Power Functions Superbike teaser

[Kierna]

I have designed a power functions motorcycle, with no stabilizers or outriggers, a real leaning motorcycle. 100% Lego. Sorting out a bricklink order, I hope it to become the first succesful Technic Cussoo. 300 or so parts.

[Darth Dino]

Hi

i can not see any images- just a blue "?". I am using Safari on an Ipad.

Dino

[lazylegoist]

i can not see any images- just a blue "?".

I can see it after clicking on "Posted Image". Not much to see though − like Kierna said, it's a teaser. I am very curious about how it works, though.

Edited October 27, 2012 by lazylegoist

[Lost_In_Noise]

hmm, looks like a monofork on the rear. Also extensive use of body panels.

[DLuders]

Here is Kierna's dark and mysterious Lego Power Functions motorcycle teaser:

[Meatman]

I don't get why people feel the need to post these teaser pics.

[Saberwing40k]

No, there's your superbike teaser. It looks awesome, please post more info.

[locoworks]

these type of bikes will need heavy wheels or a flywheel somewhere to produce enough gyroscopic force to keep it upright at the speeds it is likely to reach

[SNIPE]

Is it supposed to be in black and white?

It looks like the red technic motorbike to me

[drdesignz]

I've thought about building one before. But I wouldn't know how to make it work without a gyroscope. If you can do that with 100% Lego I'd be very impressed. Do you have a working prototype? A proof of concept of some sort?

[allanp]

I have seen videos on youtube of working lego rc bikes. This one is NOT 100% lego and uses a modified m-motor. It seems the trick is to locate the pivot axis of the steering forward of the axis the front suspention is aligned to when looking at it from the side. Apparently this will make it lean when it goes round a corner, and the gyroscopic force of the front wheel does the rest.

[Kierna]

Sorry for the late reply, and sorry about the dodgy image embedding. I'll preview this post!

Here are some more images, and answers/response to your questions/comments (in order).

Lost_in_noise said

hmm, looks like a monofork on the rear

Correctomundo, however, only telescopic front suspension systems (MTB, most motorcycles) are called forks. Motorcycle, MTB rear suspension is most often "swinging arm" type, and this bike has a single sided swinging arm, ala Ducati 916, 1098, Panigale.

For more information see Car Bibles.com "Motorbike Suspension Bible" at http://www.carbibles.com/suspension_bible_bikes.html

Locoworks said

these type of bikes will need heavy wheels or a flywheel somewhere to produce enough gyroscopic force to keep it upright at the speeds it is likely to reach

Flywheels on RC motorcycles are in fact for keeping the machine upright at very low speeds, or even at a stop for a very short amount of time. They are optional and removable, and add large ammounts os unsprung weight (the weight placed on the road, not held up by suspension components.)

The faster a two wheeled vehicle travels, the more stable and upright it will stay. This is due to centrifugal force of wheels, among other things.

I am confident in my designs abilty to stay upright at low-medium speeds.

Which brings me nicely to closing remarks. (SNIPE, thank you for re posting the sillhouette image )

drdesignz said

Do you have a working prototype? A proof of concept of some sort?

I do not have a working prototype. I haven't the parts, yet. I have built the swingarm to verify drivechain length and tension.

As for proof of concept behold this youtube video of a self balancing NXT bike. http://www.youtube.com/watch?v=VxiOy4QzD7I

The program it runs was coded by the Delft University of Technology, Bicycle Dynamics devision. It stays upright by reading from the on board Accelerometer sensor, and "steers into the direction of lean".

A man would merely need to practice controlling this machine by traditional remote input to match and exceed the NXT's abbility to keep the machine upright.

As afforementioned, the faster a two wheeled vehicle travels, the more stable it becomes, and the more reluctant to lean from vertical. My design has adjustable gear ratio's, from speeds of 7-12-16 MPH. I'll see what works best when I build it, I don't know what it will weigh. It hasn't many parts.

Alanp said

It seems the trick is to locate the pivot axis of the steering forward of the axis the front suspention is aligned to when looking at it from the side. Apparently this will make it lean when it goes round a corner, and the gyroscopic force of the front wheel does the rest.

A video of a working human controlled rc bike, with no gyroscope or flywheel. More proof of concept.

Alanp, you are absoloutly right about the geometry being key to making a two wheeler boogey. Rake, trail, and offset are all VERY important, and they are often completely ommited from the few lego bikes I find on the net.

If any of you are interesed, enjoy the Wikipedia page on Bicycle and Motorcycle Dynamics at http://en.wikipedia.org/wiki/Bicycle_and_motorcycle_dynamics.

[Philo]

Having built and programmed a NXT bike inspired by Delft University video, I'm very interested by your project! I guess that if I paid more attention to mechanical design, it would be more stable...

[Kierna]

Glad to hear of some interest, Philo! I think to most, motorcycles are black magic, people steer clear...

Huge credits to you and your webpage. It was from your PF-XL specs that I decided gear ratio's.

However, I cannot find any information about the NXT bike you buiilt. Is it on your webpage?

Also, THANK YOU for having a few photo's of the large, scaled up technic models at Legoland. They are hard to find, and they fascinate me!

[Philo]

However, I cannot find any information about the NXT bike you buiilt. Is it on your webpage?

No, I need to publish something about this, you're right!

Also, THANK YOU for having a few photo's of the large, scaled up technic models at Legoland. They are hard to find, and they fascinate me!

Ah - nice to see someone interested by these old photos ;)

[nnamhcab]

so its been a while since anyones commented did you finish the bricklink ?

[piterx]

you know what? some weeks ago i was about to start something with 2 wheels too...then i procrastinated it lol

looking forward to see this prototype ^^