Again another Marui project : Super Wheelie and Big Bear!

[silvertriple]

Super Wheelies...



1983 models, They had a 6V chassis and suspension arms colored:
- Super Wheelie - Land Cruiser white bodyshell, arms and wheelie bar were grey
- Super Wheelie - CJ-7 Golden Eagle Black bodyshell, arms and wheelie bar were red

1985 models, 7.2V chassis, with black arms:
- Land Cruiser superwheelie : Blue bodyshell
- CJ-7 GoldenEagle super wheelie : White bodyshell

And a render with the Big Bear and its unreleased prototype:

[silvertriple]

The prototype of my Universal Marui Gear (Mod 0. set is arrived...

Here is the design:



It was designed to cope with all 2WD Marui cars, and to get as closed as possible of the standard Mod 0.6 gears ratios. It includes even the motor pinions (but I may decide to remove them at the end (not yet 100% sure), it is based on the Big Bear V2 differential design and it was clustered with the intention to reduce the total cost...

I will check the fitting and clearances in Hunter/Galaxy and Super Wheelie/Big Bear gearbox tonight (in both PA12 and PA12/GF).

[Dadio]

Very cool idea , well done , fingers crossed it all fits .

[silvertriple]

I did the tests, and there is some good and some bad stuff

The Differential is a perfect fit, as expected, it works smooth and insert the axles shows the right clearances, and that on all the tests


On the Hunter/Galaxy, I did the idle gear without test fitting the new diff, as I didn't have the Hunter chassi model. Bad mistake. I should have, as I had the idle gear modded in .6 mod to get it closer to the motor to allow the usage of pinions we can find nowadays. The out diff bevel gear is larger on the new diff, and that colides with the idle gear while it was not within the older design. I cut it (removed the 2 mm added on the opposite side from the motor) to test the fitting with a motor pinion. I will review the idle gear and review my file accordingly. Not too much correction : it is adding an extrusion on one side and remove it on the other side.


On the Big Bear and the Super Wheelie, the fit is perfect between the diff and the idle gear, however in one of the configuration, I made a mistake when I set the number of teeths of the pinion, because it doesn't mesh... I did this a morning, and it seems that some home activities were a little bit more disturbing than I expected.


I will modify slightly the motor pinions to make it more resistant : there is not enough material to maintain the grub screw properly, it breaks if torquened too much...

[silvertriple]

The final version of the Marui 2WD untiversal gearset is born...


Test fit for Super Wheelie


Test fit for Big Bear


Test fit for Hunter/Galaxy


The Idle gear for the Hunter/Galaxy is on the sprue in two versions : one for standard original shaft, and the second one made to fit ball bearings on a 3mm axle (the original shaft is not a 3mm shaft but slightly more)...
I'll open a Shapeways shop for those soon, as there is already a bunch of people requesting this

[Dadio]

That's excellent work Mark .

[XLR8]

I agree, that looks fantastic!

It looks like you are using sintered nylon (polyamide)? By chance, have you performed any durability testing on your gears? I was thinking about designing a printed diff gear for my 934 project (52t and either 48dp or mod 0.6, brushed motor, 2s power) and I was wondering if it will prove to be a wasted effort. I reckon since the Big Bear has large tires and no clutch, perhaps it could present an extreme test case.

[silvertriple]

I agree, that looks fantastic!

It looks like you are using sintered nylon (polyamide)? By chance, have you performed any durability testing on your gears? I was thinking about designing a printed diff gear for my 934 project (52t and either 48dp or mod 0.6, brushed motor, 2s power) and I was wondering if it will prove to be a wasted effort. I reckon since the Big Bear has large tires and no clutch, perhaps it could present an extreme test case.

Hi Doug,
It's MJF PA12 printed (grey) . My Nichimo Spirit FF has bevel gears and internal gears SLS PA12 printed, and has now about 4 packs passed without issues, including a long run on a OnRoad asphalt track. And it survived for now. I also know that @Dadio ran some test with printed gears on one of his cars...
In the present case, the orignal gears were in mod 0.6, at the exception of mod 0.8 for the Big Bear V2 (from which I took the differential model). And the orginal gears were melting very quickly... I don't think it can be worse within an higher mod as the amount of plastic to absorb the heat for each tooth will be higher, in addition to an higher temperature deflection point...
Hope it clarifies

[Dadio]

I agree, that looks fantastic!

It looks like you are using sintered nylon (polyamide)? By chance, have you performed any durability testing on your gears? I was thinking about designing a printed diff gear for my 934 project (52t and either 48dp or mod 0.6, brushed motor, 2s power) and I was wondering if it will prove to be a wasted effort. I reckon since the Big Bear has large tires and no clutch, perhaps it could present an extreme test case.

Hi Doug,
It's MJF PA12 printed (grey) . My Nichimo Spirit FF has bevel gears and internal gears SLS PA12 printed, and has now about 4 packs passed without issues, including a long run on a OnRoad asphalt track. And it survived for now. I also know that @ Dadio ran some test with printed gears on one of his cars...
In the present case, the orignal gears were in mod 0.6, at the exception of mod 0.8 for the Big Bear V2 (from which I took the differential model). And the orginal gears were melting very quickly... I don't think it can be worse within an higher mod as the amount of plastic to absorb the heat for each tooth will be higher, in addition to an higher temperature deflection point...
Hope it clarifies

I've been using SLS PA12 gears in my Dogfighter and where I'm sure they are not as durable as injected nylon I've yet to have one fail , I think you have to think of them as a reasonable price and no longer a limited supply, in short you can drive like it's the 80s again and when they fail buy another set .

[silvertriple]

I think you have to think of them as a reasonable price and no longer a limited supply, in short you can drive like it's the 80s again and when they fail buy another set .

Very good point, @Dadio , I'll add the idle gear separately on shapeways as well, as they will be the weak point with the set. I'll also mention that motor pinions require replacement by metal ones for runs : the motor shaft is going to be hot, and that won't help... Shapeways costs are high, but that is the only way to let people access those parts without taking care myself of them...

[Dadio]

I think you have to think of them as a reasonable price and no longer a limited supply, in short you can drive like it's the 80s again and when they fail buy another set .

Very good point, @ Dadio , I'll add the idle gear separately on shapeways as well, as they will be the weak point with the set. I'll also mention that motor pinions require replacement by metal ones for runs : the motor shaft is going to be hot, and that won't help... Shapeways costs are high, but that is the only way to let people access those parts without taking care myself of them...

I really wish another print shop would follow the Shapeways business model as they are far from the cheapest and a little competition might bring their prices down , the profit I make on parts is very small , so far I don't think any part has paid me more than 5 pence per hour of my design time .

[silvertriple]

I really wish another print shop would follow the Shapeways business model as they are far from the cheapest and a little competition might bring their prices down , the profit I make on parts is very small , so far I don't think any part has paid me more than 5 pence per hour of my design time .

Same here on the wish another shop should propose the same for cheaper, and it's a pitty when you know it could be obtain much cheaper somewhere else... I'll probably have some parts with me during vintage events, as I know that Marui cars were frequent cars in France, and we even had race category specifically designed for the Super Wheelie cars, and they are quite liked by lot of people in France. But I won't print them on Shapeways...

[silvertriple]

I set a silvertriple shop on shapeways... I had to order a part from my shop, and just noticed the shipment cost which are a bit crazy...
Anyway, it's live now, people should be able to order the part and as well replacement idle gears for this set (that's the Hunter part I ordered as I needed one to replace the faulty one from the prototype).

I also tried to make sure the information provided is clear enough so people don't order just the idle gear for their car while it is just a raplacement...

Let's see how this goes... But hey, I wish there was cheaper alternatives...

[Dadio]

I really wish another print shop would follow the Shapeways business model as they are far from the cheapest and a little competition might bring their prices down , the profit I make on parts is very small , so far I don't think any part has paid me more than 5 pence per hour of my design time .

Same here on the wish another shop should propose the same for cheaper, and it's a pitty when you know it could be obtain much cheaper somewhere else... I'll probably have some parts with me during vintage events, as I know that Marui cars were frequent cars in France, and we even had race category specifically designed for the Super Wheelie cars, and they are quite liked by lot of people in France. But I won't print them on Shapeways...

I've been thinking of getting some parts printed then offer them on eBay, mostly to undercut the people selling my parts for insane mark up.

[silvertriple]

I've been thinking of getting some parts printed then offer them on eBay, mostly to undercut the people selling my parts for insane mark up.

I've got some for the few vintage events I'm going on later in May, June and July... There is generally some Marui Super Wheelies around at those events, so there might be some people buying those... And if they don't sell during the events, I may put them on ebay at the end...