Gravity Vehicle C

[chalker7]

I would think that it would be fine as long as there is a release mechanism permanently attached to the ramp. I mean the vehicle should be okay with having components that are specifically intended to interact with the release mechanism on the ramp, as long as the release mechanism cannot be 100% on board the vehicle.....but then I don't know much about this event, so don't take my words for it.

Ha....bearasauras knows exactly what he's talking about.
For any "release mechanism" to work, there must be some part of the vehicle that interacts with the ramp, so it would be tremendously difficult to legislate against your described setup. That being said, you should submit an official clarification if you suspect there will be any questions at a future tournament.

[Balsa Man]

Well, we finally got to being able to do full function testing, and start calibrating ‘the beast’ last weekend. With Regionals Mar 3, I was beginning to worry….
Its now been christened “Black Magic #33” for all the carbon fiber and black glue, and the 33 different materials in it and the ramp.

The team has been able to get a very interesting braking system working; it’s neither wingnut, nor string winder; counts wheel revs w/ very low friction; applies the brakes over about 10 to 15cm depending on target distance (which means no skidding), and is consistent on distance to …..something less than 2cm. Braking time is on the order of 1/10th of a sec (compared to no-brakes time at a given distance. The distance delta between whole wheel revolutions is dealt with by adjusting the paperclip position. Runs “the line” also to a precision of less than 2cm (at 6.5m, the most the hall at home will accommodate); speed looks decent (<2 sec to 5m). Everything seems sturdy and reliable. Now, if they make the time to do a good calibration workup from 5 to 10m, they should be ready to compete. We'll see in 3 weeks.....

[bearasauras]

Wow, that's really impressive. By the way, you're the coach for the team, right? If you are, you really impress me with how much detail you know about the events. Props to you.

[Balsa Man]

Wow, that's really impressive. By the way, you're the coach for the team, right? If you are, you really impress me with how much detail you know about the events. Props to you.

Why, thanks, bear. Yup - coach the building events. Did the whole team for a couple years, then dropped back a couple years ago to just what I really enjoy and am best at; analyzing the problem, and guiding "how do you actually make that concept happen/work, with the materials and tools you can get your hands on?" It's a mindset and a process my dad taught me many years ago; one that I have really come to treasure and value. The devil, as they say, is indeed in the details. Taught this process to my 2 sons through Jr Hi and HS S.O.-10 yrs, and just continued with the team after they moved on to College; fun and oh, so rewarding to see someone come to understand, and then apply that understanding....

[fishman100]

Well, we finally got to being able to do full function testing, and start calibrating ‘the beast’ last weekend. With Regionals Mar 3, I was beginning to worry….
Its now been christened “Black Magic #33” for all the carbon fiber and black glue, and the 33 different materials in it and the ramp.

The team has been able to get a very interesting braking system working; it’s neither wingnut, nor string winder; counts wheel revs w/ very low friction; applies the brakes over about 10 to 15cm depending on target distance (which means no skidding), and is consistent on distance to …..something less than 2cm. Braking time is on the order of 1/10th of a sec (compared to no-brakes time at a given distance. The distance delta between whole wheel revolutions is dealt with by adjusting the paperclip position. Runs “the line” also to a precision of less than 2cm (at 6.5m, the most the hall at home will accommodate); speed looks decent (<2 sec to 5m). Everything seems sturdy and reliable. Now, if they make the time to do a good calibration workup from 5 to 10m, they should be ready to compete. We'll see in 3 weeks.....

Sounds complex but effective! How are you measuring the time it takes to brake (1/10 of a second) since the time is so small?

Also, here's a question for everyone: my paper clip is in the middle of the car (but still in between both axles) since the rules don't mention that it has to be on the outside, only "on either side," which my partner and I agreed was rather ambiguous. I was surprised when I was told on Saturday that it had be moved to the outside of the vehicle for future competitions. Where are your paper clips located?

[bearasauras]

Just wondering so we can write clearer rules.....how did you interpret "on either side of the vehicle between the front and rear axles"? Did you interpret it as either "inside or outside"?

[fishman100]

Just wondering so we can write clearer rules.....how did you interpret "on either side of the vehicle between the front and rear axles"? Did you interpret it as either "inside or outside"?

Well, in this case "side" has many meanings...it can mean slightly on the left or right side of the vehicle as well as inside or outside. Anyways, we interpreted the rules as "we can place the paper clip anywhere between the 2 axles" since "either side" since the point was accessible to the event supervisor.

Just wondering, why is a paper clip required rather than, say, a thin strip of wood or a toothpick?

[bearasauras]

Yah, side has many meanings, but it says "either side of the vehicle"

As for the pointer, the pointer itself doesn't really matter in terms of making a difference in the vehicle's run. However, it was simpler and clearer to describe the paperclip then to say "something pointy" or "something sharp"

[Balsa Man]

Sounds complex but effective! How are you measuring the time it takes to brake (1/10 of a second) since the time is so small?

Also, here's a question for everyone: my paper clip is in the middle of the car (but still in between both axles) since the rules don't mention that it has to be on the outside, only "on either side," which my partner and I agreed was rather ambiguous. I was surprised when I was told on Saturday that it had be moved to the outside of the vehicle for future competitions. Where are your paper clips located?

Braking time is just the (average from a few runs) of the difference in time at 6.5m- without braking, and then with braking. It takes a little more time to whoa up at 5m, naturally, and we expect less at 10m. It is a bit complex (60+ bits and pieces working in happy harmony); talk about it more a bit later in the season..... .

On the paper clip, we read as to one or the other of the sides- where it would be easy for judges to where the point was relative to the target point.

[JTMess]

Balsa Man, what thickness carbon fiber is your team using for the chassis and where did they find it? We have been having difficulties finding carbon fiber, which we may be using for states and we aren't sure which thickness will be rigid enough without holding it. Since the Lexan we considered wasn't rigid enough, we are now looking at other materials that will prevent deformation as the car reaches the bottom of the ramp.