Overview
ROSSA’s aim is to establish a method and a set of classes to ensure there is an agreed international standard for the running of RC vehicle top speed events.
Primary to this aim is the definition of a of set of classes that RC vehicles can be segregated due to either a fundamental difference in design or a recognised and proven difference in achievable class speed
Secondly ROSSA aims to provide technical specification guidelines for the equipment to be used to accurately measure the velocity of an RC vehicle.
Thirdly ROSSA will list the official overall and class fastest speeds achieved in each class and ensure ratification of the records to the ROSSA standards so that the speed measures is a true accurate measurement of the vehicle
Classes are listed on the official ROSSA website at www.rossa.org.uk and are reviewed and updated annually.
ROSSA official classes for 2025
- Electric 1 Cell
- Electric 2 cell
- Electric 4 cell
- Electric 6 cell
- Electric Open
- Electric Bike
- Electric Open Wheel
- Electric Large Scale
- 808 (8th Scale On road 8 Cells)
- IC Small Block
- IC Big Block
- IC Open
- IC Bike
- IC Open Wheel
- IC Large Scale
- Non Wheel driven
- Mini Class
General Construction Rules
- All vehicles must be remotely controlled. No guidelines, guide rails or retaining wires are allowed
- All vehicles must have a body shell and this must be securely fastened and remain in place until the car has completed the run through the traps
- All vehicles of all classes must be fitted with a failsafe device that will stop the vehicle by application of the brakes and/or deployment of a drag chute if fitted. It must also cut the power to the transmission in the event of a signal loss.
- All vehicles must have installed suitable radio equipment with adequate range to ensure the vehicle will stay under the control of the operator during its entire run.
- Steering gyros allowed in any class
- No fuel restriction in IC classes
- No exhaust restrictions in IC classes
- Bikes to have 2 wheels, other vehicles 3 or more wheels
- All parts of the vehicle are to be securely fastened to the car such as batteries, radio equipment etc. so that it will not come loose during the speed run
- Electric vehicles that run capacitance storage devices must ensure that the max voltage deliverable to the motor does not exceed the voltage for the stated class
Note: The Open Wheel classes are for buggy type cars rather than F1 style chassis. Technical inspection will decide if the entry qualified for the open wheel class or should be entered into any of the above classes. This is to promote fair competition. For the open wheel class you can add aerofoil devices to the body or chassis as long as the wheels are visible from the top 100%, wheels on the right side when viewed from that side 100% , wheels on the left side when viewed from that side 100%, front wheels when viewed from the front 100%, rear wheels when viewed from the rear 100%.
Electric 1 Cell
Vehicles are classified as Electric 1 cell as long as they meet the general construction rules and the following criteria
· Single Electric Motor any size
· Single cell LiPo or equivalent
· Max Mah of Cells = Unlimited
· Maximum length of 1000mm
· Maximum width 300mm
· Custom or commecial chassis, drive train and suspension
· Commercial or custom body shells
Electric 2 Cell
Vehicles are classified as Electric 2 cell as long as they meet the general construction rules and the following criteria
· Single electric motor any size
· 2 Cell LiPo or equivalent
· Max Mah of Cells = Unlimited
· Max length 1000mm
· Max width 300mm
· Custom or commercial chassis, drive train and suspension
· Commercialy or custom body shells
Electric 4 Cell
Vehicles are classified as Electric 4 cell as long as they meet the general construction rules and the following criteria
· Single electric motor of any size
· 3 to 4 Cell LiPo or Equivalent
· Max Mah of cells = Unlimited
· Max length 1000mm
· Max width 300mm
· Custom or commercial chassis drive train and suspension
· Commercially or custom body shells
Electric 6 Cell
Vehicles are classified as Electric 6 cell as long as they meet the general construction rules and the following criteria
· Single electric motor of any size
· 5 to 6 Cell LiPo or Equivalent
· Max Mah of Cells = Unlimited
· Max length 1500mm
· Max width 300mm
· Custom or commercial chassis, drive train and suspension
· Commercially or custom body shells
Electric open
Vehicles are classified as Electric Open as long as the meet the general construction rules and the following criteria
· Any size electric motor or multiple motors
· 7 cell or over
· Max Mah of Cells = Unlimited
· Maximum length of 1500mm
· Maximum width 400mm
· Custom or commercial chassis, drive train and suspension
· Commercially or custom body shells
Electric Open Wheel
Vehicles are classified Open Wheel if they meet the following criteria
· Any Buggy, Truck or Truggy based kit
· Single electric motor any size
· Up to a MAX of 6 Cell LiPo or Equivalent
· Max Mah of Cells = Unlimited
· Custom or commecial bodyshell that must not cover the wheels
· Wheel diameter to be min 90mm
· Custom or commercial chassis, drive train and suspension
Electric Bike
Vehicles are classified Electric Bike if they meet the following criteria
· Any 2 wheeled vehicle with rear wheel drive
· Single electric motor any size
· Any cells
· Max length 1500mm
· Custom or commercial chassis, drive train and suspension
Electric Large Scale
Vehicles are classified Large Scale if they meet the following criteria
· Any 1/5th scale based kit such as FG or HARM
· Single electric motor of any size
· Any cells
· Max Length of 1500mm
IC Small Block
Vehicles are classified as IC Small Block as long as the meet the following criteria
· Single engines up to 0.18 Cu in (small block mounting)
· Max length 1000mm
· Maximum width 300mm
· Custom or commercial chassis, drive train and suspension
· Commercially or custom body shells
IC Big Block
Vehicles are classified as IC Big Block as long as the meet the following criteria
· Single IC engines up to 0.45 Cu in Big Block Mounting
· Maximum length of 1000mm
· Maximum width 300mm
· Custom or commercial chassis, drive train and suspension
· Commercially or custom body shells
IC Open
Vehicles are classified as IC open as long as they meet the following criteria
· Maximum length of 1500mm
· Maximum width 300mm
· Any size engine or engines, which use the expansion of gasses as its prime mover such as IC, Turbine with gearbox, Wankel, Steam etc…
· Custom or commecial chassis, drive tran and suspension
· Commercially or custom body shells
IC Open Wheel
Vehicles are classified open wheel if they meet the following criteria
· Any Buggy, Truck or Truggy based kit
· Single IC engine up to 0.45 Cu in or 7.5cc
· Body shell must not cover the wheels
· Wheel diameter to be min 90mm
· Custom or commecial chassis, drivetrain and suspension
· Commercially or custom body shells
IC Bike
Vehicles are classified IC Bike if they meet the following criteria
· Any 2 wheeled vehicle with rear wheel drive
· Any fuel
· Single engine with max size of 0.32 Cu in
· Max Length of 1500mm
· Cusom or commercial chassis, drive train and suspension
IC Large Scale
Vehicles are classified Large Scale if they meet the following criteria
· Any 1/5th scale based kit such as FG or HARM
· Single IC engine with max displacement of 70cc
· Max Length of 1500mm
Mini Class
Vehicles are classified Mini if they meet the following criteria
A commercial kit listed as being 1/12th scale or smaller OR
· Max Wheel Base = 225mm
· Max Width = 175mm
· Electric or IC power
Non Wheel Driven Class
A car is classed as non wheel driven if the propulsion system is anything other than a motive force that turns the wheels. Non wheel driven cars are further split into sub classes depending on their propulsion method. These sub groups are:
- Jet
- Rocket (Liquid, Solid, Hybrid, Steam, Pressurised gas)
- Pulse Engine
- Ducted fan
- Prop
8O8 Class – 8th scale On road 8 cell
Vehicles are classified as Electric 8O8 Class as long as they meet the general construction rules and the following criteria:
- Chassis should be 1/8th scale and commercially available GT type or converted buggy
- Chassis that are markets as 1/10 such as the TRAXXAS SLASH but have chassis wheel base measurements the same as 1/8 kits are allowed
- Chassis can be original or custom made. If custom made the original kit wheel base and width must be retained.
- The original kit parts should be retained as much as possible.
- Custom modifications to the drive train are allowed.
- Single electric motor any size
- Maximum of 8 cells
- Max Mah of cells = Unlimited
- Custom or commercially available body shell which must cover the wheels.
General Construction rules for Non wheel driven cars
The general construction rules stated previously apply to Non Wheel Driven cars with the addition of the following
- The failsafe device must cut the fuel to the propulsion system in the event of a signal loss with the exception of solid fuel rockets
Safety considerations
ROSSA does not take any responsibility for safety at events as this is the sole responsibility of the event organisers. Non wheel driven classes are defined for the purpose of ensuring equal completion between events. If an event decides to run Non wheel drive cars a number of safety considerations are listed below that you may want to consider
Solid fuel rockets must be given special considerations due to the fact that the propulsion system cannot be shut down after ignition. ROSSA suggest the following precautions for these vehicles
- Any solid fuel rocket prepared vehicle must have to prove that they have completed a successful run prior to the event. The event is for competition and not for testing prototype vehicles.
- The designer/operator must show that the burn time or the solid fuel rockets is calculated to burn up to and not passed the speed measuring equipment. They must also show that they have calculated an appropriate start point considering the burn time of the rockets
- Solid fuel rockets are to be placed singularly or one above the other. No side by side engines allowed as a miss fire will push the car offline and possibly spin
- It is suggested that a separate area for rocket cars be made available for preparation that is away from crowds and the main pits.
Speed Measurement
For a record to be ratified by ROSSA the speed measurement must meet the following minimum standards
A minimum of 2 devices are required consisting of a primary device and a backup device. The primary device must be a system that will time the vehicle over a measured distance by the tripping of 2 gates. The device must have a certificate of accuracy and be proven to be accurate within 0.1mph. The distance between the gates shall be no less than 20ft or 6.096 metres
ROSSA suggests the following equipment for the primary device
TRACKMATE Speed Trap with sensors that will span a minimum of 50ft width.
The backup or secondary device must comply with the following specs as a minimum.
The accepted speed is the speed measured on the PRIMARY device. The speed is accepted ONLY if the backup device is within 5% of the primary device.
Setup
The track for the run must be straight and level with no excessive gradients. Excessive gradient will be in excess of 1m drop in 400m.
The speed traps should be setup as per the drawing below. The transmitters and receivers need to be in alignment as much as possible. The use of a laser pen is a good way to align the traps
To ensure the speed traps are setup correctly it is recommended that video evidence is taken of the speed trap measurement and setup distance.
Please click on the Link for Speed Trap setup drawing:
https://1drv.ms/w/s!Avv-HIsOB8mFgRFIoL6OktsWYbCc
Backup device outside 5% of primary device
The speed on the primary device is recorded and the contestant is asked to make another run with his car. The backup run must be within the 5% of the first run. The fastest of the 2 runs is the accepted speed.
Timing device failure
If the primary or secondary timing device fails the event can continue with a single device. Contestants must make a minimum of 2 runs with a correlation between the 2 run of 5% or less. The faster of the 2 runs is the accepted speed
Speed Runs
For a run to be officially recognised as a ROSSA record it must comply to the following requirements
- The vehicle must have traversed the speed trap under control and on its wheels with the body intact
- The car must complete the run in 100% working order with no loss of parts or shell
- For a class record to be recognised the new record must exceed the old record by at least a full MPH.
A J Lovering
ROSSA Founder
Stuart Mutch
ROSSA Chairman
