including the flying surfaces.
      4. Fuselage form or styling in outlines both inside and plan views, as well as cross-sectional shapes.
      5. Basic construction materials and techniques such as open-bay wing structure, wood vs. fiber, reinforced plastic, etc.
    5. Airframe Requirements; Items That Can Deviate from the Original:
      1. Control surfaces:
      2. If desired on a plane with no glide control capability designed in originally, spoilers may be added to the upper wing surface at, or about, the high point of the airfoil as long as the plans do not call for any other glide control device. If the plans have a glide control system shown, it must be the one used and shall not be deviated from. If spoilers are added, they must be designed to minimize the effect on the styling of the original aircraft. An example would be on an open structure wing; the spoiler Academy of Model Aeronautics Competition Regulations | Radio Control Soaring 13 system must be of minimal dimensions including the area around the spoiler bay used to attach the covering.
      3. Any interior, non-visible structural modifications to enable the plane to handle modern launching equipment and techniques. Some examples could be:
        1. Substitute spruce for balsa.
        2. Carbon-fiber reinforcements.
        3. Larger wing joiner rods.
        4. Stronger tow hook systems.
        5. Wing incidence and decalage.
        6. Wing mounting (bolt on vs. rubber bands).
        7. Removable or bolt-on stabs rather than permanent stabs, as long as the assembled position replicates the original and the visible architecture is unchanged.
        8. Dihedral (either tips or center or both) can be modified a maximum of +/-25% of the original to suit personal preferred handling characteristics
      4. Special Items
        1. Radios can be of any type legal to operate and electronic mixing is allowable on any set surfaces.
        2. The use of landing arrestor devices is prohibited. This does not eliminate the use of a smooth surface skid to protect the bottom landing surface of the aircraft from scratches and nicks.