Scrambler C

[iwonder]

I think the full answer is on page 2 or 3 of this thread.

Basically, a falling mass launcher's final energy is the kinetic energy of the mass and vehicle. The spring launchers final energy is the kinetic energy of the vehicle only, because the falling mass isn't moving when the vehicle launches.

[tanuagg13]

The work done on the car is exactly the same, but it is applied over a much shorter distance, resulting in a larger force being applied to the car (and thus greater speed). The distance is shorter since, rather than pulling the string across ~2m, the force is exerted by the displacement of the spring by about 0.5 m.

Actually, now that I think about it, less work is done on the car in a pulley launcher, since the car exits the launcher before the mass touches the ground, while in a spring launcher the car can only be released once the mass touches the ground.

EDIT: Sniped by iwonder, but I added an additional reason (unless my conceptual view of the spring launcher is entirely wrong).

[iwonder]

Since the work applied is equal to the change in kinetic energy of the vehicle, if we simply assume that the launchers have the same work output, we have to assume they have the same final kinetic energy (final speed), which isn't the case.

And in fact, there is a much greater difference in work than the height of the release of a pulley launcher, because as the mass of the pulley launcher moves at release, whereas with the spring launcher it doesn't.

[xXclubpenguinXx]

Can someone please explain y it is better to use a spring launcher? i dont understand why one would be better if they they have the same energy input. how would we make the car turn @ different angles? is it allowed to impound more than one car?

[A Person]

Can someone please explain y it is better to use a spring launcher? i dont understand why one would be better if they they have the same energy input. how would we make the car turn @ different angles? is it allowed to impound more than one car?

The thing about a spring launcher is that there isn't the same energy input. Notice that whenever a pulley launcher is used, there is that moment when it stops abruptly. It doesn't gradually slow down like an ideal spring launcher does. That means that it is losing energy, and that's something a spring launcher doesn't do. The spring launcher saves as much energy as it can in the spring, which causes the mass to appear to slow down before it hits the ground/releases the car.

Having it turn different angles can be accomplished using turning the front wheels using some short of hold and release mechanism.

No impounding more than one car. It shouldn't be so weak that it breaks with hitting the wall or something, and I don't see a benefit of using more than one car, one run each. This rule is to prevent people from having one car for each different.

I strongly suggest reading the past replies to this thread, especially for your first and second questions. Note that iwonder gave an excellent explanation of spring vs pulley discussion in the comments above yours.

[afrocdm]

I see that everyone has been saying that the spring launcher works the best. Are there any other launcher types that are good? I'm struggling with the spring launcher right now, and I want to experiment with other launchers. Thanks!

[iwonder]

I see that everyone has been saying that the spring launcher works the best. Are there any other launcher types that are good? I'm struggling with the spring launcher right now, and I want to experiment with other launchers. Thanks!

Easiest way to work towards a spring launcher is to first build a pulley launcher, since it's basically the same design without a second trigger or spring, then work from there.

Now if you don't want to work towards a spring launcher at all, (and don't ask me why it works this way) a push rod launcher is a good second, again, don't ask why, but I've run pulley and push-rod side by side with the same vehicle and mass and the falling mass is a lot better. I think it has something to do with the mass in a push rod moving forward at the end of the launch...

Basically, with my vehicle (450something grams with egg)
Pulley - 4ish seconds
Push-Rod - 3ish seconds
Spring - 1ish seconds (sub 1 second was the record )

[fishman100]

I see that everyone has been saying that the spring launcher works the best. Are there any other launcher types that are good? I'm struggling with the spring launcher right now, and I want to experiment with other launchers. Thanks!

We did what iwonder did. If you build a good pulley launcher, it's not hard to convert it into a spring launcher. Our spring launcher last year wasn't built as well as it could've/should've been, yet it still halved our run time. And if you can't convert it successfully, you can return to a pulley launcher.

If you look at some of the scrambler pics in the Image Gallery you can get a rough outline of a spring mechanism.

[XJcwolfyX]

Has anybody been doing the bonus? We can't figure out and were wondering if other people are having issues. D:

[retired1]

The bonus is 100 points. If you can go around the can and get within 10 Cm of the distance of the straight ahead distance, then you should try for the bonus.

The difficult part of this is the need for a different steering setting for each of the possible distances. Not bad for regionals, but not easy for state and quite difficult for nationals.
Some teams will do a lot of research (testing) and will do very well. Some teams will have a great guess at the distance and do well. The majority will have problems.