I know this one guy from the UK. He's always making the damndest stuff on either a mill or a lathe. I bet that guy could whip you up a custom one that would get the job done
I wish you'd hurry up and get all your parts sourced. I'm needing a machining fix. I take it you're still trying to come up with a generator for your train?
Dear RC Talkers, I sincerely apologise, I promise you I am working at this!
The real reason its taking so long is that I am a coward, let me explain, I am the kind of person who needs to be able to see the end of the tunnel 'in 4k' before I even order materials, I wish it was different but its held me back in life/work and hobbies, I simply need a high level of certainly before I start.
However, I can offer some words of optimism,
I have a couple of UK loco's on the drawing board, a British Rail Class 93 and a class 101 or 108, they are like two ends of the spectrum, (chalk and cheese) hope this makes sense! The OS two stroke is fairly well fixed for the 3.5" gauge scale that I want to work at (A 5" gauge loco won't realistically fit in my car for transporting to the track) a gasoline spark engine, although cheaper and more plentiful is just too big!
The next problem is getting drive into the axles, the bogies have very limited room for motors, just 3" clearance between the wheel flanges. The class 93 design uses 63mm dia BLDC outrunner motors in each bogie belt driving the axles below, this requiring lots of motors and ESCs, the class 101/108 is driven by a single big PMDC motor located in the main body serving a belt driven layshaft below connecting to the bogies via telescopic carden shafts. The latter is similar to the real loco.
I am currently exploring the 'RC crawler parts bins' for axles and carden shafts, because the loco build is a big ask as it is. It would be a big help to be able to source reliable components to serve as the drive train leaving me to focus on the interesting bits, the IC generator and the loco body.
The two approaches are so different, the class 93 (any modern diesel electric loco) uses the OS120 engine, driving a BLDC motor as an alternator, a VESC to manage the charge current in to a small LiFePO4 'buffer' battery via regen. then separate BLDC motors each with their own ESCs to serve each axle motor. This is expensive and complicated but uses proven kit, just used in an unusual way!
The Class 101/108 is completely different and potentially more entertaining, OS120 drives a large PMDC motor (say 1000W) this acts as a generator, the generator electrical output directly feeds a similar single PMDC motor via multiple series current limiting resistors very much like trams or street cars work. Engine speed and simple resistor selection control the speed and torque delivered to the wheels. The later requires a fair bit more mechanical kit to get the power to the bogies and their axles, lay shafts, decent carden shafts and 90 deg gear boxes to get the drive to the wheels. The big advantage to this project compared to the cars is that high rpm is not a thing, the wheel axles only need to turn at 1000rpm Max. Torque is an issue but again this is limited by the traction at the rail which is fairly limited. The main problem is that the axles really need to be 15mm in dia. just in case someone sits on the loco!
There must be a way to break the dead lock, I know: "Just pick one and build the dang thing will you" :0)
