Elastic Car With Launcher Attachment

[supaSPED]

So pretty much, the goal of the project is to create a car which has a launcher on it (elastic powered). The car starts at one zone, rolls 4m forward (for maximum marks, it has to hit 4m on the mark), then fires at the perpendicular angle from its initial direction at a dartboard type target. (This is all on the floor)

 

That target is a circle, in which the center is 4m away from the cart pathway. The circle itself has 4 zones (bullseye, and every zone after that, bullseye gets the highest marks).

 

So, the problem that i have is that we need to make a spring which is delayed. Once we let the car travel, we are no longer allowed to touch it. We also have to let the car reach its ideal zone 4m away before we can launch the object (for marks).

 

Not only that though, the spring shouldnt be launched while the cart is moving because that will make it innacurate. Having it launch AFTER the cart stops moving is ideal.

 

So due to these reasons, i need to build a spring which is delayed. As in I can set it to launch, maybe like, a minute after its initial set up.

 

no motors can be used. teacher wants elastic energy.

[Turtle]

hey there. i don't think we have worked on this project yet. does the elastic that powers the vehicle also have to power the launcher or are you allowed multiple elastic bands?

 

so the target is on the floor, yes? i don't quite understand "perpendicular angle from its initial direction" as that would be straight up (or straight down) if the "initial direction" of the vehicle is "straight forward".:confused:

 

never mind; i get it now from the diagram. :doh:

 

keep us apprised. goodluck! :thumbs_up

[Knothead]

 

 

So, the problem that i have is that we need to make a spring which is delayed. Once we let the car travel, we are no longer allowed to touch it. We also have to let the car reach its ideal zone 4m away before we can launch the object (for marks).

 

Not only that though, the spring shouldnt be launched while the cart is moving because that will make it innacurate. Having it launch AFTER the cart stops moving is ideal.

 

So due to these reasons, i need to build a spring which is delayed. As in I can set it to launch, maybe like, a minute after its initial set up.

 

no motors can be used. teacher wants elastic energy.

 

Perhaps you could construct a trigger of sorts using an aspirin tablet or equivalent. If you moisten the tablet just before sending the car off, hopefully it will dissolve or soften enough to allow the trigger to set the spring free. You might need a slow drip thing.

[supaSPED]

hey there. i don't think we have worked on this project yet. does the elastic that powers the vehicle also have to power the launcher or are you allowed multiple elastic bands?

 

so the target is on the floor, yes? i don't quite understand "perpendicular angle from its initial direction" as that would be straight up (or straight down) if the "initial direction" of the vehicle is "straight forward".:confused:

 

never mind; i get it now from the diagram. :doh:

 

keep us apprised. goodluck! :thumbs_up

 

it doesn't need to be the same elastic. u can use as many as u want, and the car itself and the launcher don't need to be using the same elastic system. u can have one solely for the car, and another one for the launcher. u just got to be able to do it using elastic or grav. in theory, we're allowed to just make a ramp, roll the car down, and launch a thing. i just think its best if i use elastics.

[Turtle]

it doesn't need to be the same elastic. u can use as many as u want, and the car itself and the launcher don't need to be using the same elastic system. u can have one solely for the car, and another one for the launcher. u just got to be able to do it using elastic or grav. in theory, we're allowed to just make a ramp, roll the car down, and launch a thing. i just think its best if i use elastics.

 

roger that. ok, so i think a timer device as knothead suggested, but with elastic. basically a spool wound with eleastic that drives a flywheel that drives a gear that drives a wheel with a slot. a trigger bar resting on the slotted wheel rim and at right angles drops in the slot when it comes around & that triggers the launch.

 

this is just the mechanism that's in those little wind up toys that use springs. here's a neat article on one that a guy took apart & it seems to have all the necessary basics.

 

My $1 Plastic Toy Car has a Metal Flywheel and a Plastic Gearbox

 

[supaSPED]

roger that. ok, so i think a timer device as knothead suggested, but with elastic. basically a spool wound with eleastic that drives a flywheel that drives a gear that drives a wheel with a slot. a trigger bar resting on the slotted wheel rim and at right angles drops in the slot when it comes around & that triggers the launch.

 

this is just the mechanism that's in those little wind up toys that use springs. here's a neat article on one that a guy took apart & it seems to have all the necessary basics.

 

My $1 Plastic Toy Car has a Metal Flywheel and a Plastic Gearbox

 

 

wo. could u make me a diagram please, cuz there are so many this drives a that, and that drives another that, that i'm lost. sorry, im not good at this stuff.

[Turtle]

wo. could u make me a diagram please, cuz there are so many this drives a that, and that drives another that, that i'm lost. sorry, im not good at this stuff.

 

the article i linked to gives a detailed description, including gear ratios. rather than gears, you could use pulleys with elastic belts. i suggest you get one of the toys & rip into it yourself. i admit it's not going to be simple to build, so you may want to consider other ideas. what are your classmates doing?

[supaSPED]

no idea. people aren't keen in sharing ideas

[supaSPED]

wait. so how exactly is a spool wound with elastics going to drive a flywheel, or a gear, or whatever?

[Turtle]

no idea. people aren't keen in sharing ideas

 

the scoundrels!! :rant: :lol:

 

wait. so how exactly is a spool wound with elastics going to drive a flywheel, or a gear, or whatever?

 

i have attached a rough...erhm...really rough drawering of one setup i envisioned. :painting:you might get away with only this many pulleys & shafts, but you need that top pulley large. otherwise you may have to add another set for further reduction.

[HydrogenBond]

The way I would do it is tie the car to a 4M string. When the car reaches the 4M point, exactly, the string get taunt and triggers the firing mechanism. Practice until you can get the car to go as fast as you need, so the momentum of the car puts enough tension on the string to pull the trigger.