TOPIC:

It's been quite some time since I posed on TB but I thought I would share this project I am working on. Over the last year although I have been working on some of my Tamiya Porsches and other bits I have sold a lot of my NIB collection and invested in some new metal working equipment in my workshop (shed). Don't worry I still have LOTS of Tamiya projects and paint jobs  .

These bikes really do not get much publicity, I get the feeling they are a little like the Tamiya Black Porsche's I have, due to limited numbers there are small groups of enthusiastic collectors not really on forums. I am hoping I can share my projects as I "very slowly" work on them and also make some new connections.

Shout out to Sander who has been helping me track down a bike in his part of the world, that was fun! I am interested in collecting more and mine are not complete so feel free to anyone to give me a shout. This is why I am manufacturing parts for the bike, its fun and a challenge for my machining skill, plus impossible to get spares.

So this part of the project so far... This is a rider mechanism that sits inside the rider and it tilts the rider to shift the weight and therefor provide the steering, I cannot imagine it's very effective and I have not come across anyone that's ever seen one run. There is more to the mechanism yet to be built, like a small electrical contact board that looks like an RC speed controller and some other module gears I am working on at the moment. Very interestingly the mechanism has both DP and Module gears which I have learned to cut from scratch having never cut a gear before. The Aluminium plate was challenging too as it was all cut manually, I do not have any facilities to CNC this type of stuff and I am making only a few units, they are very laborious and I have probably taken 6 months to get to this point. 

Well that's it for my first post, if anyone's interested in more details I'd love to post more.



 
 
 
 

Intriguing - I'd definitely like to see more of the indexing/gear cutting setup :Y:

But this:

Purple_rob post=71921 userid=6012.. This is a rider mechanism that sits inside the rider and it tilts the rider to shift the weight and therefor provide the steering, I cannot imagine it's very effective and I have not come across anyone that's ever seen one run. ...

I don't know what you know about motorbike steering, but it only works in the "obvious" sense (move the bars left, steer left) at the sort of speeds achieved when manouvering the bike around while walking alongside it. Anything faster than that it's all about gyroscopic precession, weight transfer and - if using the bars at all, countersteering. This is learned in seconds on a bike, polished over a few days, pushing it to 110% a few months, learning to push it less but actually go faster (and not crash), years. 

Target fixation - or looking where you want to go - or don't want to go - a lot of riders focus on the diesel/crash barrier/tree they don't want to hit, and in doing so, do. If they looked where they wanted to go, they'd almost certainly make it around. This works on some really heavy bikes at very high speeds - point is, moving a 6kg object (your head, plus helmet) is enough to dramatically change course. On a light rider (75kg) & light bike (200kg, wet), that's only 2% of the mass being moved...

Countersteering, weight transfer (sticking a knee out, hanging one but cheek off the seat, pressure on the inside footpeg, that's all about moving the contact patch of the front tyre over to one side and fractionally higher up the leading edge to make a turn. This works not only on the fattest tire, but the skinniest where the contact patch is no bigger than a couple of stamps.   


I've definitely see RC bikes where the rider moves, but whether that was a realism gimmick or was providing the steering input I couldn't say. I was really impressed with the stability and agility of the little things, though the amount of traction & grip did call for a bit of subtlety on the throttle.


So ... I think quite a small weight, moves quite a small distance - in the right place - will steer an RC bike very effectively

Wahoo rob. Nice job.

Nice work indeed!

Thanks chaps, no more progress at the moment as I have stalled on these module gears. I have hunted the internet but cannot find any off the shelf parts I can modify. 

The originals are plastic and dual layer. 0.5 Module 50T and 12T, I have successfully machined a brass one from two parts/gears I made but my attempt on plastic or POM has failed. the issue is fitment tolerances really, maybe if anyone is remotely interested I will show you HA!

Jonny, re the rider mech. This was actually the first RC bike every made so I think somewhat experimental. It's certainly a unique way of tackling steering which on it's own I have never seen. I've tried to drive my YZ250 Kyosho but was unsuccessful which has some sort of pivot steering at the forks. There is a youtuber that has modified theirs and he's very experienced at RC bikes, for my runner I will have to adopt this. 

My next thought while I stall on gears is a mini cnc router to shape the circuit boards, it seems they are not bad at all on price, I have no idea on how to programme them or what software right now though. That will be very interesting!!

 

A couple of posts coming up as I have made some good progress on separate parts here. the first was I needed to recrate the contact legs for the speed controller and pondered how to make perfectly straight 2.5mm strips of 0.3mm copper. I machined this brass die which I then made a guide out of some left over ali and used it to press some strips out. I am super impressed with the result and I can move on to further shaping. The last picture if the original part and you can see the legs soldered to the board. 

 
 

So the PCB's you ask..  well this one has been very interesting as I have learned how to DIY a simple circuit board and take my Fusion 360 a little further. I found a great guy on a facebook group who was willing to CNC some PCB for me and then finished with the copper circuit. My only bug bear of this is the original part seems to be on bakelite material and I cannot source anywhere 1.6mm PCB blanks, if anyone is reading this that can help I would appreciate somewhere I can source this older stuff. I would rerun this job for further authenticity of parts. For now I have a stronger and very satisfactory brown PCB. I will line them up on my mill for precision holes. 

Last update for today. Another interesting part of the project.

Here I measured out several of the 1.2mm plate steel parts and drew them up on fusion (only one part pictured). I was able to get a small quantity laser cut and supplied with an online ordering service. From there I drilled the holes and have run tests on machining the brass fixings, they are then pressed into the plate. I have quite a bit to go even on these parts and recently built a small parts bender to achieve the angle you can see on the original part. From there they will be plated just like the original parts. 

Impressive work rob. 
for your pcb, did you see and ask to radio spares ?

Thanks mate, no I didn't but are you talking about the bakelite material? Who are radio spares? .
All my research and I found nothing.