8. With the body mounted securely to the chassis and viewed from above, the body must cover the chassis except through
windows and vents. Unrealistic overly large windows and vents are not allowed.
9. With the body mounted securely to the rolling chassis and when viewed from the rear window opening, the upper edge
of the top-plate, minus rails, cannot be above the top of the body as measured at the rear window opening.
10. Bodies must be fitted with all of the manufacturers original or exact-replica bumpers, heads, rollover bars, etc. in their
stock locations.
11. 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 rod/tube in place of the broken post.
12. Other than the plastic post reinforcements, stated in Body Rule 11, no additional weight may be added to the body.
13. The body may be lowered and lightened by removing material through the process of grinding or scraping as long as Body
Rule 9 is not violated. Bodies cannot be heated or reshaped from the original cast of the body.
14. Bodies that have a separate roof and windshield casting/molding, and have molded-in interiors (also known as Hardtops, e.g.
Aurora's '65 Mustang), may completely remove the interior portion of the body.
15. Front and rear wheel wells may be opened up for tire wheel well clearance. This opening may be no larger than a 1/8-inch
drill bit (.125") around the entire wheel well and tire.
16. Wheel wells must not be modified in such a way as to allow the use of any other wheelbase than that which was originally
intended by the manufacturer of that body.
17. Any mounting screw may be used. Non-magnetic screws are recommended so that a loose screw will not be picked up by a
passing car, thus causing damage to the car and/or the track.
18. Both front and rear screws must be used and must secure the body to the chassis at all times.
- The front windshield must be plastic or resin, clear or painted, may be glued in place or molded in, and must fill the frame.
- Tape windshields are not allowed. Side and/or rear windows may be removed. Rear windshields are optional, but must adhere
- to this same rule if used. Windshields made form Testor’s Window maker are not allowed.
Any new bodies must be submitted to ECHORR at least 60 days before the ECHORR Challenge to be legal for the event.
Bodies previously approved and no longer on market will be grandfathered in as approved, these include: Fandango,
Moonstone, GoGo, BRP, Bubba Shells, etc. as long as they meet all of the other body requirements.
Thunder Jet Rolling Chassis Assembly Regulations:
1. Only original Aurora Thunder Jet chassis assemblies with non-plated copper electrical components are allowed, including silver
color solid rivets, after market rivets are not allowed. Commutator brush springs may be bent to alter brush tension. Pickup shoe
hanger plates may be bent.
2. The rolling chassis axle, armature, and drive pinion shaft holes may be opened up slightly for increased clearance.
3. The Truck hole cannot be utilized in any way.
4. The rolling chassis assembly must not be fitted with bushings.
5. The chassis may be trimmed slightly (no more than .010) to allow for crown gear tooth clearance.
6. Gear plate rails may be cut or sanded only for purposes of lowering the body, and shall only be cut or sanded to the level of the top surface of
the gear plate. Rails must remain entirely under the gear plate clip.
7. Brush springs may be adjusted only in their original configuration to change the tension on the brushes. They may be dimpled or
a corner may be altered only to prevent the brush from spinning.
8. Guide pins shall be original design, must use a full guide pin, guide pin hole may be countersunk for body screw. No metal guide
pins.
9. Guide pins may be glued to chassis.
10. Guide pins may be shortened in length to accommodate different tracks.
11. The gear plate clamp may be bent (but not cut or otherwise altered) to improve fitment.
Armatures:
1. Only an original Aurora T-Jet pancake gray armature with a maximum of two laminations, with its original Commutator, and all
of its original unmodified windings may be used. The armature may be balanced and trued. Shims between the armature and top
plate are not allowed.
2. Each armature pole is to be measured across two separate Commutator segments. The AVERAGE of all three poles must be 16
ohms or greater. i.e.: Pole A measures @ 15.8 ohms, Pole B measures @ 16.2 ohms and Pole C measures @ 16.0 ohms This armature
is LEGAL. All measurements are to be taken at the current available room (ambient) air temperature. The warming of either the
Commutator or the armature is not allowed before/during measuring. (The combined total ohm reading of all three armature poles
must equal or exceed 48 ohms.)
3. Any flat top and bottom carbon/copper motor brushes are allowed. Brushes may be scored with one score line or an X. Brush
Tensioners may be slightly "dimpled" to prevent brush spinning. No exaggerated deep cuts or crevices allowed; this will be checked
for at tech.
No Hand Wound or rewound or de-wound armatures allowed.
Gears:
1. Only stock T-Jet or commercially available stock replacement 14 tooth brass armature pinion gears are allowed.
2. Only stock T-Jet or commercially available stock replacement 24 tooth brass idler and driven gears are allowed.
3. Only stock T-Jet or commercially available stock replacement 9, 12 or 14 tooth brass drive-pinion gears are allowed.
4. Only stock T-Jet or commercially available stock replacement 15 tooth crown gears are allowed. The crown gear boss may be
trimmed; spacer(s) may be added to adjust for proper gear mesh within the crown gear box. You can add a small delrin retainer
to either side of the rear axle for the purpose of adjusting crown gear mesh with the rear pinion. The diameter of the delrin
retainer must not exceed 0.125" with a thickness not to exceed 0.070". 4 gear specialty chassis crown gears are not allowed.
4a. Minimum gear thickness shall be .046.
5. The Crown gear shall not be metal.
5a. The Crown gear minimum diameter will be no less than .300
5b. No Chamfering or beveling of the crown gear, must maintain 90 degree angle as originally produced.
6. The crown gear “boss” may be sanded or trimmed to accommodate different gear ratios.
7. The crown gear may be shimmed inside and/or outside the chassis.
8. Gears may be soldered or glued to their respective shafts.
9. Only metal driven-gear shafts may be used. The driven-gear shaft must not exceed .065" in diameter.
10. Gear-tooth friction surfaces can only be de-burred by polishing, filing, or sanding.
11. Gears must not be chamfered, lightened, or relieved.
12. 10 and 11 tooth pinion gears are not allowed.
13. Plastictop plate gears are not allowed.
Shims between the gears and the top plate are not allowed.
Magnets
1 Aurora Super II (Yellow and blue), Johnny Lightning, Auto World or DASH magnets may be used. The magnets may be sanded
to fit the chassis. The distance between the magnets must be a minimum of .700"; no exaggerated sanding is allowed to close
the armature gap. This will be teched using our custom-designed, specially fabricated Plug.
