speed

[barrown1990]

I have designed a heavyweight thwackbot. Its designed as an extremely over armoured medium weight. Its invertible armed with several spikes so far (as soon as I work out how to do so I will post pictures of my sketches) anyway to my point. The key to this machine's survival will be high speed. My question is what would builders recommend for achieving high speed, I'm hoping to be able to completely outrun robots like the impressive Toxic 2, which if memory serves runs at 20 mph.

[Garfie489]

The key to being fast in the arena is gearing your robot so it doesnt achieve speed......

If a robot can manage 20mph, then to go faster than it usually you need to gear it to say 15mph (assuming the same motors).

A practical example is that i worked out that the featherweight im designing could do 18mph on 6s. However realistically its not going to get more than 12mph within the confines of the arena. Thus if you designed your robot to have a top speed of 12mph, then it would reach that speed alot quicker than mine and thus would be faster over the length of an arena.

You want to design something that takes into account the wheels you have with the motors that will be powering them.... Define a length (say the width of the arena) and work out a ratio that ensures the robot will stop accelerating once it hits that length. Thus that means the robot should in theory be the fastest around the arena - even if it doesnt have the highest speed

Acceleration also helps with avoiding attacks, as it gets you out of the way quicker.

[Eventorizon]

I believe Storm 2 is only geared for 12mph in the current arenas, and that it was only geared for 16mph in Robotwars. You don't need a really high top speed. you just need to get something pretty fast in a short period of time.
This can be changed with bigger/more powerful drive motors but even then you shouldn't need to exceed 15mph and even that is pushing it. I'd personally go with 12mph like Garfie.
I currently use this speed calculator - https://wahiduddin.net/calc/calc_speed_rpm.htm - Warning: The wheel size is in inches and it wants the radius, not the diameter.

[typhoon_driver]

Get a couple of big motors and gear them for acceleration as stated above.

These calculators have always been handy http://www.technobotsonline.com/calculators.html

[blazerbotics]

MONTE my thwack bot just runs on standard Boschs, but still out runs most machines and with plenty of wheel spin. It's all down to just getting the gearing spot on, don't aim for too much speed, your better off going slightly slower but quicker acceleration.

[terry]

Toxic 2 is geared a bit too high, from one side of the arena I can't hit top end and have too slow down or hit the other side of the arena. The only way to hit top end is go round in big circles and u can get up a good speed . I am going to gear down a little that will give me more acceleration and won't pull so much current. I'm looking at 15mph might do me .