A new project - Nichimo Spirit FF - The first of a kind

[silvertriple]

I wonder if the odd inverted spur gear is a legacy of re-using some of the 4wd front transmission gears designed for shaft drive from the rear ?

I don't think so: the Exceed 4WDS and its sibling the Midships 4WDS don't use it as per my understanding, although the motor had a central placement... I tend to think they just tried to keep the motor as center as possible in order to have a weight partition close to lateral center (or anything else, I'm not in the mind of the Japanese engineer who got this idea ). At the end, it's part of all those oddities that makes this car a truly unique design...

[silvertriple]

While working on the Samurai wheels, I learned a lot, and I should be able to start work in Fusion 360 for this project.

I laid down the chassis on my desk to have a more attentive look at it having teh Fusion 360 background to set my design strategy.


First I decided to keep the chassis this way at this stage. I don't want to damage it more than it is before I started the measurements. Acetone or CA solvent are out of the picture due to the risk for the chassis material, I'm considering boiling water could be a solution. That being said, I won't try this until I have moved forward on the design. I believe it is lest risky.

There is some symmetry, and some easy measurements, and there is parts where it's not exact symmetry which I will need to work out. I'm considering starting by the chassis rather than the gearbox (as the gearbox is probably the only assembly part in this buggy which does not require any rework ). I'm intending to start this next, as I do not want to start a kit right now, and I'm waiting for parts for the Samurais...

[caesar]

Great project, I've got one on my list of to do's but It's been sitting on the shelf for many years with no love. I absolutely love the Boxart, one of my favorites, it's a pity the real thing doesn't look as good. First time I took mine out for a drive it fell in half..lol.

Cheers
Rob

[silvertriple]

Well, that's the real start of this adventure...

[silvertriple]

It is going to be step by step... And I'm still not fully Fusion 360 fluent like some others here...


Here is what I have now. It takes quite a time...

[silvertriple]

As mentioned in my Marui Samurai thread, the pictures from the previous post generated some discussion with @optimaforever who highlighted the shortcomings of my silly approach to model the chassis.

I decided to restart the work from scratch using a different approach. The idea being to build a body with the different masses present in the chassis and then use shell function in confusion360 to get it unfilled.

After some time, and it goes surprisingly quicker, this is what I get:


Although this is not finished, as I have few details still to do to get the bottom right, I could not help but test shell function with the chassis next to my screen...


Enough for tonight, I need to sleep

[Dadio]

The trick is knowing when to put all the fillets in as it's a pain to change the design without backtracking ,looking good .

[silvertriple]

Small progress this morning, as I had other ongoing stuff to shuffle...
Got back in the CAD late in the morning. Few tries were required to get the bottom right, and I'm using shell to check my stuff is right


It seems to go in the right direction. Need to decide what is next on the design path...

[silvertriple]

The trick is knowing when to put all the fillets in as it's a pain to change the design without backtracking ,looking good .

Well, one thing I learned with my exchanges with Ryo is that you can play with the timeline in the project... Applying fillets and chamfer after setting the overall design should not really be an issue. I did experiment a bit for my wheels, I'm not really much concerned about those details... That being said, you should just make sure when applying fillets after fact that you don't do that in a sketch other wise you would affect its dependencies...

[silvertriple]

Doing a 3D model from an existing stuff is always going to bring some questions about why the one who did it make it this way...

I've started doing the sides of the chassis, where the battery supports are attached. There is some symmetry, but not only...

Here is the symmetry I made for the time being...


The chassis is not exactly symmetric. The right side is having some complication...


The manual is not really conclusive about this, as it is represented with a symmetry...


The top half chassis part is made symmetric, and it is not conclusive as well


Assumption: it was required to provide some place to the cables... This again shows that the one who did design this went thru some iterative steps in the design...

[silvertriple]

Melted my brain for today

Here is where I am... It definitely goes faster than what I thought initially.


I reviewed a lot of measurements within the day, and crosschecked also compared to the top half chassis... Part of what I have to do next is to position holes... Once the key elements are there it will be time to do a test print in order to assess how much I'm wrong compared to the parts around

But that will be for another day

[Dadio]

Once the key elements are there it will be time to do a test print in order to assess how much I'm wrong compared to the parts around

But that will be for another day

Measuring is a lot harder than people think I often sit and stare knowing the model is off but not knowing how ? Or I test print and there's a glaring issue I didn't see

[silvertriple]

Once the key elements are there it will be time to do a test print in order to assess how much I'm wrong compared to the parts around

But that will be for another day

Measuring is a lot harder than people think I often sit and stare knowing the model is off but not knowing how ? Or I test print and there's a glaring issue I didn't see

Well, the thing is when taking measures, you need to have the proper reference points... The chassis is not perfectly squared angle (that would not possible for molding/unmolding reasons). There is a half millimeter difference between the top and bottom of each side. For 3D printing, I'm modelling it squared. then the question is what is the proper reference for each fixation, and there is multiple measurements, on both the chassis and the part going on, and some decision... The problem is to keep coherence between all of this and confusion360 (I really like this one, @Dadio )

And then you find things that doesn't make sens at all. I hava not a single clue about why the right side of the chassis is not symmetric on the top deck side. I've took back the esc, positioned it, and it still doesn't make any sense... Why would you do something there without reasons. I've asked help to other owners for reference pictures with the electronics mounted on a Facebook Nichimo group... We'll see if we need to make it the same way it is or if it can be symmetric... And there is other points I don't get here and there at this stage. Am I dumb? Is there something I'm missing and the manual doesn't indicate? Please tell me that I'm not alone to ask myself this question while doing this type of stuff

[Dadio]

Your imagining the original designer was better than you or that the machinist that milled the molds could not make an error take the evening off , open a good bottle of wine and let it all wash over you till tomorrow

[silvertriple]

Well... It seems my chassis comes from a Vantage rather than a Spirit FF...

I think I'm getting there. I checked with the parts mounting on it, and I should not be far of having it right...


There is two holes on the bottom of the chassis I skipped as I could not find any use for them... I will test print before starting to reinforce it...

At the end, just being realist, I don't even expect it to be right from the start