How to build a Technic supercar - part 1 - Chassis, Drivetrain, Axles . V 1.3.5
This is somewhere between a guide and a MOC of the TVR Sagaris racer chassis I've been building
. Before you build a Technic supercar, there are many factors that you must consider:
-how many pieces you have
-will it be functional or aesthetic
These factors are all very important, for example if you are a first time builder and have few peices it might benefit you to build a functionless race-type supercar (i.e. stripped out interior) as the lack of functions make it less complex and there is less interior detailing to waste parts on. They are also wider so if you do choose to add functions there is slightly more space. If you are then confident to move on to a more difficult build you can decide whether or not you need more parts. I would say anybody who owns the 8279 Off Roader and the 8145 Ferrari 599 GTB Fiorano will have more than enough pieces for a 1/9 scale car (I have neither, any other bigger sets will be just as efficient).
When building the car there are 4 things to decide in order to start building - I will show the example I have chosen
1 Which Car?
2 What Scale?
4 Functions (Modular, Gearbox, R.C.)?
1 Which Car? TVR Sagaris
First of all select your vehicle and look it up on Wikipedia
Then note down:
-dimensions (Height, Length, Wheelbase, Width)
-suspension type (double wishbone, multi-link, dual swing arm, leaf springs)
-engine (orientation, number of cylinders, formation)
-drivetrain (driven axles, gearbox type)
And also look up pictures on
Google Images - use words such as 'car' side / rear / top / front
to get some views of the car
2 What Scale? 1/9
The scale obviously depends on your piece count and what functions (if any) you need to fit into your car.
As Joost Cumps pointed out, the size of the wheels you have can change the scale of the car or vice versa, i.e. the 8448 wheels are simply too large to go into a 1/10 or even a 1/9 scale model, and likewise the Ferrari wheels would be too small for a 1/8 vehicle.
I would say each scale has it's advantages and disadvantages.
[1/10] too small for functions (i.e. with suspension and drive the axles will be far to wide and disproportionate) but less pieces needed
[1/9] just the right scale for some functions (i.e. gearbox but not necessarily R.C. in front engined cars)
[1/8] needs a lot of pieces - bigger than you would think, but lots of space for functions.
When I build r.c. cars I would ideally have the driving motor in front of the engine so as to achieve XL Motor >> Engine >> Drivetrain [Gearbox] >> Wheels
It would be possible in a 1/9 or 1/10 to fit in r.c. but I would say that to do it this way, either replace the engine with the XL Motor, or find somewhere else to put it, possibly remove the gearbox and have the XL Motor where the gearbox would be and not connect the engine to the wheels. This is not to say you cannot have just a P.F. motor to raise the convertible roof for example, but if something simply does not fit you have two options; abandon it, or do some rebuilding.
To work out how big your car will be follow this simple method.
Take your real life measurements i.e. 4,057 mm
Divide by the scale i.e. 4,057 mm / 9 = 451 mm
Grab a pair of 30cm rulers and some long beams (ideally 15L) and count the amount of studs in this length i.e. 56 studs in 451 mm
repeat for all four dimensions (Height, Length, Wheelbase, Width) and note down somewhere safe
3 Race/Production? Race
Choosing between these is not very important, as it can be changed, it just needs consideration based on what you have.
4 Functions? working steering wheel, wheels drive engine, suspension, modular
whether or not you go modular I maintain that a space frame is the way to go
Some functions I incorporate without fail into all of my vehicles - working steering wheel, realistic suspension on all wheels, and the engine driven by the wheels. This is not always possible I appreciate on smaller models, such as in a 1/10 car suspension may not be an option but I try to get all of these functions into every build, and then add some more, different ones every time to make each model even better than the last.
In the following sections I have included links to some models containing the best example of these features
The way I see it is that there are only two types of steering rack - '12 tooth' and '8 tooth' (below)
using these racks with theses gears ensures that the gears are 'on the stud grid'
Always make sure you have a solid steering rack and space to get an engine in as well (if it is front engined)
In my example i have mounted the rack flat rather than upward and used a simple but large collection of gears in order to 1- get enough torque, 2- fit underneath the engine and 3- turn the correct way with the steering wheel
Because I have created a camber angle on the front wheels (see modular), the stud holes for the steering arms to connect to are too far from the 'optimal position', where no amount of toe in / toe out is created, to resolve this I removed the camber, shifted the studded beam closer to the wheels than in the photos by half a stud, and put a long plate between the beam and the rack.
Because of this, the bank of cylinders can go on either side, or a vee-type engine could be placed in (maybe the Corvette V8 typically found in TVR Sagaris racers), basically anything smaller than a V12 in length can fit and the crankshaft will not brush a cog while rotating.
When building a car where the steering wheel steers the car, you will undoubtedly want to use universal joints ('U-joints') to join the steering wheel and the steering rack. Since universal joints are prone to breaking or twisting under high torque, it is advisable to locate the gear ratios after the u-joints
i.e. Steering Wheel >> U-joints >> Gear reduction >> Steering rack
Leaf Springs are one option but they are rarely used on newer supercars - here is a fine example
Ming Thein - Ferrari 250 GTO
It is likely you will need to use independant suspension with double wishbones, luckily lego has a part for this and the shock absorbers can be mounted vertically (Tyler Reid - Dodge Viper ACR) or transversley (Tyler Reid - Pagani Zonda F)
In the past I built the axles first with a suspension bracket attached to the floor and then I built the car around this. While building my ASTON MARTIN I noticed that the strengthening beams I put around the engine were close to the shock absorbers, so in my new model the shock absorbers bolt onto the spaceframe (see modular), this is stronger and less complex.
Building modular is more difficult in that it requires more planning but it is this planning that makes it a lot easier later on to access parts and interchange. It also looks better and is quite functional. Also note that when building a race type vehicle the strength can all be gained easily in the chassis by putting lots of crossing beams, production cars are easier to stiffen with the body panels.
Personally I started by building the engine and both of the axles
Then I fitted the engine bay around the engine and made a steering rack
Then I rebuilt the underside of the engine bay to allow the front axle (above) to fit in
Then i looked back at my measurements to find out the length for wheelbase (and found that it was shorter than i had prepared for) and built a floor and place for the back axle to sit.
Then I built a connection between the front and rear of the rear axle brace and the rear of the rear windscreen to make it stiff and braced the dashboard to the center-rear floor of the cockpit, and from the rear of the roof to the offside floor to siffen the cockpit section.
DON'T BE AFRAID TO REBUILD YOUR AXLES, OR AROUND THEM, it takes time to perfect them
This is where the engine bolts in at the front, 2 of the 6 bolts to fix it in place.
There are two of these on either side to fix the engine in
This is underneath the steering rack and you should be able to see 6 of the 10 bolts that hold it in place, not including where the shock absorbers clip in.
Two of these on each side hold the top of the axle in place
And the suspension clips in like so
You may have noticed that the top wishbone on each of the front wheels is half a stud closer to the centre than the bottom, this creates a negative camber angle (Sheepo HL's idea)
Here you can see all 6 of the bolts for the rear axle, not including where the shock absorbers clip in.
And finally, where the shock absorbers clip onto the spaceframe.
Linear Ming Thein - Ferrari 250 GTO
'8448' Manual Tyler Reid - Dodge Viper ACR
Pushrod My NISSAN 370z
I doubt you can figure out how the gearbox works from that link but this should clear it up
The gear stick [yellow] shifts the pushrod [red].
The pushrod [red] pulls the driving ring [green].
The driving ring [green] changes gear.
The gearbox output connects to a driveshaft which runs underneath the pushrod [red] to rear wheels.
I'm really no exprt on R.C. functions but these two certainly are, so take a look and see what inspiration you can draw
Sheepo HL - Bugatti Veyron 16.4
Sheepo HL - Porsche 911 (997)
Jurgen Krooshoop - Ferrari F430 Spider
Jurgen Krooshoop - RC Sportscar 'Little Devil'
Let me know if I was helpful and if it needs improving, Thanks for taking the time to read this ;)