Hey everyone,
I'm sorry if it comes across as a bit selfish or alike, but I'm in a rush for school. In two days I have to order my parts and give my teacher the plans, and I haven't gotten any luck with the time stretching designer I hired before.
I'm looking to replace the round port design by a slot port on bagby's design of The Tangos. I need them to perform equally well as the round ported ones but I don't know how to do it.
I'd appreciate it if someone could help me out, and save my GIP.
Thanks in advance,
Anna
I'm sorry if it comes across as a bit selfish or alike, but I'm in a rush for school. In two days I have to order my parts and give my teacher the plans, and I haven't gotten any luck with the time stretching designer I hired before.
I'm looking to replace the round port design by a slot port on bagby's design of The Tangos. I need them to perform equally well as the round ported ones but I don't know how to do it.
I'd appreciate it if someone could help me out, and save my GIP.
Thanks in advance,
Anna
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Then you need a slot port with the same cross-sectional area as the 2" diameter round port, it needs to be 7.75" long, and once you've done that, you can play with the cabinet depth a little to get the volume the same as the original.
Hint: the volume of air inside the port is the same for the round or slot port, so the volume you've used is the difference between the volume of the wood for the slot port, and the volume of whatever material the round port was made of.
Maths lesson:
The cross-sectional area of a cylinder is just the area of the circle. Circles are unique in that a single number can be used to find a lot of different things. That number is the radius, the distance from the middle of the circle to the edge. The radius is also half of the diameter. If in doubt, draw it out - that'll make it pretty obvious.
Now, there are some simple equations we can use to find out various things about this circle once we know it's radius.
Lets say I've got one of those plastic ports that have a flare at one end, and I want to find out the length of a strip of foam I need to go around it.
Going all the way around is called the circumference, and it's simple to find. C = 2*(pi)*r
Where..
C = circumference
(pi) = 3.141592654 (a unique number that perfectly describes the ratio of a circle's circumference and diameter)
r = radius.
Since the diameter, d, is equal to 2*r, we can also write C = (pi)*d
So far, all of our units are a distance, and they're consistent. A circle with a radius of 0.5cm will have a circumference of 3.14159...cm. A circle with a radius of 0.5m will have a circumference of 3.14159...m.
The area of a circle is a little more tricky, since we're starting out with the radius, which is measured as a distance, and we're getting out an area, which is measured as distance^2 (squared)
A=(pi)*r^2, or A=(pi)*r*r. Those two equations mean the same thing,. Raising something to the power of 2 means you multiply it by itself. A power of 3 means you multiply it again. You'll learn more about that later in your academic career.
In your case, the port is 2" diameter. That means the radius is 1", or 2.54cm since you really ought to be working in Metric, and don't let the Americans tell you otherwise.
So, r=2.54cm. Put that into the area equation and see what you get.
Chris
Hint: the volume of air inside the port is the same for the round or slot port, so the volume you've used is the difference between the volume of the wood for the slot port, and the volume of whatever material the round port was made of.
Maths lesson:
The cross-sectional area of a cylinder is just the area of the circle. Circles are unique in that a single number can be used to find a lot of different things. That number is the radius, the distance from the middle of the circle to the edge. The radius is also half of the diameter. If in doubt, draw it out - that'll make it pretty obvious.
Now, there are some simple equations we can use to find out various things about this circle once we know it's radius.
Lets say I've got one of those plastic ports that have a flare at one end, and I want to find out the length of a strip of foam I need to go around it.
Going all the way around is called the circumference, and it's simple to find. C = 2*(pi)*r
Where..
C = circumference
(pi) = 3.141592654 (a unique number that perfectly describes the ratio of a circle's circumference and diameter)
r = radius.
Since the diameter, d, is equal to 2*r, we can also write C = (pi)*d
So far, all of our units are a distance, and they're consistent. A circle with a radius of 0.5cm will have a circumference of 3.14159...cm. A circle with a radius of 0.5m will have a circumference of 3.14159...m.
The area of a circle is a little more tricky, since we're starting out with the radius, which is measured as a distance, and we're getting out an area, which is measured as distance^2 (squared)
A=(pi)*r^2, or A=(pi)*r*r. Those two equations mean the same thing,. Raising something to the power of 2 means you multiply it by itself. A power of 3 means you multiply it again. You'll learn more about that later in your academic career.
In your case, the port is 2" diameter. That means the radius is 1", or 2.54cm since you really ought to be working in Metric, and don't let the Americans tell you otherwise.
So, r=2.54cm. Put that into the area equation and see what you get.
Chris
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Grab some paper with squares on it and draw it out. A 2x2 square does not have the same area as a 2" diameter circle.
Chris
True, my bad. I was in a hurry haha. But it should be the same as 1x2, though, right? That's half, just like a triangle's half of its coefficient rectangle. Was my theory right though?
And afterwards would you mind checking what I tried?
Thanks.
Oh and hey, I'm making the box from the imperial plans and i'll do the port in the imperial plans too. Then I'll just rework it to metric.
Well it's rather hard for me as I never learned the math vocabulary in English. I'm not a native, after all.
As that's still not a valid excuse: We don't. We don't get taught maths in the special school for special kids I go to. Let's keep it to an 'autistic kids' school
does any of your perhaps have another way of communicating about this temporarily? Text talking is way too hard for me if I want to explain or ask things clearly.
But from what I understand of maths: The slot port's "face" has to have the same surface area as the circle's if I make the slot port 7 inches deep, excluding wood? That means that if I make it half of 7 inches, I technically 'stack' the 'cut off piece' ontop of the other and have double the surface area on the front of the port? I don't like wide short ports, but air velocity also plays a role. Will some of you be able to tell me if the air velocity'd be too much and it'd chuff?
I'm not sure but if I can make the port 7" deep that'd be the same air velocity per square inch as the circle one right?
I'm just trying to understand this. Pardon my possible ignorance.
But from what I understand of maths: The slot port's "face" has to have the same surface area as the circle's if I make the slot port 7 inches deep, excluding wood? That means that if I make it half of 7 inches, I technically 'stack' the 'cut off piece' ontop of the other and have double the surface area on the front of the port? I don't like wide short ports, but air velocity also plays a role. Will some of you be able to tell me if the air velocity'd be too much and it'd chuff?
I'm not sure but if I can make the port 7" deep that'd be the same air velocity per square inch as the circle one right?
I'm just trying to understand this. Pardon my possible ignorance.
so that means that when the inner width of my cabinet is 7 inches wide and the round port is 2".
Area = Pi * (radius x 2)
Area of Circle = 3.1415 * 2 = 6.283 square inches
The area of a square or rectangle is: Length * Width = Area of Rectangle.
The width is 7, the missing value is x aka Length.
x * 7 = 6.283 Inch²
so 6.283 Inch² / 7 = x
6.283 Inch² / 7 = 0.897 Inch.
Answer: The surface area of the front face of the slot port, when length is equal to round port's length, and the width of the port is fixed to 7 inches, the port has to be 0.897 Inches tall?
Then I just need to add a little volume to the box in the depth, equal to the port's wood's occupied space. Volume calc, yeah!
Length * Width * Thickness = Volume.
7 * 7 * 0.75 = 36.75 inch³. Right?
I hope I got it right. I know maths but I don't tend to link Ideas to Math. Once the switch switches over though, I'm all over.
Area = Pi * (radius x 2)
Area of Circle = 3.1415 * 2 = 6.283 square inches
The area of a square or rectangle is: Length * Width = Area of Rectangle.
The width is 7, the missing value is x aka Length.
x * 7 = 6.283 Inch²
so 6.283 Inch² / 7 = x
6.283 Inch² / 7 = 0.897 Inch.
Answer: The surface area of the front face of the slot port, when length is equal to round port's length, and the width of the port is fixed to 7 inches, the port has to be 0.897 Inches tall?
Then I just need to add a little volume to the box in the depth, equal to the port's wood's occupied space. Volume calc, yeah!
Length * Width * Thickness = Volume.
7 * 7 * 0.75 = 36.75 inch³. Right?
I hope I got it right. I know maths but I don't tend to link Ideas to Math. Once the switch switches over though, I'm all over.
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