[WIP] High performance car

[Rudivdk]

It's been a loooong time since I updated on this project, but I haven't been sitting idle...

Current overall build status:

Current features (build, tested and working):

- Pushrod suspension front and rear with advanced geometry

- Steering front wheels (not yet connected to steering wheel)

- Rear wheel drive

- Fake v8 engine in the front

- 8-speed sequential gearbox (modified version of @Charbel's 8-speed sequential gearbox design), operated by single lever between the front seats (based on sequential shifter design by @Didumos69)

- Openable doors, bonnet and trunk

The gearbox was the biggest challenge, at least at this scale. I took Charbels gearbox as a base, but I felt it was to bulky to fit properly in the available interior space. So I ended up modifying the gears layout so all the gears are in a single level. This meant widening the gearbox 2x to have all gears still working, but at least I was able to build it in low enough to fit the seats above it. Below some more details of the gearbox lay-out (I will try to also shoot a video of it, I hope to get some time for that this weekend):

From above:

The ball piece in the front is the shifter. It is connected by lever (under the center console panels) towards the rear where the actual stepper mechanism is. In the back center there is the stepper mechanism (around and under the black knob wheel which you can just see on the upper edge of the photo) for the main 4-speed gearbox. On the rear left side the stepper mechanism (second black knob wheel and red 3l liftarms) to shift the additional 2-speed gearbox after the main gearbox has shifted through all 4 gears. On the left side running towards the front the axle that transfers the additional gearbox stepper movement to the actual gearbox (which is below the main shifter). After the additional gearbox has shifted, the main gearbox can shift another round of 4 gears, making it a total of 8 speeds. Additional rotations below or above the 8 speeds is prevented by a limiter. Because of the size of this total setup, I had to omit neutral and reverse...

From below:

Towards the rear (right hand side on photo) the main 4-speed gearbox with transfer to rear axle differential. In the middle (12+20 tooth bevel gears) the transfer from the main gearbox to the additional 2-speed gearbox. In the front (left hand side on photo) the 2-speed gearbox with transfer to fake engine.

Because it is a very wide gear setup, I had some serious headaches to get the chassis stiff enough, but I managed to get something sturdy in the end after several tweaks and tries.

The bodywork is actually a bit bulky and rough in some areas, but it is that way for a reason: As I stated already in my OP, I wanted to create a bodywork that is also possible to build in Dark Azure. So I had to limit myself to pieces only available in that color (and in orange) when designing. I have created a digital version of the Dark Azure bodywork, with red and white as contrast colors (real life build and digital version are not completely up-to-date with each other, so there are some differences here and there):

Edited February 15, 2019 by Rudivdk

[Jeroen Ottens]

I was wondering when we would see an update of this one . Managing to put an 8 speed in at this scale is quite impressive. How big is this one compared to the 42077?

I do like the dark azure much better than the orange TBH. Without the roof and with the angle of the shot the orange one looks more like a bathtub on wheels , but I'm sure that will improve once it gets more body to it.

I am not so sure about the two big 5x7 panels at the rear. Those open holes that show at the sides do look unfinished... I am also not sold on the 3x13 panels above the wheels. I understand why you want to use them there, but they do not flow very nicely with the rest of the panels because of those ridges in the surface (albeit that in real life these ridges are less pronounced than in those CAD images)

[Lox Lego]

wow... wonderful styling and color. Its really starting to take shape! The rear end looks well crafted... Look forward to seeing this one complete :) 

[Paul B Technic]

Wow, this is great. I am not normally a "car guy" but this is awesome.

[Rudivdk]

Thanx for all positive comments guys, really keeps me going! At times I thought to abandon this after chassis was built, just because I felt bodywork was not good enough... now I want to finish it!

I will see what is available from system parts to further "dress it up". The lack of connectors of any kind in Dark Azure is really a pain in the....

[Didumos69]

Great progress and intriguing gear box! I also prefer the dark azure / red/ white combo. In my perception the separation lines between the colors add a lot to the overall appearance and draws the attention away from the somewhat bulky shaping here and there. The clear separation between a red bed and a black cabin in my rugged super car had the same effect.

One question. Does the shifter have a return-to-center feature? If so, I would really like to know how you solved that.

Edited March 8, 2018 by Didumos69

[Rudivdk]

13 hours ago, Jeroen Ottens said:

How big is this one compared to the 42077?

Not sure how big 42077 is, but my build is 59x27x17 studs according to LDCad.

 

2 hours ago, Didumos69 said:

One question. Does the shifter have a return-to-center feature? If so, I would really like to know how you solved that.

Not yet. I did try some, but it was ineffective. I fear that it will add to much stress/friction to the already sensitive system, but I will see what I can do. I do have some ideas for that.

[Trekkie99]

Oh wow! That is sick! Love the design.  

[1gor]

Honestly it looks bulky and I do not know if there was some (in serial production) rwd hatch with V8 

...but some solutions like transmission and suspension are interesting 

[Rudivdk]

3 hours ago, I_Igor said:

Honestly it looks bulky and I do not know if there was some (in serial production) rwd hatch with V8 

Yep it sure does... This was my first and last attempt building in a color with limited parts available. I can't count the times I thought: if I only had this part in Dark Azure... its frustrating...

Actually since I had to omit rear seats, I guess this should go under '2door coupe' category, something like a Mercedes AMG.

3 hours ago, I_Igor said:

...but some solutions like transmission and suspension are interesting 

Thanx, that was my main goal in this build

Edited March 8, 2018 by Rudivdk

[1gor]

I understand

[sm1995]

On 3/8/2018 at 12:39 PM, Rudivdk said:

Yep it sure does... This was my first and last attempt building in a color with limited parts available. I can't count the times I thought: if I only had this part in Dark Azure... its frustrating...

Actually since I had to omit rear seats, I guess this should go under '2door coupe' category, something like a Mercedes AMG.

Thanx, that was my main goal in this build

Love the dark Azure version. It's rare to see a hatchback so this is breath of fresh air 

This is just suggestion, but it would be cool if you could do a Pikes peak build with this. Move the engine to the back, space out the wheels and add some crazy splitters and spoilers. 

[Rudivdk]

No progress on the build, but here is some more detailed info on the gearbox. 

All gears are on a single level, with the 2speed additional gearbox in front of the 4speed main gearbox. Below pic shows 1st gear position:

On top of that are the stepper mechanisms for both gearboxes, and the linkage to the shifter knob:

And finally a video showing it in action, shifting through all speeds from 1 to 8 back to 1 again:

Shifting from 4th to 5th gear, and even more so back from 5th gear to 4th gear is requiring some force, due to the double steppers being activated. I think I can smoothen it by adding some more strength in the chassis, as it now deforms a little under the forces, adding to the friction.

And worse, it can only be set in motion by driving it from the rear wheels. Driving it from the engine with a motor just gives to much friction to even get the gearbox moving... Hopefully strengthening the chassis will give some relief here as well, however I doubt it will be enough...

But still, as a Proof  of Concept, it is succesfull!

[brunojj1]

Your bodywork sketch looks very promising and I´m curious about the outcome, considering the fact you don´t use any angled connectors which for myself I can´t immagine ever to do.

And what an amazing progress on the gearbox, love it !

[Didumos69]

What a familiar sound ! Great job! Does it run smooth in all gears?

[Charbel]

Very nice gearbox design and very promising bodywork 

[Rudivdk]

Thanx guys! I think I am at the limit of what is possible with the available panels and beams in Dark Azure. Trying to get all bodywork securely attached to the chassis is the biggest challenge in this build, because I have to make all connections invisible from the outside to keep the colors flowing nicely. Will be a nice puzzle for the coming weeks.

15 hours ago, Didumos69 said:

What a familiar sound ! Great job! Does it run smooth in all gears?

 

11 hours ago, Charbel said:

Very nice gearbox design and very promising bodywork 

It was your designs that got this started to begin with, so big thanx to you guys!

Unfortunately it does not run smooth yet, especially the final transfer to the engine is jerky in most gears and seems to have a lot of friction. Will see if I can redesign that part, maybe shorten the engine into a V6 to give some more room for proper bracing and cleaner routing of geartransfers. It's a bit messy over there at the moment. And I am still working on improving structural integrity of the chassis to reduce warping (and thus friction) in general.

Edited March 14, 2018 by Rudivdk
Typo...

[Rudivdk]

Small update: after working some more on chassis and exterior, I had to redesign the 90 degree stepper for the additional gearbox. This proved to be the fix for the 4th to 5th gear shifting issue! It works flawlessly now with hardly any additional force required compared to other gears:

I've also created a 1st version for the seats:

Edited March 15, 2018 by Rudivdk
Fixed the images

[JLiu15]

Interesting project! Looks like a rally car style of vehicle.

Are you planning on keeping the stickers on there or removing them? I think it would look better with them removed, as I feel that they kinda distract the looks of the vehicle.

Edited March 16, 2018 by JLiu15

[Rudivdk]

@JLiu15Actually I aim for building the completed model in Dark Azure, the orange is just a testcolor for fitting all bodywork.  But I might decide to build an orange version in the end as well, without stickers.

[JLiu15]

2 hours ago, Rudivdk said:

@JLiu15Actually I aim for building the completed model in Dark Azure, the orange is just a testcolor for fitting all bodywork.  But I might decide to build an orange version in the end as well, without stickers.

I’d love to see it in dark azure! It’s one of those “emerging” colors in technic rn and I have not seen many MOCs yet in dark azure.

[ArsMan064]

Hmm, interesting project! Looks very good

[Rudivdk]

So it's been over two months, but here's an update to this build. Haven't had much time for building, but managed to get some things done nontheless. 

I built a second chassis next to the orange version, including all the tweaks I did in LDCad. Started with the red and blue livery (scavenging the parts from 42070):

After seeing @Pvdb's double shifter solution on his gearbox in the Ultimatum GTR v10 supercar MOC, I knew I had to implement that myself as well. So I made v2 of my gearbox:

Apart from working smoother compared to v1, the stepper mechanisms are much smaller (sitting lower) now and better divided over left and right side. This gave me the opportunity to increase the interior space and even include two small backseats with center armrest (still WIP):

And last but not least I shortened the engine into a V6, giving me more room to properly connect the gearbox to the engine. I started working on LDCad to flesh out the engine a bit more, and came up with this V6 biturbo+intercooler design:

So tell me what you think so far.

 

A little side note, here are some comparison pics of the orange version alongside 42077, to answer @Jeroen Ottens's question. On average they are quite comparable in size (wheelbase/trackwidth are almost exactly equal), although 42077 has a shorter rear overhang, a much narrower passenger compartment and about 4 studs less height:

Guess I don't need to explain where the dark azure parts are going to end up soon...

[LvdH]

I love that engine detail! I am not particularly a fan of the gears that shift the 2 speed gearbox (or high low range shifter). I really dislike having to allign gears so specifically to get a function to work. Still, it's looking like a great gearbox. 

I think I have said this before but the bodywork does look great! The front has a bit of an Audi feel to it. 

[Rudivdk]

On 25-5-2018 at 12:13 AM, LvdH said:

I love that engine detail! I am not particularly a fan of the gears that shift the 2 speed gearbox (or high low range shifter). I really dislike having to allign gears so specifically to get a function to work. Still, it's looking like a great gearbox. 

I think I have said this before but the bodywork does look great! The front has a bit of an Audi feel to it. 

Thanx, I'm pretty happy with the engine myself as well.

As for the gearbox, I get what you're saying, but it was the only way to make it fit in the confined space available. Control links would have taken to much interior space...

As a whole, I see the gearbox as one big proof of concept, and the rest is the packaging. I think an 8speed gearbox in the center console at this scale is just a bit too much...