[WIP] Saber 1/11 AWD Supercar

[syclone]

Hello there again! 

Having no fresh ideas for the TC16 model at all, decided to give a go with a new project. After seeing T Lego's amazing small size cars, the objective was crystal-clear. (relatively) small size, AWD, gearbox, fake engine - classic supercar basically. i started with a 1/12 model, but 56x28ZRs were perfect for a 1/11 model, so I gave in to a slightly bigger scale. Scaled using Sariel's amazing scaler basing myself off a Lamborghini Gallardo LP550. The outcome is 21 studs wide, 29 studs in-between wheels. So just like last time, sketch time!

I'm not a fan of modern cars, so I tried looking up older 90's - 00's supercars for design elements, such as vents reminding shark gills and curvy, flowing lines.

-Technical design

Building a small scale independent suspension is no challenge at all, but add drive&steering and some limitations quickly appear. One of the main problems are the enormous cardan and CV joints that take up 3-6 studs, then the titanic 3-stud wide diff with some bracing and you're off to 1/10 or 1/8 scale. Now, using Nico71's method and applying some unusual design this axle was born:

LDD FILE DOWNLOAD

No matter the number of times people tell how good new hubs are, personally I find the old ones the best out there for compact MOCs. Being only 3 studs tall, they allow for super slim suspension, something that allows me to have a frame underneath them to serve as a base and to tilt the wishbones out of the way of the differential. Now, the main drawback is the suspension travel of only 1 - 1'5 studs, but for a supercar with 1 stud of ground clearance this is more than enough. My first prototype was even smaller - at just 19 studs wide, but the steering was way too high and too jerky, one of the reasons to go with a 1/11 scale. Wishbone geometry is even LDD legal, steering is off by a milimeter or two - close enough. Rear axle is a simplified version of this with standard wishbone direction.

 

In regards of transmission, I currently have in mind an old school 4 speed manual, maybe a 4 speed sequential, driving a mini v10 - based off my own design used in the unimog WIP (with 4274 as pistons driven by technic cams)

Suspension is currently missing from all wheels, but it'll be a matter of a few parts and should be done in the upcoming update. Cya later!

Edited June 26, 2019 by syclone

[T Lego]

I am glad my cars gave you some inspiration. Interesting progress already. I am definitley going to study that front axle. Is it based on the floating diff concept?

[Jurss]

3 hours ago, T Lego said:

Is it based on the floating diff concept?

Seems so. I'm just curious, how it will be connected to drivetrain.

[Srdjan5033]

So the differential can swing up and down a bit. That is a neat trick :) How does it handle torque ? Do the gears slip a lot during movement ?

[Thirdwigg]

Some fun ideas here. I look forward to seeing how this project develops.

[syclone]

12 hours ago, T Lego said:

I am glad my cars gave you some inspiration. Interesting progress already. I am definitley going to study that front axle. Is it based on the floating diff concept?

8 hours ago, Jurss said:

Seems so. I'm just curious, how it will be connected to drivetrain.

6 hours ago, Srdjan5033 said:

So the differential can swing up and down a bit. That is a neat trick :) How does it handle torque ? Do the gears slip a lot during movement ?

49 minutes ago, Thirdwigg said:

Some fun ideas here. I look forward to seeing how this project develops.

Thank you all for your comments, it is indeed a floating differential. As of right now, it able to receive 33.84 N.cm. of torque (XL motor geared down 2.3:1 times with rear axle not powered at all in the video) without grinding gears. plus, the final model will be manual, so there shouldn't be any problems as of right now. Video to prove so (car in FWD only!!!), available in HD 1080p with close up shots while driving.

 

@JurssIn regards of how it is driven, there is a 12T bevel gear under the 20T bevel, see schematics below:

 

Now, the suspension: (purists, avert your eyes)

Simple spring suspension in front, forced into 1L space (works perfectly as the wishbone cannot go any lower than the 5x11 frame underneath and the top connector is fixed vertically and horizontally), torsion bars at rear ( at least for now, as I'm too lazy and if it works why fix it). The 9L links are part of the chassis structure and make the assembly quite sturdy (LDD legal connections too).

 

 

Not much, but it took some time with different suspension prototypes. Cya later!!!

[Lox Lego]

Woah interesting design! Looking forward to your progress 

[superdog]

front suspension is really cooool...

[syclone]

18 hours ago, Lox Lego said:

Woah interesting design! Looking forward to your progress 

Thank You!! 

9 hours ago, superdog said:

front suspension is really cooool...

Thanks!!!

UPDATE:

1. Rear axle redone front to back (quite literally) allowing the placement of the gearbox to be closer to the rear axle. The suspension is still torsion axle as it is compact and has proven to work really well; the differential has been flipped and drive is now transferred from the back. (Purple is the suspension assembly - lower wishbone and torsion axle; the 1/4 pin obviously has to be mounted on the other side of the connector)

2. As can be seen from the pictures above gearbox and engine are in place. Having failed at building a sturdy engine I opted for a more standard design. The gearbox was a headache, and it really makes one appreciate all the effort MOCers put into these to make them freely rotating. The gearratios -Sariel's tool for these cases is a charm- are (gearbox only, not counting the transfers from wheels and to the engine): 

1. 5.001:1
2. 3:1
3. 1.667:1
4. 1:1

It will take some gearing up from the gearbox output (24z gear in front) to the engine to get some decent speed, but does work good enough as of right now. 

The complex part - the shifter/stepper/selector - is still to make as well as the transfer gears to the engine. The input of the gearbox is the 24z in the back, which sits VERY close to both the differential and the 5x11 frame underneath (it actually requires the frame to be oriented a certain way to not grind - watch the small indentations on the inside)

The engine sits at a decent height and cannot be lowered as it just clears the differential underneath (still enough space for suspension action). I went for yellow color of the "block" due to only having 2x LBG cams, and yellow made it stand out just like typical red camshaft covers in Ferrraris.

Unfortunately there's not much to see underneath apart from two 12T gears

 

Finally here's how the chassis looks so far:

Gearbox in purple, steering in violet, driveshaft in lime. 

Right now I'm worried about driver/passenger comfort if a traditional seat placement is used, so I'm looking into central driver position as in a Mclaren F1. The sequential shifter will have to live above the gearbox, allowing a drivetrain to motor and leaving space for a detailed cabin as well as a gearstick and maaaaaybe a gear indicator. 

That's all for now, cya later!!!

Edited June 28, 2019 by syclone

[T Lego]

It is very fun to see you struggle with the same things as I do in this scale.  What are your PF plans? Which motors will you use and how many? btw I can strongly advice you to use chiron selectors for the gearbox. If you place them above the driving rings, you can connect them using 4 16th gears very easily and in a compact way. 

Perhabs you can use this PF lay out:

Next to the fake engine are two L motors powering the fake engine.

The servo is mounted above the gearbox facing to the side of the car.

The blue mark is where you can place a stepper.

Orange is where your chiron selectors connect.

[syclone]

12 hours ago, T Lego said:

It is very fun to see you struggle with the same things as I do in this scale.  What are your PF plans? Which motors will you use and how many? btw I can strongly advice you to use chiron selectors for the gearbox. If you place them above the driving rings, you can connect them using 4 16th gears very easily and in a compact way. 

Perhabs you can use this PF lay out:

*snip*

Weeeell, at first I had no plans at all to motorize it, just wanted a "dustcollector", buuut there should be enough space for some motors here and there. Unfortunately I can't spend 30-40 euro on electrics as I'll have to buy some parts for bodywork as well, so it'll be just a lot of innnecesaruly complex mechanisms powered by m-motors XD. Thanks for the motor placement ideas though, might end up using something similar in the end 

As a teaser, rear axle and gearbox are being completely redone due to:

1. the gearbox input/output have to be swapped as there's too much resistance if power is applied from the front.
2. rear suspension sags a lot when I added motor weight on top, plus it has already deformed a 7l axle, and a self-destructive suspension is the last thing I need.
3. motor & other mechanisms placement

Edited June 29, 2019 by syclone

[syclone]

Digital Update only:

In the end, the selector mechanism was relatively easy to make, but routing the drivetrain was a real pain, resolved in a change of approach . 

As of right now: [click the images to view full size]

• rear suspension with springs - not tested, but shouldn't have problems supporting the whole model's weight

• motorisation - complete, placement of drive motors in the rear, steering motor in the dashboard, gear selector on top of gearbox. BuWizz has a free output right now, so I plan on installing lights as well. 

 

• the gearbox - no major changes, only changed input/output sides
• shifter - not tested in real life, but even LDD "accepts" the geometry of the links, so there shouldn't be any problems.

Here's a color-coded schematic :

lime - drive
violet - steering
pink - gearbox
yellow - selector
blue - PF motorised drive

 

LDD FILE DOWNLOAD

As can be seen, shifter mechanism still doesn't have support, and PF drive axle has to be reinforced. This shouldn't take much work, so by today-tomorrow it should be done and the whole chassis rebuilt irl. Cya later!!

[Touc4nx]

Nice job putting so much complex mechanism in a small build.
I just have a recommendation : don't use 2L axle for the drive (the one in the motor),  I did that once and I broke both the axle and the gears. 
 

[syclone]

2 hours ago, Touc4nx said:

Nice job putting so much complex mechanism in a small build.
I just have a recommendation : don't use 2L axle for the drive (the one in the motor),  I did that once and I broke both the axle and the gears. 
 

Thanks! Don't worry about the axles, those were just temporary  Although I do wonder how an m-motor broke an axle...

UPDATE:

Put together the build yesterday. The gearbox itself and the shifter work very well, I also added a stopper to prevent it continuosly shifting from 4th to 1st and viceversa. M-motors would happily use a downgear, but can cope with the load. 1st and second gears work like a charm while driving, 3rd was clicking (solved by reinforcing m-motors placement), 4th doesn't have enough torque to drive the car. Basically an XL motor should be used instead, but the car can be driven and l-motors wouldn't fit and would cost extra $$. Steering has no problems at all (maybe a bit too fast). Here's a video (with suspension test at the end) and photos

 

 

Updates will be much scarcer now that the mechanical part is complete (small reinforcements here and there). Cya later!

[syclone]

Ehem, fixed it! Geared down the m-motors et voila, all works great! Some prototype seating in the video as well - adjustable forwards/backwards 

 

"Action" shot

Cya later!!!

[syclone]

Some bodywork.... clear as ever that I can't afford to build it, so going all out on it, red colour, white rims, blue interior, butterfly (typical "ricer car") doors.