M.A.R.S.  Series - 
BeachJet Rules
- as of 10/01/05 -

Note 1:     Throughout these rules, the term "Car" shall refer to a chassis and body combination and don't insinuate a specific body style. Motor vehicles with at least 1 wheel at the four corners like sedans, sports cars, racing cars, trucks, emergency vehicles, etc are all legal.

  1. Cars must be legal at start and during the heat. Every effort will be made to allow you to have your car in working order at the track. A track call may be permitted to allow car maintenance but this should be limited to getting the car running decently and not to tweak for optimum performance. 
  2. Any car deemed detrimental to the track (i.e. Riding the bottom of the slot, cutting into the slot, or greasing/oiling the track, etc.) will be removed from the track and not permitted to race.
  3. The complete car must not weigh less than 19.0 grams and no more than 23.0 grams.
  4. Additives are not permitted to aid in traction. This includes glues, oils, dirt, dust or saliva. Basically anything that will hinder another cars performance in that lane. The car must not leave anything on the track.
  5. Conductive lubes are permitted under the brushes and where the pickup shoe meets the chassis only and shall be in extremely moderate amounts. These lubes must not deposit on the track during racing or they will be deemed illegal.
  6. Weight can't be added to the bodies or chassis except on the axles outside the chassis axle holes.
  7. Handling pans are not permitted.
  8. Traction magnets of any kind are not permitted.
  9. Cars must pass freely and easily through the tech block.
  10. All 4 Tires must touch the track at the same time when at rest.
  11. Only one guide pin is permitted per car and must reside in original position. They may be glued into original position.
  12. Except where solder is permitted, lead is not permitted anywhere on the car.
  13. Lubrication of the chassis is permitted at any point provided it not doesn't make it to the track.
  14. One False Start is permitted per heat and will be defined by the race host for the particular track being run. Push starts are permitted at any time.  


These following definitions apply wherever the following words appear in the rules in CAPS and BOLD:
STOCK -                                No modifications other than those allowed in the rules are permitted.
STOCK REPLACEMENT - Aftermarket part of similar design to the same STOCK Aurora 
                                                Thunderjet part. No modifications are permitted.
ORIGINAL -                         A stock part that can have material removed twisted, bent, etc. but 
                                                not added.
ANY -                                     Any part that does the job in compliance with all the other limiting rules. 

NOTE: Although these definitions are self explanatory, examples of prohibited modifications may be included in certain sections. These examples, in no way, infer that other modification are permitted. Stock means Stock, etc.


  1. Bodies must be of the hard shell variety (No vacuum formed bodies) and manufactured by either the process of casting or injection molding and be made of resin or plastic.
  2. Bodies must be originally manufactured with the intention of being mounted, with the use of 2 screws via the 2 body mounting posts, on a/an: Aurora Model Motoring (which includes: Vibrator, Thunderjet, Wild Ones, Tough Ones and Xlerators), Bachmann, Faller, Model Motoring Inc. Thunderplus, Marx, Eldon or Tyco "S" series "HO" chassis.
  3. Bodies must be fitted with all the manufacturer's original bumpers, heads, rollover bars, etc. in their stock locations. Similar aftermarket replacement parts may be used.
  4. On a convertible body, any replacement windscreen must be the same height and width of the body manufacturer's original windscreen.
  5. No body openings other than side windows and front grills are allowed.
  6. Body must completely cover the back plastic of the chassis/gearplate.
  7. The sunroofs, front and rear windows must be made of plastic and fill the entire frame. They may be glued in place.
  8. There is no "On Market" requirements for bodies but if a new body is introduced and has not been made publicly available to the group in it's present form 2 weeks prior to the race, then it must be made available in sufficient quantity at the race. 10 is a sufficient quantity.
  9. Maximum Width:  1 5/16"
  10. Body styles:  Bodies must resemble cars that exist. No blobs or boxes with lids.  


  1. Bodies must be mounted using the original two-screw mounting points of the chassis. Cracked or broken body mounting posts may be repaired or replaced with the use of glue and/or a plastic sleeve around, or a plastic tube in place of the broken post in the original position.
  2. Bodies must be mounted using two screws. ANY screws may be used and left loose, but must be tight enough so as not to fall out. Rear screws may be glued.
  3. No weight may be added to the bodies.


  1. Bodies may be lightened by removing material from the underside. Any holes caused by lightening must be filled to original thickness.
  2. Bodies that have a separate roof and windshield casting/molding, and have molded in “interiors” (also know as Hardtops, e.g. Aurora’s ‘65 Mustang), may have the “interior” portion of the body completely removed.
  3. Front wheel wells must not be modified in such a way to allow the use of any other wheelbase than that was originally intended by the manufacturer of that body.
  4. Side windows may be removed but are not permitted to be oversized to create a small roof.
  5. Lightened bodies must maintain original outside appearance. I.E. no bubbles, warpage, excessive repairs.
  6. The body to chassis mounting posts may shortened to lower the body closer to the chassis.
  7. Bodies may be painted and/or decaled. 


  1. Only STOCK Aurora Thunderjet chassis with copper electrics are permitted. This includes Flamethrower chassis.
  2. The chassis axle and armature holes may be slightly opened up for increased clearance.
  3. Added bushings and bearings are not permitted
  4. The chassis may be trimmed slightly (no more than .010”) to allow for crown gear tooth clearance.
  5. Chassis, gearing, shafts and bearing holes may be polished.
  6. Chassis cannot be cut, sanded or drilled in any way. 
  7. Chassis cannot be cut to allow repositioning of magnets.
  8. Flashing to due to the manufacturing process may be removed.
  9. Rivets may be tightened.
  10. Replacement rivets are not permitted.  

Guide Pins:

  1. Only STOCK Aurora black plastic or similar replacement plastic guide pins must be used. They may be cut, trimmed or bent and may be glued into place. 
  2. Guide pins may be trimmed to allow smooth operation in the slot.
  3. Maximum guide pin length is ”.
  4. Rear, swivel or metal guide pins are not permitted.


  1. Magnets may be zapped.
  2. Magnet shims may consist of any material but may not be a permanent magnet. Shims must reside entirely inside the magnet cavity.
  3. Permitted magnets are: ORIGINAL Aurora, ORIGINAL Thunderplus, and ORIGINAL Johnny Lightning magnets designed for a pancake style armature. 


  1. ANY front or rear tire/rim/hub/axle combination is permitted.
  2. Only the crown gear and crown gear shims may reside on the axles between the chassis axle holes.
  3. Crown gear shims must not interfere with the rotation of the axle in any way.
  4. The center front axle truck hole may not be used.
  5. Overall width must not exceed 1 5/16" when rims are extended to their maximum width. 


Pickup shoes and springs:
  1. Pickup shoes must be STOCK copper/silver Aurora or STOCK copper American Line or BSRT 504 of any plating type..
  2. Pickup shoes may be bent but must retain a step at its original location.
  3. The step may be flattened.
  4. Pickup shoes cannot be weighted.
  5. Shunt wires, "tiger tails" or other soldering on the bottom of the chassis is not permitted.
  6. Lighted chassis must have the light bulb and wire completely removed.
  7. Pickup shoe springs must be ORIGINAL copper Aurora or ORIGINAL copper Johnny Lightning.
  8. Pickup shoe springs may be shimmed with armature spacers to increase spring pressure. Shims must fit completely inside spring hole in the chassis. 

Commutator Brushes:

  1. ORIGINAL Aurora or ORIGINAL aftermarket copper/carbon brushes of the similar style and size as the original stock T-Jet brushes must be used.  I.E. Brushes must be flat surfaced on top and bottom, .060"-.075" in height and in the stock position.
  2. Domed and silver brushes are not permitted. 

Brush Springs:

  1. Brush springs may be bent in any fashion to allow different brush tensions and/or to stop brushes from rotating.
  2. No material may be added to or removed from the brush springs.
  3. Glue may not be used under the spring to increase tension.
  4. Brush springs can not come in contact with the commutator at any time.


  1. Only STOCK Thunderjet or STOCK REPLACEMENT 14 tooth armature gears are permitted.
  2. Only STOCK Thunderjet or STOCK REPLACEMENT,  including Model Motoring, 24 tooth brass idler and driven gears are permitted.
  3. Only STOCK Thunderjet or STOCK REPLACEMENT 9, 12 or 14 tooth brass pinion gears are permitted.
  4. Only STOCK Thunderjet or STOCK REPLACEMENT 15 tooth crown gears are permitted. The crown gear boss may be trimmed to adjust for proper gear mesh.
  5. Gear tooth friction surfaces may be de-burred by polishing, filing or sanding.
  6. Beveling or removing material from the gears is not permitted. SLIGHT rounding of the edges due to polishing, filing, or sanding is acceptable.
  7. Gears may be glued or soldered to the shafts. Excessive glue or solder is not permitted. 


  1. Only STOCK Aurora Thunderjet and Tuff Ones gearplates are permitted.
  2. Any amount of the vertical gearplate rails may be removed.
  3. No part of the gearplate may be removed below the plane of the top. Minimal tolerance may be permitted due to cutting inaccuracies.

Gearplate Clamp:

  1. A STOCK copper Thunderjet or STOCK REPLACEMENT gearplate clamp must be used.
  2. The clamp may be bent or dimpled. 


  1. Armatures must be STOCK Aurora Thunderjet. Thunderjet armatures are one, or a combination of, copper, red or green colored wire on gray colored laminations.
  2. Minimum resistance across any two commutator section can't be lower than 16 ohms at an average room temperature of 65f - 75f.
  3. Re-wound armatures are not permitted.
  4. De-wound armatures and balanced armatures are permitted.
  5. Laminations may be not be trued.
  6. Commutators may be straightened and trued but must remain in the stock position. I.E. no timing changes.
  7. Armatures may be balanced by adding epoxy or by removing metal from the laminations only. 


  1. ANY controller is permitted.  
Note: All of these car rules state modifications that are and are not permitted. Any “modifications” performed on entered cars or controllers in violation of these rules will make the car ILLEGAL and/or the racer disqualified.