Scrambler C

[Cheese_Muffin_Man]

I mean in general, you could just use a plastic bag and fill it with coins. The relative lack of a rigid shape makes it great to use for a variety of launcher systems, but as syo_astro noted, it helps us help you by knowing what launcher system you're using.

Because technically speaking, you can use ANYTHING that weighs under 2 kg as a falling mass

I think I figured out a way to change it. Thank you for your advice nxtscholar and syo_astro.

[wx4caster]

There's lots of things...are you really having that much trouble with it? You could use something as one solid mass or a bunch of smaller masses put together. As long as it can attach to whatever system you're using it's fine, and there's lots of things to use depending on your system. Pulley systems make choice of what to use for a mass really easy. Pushrod systems I would guess you maybe have to think a bit more, but not really since you just have to make sure to mass your rod and then just attach a bunch of mass at the end I assume? Then I guess there's always other systems...but yeah.

We used a push rod system where the whole rod and mass were considered in the total. We attached a mass to the back end of the push rod. In our case we used Zinc BB's. in a container. This made it very easy to change the mass weight, and fine tune it by removing or adding BB's. Our rod/mass assembly was only around 1 kg, as it was plenty heavy to push our very light car. The slightly lighter mass helped reduce any skid issues.

[wx4caster]

We just finished our State competition this past weekend. So thought I would pass along a couple of thoughts and our results.

First, the rule clarification on ramps was NOT followed. They allowed ramp launchers, since the rule that talks about "the vehicle wheels having to be in touch with the ground" at the start position was poorly worded. I assumed that the national rule clarification was the law of the land, but apparently up to each state judge to enforce. So your mileage may vary on this rule interpretation. In our states case, it didn't really matter, as ramps did not perform well at all.

For the Kansas competition: the run times of the top finishers were between 3 and 4 seconds. So not much difference for points between the teams on this portion of the scoring. The distance/accuracy was again the determining factor on winners (medals!!) and losers. There were quite a few vehicles that came very close to the wall, but were off the center line. So the point to point measurement killed them. Kansas is broken into Small/Large Class, but it ended up being that the top two finishers were the top large class (1st) and small class (2nd) vehicles. Large class vehicle came within 2.4 cm from the center line/wall. The Small class car (2nd overall, but winner in Small class (our team), came in at 2.5 cm. Yes 1 mm!! decided the overall rank. The next vehicle came in at 5 cm. So highly competitive.

[Smithy0013]

So spring launchers are legal right? I just built one that works quite well but my partner is concerned that the conversion of energy makes it illegal. I also have yet to see one at a competition.

[AH98]

Yes spring launchers are allowed.

1 question for you pulley launchers guys: how are you getting it (the vehicle) to release and start moving? I thought about using a hook attached to the string and a ring attached to the vehicle to drag along the vehicle but then I thought that the hook would get stuck in the ring. Tying the string to the vehicle will not allow it to release either.

[syo_astro]

Yes spring launchers are allowed.

1 question for you pulley launchers guys: how are you getting it (the vehicle) to release and start moving? I thought about using a hook attached to the string and a ring attached to the vehicle to drag along the vehicle but then I thought that the hook would get stuck in the ring. Tying the string to the vehicle will not allow it to release either.

I'll add I don't know how you're doing the spring launcher, but I must emphasize to make sure the falling mass is what's providing the energy, not the spring (I think that's the main thing, just check the rules in senses like that that it follows specs).

As for pulleys, oo my favorite! Uh, for my Scrambler...I literally just ziptied/hot glued a hook to my car, tied a loop of string, and put the loop on the hook (I think that's just the common sense way). Of course, I'd assume that'd make no sense just saying that to most people. Should I assume your pulley launcher has something like what's shown on the wiki here: http://scioly.org/wiki/index.php/Scramb ... y_Launcher? If that's the case, I would say just try to knot a loop of string and make it taut around a sort of vertical block at the back of your car, trying to keep the vertical block just below that ledge where the bottom pulley is. I think if you don't do that, you sometimes end up with an angle such that the car gets pulled up, so you want it relatively parallel (obviously can't get it perfect). You could make that from a variety of materials, depending on how focused you are on keeping your car at a certain mass. You also may want a hook or notch somewhere at the top of that block so your string can kinda grab onto something and not just slip off? It took me some messing around to figure out what to put on the car and how to loop the string around, but it worked by states for me XD. Sorry if you don't get what I mean, but I hope that helps!

Edit: Also, if you're having trouble with the knot you should get on that! There's a few different knots I employed hehe (by that I just mean I tried different ones and multiple were useless), but you should just go simple.

[AH98]

Yes, that is what I was trying to avoid, the car being pulled upwards or getting caught at the moment where it's supposed to be released from the "launcher".
hopefully I can also avoid it slinging wide left.

[nxtscholar]

Yes, that is what I was trying to avoid, the car being pulled upwards or getting caught at the moment where it's supposed to be released from the "launcher".
hopefully I can also avoid it slinging wide left.

Slinging wide left? Elaborate a bit more? Like, during the course of the run? Immediately after launch?

In general, I'd just make sure your pulleys are as aligned as possible. In addition, I'd double check and see if the weight distribution of your car is as even as possible.



Oh, and with regards to the spring launcher, just to add a clarifying comment, the idea is that the spring can't already be stretched (and thus already containing elastic potential energy) at the time the mass is dropped. Otherwise, conversion is allowed.

[syo_astro]

Yes, that is what I was trying to avoid, the car being pulled upwards or getting caught at the moment where it's supposed to be released from the "launcher".
hopefully I can also avoid it slinging wide left.

I agree, you don't want it pulled upwards! My scrambler solved that by not doing it (I guess I won't elaborate too much on that, though I think you can figure out what I mean). But I've seen various launchers, and I think if you keep the bottom pulley fairly low and the top of the car where the string attaches fairly parallel it shouldn't be as bad. I find the string gets caught more when you're using bad pulleys (ie. weak, not large enough sheaves/groove so string gets stuck, too high friction, not properly attached, etc) like I stupidly did for invites/regs >.< (really should've ordered better ones earlier). As for slinging wide left, I am with nxtscholar. The pulleys if they are set up like they are in the wiki should be fairly aligned (unless of course you didn't do that), so slinging left or right shouldn't be as much of a problem, center your car too and it really shouldn't be.

[thsom]

Hey guys, is it allowed to step on the track when aligning your device/car? I don't see anything against it. All I see is that the device mustn't be on the track and that the track must stay dry.