Packing volume tolerances + / -

[ScoopUK 0]

Hi,

I'm turning to the community as I haven't yet got a response from my container manufacturer (pre-empting the smart arse stock reply). Hopefully they are busy building my gorgeous rig rather than answering stupid e-mails

I've read many times that as a rough rule of thumb you can generally go up or down a size of canopy (assuming its a like for like type of canopy).

My container is sized for a specific canopy which I have already but I may buy another as I just fancy a new one and I've been offered a good deal which makes it more worthwhile.

The new canopy I'm looking at, depending on which packing volume figures you believe, may be larger in volume anything from 4-29 cu in. Is this a possible issue or no problemo? I don't really have an understanding of how much 29 cu in is in my head.

Ta very much

[Quagmirian 40]

Twenty nine cubic inches is about the difference between a Sabre 190 and a Sabre 210, one size in other words. You can tell us what canopy and container combo you are looking at, and see if anyone else is using it, and with how much ease.

[BeteNoire 0]

ScoopUK

I don't really have an understanding of how much 29 cu in is in my head.

The cube root of 29 is about 3.07, or in other words a cube that is 3" on each side. That's not much volume. It's about the size of two doughnuts stacked one on top of the other.

[JerryBaumchen 1,048]

Hi Scoop,

Quote

I don't really have an understanding of how much 29 cu in is in my head.

Few people do. Try using this formula: Sphere = (4/3) pi r^3

Do this: sphere = (4/3) pi r 3 = 29 cu inches

Now solve for r and then you will know what a ball that has a volume of 29 cu inches is. This should get you into some ballpark idea.

No, I am not going to do your homework for you.

Best of luck,

JerryBaumchen

[Quagmirian 40]

A radius of about 1.9 inches sir. Anyway, a better solution to the problem is the imagine a cube with edges of length L and volume V. In this case that makes a cube with sides of about 3 inches.

[JerryBaumchen 1,048]

Hi Quag,

Quote

. . .sir . . .

Let's have none of that 'sir' stuff, OK.

Just after I posted that info I got to thinking and came up with a better idea.

1. Since I do not know, I will make an assumption that his main pack tray is 12 inches wide ( east to west ).
2. Since I also do not know, I will make an assumption that his main pack try is 6 inches long ( north to south ).

Take 12 x 6 = 72

ETA to change this: Now take this 72 cu inches and divide by his 29 cu inches and you get 0.4 inches thick. So a canopy of 30 cu inches greater in volume ( for many rigs ) would be about 3/8 inches thick.

Something to do on a rainy afternoon, ETA: If I was paying attention.

JerryBaumchen

[DBCOOPER 1]

ScoopUK

I've read many times that as a rough rule of thumb you can generally go up or down a size of canopy (assuming its a like for like type of canopy).

I think thats an old rule of thumb. I think todays manufactures make the rig for the canopies you tell them your going to put in it. Thats been my experience with Sun Path and UPT.

Replying to: Re: Stall On Jump Run Emergency Procedure? by billvon

If the plane is unrecoverable then exiting is a very very good idea.

[BeteNoire 0]

JerryBaumchen

Just after I posted that info I got to thinking and came up with a better idea.

1. Since I do not know, I will make an assumption that his main pack tray is 12 inches wide ( east to west ).
2. Since I also do not know, I will make an assumption that his main pack try is 6 inches long ( north to south ).

Take 12 x 6 = 72

Now divide by his 29 cu inches and you get 2.48 inches thick. So a canopy of 30 cu inches greater in volume ( for many rigs ) would be about 2 1/2 inches thick.

I think you divided at the end when you should have multiplied.

A pack tray that is 12 x 6 is 72 sq. inches. So a one-inch thick layer of fabric on top of that would be 72 cubic inches. But the 29 cubic inches in question is only 40% of 72 cubic inches. So the layer of space that 29 cubic inches would occupy is only 40% of that one inch layer, or .4 inches thick. And .4 inches is a layer only about three-eighths of an inch thick.

I don't think there's many of us whose pack trays are so tight that we couldn't stuff another 3/8" layer of fabric in there.

[JerryBaumchen 1,048]

Hi out there,

Wow, I just keep making this worse.

Quote

Now take this 72 cu inches and divide by his 29 cu inches and you get 0.4 inches thick.

Wrong, wrong & wrong again.

Now take this 29 cu inches and divide by his 72 cu inches and you get 0.4 inches thick.

That's much better.

Maybe that is why I was never a 4.0 student.



JerryBaumchen

[theonlyski 3]

JerryBaumchen

Maybe that is why I was never a 4.0 student.

I couldn't even spell 4.0!

"I may be a dirty pirate hooker...but I'm not about to go stand on the corner." iluvtofly
DPH -7, TDS 578, Muff 5153, SCR 14890
I'm an asshole, and I approve this message

[sundevil777 93]

The 72 was square inches, not cubic.

If you're going to make fun of yourself, then expect us to pile on...

People are sick and tired of being told that ordinary and decent people are fed up in this country with being sick and tired. I’m certainly not, and I’m sick and tired of being told that I am

[JerryBaumchen 1,048]

Hi Cliff,

Quote

If you're going to make fun of yourself, then expect us to pile on...

Have at it; I deserve it for the pathetic exercise.



JerryBaumchen

PS) Isn't there some rule/old adage about do not do things when you are tired? I just might learn that one day.

[BeteNoire 0]

JerryBaumchen

Just after I posted that info I got to thinking and came up with a better idea.

1. Since I do not know, I will make an assumption that his main pack tray is 12 inches wide ( east to west ).
2. Since I also do not know, I will make an assumption that his main pack try is 6 inches long ( north to south ).

Take 12 x 6 = 72

I think you divided at the end when you should have multiplied.

A pack tray that is 12 x 6 is 72 sq. inches. So a one-inch thick layer of fabric on top of that would be 72 cubic inches. But the 29 cubic inches in question is only 40% of 72 cubic inches. So the layer of space that 29 cubic inches would occupy is only 40% of that one inch layer, or .4 inches thick. And .4 inches is a layer only about three-eighths of an inch thick.

I don't think there's many of us whose pack trays are so tight that we couldn't stuff another 3/8" layer of fabric in there.

[Festus 0]

I think you divided at the end when you should have multiplied.

A pack tray that is 12 x 6 is 72 sq. inches. So a one-inch thick layer of fabric on top of that would be 72 cubic inches. But the 29 cubic inches in question is only 40% of 72 cubic inches. So the layer of space that 29 cubic inches would occupy is only 40% of that one inch layer, or .4 inches thick. And .4 inches is a layer only about three-eighths of an inch thick.

I don't think there's many of us whose pack trays are so tight that we couldn't stuff another 3/8" layer of fabric in there.

You betcha!

[BeteNoire 0]

Good math! I'm glad someone was allowed to specify it.

[JerryBaumchen 1,048]

Hi Festus,

Quote

I think you divided at the end when you should have multiplied.

A long time ago I learned that I cannot walk on water.



What I should have done, is stayed completely away in the first place. All I continued to do is make myself look like a mathmatical idiot.

There are those days when one wishes he/she should have simply stayed in bed.

JerryBaumchen

PS) And with most packtrays larger than 12 x 6, it is not even as much as 0.4 inches, which is about 3/8".

Now, did I get that right?