Bormac's Nichimo Midships 443 WDS - An unexpected project

[XLR8]

After that, I had to take care of the tire. I'm still thinking about TPU for printing tire, and I saw some videos with some rubber resin printed tires, and the result seems very good... I keep that in mind for later, but in the meantime, applied a profile, a revolve...

Was this video one of them by chance? I caught this video just this morning.



Of course we don't know how well they will perform on various surfaces but it looks promising nonetheless.

[silvertriple]

After that, I had to take care of the tire. I'm still thinking about TPU for printing tire, and I saw some videos with some rubber resin printed tires, and the result seems very good... I keep that in mind for later, but in the meantime, applied a profile, a revolve...

Was this video one of them by chance? I caught this video just this morning.



Of course we don't know how well they will perform on various surfaces but it looks promising nonetheless.

Yes, that was exactly that video plus some others on the same topic. I found this to be a potential solutions for some car with tires really difficult to find... And with a SLA printer, the precision is really higher, and I believe it could be possible to print tires with lettering as well...

[Dadio]

I've not used that resin but have used Siraya Tech Tenacious , it's flexibility is similar , for the shelf it would be excellent and light running on loose surfaces (dirt) it would work but it has none of the natural grippiness of rubber so on road it would not perform well , I've also noticed that despite it's flexibility if it's held flexed or under lightly tightened screws it splits over a relatively short time like over two or three days .

[silvertriple]

Yesterday, I started to work on the roll cage. While on the Spirit FF it was symmetrical, it is not the case here...

The approach I took was to set the symmetrical things first, then apply a mirror and finish each side more or less independantly.

For the symmetrical part, I started to set the seats points as bodies.
Then I created a sketch going thru each of them, with the target of setting a pipe between the different bodies. There was a bit of work to make everything right, but at the end I had it.


The I applied the component mirror to get that on the left side.

Once done, I started the right part. One could have thought about a 3D sketch, but it is not the approach I took. I started by creating the seating point on the chassis side, then the pipes parallel to the chassis plane, it was quite easy to define as the lines are either parallel to the ground, either parallel to lines already defined for the bodyshell. Once that part was done, it was definitely easy to set axis from each of the end, and used those to set plans to get the inclined parts.


I proceeded the same way for the left side, at one exception : I did hava already the plans in place for the last steps as I had them set from the right part.


Next I took care of the braces. While doing this I noticed a discrepancy of .40 millimeter on all the braces. The space available in between the two roll cage side is too big of less than half millimeter. I rechecked my chassis measurements, and they are fine: the designer probably relied on the flexibility of the plastic...


Wing support and additional front part were added last night...

This morning, I built a wing... I'm not going to detail the build, but once you understand how to work with multiple bodies, it is fast.


The wing was promptly added to the car...


And I applied a quick paintjob...



I will add a driver figure at some point, just because it needs it to be called finished. I will start to proceed to print dimensional tests within the next few days...

But first, I need to model the Exceed roll cage and wing...

[Dadio]

Its a much more elegant design than the other Nichimo cars , great job !

[silvertriple]

Its a much more elegant design than the other Nichimo cars , great job !

The thing I can't explain is that I started to develop some love for the ugly duckies Spirit and Exceed

[Dadio]

Hey probably my favourite car is the Yokomo yz-834b , hard to describe it as pretty more brutish and boxy .

[silvertriple]

This morning, I started by using the slicer to prepare a set of test print and launched a print of the motor plate. The first test I did last week was non conclusive as the PLA was probably affected by storage issue. I had the dryer running all afternoon yesterday before I run some night prints, and that should be better today.

While doing that I started to model the Roll cage of the Exceed.


This exercice confirms the requirement for test print of the top chassis: At the end of the Midships roll cage, I noticed a discrepancy of .4 mm (39 in real, versus 39.4 in virtual) between the brace length and what I need on the model.
While working on the Exceed cage, the brace are this time too long (36mm in real while 35mm in virtual). Something is definitely wrong there
I think I know what is the culprit, but will have to confirm this by the chassis test print.

Anyway, once my roll cage sides were modeled, the print of the motor plate was finished. I launched another print (Front Gearbox - 9 hours) and started to test my motor plate.
First with the front part allowing to fix the motor...


Everything is good, next is to see with the motor plate, the real one.
I used screws and introduced them in holes.


There is a non critical element incorrect - the center hole for the motor has the side on the transmission too short of .5 millimeter. The rest is fine. Not really an issue as this measure is not used anywhere else.

In the afternoon, I did nothing related to rc while the front gearbox was printing. It was finally printed about 20 minutes before the late dinner, and I took the time before the dinner to test it. I made multiple checks


First, the overall shape is perfect, and the centering points are perfects as well. The front part allowing the fixation of the motor is also lining up perfectly (that was the only element I took from the motor plate).
I did 2 mistakes : gearbox fixation to chassis is half millimeter behind what it should. And the top closing hole is half millimeter too high. All others elements are perfectly lined up.

I will continue to proceed into the test with the rear gearbox. I mainly need to validate the fixations points, are other elements are non critical (as long as the one printing the gearbox would print both side rather than just one). I launch the print before going to sleep tonight. Next in the pile will be the chassis and depending of the result the top chassis...

[silvertriple]

I did not took pictures during the test of the rear gearbox. I spoted instantaneously 2 big mistakes and one smaller:
- the top of the gearbox was off of 1.5 millimeter, which explain partly my rear input rod issue colliding the top chassis
- the rear extension that aims to fix the roll cage was off because I measure the tangent and applied the circle center there (it was likely too late when I did that last sketch).
- another half millimeter with the gearbox fixation points (too high).

All were corrected, as well as the other mistake identified during the previous tests before extracting a stl to print a chassis. It's on going and will take about 24 hours print (it's 9 hours this is ongoing).

With the corrections, done, I had multiple checks here and there to get other things corrected : it's easier to spot a mistake when you have a data point saying you this is wrong (and the roll cage was showing some issue).
I checked the top chassis and corrected the hole position. Symmetry and half millimeter wrong means 1 millimeter wrong at the end. The result is that now the roll cage of the Exceed seats perfectly on both top chassis. The roll cage of the Midships rely on its flexibility to join the braces. Not sure why they do it this way, maybe they found out having it under tension makes it less prone to break at the first roll over...

I finished the roll cage parts of the Exceed


And since I had already the wheels (they are the same as the Spirit FF ones), I just added them.


I still have a wing to model, and for the bodyshell, a gentleman send me some picture, but it maybe too difficult (I may have to get a TBG bodyshell to model it - it's not as critical as the plastic parts or the Midships bodyshell anyway)...

Still few parts to validate :
- top chassis,
- arms

Still some areas of work :
- center diff to make it printable
- define a possible lock for the center diff (I had some demand for this)

[silvertriple]

It is still printing... So I did move forward on what was lest on the table possible to model... The Wing and the roof.


Other parts I had already (resistor cover and its support). Now, I need to find an Exceed body shell, even in bad state for next step...

In the meantime, I decided to retry to put both cars in the same file. There was an update of Fusion 360, I noticed that as I needed to reset the rights for accessing folders on my computer, and before that each time I tried, it did not work and I got a massive crash. Both cars file are read only now. I created a new file where I put a link to both the Midships and Pegasus Exceed...

And tada






You may have already noticed I like to work on vintage cars by chassis series (Hunter and Galaxies grouped together, Ninja Coors and Shogun). Having the 2 cars CAD models in the same pictures is just a great achievement and nice reward... But now, I really really really need to find an Exceed body shell

[Dadio]

I hate that feeling when Fusion starts to take long pauses and the menu goes black , never knowing if your going to loose what you've just drawn up .
24 hour prints leave me nervous as well

[silvertriple]

I hate that feeling when Fusion starts to take long pauses and the menu goes black , never knowing if your going to loose what you've just drawn up .
24 hour prints leave me nervous as well

I had a few crashes with the Nichimo... I was surprised the 2 cars in the same file did actually work... I may try to add the Spirit in a copy of that file for the fun

And yes, 24 hour prints leave me nervous as well... All the more so as the end filament sensor is loose, and that it's a long time we did not have a power cut, even small (and my printer worked continuously for the last 48 hours with multiple prints, without a single issue (i'm nervous, now, thanks )

[silvertriple]

Short update, no pictures.
Long print when fine.
I had a doubt on the length, it was confirmed. The cause was a cumulation of 3 mistakes, and one of them was a 1.5mm mistake in one of the non printed parts of the Spirit FF (NB: Carbon Fiber battery door), the other was the fact I did model with the right length, but the top part of the chassis was not taking into consideration the angle of the gearbox attachement.
I spent my evenning to correct the chassis parts, and will review the roll cage tonight. I'll have to do the same for the Exceed...
I've relaunched a print of the chassis, as I want to be sure of my work when sending the Midships and parts to Jason...

[Dadio]

A thing I've started doing recently that's really helped me with measurements is to do the math in Fusion , if you need a 2.5mm hole with its circumference 5mm from an edge you can do the little bit of math 2.5÷2+5= in the measurement window so instead of doing the math elsewhere and drawing a line 6.25 mm long , instead if putting 6.25 in the window you type 2.5÷2+5 and it makes the line that length , when I've been at it for hours little errors in my basic math can creep in but this way works for me .

[silvertriple]

A thing I've started doing recently that's really helped me with measurements is to do the math in Fusion , if you need a 2.5mm hole with its circumference 5mm from an edge you can do the little bit of math 2.5÷2+5= in the measurement window so instead of doing the math elsewhere and drawing a line 6.25 mm long , instead if putting 6.25 in the window you type 2.5÷2+5 and it makes the line that length , when I've been at it for hours little errors in my basic math can creep in but this way works for me .

I was doing that as well... But one thing I find even more efficient in this case is to draw a draft line at 2.5mm from the edge, set a circle of 2.5mm and apply a tangent constraint: this is direct read from the way you did the measure, and easier to debug if you need to come back later on that. Here the biggest mistake was basically done during the Nichimo Spirit definition, while I was not doing any of those tricks...