TheMindGarage

Interesting stats. I knew that there were a lot of pins, but I never thought the proportion was quite that high. I guess they are one of the most important parts - they are like bolts and screws (in a world where glue, epoxy and welding don't exist).

I see. I wasn't quite sure what kingpin inclination was - I'd hardly heard of it. All of the effects are negligible, and if they are clearly visible, then they've been overdone and the car will handle badly. The only advanced geometry that should ever be obvious is Ackermann steering.

Nice so far! After my current MOC, I'll start work on my first entry. Unimaginatively, it's a Porsche 911 GT3 RS, but my aim is to make one with lots more features than the LEGO set (tuneable suspension, 4-wheel steering, better gearbox) and smaller (1:10).

If you need small size, I recommend using a live-axle suspension. Non-driven steered suspension is possible with an 11-stud gap. Some time ago, I made one with a 9-stud distance between the wheels, but I'm pretty sure it required larger wheel rims.

I'm planning two entries, and one is going to be this model. I bet nobody's going to have the same features as I'm planning though...

Either build the entire steering setup at an angle, or mount the top suspension arms half a stud further back than the front ones. Either way, you'll need to be careful to avoid having too much toe (that's when the wheels either point really far inwards or outwards when going straight).

Not sure about the first one. As for PF, that's fully allowed. Apparently even MINDSTORMS parts are allowed - I might use some of those...

You can still get virtually everything you want with LEGO's hubs. You can also use a custom hub built from LEGO pieces like you did in your earlier pics - these work just as well. Moving the upper suspension wishbone back half a stud will give you castor (and I think kingpin inclination as well). As for camber, I think AkiyamaWateru is referring to the idea of suspension camber varying as the suspension compresses. I don't think it's essential - with LEGO vehicles the effects of all these are negligible. But if you want it as a technical highlight, I would build a mock chassis as suggested and play around with different linkages.

Looks OK so far. I've only very recently explored camber and castor angles. For camber angle, I use an "L"-shaped beam extending one of the suspension arms very slightly. Effectively the suspension arm goes from being x studs long to sqrt(x^2+1) studs thanks to Pythagoras. For castor angle, your method seems pretty good. Normally, I do it the other way and mount a suspension arm half a stud off-center.

I like it! Soon I'll start work on my own 911 GT3 RS - not using the set, just using the parts I have. It'll be smaller, at 1:10 scale, but have more features...

Pretty sure it's 8mm, but it shouldn't make much difference. As long as it's 1:8 scale or smaller, it should be fine. There is, but it's 13. So anyone on this site should be able to enter.

The set is rather overpriced in my opinion (even more expensive than the Bucket Wheel Excavator), but check this out: Set costs $300 Real Porsche 911 GT3 RS costs $175,000 Set is in 1:8 scale Scaled up set (scaling in each dimension, so x 83) costs $153,600 So if you scale the LEGO set up to full size, it's actually CHEAPER than the real Porsche! I'm actually quite surprised given that Porsche cars tend to be cheaper than other supercar brands. Although the same cannot be said for my 1:10 Nissan GT-R (still in progress) - all the electronics (1 EV3 set plus an extra motor) plus the parts add up to about $600, which when scaled up is about 6 times the price of the real car...

I have the 42043 - great set at a great price. When 42055 comes out, that's the set that I've got my sights on. I've heard it'll be considerably cheaper than 42056, and it has so many more pieces.

If I were you, I would have separate motors for the drive (if you want speed, either two or four RC motors). Then have a Medium motor with pneumatic pumps for the suspension and doors. To get decent power out of an LPE, you'll need a ridiculously fast compressor. If you wanted to run Nicjasno's LPE at 1500 RPM, calculations in one of my earlier posts show that you need 350cc of air per second, all at high pressure (preferably 100 psi). The best data I've found says that it takes around 160 pumps of the small blue pump to fill an airtank (28cc) to 25psi. This means you'll need 5,000 pumps per second - not feasible. Either you'll need a pump running at 300,000 RPM (not happening - the only thing I've ever gotten to go CLOSE to that speed is an 8-tooth gear while messing with flywheels), or an "army" of several hundred pumps powered by an RC motor. In either case, the pump's internal valve means that you probably won't get above 30 psi or so.

Looks really strong, especially with those turntables!

Finding the Xth root of Y is not too difficult. If you can make an xy function, finding the xth root of y is basically doing y1/x. As for log, there is a Log function in the Advanced section of the math block. If you want log of any number, use this: loga x = ln x / ln a. If you prefer to work with log10 instead of ln, it will work as well. Curious as to how you did the factorial. I'm guessing it was using recursion.

That's true. A search shows that a pneumatic cylinder has a total volume of about 7cc. Nicjasno's V8 has a 2-stud stroke, so 3.5cm per stroke. 8 cylinders at 1500 RPM will require 350cc of high-pressure air every second. Most paintball-gun tanks seem to hold approximately 700cc, at 3000psi. So if you run your LPE at 100psi, you'll only get 1 minute's running time from it.

With a compressor, the motor that pumps the air is on-board and pumps continuously. With air from a tank, you just have the tank. The latter option is better - since LPEs aren't even close to 100% efficient, you'd always be better off using the compressor motor to drive the car directly. However, LPEs are far more powerful than any reasonable number of LEGO motors - their power is probably in the brushless range... A (slightly inaccurate) analogy might be a real car with an internal combustion engine. The airtank method basically amounts to a normal car - the fuel is stored in a tank and used by the engine. As for the compressor method, that's more like having a massive motor power an on-board oil-extracting machine and a fractioning column, which generates the fuel used by the engine. Given that cars don't tend to drive around with fractioning columns mounted on-board, stored energy is definitely the better option.

I think the most common method is to use a small tank of highly pressurised air, such as those from paintball guns. This gives you limited running time, but avoids using compressors. After all, nothing is 100% efficient, so if you used a compressor, you'd be better off using the motor from the compressor to power your creation directly.

1500 RPM is a remarkable feat anyway. Each cylinder tip must go from full speed to a standstill in a quarter-revolution - 10 milliseconds. This happens in 8 millimetres (total stroke is 16mm). Using basic equations, that means that these parts are undergoing acceleration of 160ms-2 (about 16 Gs) for much of their cycle. If you ran it at say 3000 RPM, acceleration would be 64 Gs. LEGO isn't built for that (unfortunately). I'm not sure about torque, but at 8 bars (max recommended pressure), each cylinder could exert up to 10kg of force (a quick check shows cylinder bore is 13.2mm). So pretty powerful. The only problem is the amount of air it would need - 200 cylinders worth of air every second.

A computer for pics of any real-life images of models I'm making. Occasionally I look up mechanisms or cars that I could use as future MOCs.

That could be pretty useful. I often want half-stud axles for various reasons, such as building gearboxes with the old driving ring type that are offset by 0.5 studs to get the changeover catch placed on a whole stud. It gets annoying to have to either use whole studs or those 5.5 stud axles with a stop 1 stud from the end.

I checked by commenting on the official page. It can be anything - an existing model, a mashup of multiple models or something completely new as long as it's Porsche-like. Also, military stuff is banned, so no Tigers unfortunately...

I don't think anyone will have problems with the maximum dimensions. The most restrictive of the limits is probably length, and 60cm works out at around 1:7.5 (assuming a 4.5m long car). If you want to go big, just build 1:8 with 80-90mm wheels.

Wow! That's amazing for such small size! Truly exceptional.