TheMindGarage

Interesting to say the least, although I think more ground clearance and a wider snowplough are in order here. Interestingly, you can order a normal Porsche 911 (even a Turbo S) with snow chains, but that option doesn't seem to be available on the GT3 or GT2...

But surely revolutions per second is the same as rotational speed? 2Hz is 2 revolutions per second since both have units s^-1. Unless I've done something horribly wrong...

Speed is frequency. 1Hz = 1 revolution per second. I'm just using SI units to make the power conversion easier.

I'd have expected the speed to stay equal to the average of the two input speeds (although of course any resistance or friction will slow down both the output speed and the input speeds). Perhaps someone should test this out using more extreme differences in speed and torque.

I have always believed that an adder sums torque and averages rotational speed. However, I seem to have stumbled across a problem in my understanding. For example, take this hypothetical case (I'm using SI units for this example, not RPM and Ncm which are commonly used for LEGO motors): Motor A rotates at 2Hz and has 4Nm torque - power is 8W. Motor B rotates at 4Hz and has 2Nm torque - power is 8W. Total power of the two input motors is 16W. Adder output rotates at 3Hz and has 6Nm torque - power is 18W. Where the heck did those extra 2 watts come from? If I was on Youtube, I'd stop here and claim that I've created "free energy", solved the world's problems and defeated the laws of physics. But clearly that isn't the case. So what's going on here? The only thing I think that could explain it is that the torque is not summed and that the output torque is only 5.67Nm instead of 6Nm. Please could someone with more experience in this field clarify?

Looks awesome! As it happens, I'm currently working on a 2017 Ford GT model as well using both EV3 and PF.

Try using the Unregulated Motor block set to power 100. That's what I've always done. You only really need the normal blocks when fine speed control is needed, such as when driving a tank.

I think it's because the Motor Control and IR Control use the unregulated motor rather than a normal power block. The unregulated motor block (set to 100) runs each motor to its maximum potential, whereas a standard block tries to regulate to keep a constant speed. When using multiple motors, a standard motor block also keeps to the speed ratio you set (for example when turning a tank) which means that it may reduce performance in order to "wait" for the slower motor.

Yes, this is a giant F1 car. It's around 1.2 metres long and large enough to sit in. The main features: Pedal-driven rear wheels 8-speed sequential transmission shifted via paddles on steering wheel Rear disk brakes activated by button on steering wheel Electronically-controlled limited-slip differential Rack and pinion steering connected to steering wheel Display showing pedal RPM, gear and wheel speed The car uses MINDSTORMS EV3 to operate the functions. It uses one standard EV3 set's worth of electronics plus an additional Large motor. The gearbox is a 4-speed design expanded with a close-ratio 2-speed (ratios 1:1 and 1:1.2) giving 8 speeds in total. A single motor controls it - each gear requires 180 degrees of rotation. Rotating by 90 degrees puts the gearbox in neutral. A Geneva mechanism is used to control the 4-speed - when the 2-speed goes from the high gear to the low gear, the 4-speed is advanced one gear. This is how it shifts from gear 2 to gear 3. In order to reduce the amount of torque handled by the gearbox, it is geared up very highly. This increases friction and reduces efficiency, but there is no shortage of power (I calculated a human’s power output at over 100 EV3 Large motors!). The limiting factor here is how much torque the parts can handle. The disk brakes use a 49mm tyre as the disk and red rubber pads from the EV3 Expansion set. There are two sets of callipers on each wheel (4 pads per wheel in total) giving huge stopping power. A rather complex linkage allows a single input to control both sets of callipers at the same time. An EV3 Large motor pulls on the beam which activates the brakes via a bell-crank linkage. There are two brake motors so the EV3 can operate them independently - this is important for the next step. The differential is very ruggedly-built to prevent gear slippage or parts breaking. An extra small differential measures the speed difference between the two outputs - this goes to a Medium motor used as a rotation sensor. This allows the percentage differential slip to be calculated - if it exceeds a certain limit, the faster wheel is braked slightly (via the disk brakes) to give more torque to the slower one. The clutch ring is manually operated by a switch under the steering wheel- when engaged, it locks the output to zero, making the differential operate as a solid axle. This is a very similar system to the one used on the million-dollar McLaren P1 hypercar. The wheels are made from tank tread links bent backwards into a tight loop. Not sure if this is considered a "legal" solution, but it works very well. The front wheels have 42 links and the rears have 48. The rear wheels have very tight spokes in order to allow them to take the massive weight of the driver. The wheels started gaining camber (tilting) and falling off under load, so I added extra support on the other side of the wheel. The beams are set up to be under tension to push the wheel towards the axle and prevent it from falling off. The rear section uses many layers of beams and frames to make it strong enough to withstand the weight of the driver. Extra diagonal beams (the white ones) are added - they are positioned in a perfect 3:4:5 Pythagorean triple to avoid having them under compression or tension. I used a Warren truss for the central structure - that bit is virtually indestructible. The front section doesn’t look very strong, but the extra vertical beams allow it to withstand plenty of load. The chassis is very sturdy, but with a driver on board, it tends to bend quite a bit and suffers from some serious body roll issues. The steering uses a rack-and-pinion system with just over half a turn from lock-to-lock. This is similar to the steering ratio used on F1 cars. Two large custom-built universal joints are used for the steering shaft. The shaft is reinforced to prevent torsion - even a little twisting would result in inaccurate, floppy steering. The steering wheel is made to look like an F1 wheel. The two rear paddles are for the gears - right for shifting up, left for down. The front left paddle activates neutral gear when held - as soon as it is released, the transmission returns to the last gear selected. The front right paddle activates both brakes simultaneously. Each paddle presses a button on the EV3 infrared remote which is in the middle of the steering wheel. Its signal shines through the turntable and is captured by the IR receiver on the other side. This allows signals from the steering wheel to reach the EV3 brick wirelessly. The paddles have a very short throw and a crisp feel - they’re one of my favourite parts of the car. The car has a full display with features like an RPM bar and wheel speed shown (since the wheels have very little grip and are liable to doing burnouts, actual speed will be quite different). The gear number is also shown. The RPM is measured by a touch sensor and a cam connected to the pedals. The cam bumps the touch sensor every 1/7th turn of the pedals. I initially tried to use a Colour sensor to detect the black chain links against the greys but the difference in reflected light was insufficient for it to be reliable. Strength-wise, the chassis can easily deal with 20kg on the seat. Perhaps it would be ideal for a 6-year-old gearhead. Unfortunately, I'm a lot more than 20kg, so I kind of broke it. Here's the aftermath: Here's a video of me explaining and demonstrating the features of the car. You can also skip to 10:56 to see me try out the car... [All music is composed by me. My F1 V10 impression is not edited in any way!] In the end, I think it was a successful experiment. I intended this MOC to be a testbed for various ideas I had, and you might possibly see a scaled-down version of some of the mechanisms (such as the differential) in a normal-sized car of mine in the future. After all, that's why real-life car manufacturers build concepts and sell low-volume cars at a loss. If it wasn't for that, we wouldn't have the Bugatti Veyron, Pagani Zonda R, Lexus LFA and other amazing machines.

I never knew those red double-attachments were so rare. I got some from my EV3 Expansion Set.

Swap the ones closest to the motor. There should be one more that controls one of the turntables - leave that in because it stops the motor from stalling. You can also replace the 8/24 gearing (the one that has the clutch gear) with 12/20 for better performance. If you add another motor, 16/16 is possible. Going faster is a bad idea unless you gear down the bucket - at these speeds, objects will remain in the bucket and not have time to fall onto the conveyor belt.

I've found a solution with the BWE rings and 12-tooth gears. Using 8-tooth gears is pretty impractical because you'd need half-stud spacings. If you position the 12-tooth gear 8 studs away from the center, you can drive the 140-tooth ring. You can also do this by doing a 7/4 offset - that's 7 studs horizontally away from the center and 4 vertically (total distance is 8.062 studs which might increase friction a little but it would actually reduce backlash further). I don't think backlash is a problem anyway because it's only rotating in one direction. As long as the resistance/friction on the output remains constant, the backlash shouldn't be a problem. In fact, it might even be beneficial to have a little to prevent jerkiness or vibrations from affecting the speed. You could use a flywheel or a viscous coupling (one that winds up using rubber bands or springs) to smoothen the motion of the cylinder.

No. I sanded the 9 end down to make it round. I'm yet to need the 5 end so it's still "rough". I forgot to mention, I broke a 15-stud beam once by using it as a hand crank. I was building a giant flywheel cannon and the torque was too much for the beam to handle. I had to make it stronger. The same device wore off the red bits on a transmission driving ring that engage the gear, making it useless. I think the grey ones are stronger but I didn't use them because I wanted to save them.

I ran out of light grey 9-stud beams so I cut a 15-stud one (had tons of those lying around) into a 9 and a 5.

The top button is a toggler. Basically, it remains on even after you release the button. Pressing any button (not just the top one again) will turn it off. I'd advise you to use a different button.

I don't think I used exactly the same setup as Sariel's, but I have made a virtual pivot with suspension: Here you can see the two extreme positions of the suspension overlaid. The grey link connects to the longitudinally-mounted shock absorbers. A steering rack is connected to the suspension arms - as the rack moves, the suspension arms rotate, steering the wheel.

I just named mine after an existing BMW bike name.

This is my entry to the Rebrick BMW Motorrad competition. Its goal is to balance both performance and sustainability to show that high-performance vehicles have a future in a world concerned with emissions and fuel consumption. I used double wheels on both the front and rear in order to make this model driveable. The wheels are made from 36 chain links bent "the wrong way" - they are around 16cm (20 studs) in diameter. The whole model is about 55 studs long and 13 wide. The drivetrain consists of a PF Large motor geared 1:1 and a PF XL motor geared 5:3. They are hard coupled - yes, I know this is frowned upon but it provides a compact solution, and the load on the motors is no different to driving a car up a hill. The motors are mounted inside the rear wheels to save space and simplify the drivetrain. The motors are connected to an IR receiver which is mounted inside the main body. The battery pack is positioned at the very bottom to lower the center of gravity and increase stability. There is a shaft connecting a 4-cylinder piston engine to the wheels. This piston engine runs on E85 bioethanol which is derived from plants. This means it is renewable and carbon-neutral - the carbon dioxide released when burning it is compensated for by the plants used to make them photosynthesising. It also has a higher octane rating than gasoline, meaning it can actually provide better performance than the fuel it replaces. E85 biofuel engines already exist - all recent Koenigsegg vehicles are capable of running on both gasoline and E85, and these engines can produce up to 1 megawatt from a 5-litre V8. I believe biofuel is the future for high-performance vehicle manufacturers such as BMW. The front suspension uses a Duolever setup where the front fork is suspended on two parallel wishbones. The front wheel is able to move up and down and steer, while having the shock absorbers mounted on the wishbones rather than as part of the forks. A steering linkage allows a PF Medium motor to control the front wheel. The rear suspension uses a similar system called Paralever. It is essentially one half of a car independent suspension, complete with universal joints. It is sturdy and keeps the rear wheel's motion vertical when the suspension compresses. The front and rear wheel arches use the bucket wheel parts from 42055 as an internal structure. I used pneumatic hoses as part of the structure to give the flared appearance of the rear arch. greenshotcertificity.com Every part of the motorbike is designed with the BMW brand in mind (honest, it's nothing to do with the lack of turn signals ). The panelling (especially the side intake) is inspired by the BMW i8, a hybrid supercar by BMW. The suspension matches the types used on current BMW motorbikes, and inline-4 engines are commonly used on both their bikes and passenger cars. Here's a video showing the bike's drifting and burnout capabilities. Music is composed by me. Enjoy!

You mean MUSCL3 CAR? The 4-speed is very similar to that used in Sariel's 4-speed. The main difference is the structure - whereas in Sariel's version some gears are on the outside, in my version all the gears are supported on both sides, meaning my version handles more torque. The Community Challenge on the MINDSTORMS Gallery? Since it might become an official one, I haven't published a set finish date. If it doesn't become official, I will make a separate post on the Gallery stating the finish date. It should be ready for then.

It's difficult to get gear ratios other than 1:1,1:1.667, 1:3 and 1:5 (I have made a closer-ratio 4-speed box but it's more complex). Make sure you reinforce the gearbox strongly - both sides of each gear should have a beam securing the axle. As a last resort, gear up before the transmission and gear down afterwards. This will reduce efficiency but reduce the amount of torque the gearbox has to deal with, meaning less gear clicking.

I've found that it works better with the two 24-tooth clutch gears next to the motor replaced with regular ones. You can also gear the system up considerably - replace the 8/24 gearing with 12/20 or even 16/16. If you go for 16/16, the whole thing will run at 3x speed but you'll have to reduce the speed of the bucket wheel otherwise objects will miss the conveyor belt.

Looks amazing! I saw the first picture on my email digest and immediately knew it was a Miura before even looking at the title! That's the mark of a great MOC.

Sheepo has some good ones, but instructions are expensive. 5+R is a very difficult combination to build because you need three driving rings. Would a straight-8 (8 forward, no reverse) be an option? That would be easier because you can make a 4-speed sequential connected to a 2-speed (I recommend having the 2-speed's gear ratio difference around 1:1.25 - this can be done with a 16-tooth and a 20-tooth).

Looks don't tend to be my strong point, but glad you liked it!

It's already taken apart, so no instructions. I'd rather spend the time to make more MOCs. I have quite few pieces (I run out of a lot of things when building this - collection is probably in the region of 8,000 pieces), and I definitely don't have enough white parts to make it in white (I think I have two 16-stud white axles and that's it).