Marui Samurai - Another SilverTriple's journey...

[silvertriple 3557]

Thinking about my Samurai N°4 which is still in parts and incomplete currently...

Missing elements are actually very few :
- Center differential
- Sprocket

I'm thinking now that based on what I have done with the Ninja, I have already a good part of the Center diff already : the main gear is a derivation of the rear diff gear, and for the big bevel gear, they would be easily derived from the rear diff big bevel gears... So this should be easy to pull a model for Samurai center diff (I could cheat with an aristo craft hitec Kangaroo's spooler, but that would be no fun )... 

Then it would remain the sprocket... I need to find data on how to design one, so if one has a lead to design information of the sprocket, I would be interested :-)

 

[silvertriple 3557]

I had this in mind for quite a while... My Samurai tires were too Tamiyaish. I had to do something. And I wanted some tires I won't care to deplete if I run them...

Few months ago, I did a CAD model for the Samurai tires... I had this in mind for quite a while... I got new printers, and it allowed for new capabilities


https://www.youtube.com/watch?v=8ieybnksx30

And then, after few prints

Time to show off...

I love the Samurai, and this one is a very unique model...

[silvertriple 3557]

As I want to test the tires, and I don't want to glue them on rims, I've reprinted rils with rings to have the tires maintained in position... 
https://www.youtube.com/watch?v=6kDtvnizYrY

I've some hope it will be fine for testing the tires a bit at least. I may end up gluing them, but I would like to preserve the possibility of doing another test run with printed tires done with different resins... The weather is very changeant here, so I may not do the test run now and wait there is bit of sun for this...

[silvertriple 3557]

I may not be the best at this...


I could have probably made it cleaner... but this is the first time I'm doing this, actually...

[silvertriple 3557]

I remember having an argument on lettering the tires or not, and lettering the tires with a very simple font instead of trying to reproduce the original Marui font...

What do you think?

[silvertriple 3557]

I could not resist... The weather is not good, but trying to run on asphalt is not requiring too much of cleaning afterwards...

For memory, I printed 7 Samurai tires in total : 4 fronts and 3 rears. Two of the fronts (one of them which was lettered) had an issue due to cup suction effect, and there is a small cut on the side of the tire (you can see on the A of traction which is having a mark on the previous post). I've mounted the other printed fronts (with a hole in the thread) for the test run. The rears were not affected to the same level, so they are good to go. The rear seems to be seated properly, while for the front, I may need to review them slightly to get a better seating. In the meantime I put some double face tape in the slot to ease adhesion...

I started by running slowly inside, and it seems good : it grips nicely inside. Let's go for asphalt for a very short run...

First conclusions : 

• it grips
• it grips to the point I need to glue the rear

I've not pushed more, I'll found a solution to get the rear seated properly (it may be a question of removing half of a millimeter in the inside diameter, but what I could see while doing this test is already a good sign, and it's encouraging  :-)

[silvertriple 3557]

I took some time to add a minor detail to my Samurai tires...

And I did that on tires which are targeted to run...

[optimaforever 87]

it's handy not to have to paint tire letters 

[silvertriple 3557]

1 hour ago, optimaforever said:

it's handy not to have to paint tire letters 

I would love to have the capability to get it printed in the right color, unfortunately, this is not possible in SLA. Those tires are printed in SLA resin, and the exposition to UV leading to polymerisation of the resin happens in the bottom of the resin bath, which means it would require a bit of engineering, 2 resin printer and 2 different resins, plus all the problematics of having them set exactly the same way and pausing the print at each layer and doing the withe after the black and get back to the black to achieve this. I don't think this will be possible, at least for now...

[silvertriple 3557]

I ran the Samurai this afternoon for about 10 minutes... The tires grips and the behavior of the car is just normal... Full throttle, braking, turning, everything is as normal tires...

 

The tires still look good after the 10 minutes run...


Conclusion : 3D Printed tires are viable...

[silvertriple 3557]

As mentioned, I ran both the Samurai and the Ninja on the offroad track, during Montluçonnaise 2023... The printed tires performed well in both case. I'm very happy with the traction and they way the cars behave with them...

And there was a short movie made at the end of the Samurai run (the last few minutes of the run unfortunately)...
https://www.facebook.com/660479312/videos/633463924952838/

The Samurai is light and there was plenty of grip with the tires... And that was somewhat similar for the Ninja : plenty of grip, with a layout close to the Optima. I was really surprised how well this one was during the run. And with a Sport Tuned motor, there was largely enough to open wide, with a very predictable behavior, like the Turbo Optima or the Javelin (but lighter than those)... 

Tires conclusion : they work well on the track. I can improve the printability by changing a few things in the internal design, and once this will be done, they will be ready for publication...