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Hirobo Bearcat SS - Let's start something else... 3 weeks 2 days ago #71743

Still working on the front train...

King Pins are very easy to model...


Then comes the knuckles, and let's be clear, this is likely the most complex car to model on this car

The part holding the pivot ball is angled, but while the angle is easy to define (same as the chassis kick up, 20°), the work to put it in CAD involves multiple bodies to get it right.


I got up to 11 bodies for this small and unique part, to finish with just one at the end by combining all of them...


And it remains to add the axle component (which is an issue somehow, and a frequent one, apparently, as the axle is out of the knuckle for the right one. Fortunately, I found a cheap set of brand new knuckles in France and it arrived yesterday).


Last, I added the joints and get the front train components I add on my table when starting the arms parts

 
I buy kits to built and ru(i)n them :-)
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Hirobo Bearcat SS - Let's start something else... 3 weeks 1 day ago #71761

I opted to pursue the tasks with the gearbox...


One asked me why not starting by the pulley and differential... I have an issue with both : no way to remove outdiffs from the differential shafts, and no way to remove the shaft from the pulley. I'm not really sure what happens here : the grub screw have been removed, the pulley turns freely around the shaft, but no way to get it sliding off the shaft...


Any case, for the time being, I'm going to work on the gearbox parts...
I defined first one single sketch with my main dimensions


On this one, I won't use the shell command : it's super simple first, and secondly all the wall don't have the same thickness...

It was quite quick to get in (3 sketchs). There is a subtility, as you actually need to do the mirror before applying the last sketch to get the right side quicker...


Here is the reason : the wall end is subdivided in two parts to make the gearbox watertight...


I took the mirror I created before last step to work out the right side. There is a difference as the bearing cage is reinforced. Funny, the bearing was broken inside :)


And we have the gearbox case...
I buy kits to built and ru(i)n them :-)
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Hirobo Bearcat SS - Let's start something else... 3 weeks 4 hours ago #71764

There is a bent in the motor plate, I believe it is not by design, so I'm modeling without the bent (nb : the motor was going down, because of this, and the chassis is bent as well, and it doesn't seem to be intended).

The design is very easy to read, so that's easy.


One extrusion later and that's it, I have the motor plate.


Next is the belt cover, from which I could check the measurements are right...


A few extrusion later, a shell, and some additional extrusion, and it's almost done.


There is a cut, but it's not as big as it would be required in theory: the mount rely on the plastic flexibility.


I did the cut so it does not rely on the plastic flexibility, as it could allow for other material printing (thinking of transparent resin, as there is no real constraints on this part).


Next I'll work on the chassis...
I buy kits to built and ru(i)n them :-)
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Hirobo Bearcat SS - Let's start something else... 2 weeks 6 days ago #71770

Yesterday, after the gearbox, I started to work on the chassis... In this case, I thought it was making more sense to build the base first and then to build the walls...

I defined the profile of the base, and used extrusion to set both the base and the bottom ribs for a start.


Then I defined the rear holes and gearbox supports... and the walls coming on top of the chassis.


I then went to sleep last night, and had some time to think within my day of work in the office. My plan was to build side bodies, and then to join them to work the side walls from that. They are angled, and it is clearly visible, so I'm not going to model it vertical this time.

I started to build the pillars on which the top deck seats.


Then I defined the profile of the side walls, with the intention to recut the pillars and to build the side walls (Before building those side walls, I had to do 180° revolves after the cut to make the proper form of the pillar on the external side of the wall
I

Then some symmetric extrusions to cut those walls with a sketch defined on the mid plane, and there it's time to combine the bodies...


And to complement the front end with the ribs...


Last step is about adding the bottom holes...


And we have a Bearcat bottom chassis...
I buy kits to built and ru(i)n them :-)
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Hirobo Bearcat SS - Let's start something else... 2 weeks 6 days ago #71771

😲😲😲😲

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Hirobo Bearcat SS - Let's start something else... 2 weeks 2 days ago #71787

After the chassis, I had to do the top deck. This is an important part, may be not the most exposed or broken on bearcat chassis, but it has one key advantage for me. The length is easy to measure first, and second due to the geometry, it will help to check the estimation done with the ruler for the front chassis dimensions...

Lets start :)
First a sketch for the main surface definition...


Then we do some extrusions.


The holes in the front are physically on the same plan axis that some of the holes on the bottom part. Let's do a sketch to see this...


I have now a god view of the mistake on the length. About 4mm. I need to find a better caliper, but have nothing long enough to do it at this stage, so this check was important, and even useful. I changed the overal dimension of the chassis. I may have to do minor adjustment here and there still, but at least, the front part is now going to be correct.

Those who know the Bearcat/ Bearcat SS/Tomcat may spot a mistake that I did there : the plan need to be offset for the revolve as the front superior fixation is not on top of the bottom fixation. That was corrected later on when dealing with the front sway bar attachement...


The most difficult thing on this part was actually the addition of the battery strap support. I did combine multiple bodies, and sometimes when doing this kind of thing you get some aberration with no reasons for it, and you have to work it out so the combine bodies function works.


Had a few additional extrusion not shown here underneath the top deck to correspond to the functionalities (even some I won't even use myself - reinforcement for MSC for example).

Then time for some rewarding work : joints !


But before, let's create a bumper... (easy to do :) )


Then added gearbox and suspension parts in...



And I just noticed doing that there is a missing black plastic part still missing on top of the rear train. I will add that one before moving to the roll cage part...
I buy kits to built and ru(i)n them :-)
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Hirobo Bearcat SS - Let's start something else... 1 week 6 days ago #71832

Old nylon, combined to storage, usage and measurement precision...




Result is that holes don't line up... did measurements again, and it is the same. That being said, the chassis is not perfectly flat. The motor plate neither...
Solution one : amend the measurement, so everything line up.
Solution two : take consideration to the fact that nylon is flexible, it won't matter, and keep it this way.

I choose solution one and amended the measurements by a quarter millimeter on the front, and the same on the rear. everything now lines up perfectly.


Any case, I won't have any certainty about what is right, and my experience with the Samurai shows that production variance may play a role as well in the measurement...

I then started to work out the roll cage.

First the nerf bars


Next is the center part (almost one sketch only)


Next is about the long parts I defined a plan between the axis of the holes at the rear end of the chassis and the holes of the center part, and draw the part...



I still have 5 parts to define and add to have the roll cage complete and next will be the bodyshell... But not tonight, as I need to sleep :-)
I buy kits to built and ru(i)n them :-)
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Hirobo Bearcat SS - Let's start something else... 1 week 5 days ago #71839

I pursued this morning with the small part between the central part and the nerf bar. For the first time, I used a 3D sketch.


Next was to focus on the braces. They are all identical, although the one installed in the wing mount position could have been done differently.


Once that was done, I took a break (and pursued my office work). During lunch break, I built the body shell.
It's basically a 6 extruded solids. 2 of them got some sweeps, chamfer and fillets applied. and Then I combined them, applied a shell and combined to the 4 other bodies.
and then added a bit of finition.


And here we are...


Next, I'll focus on the diff, pulleys and belts, and then other metal parts...
I buy kits to built and ru(i)n them :-)
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Hirobo Bearcat SS - Let's start something else... 1 week 1 hour ago #71909

After a break with some work on the track cars for the onroad vintage event in Macon next week-end, my on road cars are ready.


My son took my tools to work on his Tamiya TA02 Calibra, and I won't start any additional NIB this week...

The result is that I could resume work on CAD :-)

Finally succeed to tear down the diff to parts... I'll get back to this later on but not today, as it is along story (yes, there was issues, I think I have an idea on how to solve this, but take this as a teasing :-D)

Took the diff, and modelled the pulley case : it's were pulley profile is easier to model. It didn't took much time than to measure count, sketch, do extrusions, a circular pattern with the number or tooth (42), and moar extrusions, some additional bodies, another circular pattern (4), a revolve cut and a combine...


Once there, the other side is easy.... Done!


Pulley, although I didn't succeed (yet) to get it from the axle was easy to model (as soon as you have the recess size information, and the dims of the tooth, it's dead easy with a circular pattern)... Done, bit without the metallic core, as I took the assumption this one should be printable in one go...


Next is about the pinions and the diff internals. But that will be tomorrow or later :-)
I buy kits to built and ru(i)n them :-)
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