Again another Marui project : Super Wheelie and Big Bear!

[silvertriple]

Initially, when I got my two 44B chassis, I was at my friend's place to get 2 cars I had a deal on since few months...

The first one is a Super Wheelie (7.2V, not the early version), with a Toytoa Land Cruiser body


The second one is a Big Bear, with Lunchbox wheels (unfortunately, I don't have the chance to get one with nice original tires).


I wanted those cars to model the chassis. And now that I have some ideas on how to proceed for the body shell, I may even do that.

I tore down the Super Wheelie this afternoon, as the project box I was using for the Ninja got free this morning.

The chassis is fairly simple. There is more parts on the bodyshell than on the chassis itself




At the end (it was definitely very quick to get it in parts), this is the content of my box...


The Big Bear should follow at some point as well...

[Dadio]

The dust of ages is calling

[silvertriple]

The dust of ages is calling

The Big bear is a bit cleaner... I'm going to tear down the Big Bear before starting CAD models... i've tried to remove part of the dust, and it will require an ultrasonic cleeaner, I believe, based on what I saw (never saw a chassis that dusty)...

[silvertriple]

The Big Bear spent some time on operation table...


It was even quicker than for the Super Wheelie.


All is now in the box. I've not tore down the bodyshell, this will be for later...

[silvertriple]

The chassis is quite simple compared to most of the chassis I dealt with earlier on.
2 sketches, few extrusions and a shell, and we get the front idea already in.


Then we have to do some cuts


After that, I added the rear battery support...


Next is to deal with all the fixation and features of this chassis...

[silvertriple]

And the work continued in the afternoon...

I first focus on the front end


Then worked out the rear end and the center


Looking at the measurement precisely, the conclusion is that both chassis I have are 6V versions, which means they are Super Wheelies. The Big Bear was always a 7.2V version... That being said, both gearbox are coming from 7.2V cars as they include a metal plate... In short, both cars are made from parts...


Here is the 6V chassis completed... (I will have to get the pictures of a 7.2V chassis and measurements to get the 7.2V chassis version).



While doing this, I noted down a chassis deformation on the right side, probably due to the reinforcement on the left side (probably defined this way to protect the gearbox)... Definitely room for improvements...

[silvertriple]

Few minutes later... I rechecked the pics and the second chassis is indeed a 7.2V... Fortunately, it is also in the box.

And the chassis is modeled in 7.2V version as well.



NB : antennae support added as well on 6V version.

[silvertriple]

As the main gathering for Xmas in my familly is today for the lunch, we had a bit of preparation, but it left me some time to work on some parts modelling...

I started by the Big Bear front arms...


The part design is a little bit cumbersome, but it's easy to get it right once you understand how it is made (observation matters, as usual). I'll have to print a section to check, but I'm almost sure it won't require any modifications... I completed with hardware and joints, and the mirror parts.


Then I switch to the front arms of the Super Wheelie... It's definitely easier to get than the Big bear arm...


The design of the knuckle is similar to the big bear, with a few changes in measurements...


I don't know what I will do next: the gearboxes are still full of grease, and I'm a bit afraid to put them on the table, as my mother won't like this

[silvertriple]

As I had to do a detailed post on the chassis différences for another forum :

In practice, Hump packs 7.2V did not work with the 6V Super Wheelie (1983), because of the bodyshell which was not allowing room for the additional cell over the battery. This chassis was revised in 1984 for the Big Bear, and the revision was later applied in 1985 for the second iteration of the Super Wheelies...

Here is the pics of the 2 chassis together :




On the Big Bear and Super Wheelie reedited, the battery room has been extended on the side, with a different position for the wire cut-outs as well. There was also additional holes prepared (presented drilled on the shemas) to fix the steering servo (on the first super wheelies, it was fixed with double face tape)...

[Dadio]

Do both bodies fit both chassis or does the extra width in the chassis of the Big Bear stop the Super Wheelie body fitting ?

[silvertriple]

Do both bodies fit both chassis or does the extra width in the chassis of the Big Bear stop the Super Wheelie body fitting ?

I'm sure Super Wheelie 7.2V (1985 and after) and Big Bear bodies fit the V2 chassis. I will have to check more precisely for the Super Wheelie 6V bodies, but I believe they were not modified, and they should fit both chassis.

[silvertriple]

In the evening, I took the gearbox parts on the desk. I'll take care of the gears later on, but for the time being, i'm only taking care of the gearbox case...

With the 7.2V, Marui introduced a metal plate of .5mm taken in sandwich between both side of the gearbox. I've started by this part. I question myself about using Canvas mode and and I did not use it as the design is quite simple. I may use a canvas at some point to check the design.


The I took car of the left side. The design is easily derived from the motor plate, so it's easy.


Next I took care of the right casing, which is slightly more complex, because it will require to do some independant bodies and cut them before joining them to the gearbox casing...


At the end, I have the gearbox...



Next I'll complete the gearbox with the rear arms so I have complete suspension, and I'll do this for the Super Wheelie first and then the Big Bear...

[silvertriple]

This morning, I decided to start working on the Super Wheelie rigid axle assembly. I'll tackle the Big Bear one later.

First, I completed the gearbox with the motor (no gears yet), and the motor cap. All those part are in the common Gearbox file.


Then I opened a new file, as it is time to create a Super Wheelie fork for the rigid axle assembly (Big Bear will have its own).

Before starting to make the arms, I tackled the wheelie bar (there is none on the Big Bear, I'll have to see later on). This part is weird, it seems it was designed while second thinking and not having the plans in mind. Logically, you would make all the profiles concentric, and it is not.


The other face is directly derived from the first one...


I quickly add the rollers on those


And then I simplified the parachute (I may come back later on this one).


And now it is time to tackle the arms. I started with the left one. The design again is quite simple and easy to read and reproduce, specially when you have the other parts around.




For the right arm, I took the left one, made a mirror, removed whatever was not needed and added the specificities, based on the motor cap holes projection...


And here is the main components of the rigid axle..



Next step : take care of the same elements for the Big Bear...

[silvertriple]

Today, I started working on the Big Bear rear arms... Again it is quite easy to read and to draw. I applied the same process as for the Super Wheelie : started by the left one, then took a mirror and changed what was required to make the right arm.



And then we have the Big Bear rigid axle assembly...




Once this was done, I opened a new file to deal with the Super Wheelie gearset...
I started by the diff main gear. 60T, module 0.6 (on the Big Bear V2, they changed and made the transmission on Module 0.

This was quite easy to deal with.

Next was to complete the diff with the bevel gears. All four are 20T (on Big Bear V2, there is 5, but that's for later), which means it is 45° cone.


Later I had my differential completed...



I then completed the transmission, but doing so, I decided to add some ball bearing casing in the left gearbox (in V2, they added one one the right side, behind the motor plate, but not on the left side).


And here is the elements I added in the gearbox and rigid axle...


Here is the gearbox without the left part (without and with the gearbox plate (added in 7.2V versions)...



And the left part with its content without the idle gear...


And the gearbox is complete...


I did further checks (in real, with all in place in the gearbox) : the diff is moving over 2 mm, and is going in contact with the motor plate. This is in line with the model as figured out on the section analysis : my model seems correct.


I would add some washer to avoid any issue : .8mm should be good.



What should I do next : Big Bear transmission or something else?

[silvertriple]

As a good friend of me allowed me to have my hands on a Big Bear V2 diff, I did model it.

Small bevel gear are 18T, there is 3 of them, big bevel gear are 27T. They are in mod .8.


First, I started by the easy thing (this is a circular pattern, nothing more complex here).


Then I started to work out the bevel gears


and a few sketch later...


And with axle (of a differnt diameter for the Big Bear)


Here in situation :


You may note that there is no motor pinion and idle gear yet : I have no clues what they are exactly, except the mod .8. I will have to find out, but I have no gears for this.
Based on the fact the Diff has similar diameter than the 60T mod .6, the smalle gear should be 10T mod .8 to be in correspondance with the 11T Mod .6 of the original idle gear...
The rest is however unclear, and I may have to wait my friend to get back in his big bear transmission to get a view of the reinforced transmission remaining...

In the meantime, I have my axle and diff enclosed in the rigid axle.