Bridge B/C

coachchuckaahs
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Re: Bridge B/C

Post by coachchuckaahs »

We have used that method (onset of buckling) for helicopter motorsticks. These were fairly small (1/8" square), and about 16" long. We did brace them, but we found that onset of buckling did not correlate 100% with density. It was the outliers (high onset of buckling combined with low density) that were selected. Out of 36 sticks for our last build, we selected 3 as "useable". These were sticks my students cut, from 5 or 6 different sheets. Sticks immediately adjacent on the sheet were not necessarily similar in performance!

While there may be some correlation, onset of buckling is different than bending stiffness. We also tested bending stiffness with a given length of wood stick, one end on a scale on top of a knife edge support, other end on a box to make it horizontal. We pushed down the middle of the stick until it met another box (defined deflection), and read the scale to get a representation of bending stiffness.

Coach Chuck
Coach, Albuquerque Area Home Schoolers Flying Events
Nationals Results:
2016 C WS 8th place
2018 B WS 2nd place
2018 C Heli Champion
2019 B ELG 3rd place
2019 C WS Champion
AMA Results: 3 AAHS members qualify for US Jr Team in F1D, 4 new youth senior records
ananyashah
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Re: Bridge B/C

Post by ananyashah »

Hi
I am competing in division B and have a question about the pass-thru block
Where does it loading block pass through? Does it go through the clear span, or does it go through the bridge?
Thanks
jgrischow1
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Re: Bridge B/C

Post by jgrischow1 »

ananyashah wrote: January 2nd, 2022, 9:56 am Hi
I am competing in division B and have a question about the pass-thru block
Where does it loading block pass through? Does it go through the clear span, or does it go through the bridge?
Thanks
It goes through the length of the bridge like a car or train would.

Hope I'm allowed to post this video; it's very helpful. I suggest everyone watch it:

https://drive.google.com/file/d/18hmCZE ... PqzOl/view
scioly2345
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Re: Bridge B/C

Post by scioly2345 »

Hi,
I have a question about the Div C pass through block,

So is there anywhere in the rules that says the bridge has to be still on the test supports while you put it through? At a recent comp they had me out on the load assembly with just the block and chain and show the pass through just until the chain,
But for an upcoming comp, I'm thinking of changing my design in case they make me set my bridge on the table, not move it, and put the pass through block through it
Because my current design the pass through goes well if I can move my bridge in my hand (but if stays on the table, it wont go through), and there's nothing in the rules stating that the pass through can't go in at an angle or be manuveured, it just needs to get from one side or another.
Does anyone have their own experiences from other comps with the pass through block to help me out?

Thanks a lot.
2016-2019 Brother Joseph Fox Latin School
2020-2022 Kellenberg Memorial High School
2022 events - Bridge, Write It Do It, Wright Stuff
God Bless and Rest In Peace Len Joeris (Balsa Man)
“for the betterment of science”
knightmoves
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Re: Bridge B/C

Post by knightmoves »

The rules are silent about where the bridge is when you run the pass-thru block though it, but they do say that the block must pass "horizontally". So it can't pass at an angle, or be significantly maneuvered.

The 50 cm dowel sticking out of the block somewhat limits the maneuvering you can do.

My interpretation of the "height" and "width" of the block is that those dimensions must be vertical and perpendicular to the bridge respectively.

I would expect the norm at a competition to be that the ES would expect you to set your bridge on a table, and move the block horizontally through it. But all our competitions have been satellite this year, so I don't know what other teams have done.
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Re: Bridge B/C

Post by jgrischow1 »

Often at in-person tourneys (if you're old enough to know what those are) the first time block of the day is the first taken when signing up for Bridge. I must be dumb because I don't immediately see the advantage. Help!!
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Re: Bridge B/C

Post by coachchuckaahs »

jgrischow1 wrote: January 30th, 2022, 5:19 pm Often at in-person tourneys (if you're old enough to know what those are) the first time block of the day is the first taken when signing up for Bridge. I must be dumb because I don't immediately see the advantage. Help!!
I don't know about Bridge, but in the flying events the more desirable slots tend to be late in the day, first to know what others have done, second to study any drift or other issues in the room, and third, warmer air tends to help a little tiny bit on rubber performance.

That said, I suspect that early time slots go fast, in WS as well, due to the balance of other events. For some reason my kids always seem to have more availability in that first slot, so we jump on it fast (or whatever timeslot fits their schedule) so they do not have to trade out events to still do WS.

Are there any factors, other than risking damage, that would make Bridges more favorable in the am? I cannot think of any.

Coach Chuck
Coach, Albuquerque Area Home Schoolers Flying Events
Nationals Results:
2016 C WS 8th place
2018 B WS 2nd place
2018 C Heli Champion
2019 B ELG 3rd place
2019 C WS Champion
AMA Results: 3 AAHS members qualify for US Jr Team in F1D, 4 new youth senior records
jgrischow1
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Re: Bridge B/C

Post by jgrischow1 »

coachchuckaahs wrote: January 30th, 2022, 5:36 pm
jgrischow1 wrote: January 30th, 2022, 5:19 pm Often at in-person tourneys (if you're old enough to know what those are) the first time block of the day is the first taken when signing up for Bridge. I must be dumb because I don't immediately see the advantage. Help!!
I don't know about Bridge, but in the flying events the more desirable slots tend to be late in the day, first to know what others have done, second to study any drift or other issues in the room, and third, warmer air tends to help a little tiny bit on rubber performance.

That said, I suspect that early time slots go fast, in WS as well, due to the balance of other events. For some reason my kids always seem to have more availability in that first slot, so we jump on it fast (or whatever timeslot fits their schedule) so they do not have to trade out events to still do WS.

Are there any factors, other than risking damage, that would make Bridges more favorable in the am? I cannot think of any.

Coach Chuck
Good point about the flying events. Yeah, I was thinking maybe "humidity" or whatever, but anybody serious enough to worry about humidity would presumably be storing their bridge in an air-tight box with silica.

I would also be interested in knowing before they changed the rules to make clear the sand must weigh between 15,100 g and 15,200 g if a _later_ time slot was more desirable because perhaps after each test a little more sand leaked out and by the time 3:00 rolled around the bucket only weighed 14,782 g or whatever for the more careless supervisors.
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Re: Bridge B/C

Post by scioly2345 »

What size bass do you guys use (if you use bass)? Or any other kind of wood for tension size?
2016-2019 Brother Joseph Fox Latin School
2020-2022 Kellenberg Memorial High School
2022 events - Bridge, Write It Do It, Wright Stuff
God Bless and Rest In Peace Len Joeris (Balsa Man)
“for the betterment of science”
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Re: Bridge B/C

Post by sluelway1973 »

So we want to clarify the pass through block. Must the pass through block pass through unobstructed on a level plane or can the block pass through horizontally but on different planes?
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