So why should it be any different with this featherweight?
Meathammer was designed back in 2005/06 when using 4 drill motors was a bit of a novelty... it was made more novel still by mounting the epicyclic gear cages directly to the chassis, which unfortunately sends all the drive shocks back through the gearbox.
The original version ran for a number of fights at modelworld 2006? and even won some, especially the sumo, which favoured its very low profile.
I've just rebuilt the gearboxes with all metal gears, and tested it, and it seems it should last for at least one fight… but as I put it in the car after testing, I noted one of the wheels had nearly fallen off. Mark that bolt for Lockthreading!
All this got me thinking if I could make something less likely to lose a wheel, break a gearbox etc
I have a huge pile of bits and bobs that were destined for heavier machines, and so are less likely to break, so I thought I'd try and lash them together into a more robust unit, instead of mashing on the same old design.
So here's the parts list:
2 X 30A Indiana General motors, which first saw light of day in the original KillerCarrot, then in a middleweight version. Their big advantage is they only draw 30amp at stall (Some might see this as a disadvantage), and they are only 80mm across, meaning I can run them direct to 100mm wheels. They are hugely heavy though.
|KC1 rebuilt with steel shell back in 2001|
A length of 12mm silver steel driveshaft
Sabretooth 2X25 ESC which should cope with the motors, as they allow a brief peak of 50Amps.
2 X 18Volt 1.8Ah Lion battery packs from an old strimmer.
4 X 100mm Blue trolley wheels.
A bunch of old lexan, and some bolts and steel and whatnot… and an old 40MHz Tx/Rx set.
All I need to machine are a couple of wheel mounts to fix the wheels to the driveshafts, and a couple of motor mounts, which will be made of a bit of angle (If I have any… )
Here's a photo of the parts…
...and hopefully the next post will be an assembled "thing" ready for testing.
So here's the design: direct drive full body spinner. The motors turn at 100rpm per volt so 18 volts gives 1800rpm, thick driving straight forward on 100mm wheels gives 314mm travel for each rotation, which is around 33kph or 21mph. It will be fun to see if it is in any way controllable.
As a full body spinner the circle described by the axles is around 35cm which means it takes about 11 wheel rotations to turn the body, which means at full blast it should spin the body at 165 rpm.
Maybe… but I've run out of steam today, and will leave the machining till next week.