Sand Loading Device

[Crazy Puny Man]

We team had one of those (or has, I guess) it's very sturdy and all, but it really dont like the gate on it and for the price it could be a built a little nicer (of course, I don't know if ours is as it came or had been changed up, so there's that).

Forgive me for my ignorance here, but is there anything wrong with just pouring the sand scoop by scoop into the bucket?

[iwonder]

There's nothing _wrong_ with it, but it's nicer to have the smooth and even flow from these kinds of loaders. The scoop is a little slower, and it can cause the bucket to jerk around or depending on how careful you are dropping the sand into the bucket might be an issue.

Also, with these you can load faster, which is beneficial since you want to get the load on and off the structure as fast as possible.

Of course how much that matters depends on where you are from an effciency standpoint. It won't help a team just starting much might it might differentiate first and second at higher competitions.

[chinesesushi]

Nothing wrong with sand loading by hand, but most official competitions use that exact launcher as far as I can tell. I load by hand at home and at school as we do not have one of these machines . And yeah, iwonder, I agree it could be built a little better for the price XD.

[iwonder]

Honestly the only places I've seen an auto loader used were at my schools invite and I think one other large invitational. Our state contest doesn't use one, but I'm pretty sure nationals has one every year.

[calgoddard]

Quote "Forgive me for my ignorance here, but is there anything wrong with just pouring the sand scoop by scoop into the bucket?"

Yes, "free pouring" can lead to inaccurate scores. As the student is pouring, the structure collapses, but the student intentionally or unintentionally pours the sand remaining in the scoop into the bucket in one fast motion, almost simultaneously with the collapse. Some ECs let this go, and the score is calculated based on the weight of every bit of sand in the bucket, when the balsa structure actually collapsed before some of that sand was carried by the structure. Some ECs reach into the bucket and grab a handful of sand of a size they feel is "fair" under the circumstances, and remove it before weighing the bucket, in an attempt to remove the amount of sand they felt was poured into the bucket after the structure collapsed. Clearly this is a very inaccurate "fix."

In general, the automated sand loaders lead to more equitable scores. However, I have seen students, again intentionally or unintentionally, have the chain between the loading block and the bucket partially hung up on, or frictionally engaged with the loader spout in some fashion. This became evident at a State competition when a number of structures in a row carried the full load when clearly that was not physically possible by casual inspection of the size and design of the balsa structures themselves. By the time the error was recognized it was too late to prove it. The winner of the event was then the lightest balsa structure that had its chain hung up on the spout regardless of its design and true load carrying ability. Pictures and videos of competitors' devices are not allowed at our regional and state competitions, so there is no visual evidence upon which to base a protest.

[John Richardsim]

Honestly the only places I've seen an auto loader used were at my schools invite and I think one other large invitational. Our state contest doesn't use one, but I'm pretty sure nationals has one every year.

Correct me if I'm wrong, but I'm pretty sure boomilever was loaded by hand at 2013 nationals. Not sure if it was at 2014 nationals though...
If possible, you should definitely consider loading a bridge by hand prior to any competition that may have you load by hand (especially if they've never used sand loading devices in the past). This past season, after states, my team's boomilever competitors practiced loading by hand on several boomilevers (including one I built; it didn't fare out too well).

[iwonder]

However, I have seen students, again intentionally or unintentionally, have the chain between the loading block and the bucket partially hung up on, or frictionally engaged with the loader spout in some fashion. This became evident at a State competition when a number of structures in a row carried the full load when clearly that was not physically possible by casual inspection of the size and design of the balsa structures themselves.

What style of loader/chain was being used in that case? There aren't a lot of styles that I can imagine being able to catch on the loader and support 15kg (I don't think any chain would be elastic enough to 'split' the load between the bucket and the loader-support)

Oh, and yeah that year might not've loaded by machine. That line came from my coach (as reasoning to have bought a very expensive autoloader many years ago).

[hren science]

forgive me but im new to scioly. so do you have to make a sand loading device?

[bernard]

forgive me but im new to scioly. so do you have to make a sand loading device?

No, regional, state, and national tournaments provide any testing apparatuses needed to run an event. If your school hosts its own invitational, it may need to provide the loading device/testing apparatuses.

[calgoddard]

Quote: "What style of loader/chain was being used in that case?"

The state competition I referenced was several years ago. No pictures or video were allowed, except of your own team. I did not take any pictures of our teams' tower mounted on the sand loading device in question. I do not currently have any access to any such pictures.

To the best of my recollection, the sand loader that was used had a configuration similar to the commercial one identified above. It had a lever that was moved forward to dispense the sand, and the sand automatically stopped dispensing once the structure collapsed. The problem was that the chain from the loading block draped over some portion of the spout and/or gate mechanism, resulting in the loader carrying the weight of the bucket and sand deposited therein, at least for a major portion of the loading sequence during the competition loading of at least some of the balsa structures, including, apparently, the announced winner.

I am not inferring that the lever actuated sand loader in question was improperly designed or built, just that when using such a sand loader, care needs to be taken to ensure that the loading block, bucket and chain are correctly set up for each balsa structure that is tested.