[TC18] Dart

[Rudivdk]

After a good few hours of building I have something presentable. I call it 'Dart'.

Bodywork inspired by the style of cars like Lotus 2/3-Eleven, BAC Mono and KTM X-Bow:

 

It features all wheel independent double wishbone suspension. 

Front suspension has pushrods, Front axle is steered via the steering wheel using a mechanism similar to the Corvette.

 

Rear axle has classic 'standing' spring layout. It also has a floating 'diff' (actually not a diff but just drive transfer cage).

I'm gonna rebuild the rear suspension, maybe try a pushrod setup as well to see how that behaves, and put a mini-engine on top. If that gets too bulky, I might omit the engine and go for an 'electric' car, maybe mock up an electric motor somewhere. I have to put some interior to it, and finish up the chassis and body on the right side and rear of the car. Still in doubt about rear wing or not, maybe I'll make a split wing (right side and left side, but nothing in the middle).

I will post some more details of the chassis when I make the final version, the current version is quite messy and very WIP when it comes to stiffness of the whole thing...

[Jeroen Ottens]

Very innovative use of the panels surrounding the cockpit area

[Jeroen Ottens]

Very innovative use of the panels surrounding the cockpit area

[Jurss]

Some kind of future car from 1970s :)

[zux]

Suspension setup used in the rear will, probably, be used on many entries in this competition.

[Rudivdk]

  On 3/31/2020 at 10:05 AM, Jeroen Ottens said:

Very innovative use of the panels surrounding the cockpit area

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Thanx, seems this scale opens up new possibilities for a number of parts. But I kinda stole the idea from @Charbel's wacky race car a few years back...

  On 3/31/2020 at 11:01 AM, Jurss said:

Some kind of future car from 1970s :)

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I was aiming for one of those extreme single-seaters, but your description is also cool

  On 3/31/2020 at 1:42 PM, zux said:

Suspension setup used in the rear will, probably, be used on many entries in this competition.

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Probably yes, options in this scale are very limited... I changed the arms to 4long, but the setup is almost the only possibility for independent with drive. And you can't even properly fit a diff...

At least the front is different and less standard. More pics of that later.

[msk6003]

Looks like hotwheels twin mill car. good.

[Rudivdk]

My kids have loads of hotwheels racers laying around the house, so unconsiously I might have been a bit influenced by that style....

[Rudivdk]

I think I´m done...

First some pics of the finished 'naked' chassis (all the pins and axles protruding everywhere are for bodywork attachment). It is really rigid (it's becoming a trademark I think...), and the interior+bodywork adds even more strength later on, especially in the middle section.

It features:

• Independent double wishbone suspension on all wheels
  • Front wheels with offset pushrod setup
  • Rear wheels with classic vertical spring setup
  • Rear axle has floating 'diff'
• Steering via steering wheel (no gears used!)
• Fake mini V6 engine in the back, directly driven from rear wheels

The build

The biggest challenge was the front suspension:

Since I wanted a low front end for the car, vertical springs was not an option. So horizontal with pushrods. But the springs are too long to be mounted side by side, and so I ended up with offset springs mounted alongside each other. I think this setup would only work at a model this small, on bigger, heavier models with harder springs a lot of bending forces will come in to play disrupting the functionality.

In the rear I just could not get a full diff between the wheels, so it's just a 90-degree drive transfer cage, mimicking a floating diff:

Rest of the setup is pretty straightforward, with 2 lower arms and 1 upper arm.

Here is all the interior and bodywork parts layed out. It comes together almost modular:

First I'll add the interior. It's a single seater vehicle, with low windscreen and big rollbar behind the driver. Of course some proper dashboard with 'instruments' is in front of the driver:

After all bodywork is attached, this is the final product:

I'm still thinking about adding a (partial) engine cover to make the engine blend in a little more. Right now it has a very high 'Hotwheels' feel to it...

[Rudivdk]

Added the engine cover, looks more balanced now IMHO:

[Zerobricks]

Looking very futuristic indeed! is there a way to place the engine lower?

[Rudivdk]

Not in this setup with the 3l axles as pistons. The crankshaft is as low as possible without colliding to the rear axle underneath. Only option is to use an engine design similar to @apachaihapachai's F355, which uses 2l as pistons. It would lower the top of the engine with 1l. I'll give it a try to see how it looks.

[Rudivdk]

The idea of not having a diff in my rear axle would not let me rest...

So I pondered, tried and finally I came up with this:

A 15-wide full independent suspension with drive through floating differential. I'm not sure but I think it's a first in Technic?

The black part is the enabler for this suspension since it fits inside the rim, thus giving the much needed 2studs extra width for the torque tube housing to hold the diff. But it is also the weak spot, as it wants to disengage from these  under sideways loads, and it does not need a lot of force to do so...

Still I think it is good enough to have a go with, so I'll try to incorporate this in my model instead of the current axle.

 

Edited April 2, 2020 by Rudivdk

[syclone]

Not a first, but a neat solution. Love the design, hopefully we'll get these wheelarches in other colours, probably would look good in light bley, lime or blue.

[johnnym]

  On 4/3/2020 at 12:58 PM, syclone said:

Not a first, but a neat solution. Love the design, hopefully we'll get these wheelarches in other colours, probably would look good in light bley, lime or blue.

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+1 for lime wheel arches.

[Rudivdk]

  On 4/3/2020 at 12:58 PM, syclone said:

Not a first, but a neat solution.

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Thanks, do you happen to have a reference to other similar solutions? Are they here on EB as well? Would love to see them and compare.

Anyway, after succeeding with the diff I went on and rebuilt the entire chassis (again ). I improved the steering a lot, I made it a two-seater car, and was able to fit a 2-speed gearbox between the seats. I changed the engine design to the same design used by @apachaihapachai in the F355 (disclaimer: I take NO credits whatsoever for that design!). It's top is almost 2 studs lower, it makes a world of difference to the appearance. Last but not least I added a removable hardtop roof to make it look a bit less like a pure circuit race car. The roof makes it now exactly 11 studs high, width is 15 studs and length is 37 studs.

Only thing left to do is the dashboard/interior.

New chassis:

Bottom view of the rear axle and central 2-speed gearbox:

Gear shifter mechanism for the gearbox. Yellow 3L tile in the bottom keeps the shift stick inside the ridge of the driving ring, so it never disengages. Shift stick is an old 5L antenna upside down through a balljoint with axle hole, clamped in between two studholes. Works like a charm and extremely compact!

And the gearbox from the bottom + steering mechanism (to the right):

Steering now uses one of these  instead of Corvette-like linkage+pins solution. This gives much much better steering lock and implements a bit of Ackermann geometry in the extreme positions (due to slack in parts I guess, but nontheless it corners like a go-kart). Also it enables HOG which makes the car much more playable.

 

And finally with all bodywork attached and hardtop roof installed. The guys are having a great time:

Convertible:

Please share your thoughts!

 

Edited April 3, 2020 by Rudivdk

[MangaNOID]

This is a superb design. I prefer the roof off, the roof makes it less futuristic somehow, but either on or off its a 

 

 

Edited April 4, 2020 by MangaNOID

[johnnym]

@Rudivdk: That's one cool car. I especially like that you included the Technic figures. I believe it is not that widely known, that they fit the 42093 scale very well.

[Rudivdk]

  On 4/4/2020 at 4:43 AM, MangaNOID said:

This is a superb design. I prefer the roof off, the roof makes it less futuristic somehow, but either on or off its a 

 

 

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Thanx! The roof was actually intended to take some of the sharp edges off of the design, e.g. make it look less futuristic. So I guess that worked

  On 4/4/2020 at 6:15 AM, johnnym said:

That's one cool car. I especially like that you included the Technic figures. I believe it is not that widely known, that they fit the 42093 scale very well.

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Thank you! I do like those Technic figs and they fit this scale near perfectly. Unfortunately TLG does not design their cars with these guys in mind, they don't fit official models in this scale like 42093, 42098 and the older 42075 for example.

[vascolp]

This is really cool, I love the rear suspension and the gear shift stick!

About the roof, hey its a convertible, it has both options! Just make a stand-alone wind shield to the open version.

 

[1980SomethingSpaceGuy]

It looks nice ! Especially with the roof on, IMO. 

NPU of the side panels around the cockpit! 

Maybe you could find a way to get the headlights a bit smoother (lower)? I would have some ideas but I don't know if you have those parts in orange or if they even exist in that color.. 

[Rudivdk]

  On 4/6/2020 at 6:55 PM, 1980SomethingSpaceGuy said:

Maybe you could find a way to get the headlights a bit smoother (lower)?

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How 'bout this:

 

  On 4/4/2020 at 9:42 AM, vascolp said:

Just make a stand-alone wind shield to the open version.

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Done (I re-installed the mini-windshield from the initial single-seater version...):

And some sparse interior fittings:

@nico71 gave me a tip on YT for improving the engine. Although it didn't work out for me (too much friction and jamming of the crankshaft), I did upgrade the engine to a V8 and added some detail on it:

With these last updates I consider Dart done. I will probably shoot some videos and edit a presentation vid for the contest.

In the meantime I think Dart needs a big brother... meet 'Dirt':

A full suspended rear wheel driven classic pick-up. It's roughly the same scale and should fit the contest if the 49,5 wheels (carried in the rear bed) are put on...

Now who do you think should enter TC18...?

[1980SomethingSpaceGuy]

  On 4/7/2020 at 8:30 PM, Rudivdk said:

 How 'bout this

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Brilliant! 

[Silvavasil]

Brilliant! Allowed to be inspired?)

[Erik Leppen]

I really love this design. Very good use of the panels. I like the inverted 3x13 panels on the sides. It looks a bit like a car from a futuristic video game. Is it weird to get a Carmageddon vibe from this?

Also it's rather functional! Cool that you managed to put a gearbox in and I really like your floating-diff rear-suspension design.

My only very tiny gripe would be that the mirrors stand quite tall. I'd put them 1 stud lower. That's all :D

Also the orange color is really popping out, very striking. Love it (also the blue engine details) :)