Again another Marui project : Super Wheelie and Big Bear!

[silvertriple]

Yes, but there is absolutely no room to make this in mod 1 in this gearbox... I had a quick look at cnc and cost would be crazy high... I need to think more...

The honest way forward may be to publish or sell the file and let people decide for themselves how to proceed .

I'm still unsure about this : the experience of some of my friends shows that you may give any warning about something in the explainations when you sell something, people barely read those before clicking... And that is a problem at the end...
I still need to do a final validation of the diff cluster, but this is just a final validation (I made changes following the mistake I made on the first version). I will probably take the approach of putting just the diff on shapeways and to put the files to complete it for Hunter, Galaxy, Super Wheelie and Big Bear on Printables and Cults3D...

[silvertriple]

Big Bear transmission inspection after about 2 and half hours of Lipo 2S (4000mAh) heavy runs (intentionally ran it quite brutally for this as I needed to know about the resitance of my gears - about 4-5 packs passed).




The nylon diff is not showing any signs of wear. it was a mix of different printed parts, but I'm quite sure they would be resistant enough. So this is perfect now.

I have some thinking about the Super Wheelie and will get another idle gear with a small modification printed in SLM, and normally it should be fine... When ordering this I'll get the final diff gear printed set and a metal printed idle gear for the Hunter as well... The Big Bear was clearly the most challenging to tackle, and the nylon idle gear of the Super Wheelie and Hunter are still alive at this stage (but shows clear signs of wear on the Super Wheelie). SLM will come to the rescue...

[silvertriple]

My daughter loves to run cars in vintage events, and she asked for a bit more cars than her Lunchbox and here TT01 to have more variety (the DT03 is nowhere a vintage car, so it's no go for vintage events). And she confesses recently that she likes the Super Wheelie. Luckily, someone proposed me one recently, we agreed on a price but it was delayed because I just got two recent entries that day... My friend sold his own Super Wheelie he played when young adult and he kept it as he had kids and he expected the kids of his kids to pick up rc... He decided to sell it while the targeted kids seems to have only interest for their playstation, and he wanted to find a new home with someone who wanted to run the car... There will be a bit of work, in particular for the windshield and its attachement, likely a bodyshell clean-up and some nice paint to follow...






My daughter is happy, but she told me she expects it to become more pink

[silvertriple]

Following the expérience with the Big Bear idle gear, I redesigned the diff cluster. I also made a different version of the idle gears designed with SLM metal prints in head.


I've set an order online for a final check. The Super Wheelie Idle gear is printed in 2 versions, so I should be able to assess the needs for the tolerance, and eventually review the idle gears accordinly for Hunter and Big Bear. I'll be clear on this by end of next week, I suppose.

[silvertriple]

Got a delivery today...

Diff sets and idle gear for the 3 targeted configuration. This should allow me to check the assumptions about SLM printing tolerances and validate what is needed for Super Wheelies. The Big Bear idle gear is the same dimension as the one working already so this is good. And I'll should be able to assess the Hunter/Galaxy one as well...


I also got a gearbox printed for teh Super Wheelie. I wanted to print one and check my dims for the ball bearings addition before to add this into shapeways...


Later on within the week : test duties

[Dadio]

Testing is tough work but somebody has to do it

[silvertriple]

SLM idle gears prints are kinda "predictable"
- Big Bear idle gear is spot on, as long as you get the tolerance for the shaft right (+.3mm)
- Hunter/Galaxy is spot on, as long as you get the tolerance right for the shaft and the ball bearings casing (+.3mm)
- Super Wheelie : the big part of the idle gear needed an offset of -.1mm everywhere on the external profile of the bigger gear. Rest of the design is fine (The print with initial design is again 19.4mm for 19.2m diameter expected, while the one with -.1m offset of the external profile is 19.2mm and working smoothly).

So this is it... Diff set remains to test in the different configurations, but at least I have now idle gears for those cars working and reliable...

[silvertriple]

Focus on the Super Wheelie. I put the new diff in. It required a minor shim addition between the locks and big bevel gear on each side but it is now perfect (nb: the previous big bevel gear got printed with some supports, and the left overs were what was maing the diff working ).


I'll have to check out the same for Hunter/Galaxy and for Big Bear before doing the modification on the design (it will be very easy to do). In the meantime, the Super Wheelie works, there is no cracking sound anymore and I don't care opening full throttle... But the motor is probably quite worn, and I'll need to replace it at some point...

[silvertriple]

I'm thinking about the way to propose the diff and the idle gears...
MJF PA12 parts are easy, I juts have to put them on Shapeways, but they are incredicbly high price compared to where I got them printed, but that would work.

For the idle gears, the problem is different : Shapeways only propose SLM for Aluminium, and I believe it won't be as resistant as the stainless steel I got them printed on my side. They do Stainless Steel in Binder Jetting process but it is clearly not as good as SLM in terms of precision.

[Dadio]

I'm thinking about the way to propose the diff and the idle gears...
MJF PA12 parts are easy, I juts have to put them on Shapeways, but they are incredicbly high price compared to where I got them printed, but that would work.

For the idle gears, the problem is different : Shapeways only propose SLM for Aluminium, and I believe it won't be as resistant as the stainless steel I got them printed on my side. They do Stainless Steel in Binder Jetting process but it is clearly not as good as SLM in terms of precision.

I guess price wise you have to compare to original parts , I don't know the price of original gear parts for the Hunter etc but the dogfighter gears I have on Shapeways are massively cheaper than genuine old stock as are the Holiday Buggy gears .

[silvertriple]

In addition to the gearset, I also did some enhancements to the Super Wheelie/Big Bear gearbox.



The modifications are the following :

• inclusion of ball bearing MR63ZZ (3x6x2.5) at each ends of the idle gear shaft. This will require to increase the diameter of the hole in the metal plate slightly, but ultimately will remove some of the issues with the gearbox

• slightly increase the diameter for the motor location. As matter of fact, it is one of the difficulty with those machines : with the original gearbox, you can put a standard modern silver can as they are done slightly different : you have to put it using force, and it results sometimes in broken parts

I have no pics of the test fit, but I've check and everything is fine. The test part will be put on the side for the time being, it is going to be part of a printed car ... But this is for later on.

[silvertriple]

I finally put the gearsets as files on Cults3D - search for "Marui 2WD" and you should find them.

[silvertriple]

Now that internals are tackled, it's time to deal with what is around...

I took the printed parts, a brushless and tried to figure out...



The motor cap will require a modification for this, for the contact tabs, the sensor and since the motor is slightly longer than a 540 another modification to reinforce the part, and let's not forget the wheelie bar and the suspension arms that goes on that part...



It's now ready to print. I'll have to review the Wheelie bar attachments and to design one for the Big Bear as well...

[silvertriple]

Holidays started after a hard day of work... And it is time to get ready for next steps on this project...

I prepared some clusters for MJF PA12 prints.

Front Arms


Rear Arms


Wheelie Bar


The target is to get them printed in White, so I can dye them in a specific color (I said my Super Wheelie will be a bit special )

[silvertriple]

As I'm doing this for the Super Wheelie, I feel the need of doing it as well for the Big Bear...



Next steps :
- Review the chassis to enhance it a bit (give a few millimeters more for more battery pack compatibility, few reinforcement, shocks mount(thinking about it, at least), some elements to ease cable management
- Prepare a gearbox cluster. Not sure if I do a brushed and brushless version or one that do both (with the two motor caps)
- the plan is to publish the files (all clusters and unitary parts), and to include a step file for the brushless motor cap so one can eventually modify it to suit his own brushless motor