Gravity Vehicle C

[chalker7]

Understand and do appreciate the sufficient space issue, and it may, in the bigger/national perspective, be an insurmountable barrier. On the other hand, the ~12m practical limit you note seems ....pretty conservative.
Did a quick check on basketball court dimensions:

Regulation Sizes- Official Measurements:
Court Size Overall:
•NBA and College – 94 feet long and 50 feet wide
•High School – 84 feet long and 50 feet wide
•Junior High – 74 feet long and 42 feet wide

Many regionals (and even state tournaments) do not necessarily have access to a basketball court, in fact many resort to running the vehicle events in hallways.

Sorry...accidentally posted under my account from High School up there (don't know why my computer logged me in as that).... The point remains, a basketball court is not a given.

[Balsa Man]

Understand and do appreciate the sufficient space issue, and it may, in the bigger/national perspective, be an insurmountable barrier. On the other hand, the ~12m practical limit you note seems ....pretty conservative.
Did a quick check on basketball court dimensions:

Regulation Sizes- Official Measurements:
Court Size Overall:
•NBA and College – 94 feet long and 50 feet wide
•High School – 84 feet long and 50 feet wide
•Junior High – 74 feet long and 42 feet wide

Many regionals (and even state tournaments) do not necessarily have access to a basketball court, in fact many resort to running the vehicle events in hallways.

Sorry...accidentally posted under my account from High School up there (don't know why my computer logged me in as that).... The point remains, a basketball court is not a given.

Just in the context of discourse; not trying to argue, beat a dead horse, etc., and with all due respect for the problem of establishing venue parameters that can work for everyone -

What got me going down this path is having realized how the way it is this year disproportionately impacts the “good” vehicles; the ones that run pretty fast, and pretty straight. Among this “upper end”, things (design, build) where a team has done a little better – a little more v, a little less rolling friction, get lost in the human timing error bars; they’re not correctly/precisely scored or ranked; inside the upper range of performance, it’s just a dice roll. That’s inherently unfair.

When there is a way to precisely and reliably measure/score/rank those performance improvements that a team may put a lot of effort into producing, it needs to be given serious consideration. The “winning differences” in speed that can be engineered above a certain level are small, but real; they can’t be reliably measured by a start to stop time measurement; they can by a max roll measurement.

Understand that some venues don’t have a gym option. So what would be the impact- the effect on the event, and scoring ranking – if a tournament didn’t have a gym, and had to go with a hallway to get a 25m track?
The “good” vehicles are not going to have a problem “staying off the walls”, and they would get the precise/reliable (and correct) scoring/ranking that measuring max distance capability gets you. The more linearly challenged vehicles would get ranked in appropriate order for how they deal with the challenge of making it roll straight. No unfairness, and elimination of the current wild card factor. Rules could specify min length and width; as noted before, weight and ramp height could limit length to something every venue could come up with…..

Balsaman, I like your idea for the change in the competition you mentioned, but as I understand it, if the team's car were to not go straight the first time in the max distance run, they would then have to try to make thier vehicle not go straight in thier next 2 runs, which seems to me to be a counterintuitive way of measuring accuracy. Just a thought, though: otherwise, I really like that idea.
On an unrelated note, how is it that your get your car's wheels to be in the perfect rectangle necessary for an accurate run?

No, my thought on giving teams the option, and challenge, of placing "their" target point on/along the distance line following their max distance run is this. If they've tested enough to know their car consistently runs a line (i.e., if you don't adjust the ramp and/or alignment of car on ramp, it'll run the same line), then they'd put their mark where it crossed the distance line, and know their left/right error on their first distance precision run was going to be pretty close, and the challenge would be setting the braking distance, and then in the second distance precision run, further refining braking distance, and possibly minor L/R clip placement. If it "did not go straight" in the first (max dist) run, they'd have to decide, did something "go wrong" (that they can eliminate in the distance precision run(s), in which case they'd put 'their target mark' where they think it will go - and then see how precisely they can dial it in to that marl in their two distance precision runs.

On wheel alignment precision, it is a pretty simple "how do you build with precision" problem. Step 1 is precise measurement, step 2 is building to your precise measurements. Get parallel sides on your chassis plate; get axle lines perpendicular to the sides. Make a guaging/measuring bar for the distance between axles; align the axles so on each side, the distance between axles is the same; you can do that pretty easily to a thousandth of an inch or so. A number of ways to build simple jig(s) to get precise alignment, too. There is also the option of building in adjustment capability. We put our front axle on in good alignment with an axle line perpendicular to the sides. We established a rear axle line parallel with the front axle. We mounted the bearing carrier for one side of the rear on the rear axle line. On the other side, we put in a screw-adjustable bearing carrier, centered at the line. Has about 1/16th" room either side of center; so you make runs, and adjust the screws till it runs straight.

[fleet130]

In the original "wheeled vehicle" event (Mousetrap Vehicle), the object was for the vehicle to go as far as possible. In a few years, vehicles were capable of traveling significantly farther than the length of a gymnasium (a few more than twice the length the length). The goal was changed to a fixed distance (20 meters) so the event could be run in most gymnasiums. There were still complaints that sites were unable to accommodate this distance, so it was reduced to 12 meters. Even at 12 meters, there were complaints that the distance was too far for sites to accommodate. The distance was reduced to 10 meters where it has remained (for the most part). While those complaints may/may not be valid today, there would probably be resistance to increasing the distance. In any case, discussion is good and suggestions are always welcome!

[fishman100]

A belated congratulations to Balsa Man, your vehicle and ramp looks great!

What if next year, the size of the Launch Area could be increased to a 200cm x 75cm rectangle, and the target point can be placed at any distance from 5-10 m (in different intervals depending on the tournament) and anywhere along the 200 cm of the track, not just along the center line of the Launch Area?

[illusionist]

States went very, very badly. Not sure why, but our vehicle (which was off by 1.8cm from the target point when measured as a point to line distance, parallel to the track) curved so that it wound up about 20cm to the left of the target point.

Overall though, I was surprised at how competitive this event was. Relating to what BalsaMan said about the timers, my friend's team missed the sixth place medal due to the lack of the timers' accuracy. In terms of vehicle design though, I didn't see any really clever designs like BalsaMan's team's.

[twototwenty]

Did you see lots of really long cars, like there were at my states? I think that idea is clever, if not particullarly hard to come up with, but, once again, the advantage it gives is eaily lost in timing innacuracy.

[bearasauras]

I'm sorry to hear that. How bad was the timing? Did they have 3 timers, then taking the median?

[illusionist]

Most of the vehicles seemed to be about 40cm long. There were a few really short ones (which performed poorly), but none that i saw that were really long.

Bear- They had 3 timers, although I'm not sure if they took the median or the average of the three.

[bearasauras]

Were they using the excel scoresheet from the National web site? If they are and they're putting in all 3 times, it'll take the median automatically, and hopefully that'll make timer errors less of an issue.

[illusionist]

Were they using the excel scoresheet from the National web site? If they are and they're putting in all 3 times, it'll take the median automatically, and hopefully that'll make timer errors less of an issue.

Sorry bear, I wasn't able to get a good look at the supervisor's computer. However, he was using an excel sheet, though I don't know if it was the Nationals one.

By the way, our vehicle was made of plastic K'nex toy parts and CD wheels. It's able to get to 10m in 4.7 seconds and is quite accurate. The team that got 4th at Michigan states also used K'nex and CDs. Just goes to show that you don't need a complex or expensive device to perform well.