As we head into the final year of our current 3 year rules package there are a few updates to be made; most as a result of technology changes or keeping up with racers' creativity. A complete update of the rules package will be done and posted shortly.
1) As announced last season, the truck class will switch to Novak Vulcan 17.5 handout motors.
2) There will be a minimum roof height for the truck class based on cutting the Protoform body on the molded in trim lines. The number will be published shortly. NEW MINIMUM ROOF HEIGHT WILL BE 4.50".
3) The SK class will switch from open ESC to blinky ESC.
4) The new SMC 4200 spec pack will be allowed along with the existing 4025 pack.
5) Receiver packs will not be allowed; internal or external electronic boosters only.
6) The 13.5 motor list will be updated a little closer to the start of the season.
7) No large capacity capacitor banks; ESC OEM equivalent capacitors only or 10,000 microfarad maximum for glitch busters type capacitors.
8) ESC’s must be configured so that they cannot be wirelessly updated when presented for technical inspection and as used in all competition (qualifying and mains). Some examples include removal from the car of any separate, external wireless modules; removal of any specific receiver used to enable wireless programming; and / or a locked software mode in the ESC which prevents wireless updating (locked mode must be indicated by a specific distinctive blink code or LED color).
9) the 17.5 open ESC stock class is officially removed from the class list
10) the Mudboss class will be run as a local track option class where there is interest. It will not be a points championship class.
Some comments on ESC voltage feedback and the reasons we are taking the approach of not allowing receiver packs.
At the conclusion of the 2013 – 2014 indoor carpet season some concerns were raised about a particular Hobbywing ESC regarding its ability to pass voltage from the receiver pack through the ESC, so called voltage feedback.
Immediately prior to the start of the 2014 – 2015 season; testing revealed that other ESC’s in common use in carpet oval racing also had this capability.
The main concern regarding this capability is the potential for the receiver pack to charge the main battery to a voltage higher than that allowed if the vehicle switch is left in the ON position or turned to the ON position after the vehicle has been through prerace technical inspection. A secondary concern is the ability of the receiver pack to provide power directly to the ESC and motor. However, because of the limited size of the wire from the receiver pack to the receiver and from the receiver to the ESC; this secondary effect provides little or no practical benefit in competition.
For the 2014-2015 season, the BRL addressed this issue by requiring vehicles be impounded after prerace tech with the switch turned off until immediately before a race heat. This minimized any possibility to use the “feedback” to charge the main battery.
Additional testing during the season showed that this feedback charging occurred to varying degrees with several different brands of ESC’s commonly used in oval competition. It also showed that at least for some ESC’S the degree of charging depended on the difference between the main pack voltage and the receiver voltage (lipo RX packs charged faster and to a higher voltage than LIFE packs). An apparently simple fix, removing the red wire between the ESC and the receiver, was tested but it was found that some common ESC’s either would not work at all without the red wire in place or had a voltage threshold where they stopped working that could be reached during a 4 minute race, especially in spec pack classes.
As we evaluated possible solutions to the problem we were looking for a single solution that could be applied across all known and future ESC’s. Allowing only ESC’s that did not feed RX voltage to the main pack was considered. However that would have meant continuous testing of ESC’s for this capability as new brands and models are introduced. That is not something any of the oval organizations, including the BRL, are equipped to do. It also would have meant a sizeable number of ESC’s in current use would have been banned. There is also the risk that enterprising racers could have modified an allowed ESC to provide the voltage feedback. We’ve seen racers be able to modify the BEC in a 2 cell ESC to make it work on 1 cell. It isn’t much of a leap to imagine modifying the BEC to allow voltage feedback. In some cases it could be as simple as eliminating a single diode.
For the same reasons; creating a matrix of ESC’s allowed with the red wire and those allowed only without the red wire was considered as a solution and rejected.
The only realistic solution that can be applied across the board in the same way for all ESC’s is to outlaw the use of receiver packs and require all power come from the main 1 cell battery. Racers will be allowed to use either an electronic voltage booster internal to the ESC or an external electronic voltage booster. The laws of physics mean that no electronic booster can create more power or energy from the main battery than was present in that battery to start with.
1) As announced last season, the truck class will switch to Novak Vulcan 17.5 handout motors.
2) There will be a minimum roof height for the truck class based on cutting the Protoform body on the molded in trim lines. The number will be published shortly. NEW MINIMUM ROOF HEIGHT WILL BE 4.50".
3) The SK class will switch from open ESC to blinky ESC.
4) The new SMC 4200 spec pack will be allowed along with the existing 4025 pack.
5) Receiver packs will not be allowed; internal or external electronic boosters only.
6) The 13.5 motor list will be updated a little closer to the start of the season.
7) No large capacity capacitor banks; ESC OEM equivalent capacitors only or 10,000 microfarad maximum for glitch busters type capacitors.
8) ESC’s must be configured so that they cannot be wirelessly updated when presented for technical inspection and as used in all competition (qualifying and mains). Some examples include removal from the car of any separate, external wireless modules; removal of any specific receiver used to enable wireless programming; and / or a locked software mode in the ESC which prevents wireless updating (locked mode must be indicated by a specific distinctive blink code or LED color).
9) the 17.5 open ESC stock class is officially removed from the class list
10) the Mudboss class will be run as a local track option class where there is interest. It will not be a points championship class.
Some comments on ESC voltage feedback and the reasons we are taking the approach of not allowing receiver packs.
At the conclusion of the 2013 – 2014 indoor carpet season some concerns were raised about a particular Hobbywing ESC regarding its ability to pass voltage from the receiver pack through the ESC, so called voltage feedback.
Immediately prior to the start of the 2014 – 2015 season; testing revealed that other ESC’s in common use in carpet oval racing also had this capability.
The main concern regarding this capability is the potential for the receiver pack to charge the main battery to a voltage higher than that allowed if the vehicle switch is left in the ON position or turned to the ON position after the vehicle has been through prerace technical inspection. A secondary concern is the ability of the receiver pack to provide power directly to the ESC and motor. However, because of the limited size of the wire from the receiver pack to the receiver and from the receiver to the ESC; this secondary effect provides little or no practical benefit in competition.
For the 2014-2015 season, the BRL addressed this issue by requiring vehicles be impounded after prerace tech with the switch turned off until immediately before a race heat. This minimized any possibility to use the “feedback” to charge the main battery.
Additional testing during the season showed that this feedback charging occurred to varying degrees with several different brands of ESC’s commonly used in oval competition. It also showed that at least for some ESC’S the degree of charging depended on the difference between the main pack voltage and the receiver voltage (lipo RX packs charged faster and to a higher voltage than LIFE packs). An apparently simple fix, removing the red wire between the ESC and the receiver, was tested but it was found that some common ESC’s either would not work at all without the red wire in place or had a voltage threshold where they stopped working that could be reached during a 4 minute race, especially in spec pack classes.
As we evaluated possible solutions to the problem we were looking for a single solution that could be applied across all known and future ESC’s. Allowing only ESC’s that did not feed RX voltage to the main pack was considered. However that would have meant continuous testing of ESC’s for this capability as new brands and models are introduced. That is not something any of the oval organizations, including the BRL, are equipped to do. It also would have meant a sizeable number of ESC’s in current use would have been banned. There is also the risk that enterprising racers could have modified an allowed ESC to provide the voltage feedback. We’ve seen racers be able to modify the BEC in a 2 cell ESC to make it work on 1 cell. It isn’t much of a leap to imagine modifying the BEC to allow voltage feedback. In some cases it could be as simple as eliminating a single diode.
For the same reasons; creating a matrix of ESC’s allowed with the red wire and those allowed only without the red wire was considered as a solution and rejected.
The only realistic solution that can be applied across the board in the same way for all ESC’s is to outlaw the use of receiver packs and require all power come from the main 1 cell battery. Racers will be allowed to use either an electronic voltage booster internal to the ESC or an external electronic voltage booster. The laws of physics mean that no electronic booster can create more power or energy from the main battery than was present in that battery to start with.