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What is the usual/average size of a featherweight? A rough starting point width by length.
I know there's a weight limit and no real restriction but what size should I be looking at making my robot? I have looked and seen various sizes recommended on forums but they vary greatly. Yet in the videos on YouTube the robots all look a similar size.
I don't want to make a robot that fits in a cereal box that ends up squashed by something the size of coffee table.
How big is your robot?
I struggled with this at first too. It needs to be a bit bigger than your average RC car. The closest thing I can think of to compare the size to is a briefcase, but not quite as big as a suitcase. Something like 400mmx350mm or a bit bigger. I don't have my bot to measure with me at the moment, but that should give you a vague idea.
Hannibalito3 is 460mm wide and 380mm long.
Luna-Tic measures 400mm wide and 500 long (550mm including the lifting scoop).
Stumped me to stat with as well. What I did was start with what I knew. I'm using cordless drill motors that are 150mm long and they are end to end either side of the bot, allow 50mm between them for space, that's 350mm. The wheels screw directly to the motor, so no added width there, finally adding the thickness of the side armour with a little space for the wheel to wobble about in, comes out as 400mm.
To work out the length, as I'm using 4WD skid steer, I wanted the wheels to be square to each other (the same distance apart sideways as they are long ways). Adding a little wedge on the front of the chassis itself and the scoop, comes to as it is. Its maybe a little on the larger size, compared to a two wheeled bot but it has a nice low profile and plenty of pushing power. (I hope, not combat tested yet) ;-)
There's no wrong size, but make sure you can fit everything inside. Weight is the major issue of concern, weigh everything as you fit it and keep track of the 13.6kg allowance. So if you can make it 50mm smaller do, that will save you weight in the long run regarding chassis and armour.
Inb4 Japanese Fighting Tortoise
Hardwired 2 and 3 are both about 300x400 or round about that - that said, the non-scoop parts of HW2 would fit on the size of an A5 piece of paper, which makes maintenance a bit of a pain. On the other side of things, my beetleweight Fhqwhgads is the same size and works on the whole massive air gap principle which has worked so far. Either can work but there's definitely a need to make effective use of the size in either scenario...
It also depends on what you're planning to make it from. If you plan on building the whole thing from Hardox, you'll have to make it smaller than if you were planning to use aluminium or HDPE. A lot of Hardox FWs I've encountered seem to be around 350mm long and wide, whereas my HDPE bots are around 50% bigger.
Also, bear in mind whether you want to enclose the wheels or not. Putting the wheels on the outside leaves them more exposed, but it means you can make the chassis narrower.