silvertriple

The almost complete Marui tire collection in CAD (the only missing one is the foam tire of the Coors in onroad version)

Since those were missing in the CAD collection, I modeled the Samurai tires... They are quite similar to the Ninja tires in the spirit, somehow, but require a heavier timeline in CAD software... Ultimately, it did not took much time to complete those.

Pursuing my target to model all tires from Marui range One additional set is done. And since I love to spread the Galaxy love as well, the other face is different The front tire should not be that expensive to print in MJF rubber like to do some test on the wall thickness and to adjust it to find the sweet spot...

While working in the Big Bear tires, I learned a lot, and I got a lot of ideas... While I don't need Ninja tires for the time being, it's not the case for the Shogun and Coors. I have this silly idea it would be great if I can do something with injection molding, with a target to be able to work out a tire in one single action from a mould. That's the new step of this tire challenge. The Big Bear tire is still mainly conceptual, but I believe it should work but it is likely too big to work it as a test case. I need to work with a smaller tire first. I decided it would be the Shogun/Coors tires. I would need 8 of them, and they are the same for both cars. Their format is quite standard, and this model can be used i quite a bunch of cars I have due to the rim size. Well I could probably use Tamiya Manta Ray or Hotoshot tires, but that is far too easy approach. I love challenges, and that's the way I learn :-) So first step, I got my model reviewed to include lettering. I wanted to put the model on the side, it will be a nice touch if I succeed to produce those, no one will ever have the same tires on a Vintage event, unless I decide it to be this way :-) But since this tire is targeted to be used on both Coors and Shogun, I decided to put something else on the other side :-) Once this done, I started by doing a square extrusion from the center, and cut the tire body inside that square and started to look into the profile. I had a look at many videos, tutorial and readings over the last few days. They've started to flow in my brain, and it fuels lot of ideas :-D IWhat I had in mind this night was : - injection at bottom point - central mould part will be a 3 floors tower with a central key used to lock those floors. each floors will be 3 or 4 parts. And the middle floor will be used to lock the first and third floor. and for unmolding, it will be used to unlock the mold. - external side would be in 5 or 6 parts : 3 or 4 for the tire thread, on on a bottom, one the top. bottom and top will be locking the center key. and bottom will have injection ports. and top part will have to include air vents and provision for air channels (I may have to add another part for this) NB: I did not even considered the foam tires of the Coors for this exercice. I'll tackle that later, but that will be far too easy for what I need now

As I found some tricks for the Big Bear tires, I modified my Ninja tires... What to should I do with this? That's the question :-)

After some feedbacks and further checks on the pictures, I decided to review the model slightly to make the chevron profiles different... I also included some lettering (a plan under the surface, a text, an extrusion, shaved with a revolve at an offset of .5mm of the surface of the tire). I added colours in order to make it more realistic When discussing yesterday with a member of another forum, he reminded me about the support issues I had the only time I tested flexible filament on my own printer: they are a mess to remove, which means it is definitely not going to be easy to print in flexible material using FDM. This turned in my mind the whole night. This morning decided to have a look at few options. First, I went to I.materialise.com to price the STL in MJF rubber like. Very simple : definitely too much. That won't work. Then I had a check to see if there was other providers doing similar Rubber like printing online, and it seems that only few printers actually print flexible material. Ultimately, this tire maybe printable with dual head printer and soluble support materials... Not the usual printer most of the people do. Maybe printing two halves, integrating the sleeves to act as support could work. I may have to create STL for this... Next element I thought about is a mould. I decided to do an attempt to create stls for a mould. Printing moulds should not be an issue, and won't require any supports in the important side. Which also means proper finish... I used the tire model as cut in a mould, and made few parts for this. The mould would be composed of two parts for each halves. An external side, with the chevron, and the lettering and the tire side An internal side Each halves would be moulded separately, and the center part would be removed before assembly of the two halves. I believe the external mould would help into this assembly, and I created some elements to make sure the two halves would be oriented properly (one of fixations attachement is bigger to make sure it is proper). Printing those parts should be easy. a release agent would likely allow for multiple tires from the same mould parts... I received some feedbacks from a friend with moulding experience and I'll review the moulds slightly, but the general idea is there.... (and while I may not try to print Big Bear myself as I have none, I may want to try to print or mould some buggy tires, and I may try that on some of the other tires I modeled recently)...

Few parts I luckily catched at incredibly low prices arrived yesterday, mainly for the Ninja/Coors/Shogun project... First a lot of parts in which is there is some gears and diff for the Ninja/Coors/Shogun, some Samurai parts, and some Marui 2WD parts (i'll get on those later on :-) )... Then a Ninja body set, found on ebay early this week, for less than the price of a TBG reproduction body... I did not even thought twice before clicking buy... I was missing stickers for the Ninja. This means I'll have a shelf body and a runner body. For the runner body, i'll build masks from a scan of the original stickers... I have a a Super Wheelie waiting for me with a friend in an unknown state. I'll get it probably in the second half of August. In the meantime I have found a set of wheels And the parts coming into this lot I received maybe very useful for this Super Wheelie. But there is some details about Marui history that are called back by some of those parts... Both set are also for the famous MT60-RC09 Mitsubishi kit which appeared in Marui's 1986 catalog and which was never released. I have parts for a car which never existed :-)

That was the plan :-). (you may not have followed, but I'm no longer a beginner in the matter :-)

Each problem at a time That said, there is various possibilities I can think of - 3D printing first : TPU with FDM printer (filament), TPU with MJF printing process (online services), TPU Foaming Varioshore (filament), Rubber Resin with a SLA Printer - use the model to create a mould, used to for molded injection process I can explore the 3D printing side. For the second one, I'll contact some people to see if it is a possibility... Wanted to be sure I can derive the other side from the first one, and it works. Now the next step is really to focus on the way to get the right profile. And eventually to get the BIG BEAR markings on the side

The Big Bear chevrons made turns in my mind during last night. This morning I woke up with few ideas I had to explore. I went to the office, and during my day of work a few other ideas poped up. I got back to RC stuff around 23:20, it's about midnight, and I may have a good idea on how to proceed with my tries of tonight... I just have to refine the wave and some bits, and obviously add the other side, but I think I got the way to proceed now... Will refine this tomorrow :-)

It is possible to print in TPU using MJF process (online printing services), rubber resin using a SLA printer, or using TPU foaming varioshore filament... At this stage I'm trying to do decent STL file (don't even have a Big Bear at the moment, but found this to be quite fun to find new tricks in Fusion360)...

Yesterday morning, a friend told me he was said some people would love to see Big Bear tires on Thingiverse... Among my contacts, I have 2 friends wih Big Bear I can chat with when this was landing in my chat, and I contacted them... First one was not having the tires, as his Big Bear runs on Lunchbox tires... Second one, in Norway has the Big Bear, and the original tires which are mounted on it... I asked him if he can draw the wheels and tires profiles and provide measurements, and explained what I had in mind. He told me he would do that in the afternoon, and later on I received pics (quite a good number, of all faces and profiles, plus drawings and measurements)... I drawed a profile, made a revolve and started to decipher how I could do the chevrons.... Made multiple tries, not yet happy, as it still require work... But it starts to look alike... Still some work, to get something closer, but the general idea is there...

I worked out a mould from the body shell. it's not perfect, but it is approaching from the bodyshell. I send both Fusion file and the pictures to get the feedback on this. Maybe this could work... Let's see what @yogi-bear will say

I checked on the chassis and the servo I had in the car. I did not have a chance to drive it before tear it down, but I remember the front wheel were not lined up properly. I had a look at the standard servo and the way it should be to have the head centered: in the case it is centered, it does collide (slightly) with the bottom chassis. I could gain slightly by reviewing the profile of the sides of the chassis, but it would still collide a bit, requiring at minima to file something (either the chassis or the servo holes extension)... I'll review the side profile, the top deck and will call it done :).

Today, after my work day, I took the Shogun chassis to check the status and content. One hour to tear it down to parts. It goes quite fast. It is definitely faster than when you tear a Samurai down to parts Status : - the sway bar is missing (but I knew that when I bought this car) - rear gearbox is complete, but having small bevel gears in Nylon instead of metal (they were in Nylon on the Ninja) : I have metal small bevel gears somewhere for a while, as I suspected it could be the case. - the right side of the gearbox is coming from a Ninja (black instead of grey) and at least two of the holes are bad. The holes may be an issue easy to repair, but it's black. The plan is to rely on OptimaHouse rear gearbox instead of this one, and I got it printed by Ryo in grey polyamide. It's lighter grey than the original one, but I intend to dye it in the proper shade of grey. - the rear shocks are not Marui shocks, but Tamiya Super Hotshots rear shocks. Fortunately, I have a set of NIP Marui yellow shocks. - there is a few metal sleeve which have been replaced by copper, but I have what is needed to replace them. - the central shaft is missing on one of the three cars, I would assume it is this one at this stage. - the front gearbox is missing the bevel gear going to the central shaft. Fortunately, I have one already. This car being the one in the worst state from the three Ninja, Coors and Shogun, I would say it is not to bad... And it's not that dirty, I guess the cleaning would not take much time (and there is not much metal parts neither, as all was entering in the two small buckets you can see on my work plate.