2007 Thunderjet World HO Slot Car Championships

United Federation of HO Racers Association

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Thunderjet World Championships Rules
for the 2007 UFHORA Nationals

Complete car regulations

1) The complete "car" must not weigh less than 19.0 grams and no more than 23.4 grams.

2) The complete "Car" must not exceed the maximum allowed width of 1.3125" (1 5/16").

Body regulations

Note: All of these body regulations state modifications that are allowed. Any modifications performed on "entered" "cars" that aren't in these regulations will not be allowed and the "car" will be deemed illegal.

1) "Bodies" must be manufactured by either the process of casting or injection molding and be made of resin or plastic and may be painted.

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 Thunderplus, Marx, Eldon or Tyco "S" series "HO" chassis.

2a) "Bodies" must be fitted with all the manufacturer's original or exact replicas bumpers, heads, rollover bars, etc. in their stock locations.

3) The "body" to "chassis" mounting posts may shortened by cutting or grinding for the purpose of lowering of the "body" on the "chassis assembly".

3a) Cracked or broken "body" mounting posts may be repaired or replaced with the use of glue and/or a plastic sleeve around the original post or a plastic tube in place of the broken post.

3b) Other than the plastic post reinforcements stated in regulation 3a, no additional weight can be added to the "body".

4) With the "body" mounted securely to the "chassis", and when viewed from above, no part of the "chassis assembly" may be viewable except through the "body manufacturer's" original windows, detail ducts and vent openings.

5) The "body" may be lightened by removing material through the process of grinding or scraping, as long as regulation 4 is not violated.

6) "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 completely remove the "interior" portion of the body.

7) Front and rear wheel wells may be opened up to allow for more tire to wheel well clearance. This opening then measured from front to rear must not exceed 140% of the tire diameter.

7a) With the body mounted securely to the chassis, the highest point of the wheel well arch must not exceed more than .125" (1/8") from the top of the tire.

8) 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.

9) Any stock size body mounting screw may be used.

9a) Both front and rear screws must be used and must hold the body firmly at all times so as not to be able fall out.

10) The front windshield must be plastic, clear or painted, and may be glued in place and must fill the front windshield frame.

10a) You may remove the side and/or rear windows.

11) Only bodies readily available to the public 90 days prior to the race will be legal.

Chassis assembly regulations

Note: All of these car regulations state modifications that are allowed. Any "modifications" performed on entered cars that aren't in these regulations will not be allowed and the car will be deemed illegal

1) Only original Aurora Thunderjet "chassis assemblies" with copper electrics are allowed with the exception of any readily available, commercially made pick up shoes.

2) The "chassis" axle and armature holes may be slightly opened up for increased clearance.

2a) The "chassis assembly" must not be fitted with "bushings" or bearings.

2b) The "chassis" may be trimmed slightly (no more than .010") to allow for crown gear tooth clearance.

3) Any original Aurora pancake style "armature" with no more than two "stack" grey laminations and with all of it's original windings "unmodified" may be used and may be balanced.

3a) When measured across two different commutator segments, "armatures" must have an ohm rating of 16.0 ohms or higher at an average room temperature of 70f - 75f.

4) Any and only original Aurora motor magnets or Johnny Lightning magnets must be used. Johnny Lightning magnets may be sanded to a minimum front face to the apex of the radius of .000, and .000 from end to end.

4a) Magnet shims may be used, but must be made of a non-ferrous material.

5) Any and only carbon/copper motor brushes are allowed.

6) Only 14 tooth "armature" gears are allowed.

7) Only 24 tooth, brass idler gears are allowed.

8) Only 9 tooth rear end (final drive) pinion gears are allowed.

9) Only 15 tooth crown gears are allowed. The crown gear boss may be trimmed or a spacer may be added to adjust for proper gear mesh.  Commercially made crown gears with a minimum .300 OD are allowed.

9a) Gear tooth friction surfaces may be de-burred by polishing, filing or sanding.

9b) Gears may not be chamfered, lightened or "relieved".

9c) Solder or glue may be used to secure the gears to their respective shafts.

10) Any front and rear wheel, tire and axle assembly may be used.

10a) Front and rear axle washers (spacers) are allowed.

11) The center front axle truck hole must not be utilized.

12) The "step" in the pick-up shoe must remain intact and be unaltered, except for only that the first bend may be changed slightly so that proper "pick up shoe" to "rail" contact can be achieved. No attempts to "flatten" the "step" are allowed. The tops of the shoes may be bent to restrict travel of the shoe, up and down.

13) Any amount of the vertical "gear plate rails" above the "upper horizontal plane" may be removed. No amount of material may be removed from the "gear plate" at or below the "upper horizontal plane". The serial/patent numbers and letters must also remain intact.

13a) Only original Aurora black plastic or identical replacement plastic guide pins must be used. They may be cut, trimmed or bent and may be glued in place.

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