Hey y'all! I was just surfing around YouTube when I came across this crude-looking, but awesome stunt car. It is a shortened 2-door VW gold, with raised suspensions, and a egg-like rollover on the top of the car. The driver will be able to floor the VW golf forward, slam on the brakes, and have the entire car roll forward and keep going. Here is the video:

http://www.google.com/url?sa=t&source=web&cd=1&ved=0CEQQtwIwAA&url=http%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3DLsQEuDKDjTs&ei=VsSpT8qoDqno2gXv1eWmAg&usg=AFQjCNHLu8fkNZORllyONJhh4_sI_ApFMA

Ok, so, I was wondering to myself...is this possible. With Lego, and of so, how should I go about building this stunt car? Here are my ideas so far:

•small, sturdy frame

•stiff front independent suspension, rear suspension similar to Zblj's redneck roller coaster

•maybe a battery box that slides foreword and back, and slides forward when the car stops abruptly.

•some type of remote-control wheel-lock system for abrupt stops

•rollcage made with flex tubes

•small-wheel-scale

I am very much pondering the possibility of this project, let alone how to go about it... I am just stuck on the whole how-do-I-do this??? Aspect of the build. Does anybody have any ideas or suggestions or techniques for this project???

Thanks so much for reading, I look forward to this project!

I doubt one could accelerate a lego motor fast enough to get enough momentum to roll over, and even if enough speed is generated, you would need to brake instantly without harming the motor(maybe some sort of gearbox that disengages the drive axle?). The instant stop could be done with a disc brake and a pneumatic cylinder with enough air pressure built up that it puts pressure on the disc immediately after the switch is pulled. It might be posssible...

tim

Edited May 9, 201212 yr by timr

I doubt one could accelerate a lego motor fast enough to get enough momentum to roll over, and even if enough speed is generated, you would need to brake instantly without harming the motor(maybe some sort of gearbox that disengages the drive axle?). The instant stop could be done with a disc brake and a pneumatic cylinder with enough air pressure built up that it puts pressure on the disc immediately after the switch is pulled. It might be posssible...

tim

The whole drivetrain idea is going to be powered by a RC buggy motor for sure. Also, I was thinking about some gear-and ratchet lock system that you can engage by remote...

I think it's possible, but weight distribution will also be important. You want the back end as light as possible, so I would mount the battery box in the front, maybe even in front of the front axle. The motors should be in the front as well.

Basically, you want the center of gravity just slightly behind the front wheels--just enough weight to keep the rear wheels on the ground. If you can do that, then I don't think it would take much to flip it over. Speed and braking would also play a role.

Edited May 9, 201212 yr by dhc6twinotter

Yes, perhaps I may mount my bb in front of the axle, however that will throw off the whole shape of the car...

I think it's possible, but weight distribution will also be important. You want the back end as light as possible, so I would mount the battery box in the front, maybe even in front of the front axle. The motors should be in the front as well.

Basically, you want the center of gravity just slightly behind the front wheels--just enough weight to keep the rear wheels on the ground. If you can do that, then I don't think it would take much to flip it over. Speed and braking would also play a role.

Hi

i do not think that heavy parts have to be in the front. At firtst that will help you to turn over - but not completely. I think you will stuck right on the cars back. The more the heavy parte in the CENTER of the cars circular cage, the less this parts have to be lifted or moved in some way. Think of a ball will very heavy center, it still moves/rolls easily. If you have the weight centered somewhere outside the middle, it will not roll anymore.

Dino

Hi

i do not think that heavy parts have to be in the front. At firtst that will help you to turn over - but not completely. I think you will stuck right on the cars back. The more the heavy parte in the CENTER of the cars circular cage, the less this parts have to be lifted or moved in some way. Think of a ball will very heavy center, it still moves/rolls easily. If you have the weight centered somewhere outside the middle, it will not roll anymore.

Dino

I'm not an engineer, so you may be right. I do like my theory, and If I were to build this, I would build it as I described. If it doesn't work, then I'll move the weight back. I would think that if there was enough weight to get the car over, there should be enough momentum to carry it all the way back over.

The circular cage on the Roll Golf isn't perfectly circle. The apex (not sure if that is the correct term) of the circle is above the base of the windshield, or just to the rear of the front wheels. The Golf has the engine mounted forward of the front "axle", so it's already a pretty nose-heavy car. With the wheelbase shortened in the Roll Golf, it becomes even more nose-heavy.

But what do I know, I'm not an engineer....I could be completely wrong.

I find it interesting that they used the AWD Golf Syncro for the Roll Golf. Can't see what benefit that would have, but maybe it's just the car they had on hand.

EDIT: here's another video that shows more of the real car:

Edited May 9, 201212 yr by dhc6twinotter

Hi

you can see in the video why they needed a Syncro. Syncro is the VW naming for AWD in the 90' . In some shots the car drives back just on its frontwheels and forth just on its backwheels. Therefore you will need the AWD.

Dino

Edited May 9, 201212 yr by Darth Dino

this video shows no sign of AWD:

and this video shows some experiments about the shape, and weight distribution:

i think you will need no suspension, (or it have to be very stiff)and weight a bit to the front, but not too far

if you cant do it, i will make a try at some point.

I doubt one could accelerate a lego motor fast enough to get enough momentum to roll over, and even if enough speed is generated, you would need to brake instantly without harming the motor(maybe some sort of gearbox that disengages the drive axle?). The instant stop could be done with a disc brake and a pneumatic cylinder with enough air pressure built up that it puts pressure on the disc immediately after the switch is pulled. It might be posssible...

tim

I've made tons of simple IR controlled cars that can pull wheelies like its going out of fashion using just an XL motor for drive. I'm sure if it was rigged up right he could get the speed to make his car roll over.

I think there was an episode in Scrapheap challenge where they had to build a rollcage-buggy. I'll try and find it.

There were some tips on how to make a car roll-over concerning weight distribution and suspension.

Very ambitious project! I'm very curious to see the result!

Here are my thought about the rollcage and the weight distribution: (please note, they are only guesses)

The reason for the shape of the rollcage of the VW, shown in the video, is is probably made irregular because it needs to be.

Maybe its due to the engine being heavy on the front - what dhc6twinotter was talking about.

Dino's statement sounds to be true in general - if the COG is in the middle then the rollcage should be circular to make the roll-over easy.

But i suppose that since they couldn't change the COG of the VW easily, the decided to make the rollcage flatter on the front and steeper on the back. I think while rolling over, the rollcage is designed to use the weight of the engine to accelerate the roll and aid in completion of the roll.

in the video it seems to me that the cars starts to turn faster in the end before finally slamming into the ground.

Back to the topic:

I doubt the rollcage needs to be irregular, if the centre of gravity is close to the middle of the car.

The height of the COG is important too. A top-heavy vehicle would roll over easier during a sudden stop.

I think they raised the suspension of the golf for that reason exactly.

And finally - as 88high mentioned in the beginning, a shortened wheelbase also aids in making the car less-stable.

Hope my line of thought helps :) I might be completely wrong though! Please keep that in mind.

Good luck with your project!

P.S.

Oh yeah, and remember to NOT put a windshield on the car!

Edited May 10, 201212 yr by le60head

this video shows no sign of AWD:

You're right, definitely no AWD there. It looks like they added it later, and used the chassis from a Golf Country syncro with springs from a Honda Civic.

Apparently, they added the AWD because they wanted the car to have the ability to do a wheelie, as Dino mentioned. This is supposed to soften the landings a bit. The Civic springs were both longer and stiffer than the Golf springs.

Interesting project.

Edited May 10, 201212 yr by dhc6twinotter

Alright! Gonna start th project tonight!!!

Alright! Gonna start th project tonight!!!

Great! I'd love to see this work.

Good luck :)

I've tried searching for the episode of Scrapheap challenge i had in mind, but i can't find anything. Weird :/

I'm sure i've watched some show that featured a challenge to make a rolling-over atv-s (quad bikes) or smth.

I think it was smth like that.

If anyone remembers watching that episode, please let me know. I think it's relevant to this topic.

P.S.

Here's a vid:

Edited May 11, 201212 yr by le60head

you could try to work up a mechanism using the red driving rings used in transmissions to disengage the motor, and apply a brake to the axle or wheels at the same time

Ok, I just tried out muy chassis, and i just cant get the whole car compact enough. I am trying to use a front axle similar to zblj's redneck rollercoaster. ZBLJ PLEASE HELP MEEEEEE!!!