3d. The minimum distance between the edge of the unwalled part of the arena and the battle box (and therefore the width of the ditch) is 150mm.
Simon Windisch wrote:Remove rule 3d "The minimum distance between the edge of the unwalled part of the arena and the battle box (and therefore the width of the ditch) is 150mm." I don't think that we have a single arena that conforms to this rule, so drop it, or perhaps alter it in line with reality.
Andrew_Hibberd wrote:The rule could be reworded to a reasonable distance, or 4"/100mm
BeligerAnt wrote:The reason for specifying a 150mm ditch was precisely to avoid problems of robots not falling cleanly off the arena. Peter Waller's and PeteC's arenas meet this, I think Oliver's mostly does. Since the maximum length of a robot is about 140mm, a 150mm ditch really is the required minimum. IMO this is one of the most important requirements for a battlebox to avoid adding to the problems of deciding if/when a robot has left the arena.
razerdave wrote:This should be 150mm Minimum, because there are robots that can brace themselves over a 100mm gap and still drive back onto the platform (Baby Hell for example)
Mine is 145mm from the edge of the arena to the inside of the battle box.
You have to remember once over half the weight is over the edge it is going to start tipping unless you have suction.
The reason for 150mm was that the longest possible robot is around 140mm, so we rounded up to a nice round 150mm or 6".
In practice 145mm is adequate.
Peter is correct that once the centre of gravity goes over the edge of the arena the robot will start to fall. However, since most robots have the wheels at the back and are probably around 120mm long, a 100mm ditch really isn't wide enough to stop a robot bouncing or driving back into the arena - especially if it leaves the arena at speed.
Mine is about 150mm on the two open sides...I can drive a robot around the dropoffand that was actually part of my thinking in retrieving the robots.
I think you could spend forever trying to agree the perfect size for this and never reach a consensus. It seems to work with most of the arenas we've got; most people don't build arenas and if they do, it would make sense for them to follow the rules we've got at the moment but if they have 120mm rather than 150mm for some practical reason, does it really matter? I'm not talking about the precision of the rules but about the cost and practicality of transporting an arena about.