10.5 SPEC MOTORS listed on our 10.5 Spec Motor List by April 1 prior to start of season.
Additional 10.5 Motor Requirements:
- Max of 12.5mm or smaller in diameter sized rotor.
- The three slotted stator must be wound with 10.5 turns of 2 strands of a maximum diameter of 0.813mm and two strands of a maximum diameter of 0.643mm per slot.
- No motor will be approved with a resistance less than 13.6 milliohms* between any 2 phases of the motor (AB, AC, BC), when measured at 25C with an Instek GOM 802 milliohm meter.
(Source: Dixie Nats 2019 Rules)
Any ROAR Approved Hard Case Battery.
Checked batteries shall be no more than 10° F above the temp of the control pack.
No additional batteries are allowed including those used to power receivers or cooling fans.
Electronic Speed Control
Non-adjustable (preferred) or Blinky mode. Timing cannot be added to the ESC.
No additional devices will be allowed connected to a car’s ESC other than a cooling fan during a qualifier or main.
Cage – Sprint cars must have a scale appearing contemporary cage made out of rounded stock. The cage must be symmetrical left to right and mounted level to the chassis. Unrealistic shaped cages designed to exploit the rules below are not permitted. Maximum cage width at driver halo, down tubes, and top frame rail: 3.600″. Maximum cage height 5.5″ from top of chassis to top of cage at highest point. All cage and body components such as cage, bumpers, nerf bars, hoods, side panels, tanks, etc. must be mounted on the centerline of the cage. Chassis may not extend outside of the side panels by more than 1/4″ on either side.
Bumpers – A flat, curved or tubular front bumper (or combination of) must be used and may not be designed to direct air or create downforce. Maximum height of front bumper is 1.75” from the bottom of the lowest point of the chassis. Scale appearing side nerf bars must be used on both sides of the car (left side of nitro sprint is optional due to clearance needed for nitro exhaust).. A scale appearing rear hoop style bumper must be used. Bumpers and nerf bars must be made of a shock absorbing material.
Tail tank – A traditional scale appearing rounded style three dimensional rear fuel cell must be used.
Headers – Three dimensional scale appearing exhaust headers must appear on both sides of car in “engine area” (left side of nitro sprint is optional due to clearance needed for nitro exhaust).
Side panels – Flat side panels may be made from molded or fabricated polycarbonate. Maximum
height of side panels in front of the driver cockpit is 3.80” from the bottom of the chassis. Must have minimum of 3/4″ high by 2.5″ long openings on both sides of cage in driver compartment. Additional material may be used/added to either side of the side panel openings to replicate a scale appearing driver but may not exceed 1″ x 1″. (Note that the top wing mounts may cover these openings for winged classes.) Side panels may not extend beyond the rear of the cage by more than 0.25”. Side panels may not extend above or in front of the front downtubes. Scale appearing driver arm guards and engine vents may be used but cannot extend more than 3/8″ from the side panels. No other flares or turnouts designed to deflect, trap and/or form a pattern for air to travel in a directed manner are permitted except for those used to cool electronics.
Hood Area– A scale appearing hood must be used and is defined as beginning at the front axle and ending at the front of the driver cockpit. The hood must be symmetrical from left to right. The hood must be tall enough and wide enough to allow room for a scale engine intake and air cleaners (no unrealistically low or flat hoods). Minimum vertical gap from top of hood to bottom of front cage crossbar: .750″. The hood may not drop below the nearest point of the side panels by more than 3/8” and may not have any channels more than 0.25” deep designed to trap or direct air.
Nose Area – A molded or fabricated nose piece may be used and is defined from the front axle forward to the front bumper. Front bumper may not extend more than 3” from front axles. Nose piece (any lexan) must be at least 3/8″ back from the leading edge of the front bumper. Maximum width of nose piece/bumper is 3.75″. Maximum width of any surface designed to add downforce is 3.125”. Nose piece may not extend above the cage downtubes or an imaginary line connecting the downtubes if the cage is a split design.
***Note that the hood and nose piece can be one piece or multiple pieces for the purpose of easy access to electronics and suspension but are defined as above for purposes of aero rules.
Front wing/mounts – For front wing dimensions see appropriate wing drawing pdf. The front wing center section may not extend in front of the front bumper. Front wing mounts may be made of lexan but may not exceed 1.75” in length and 1.75” in height and may not extend in front of or behind the center section of the wing.
Top wing/mounts – For top wing dimensions see appropriate wing drawing pdf. Top wing minimum height at leading edge: 5.00″ from bottom of chassis. Top wing maximum height at leading edge: 6.50″ from bottom of chassis. Center section and side panels must be made from at least 3 separate pieces of polycarbonate, carbon or aluminum material. All corners and edges must be rounded and free of sharp edges. Main and Front wings must be mounted so that they are centered on cage, no offset wings. Wing center sections must have all 4 corners set at 90 degree angles, no canted or angled panels. Wings must also be mounted level from side to side. Center section of wing may not extend beyond leading or trailing edge of side panels. Side panels must have braces that hold side panel rigid at 90deg. to center section during race conditions. Two braces are required from top of the center foil to the left sideboard and one brace is permitted below the center foil to the right side board. Braces can be a maximum of .750″ wide and front edge of front brace must be no more than 1.5” back from side panel leading edge. Side Panels may have front, back, top and bottom turnouts of no more than .375″ and are included in max dimension. Flat foil center sections will be allowed a .250” turndown at the leading edge.
No additional lexan or any other material may be mounted to nerf bars, bumpers, cage, wing or any other part of the car that will trap, alter, or direct air flow for the purpose of gaining an aerodynamic advantage.
The 6×6″ wing will be the standard Sprint Car wing size.
Top wings are mandatory and front wings are optional for all sprint classes.
6×6″ Foam Tire Wing: See Drawing
Top wing mount can not exceed the dimensions of the following template: SEE DRAWING
Maximum Overall Length: 18.000″. Maximum Chassis width: 4.025″
All foam tires must be wiped clean of any traction compound before setting the vehicle down on the track. Tires will not be allowed to leave tracks on the racing surface or pit lane. One warning will be issued before disqualification for the day.
No rubber street tires, mini pins, ribbed nor slicks