Hey y'all it's been a while. After quitting the hobby 9 years ago I never thought I'd return... but I got the itch to build again when I found my knex collection whilst cleaning up the house and some knex vids popped up in the yt feed.
Started of by building a ballmachine (which you can see here: https://www.youtube....h?v=RJ0FHCPwhxg)
But in the meantime I was working on an exciting new innovation for VV Coasters which would hopefully solve the speed preservation issues that haunted my childhood coasters. Inspired by the 3D printed wheel assemblies for SS trains I decided to finally put my years of studying mechanical engineering to good use and design something similar for VV. When I started the project I wasn't sure if it was gonna be possible to get even close to the efficiency of SS coaster trains cause of some of the inherent problems VV track has; the small scale and frequent splicing of track; but I was willing to give it my best shot.
I'm now a little less than a month into designing and WOW I'm happy with the results so far; I'd dare to say that with these trains VV coasters can rival SS coasters in terms of speed preservation 
anyway here are some pictures of the design (keep in mind the aesthetic is very much work in progress):
^3 car train I currently run on my WIP coaster. Width and height basically the same as standard micro car. Length a little longer than 3 micro cars. The tape is to hold some weights in place, I've found that this improves performance further but I haven't found a way to integrate this into the design.
Tried out several different methods of connecting the nose and back cars together (ranging from rubber bands to lego universal joints) but what I ended up with is VERY similar to the SS trains: a rod to connect the nose with the first car (this allows the nose and first car to roll independently whilst still keeping the train 'level') and ball joints for the rest of the connections for maximum maneuverability.
As you can see each wheel assembly can rotate and tilt independently from eachother.
Chain Dogs and their spring are taken out of the regular knex cars and can easily be attached or removed from underside 
Played with different wheel setups and this 5 wheel setup worked best. 
A tight fit around the track is neccesary, but not too tight or it can get stuck.
All parts except for nuts/bolts/bearings are 3D printed in PLA on my sovol sv06 with a 0,4mm nozzle (0,2mm layer height).
The bearings have an OD of 8mm, ID of 4mm and width of 3mm
Everything is held together by m2 bolts, nuts and washers. Except for the connection of wheel assembly to orange car, those are m3s atm.
I made a video on how an earlier prototype compared to regular knex car on my yt a week ago: https://www.youtube....rts/uerDENuCXxA
But the performance can be seen way better on the model I'm currently building:
Testrun video:
https://www.youtube....rts/P2LbmS_4kaI
I'm incredibly stoked it's able to clear this layout. Especially the high speed turn and bunny hop used to be real speed killers for VV cars, but my trains don't have much issues there:)
I'm still working on improving the design. There's a couple parts I'm not quite happy with yet. Once I've finished I plan to share the 3D print files (for free) and make an assembly tutorial so that everyone that is interested can make one themselves. I expect that to happen within a month.
If there are any CAD/3D printing savy folks in here that would like to have a deeper look into the current design please send me a msg and I can send you the STEP files. Would love to get some feedback.
Edited by sathothy, 06 June 2023 - 07:34 AM.
