DIY Differential Cut UQ Calculator

[Kayak_Medic]

Interesting.
Just tried it here and all the boxes in the input column are editable.
Which worksheet do you find the problem, the Metric Input sheet, or the Imperial Input sheet?
(note - you cannot edit the imperial figures on the metric sheet and vice-versa on the Imperial one)

That's the issue.... I was trying to edit an imperial value on the metric sheet

[Kayak_Medic]

So, I'm finally about to bite the bullet and attempt my first UQ. According to the calculator, my outer shell fabric needs to be 62.46 inches wide for a 48" wide UQ with 3" baffle height. Problem is, my fabric is only 58" wide. What are you guys doing to make up for the lack of width? I'm assuming that 7" of that is used to box the sides of the quilt 3," so couldn't I just add that 7" to the bottom fabric instead?

[PharmGeek]

So, I'm finally about to bite the bullet and attempt my first UQ. According to the calculator, my outer shell fabric needs to be 62.46 inches wide for a 48" wide UQ with 3" baffle height. Problem is, my fabric is only 58" wide. What are you guys doing to make up for the lack of width? I'm assuming that 7" of that is used to box the sides of the quilt 3," so couldn't I just add that 7" to the bottom fabric instead?

I’m not sure how each calculator is doing it but I see the “walls” as not part of the differential...




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[Kayak_Medic]

I’m not sure how each calculator is doing it but I see the “walls” as not part of the differential...




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I used the calculator from this thread. I decided a 44" wide UQ would be sufficient. If you look at my results, you'll see the wall around the quilt is figured into the outer layer. You can see this when you multiply the outer layer baffle width by 9 since that's how many baffles it's calculating for. You'll see the calculator adds 7" in both directions to count for the 3" wall and 1/2" seam allowance.

Screenshot_20180202-003613.jpg

[PharmGeek]

The added width problem is real

I’ve asked Dutch for example if we can get a wider calendered fabric - basically not possible at this point.

If you want like 65 inches then the only option is to cut extra lengths of fabric and sew them on to effectively widen the fabric

Most just narrow up the UQ to where is works

I made my wife an UQ that had 3 inches of loft - got the same result as you and sewed on added width




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[Merganser]

Looks like Deopbox won't let me change the permission settings unless I upgrade to "professional" (bah humbug).
Have you tried the link to the one on the forum,
Attachment 157672

Thanks for sharing your update!

[Car Camper]

When I started out making my DIY down-filled underquilt, I knew I would need to calculate my overall material size to have a sufficient amount of outer shell material to accommodate the "lumps" inherent in the differential design, as well I would have to calculate the required amount of down to fill the baffle volume. The Red River Gorge Underquilt How-To provides some nice starter calculations for fill volume but lacks the means to calculate the outer shell area. As tends to be habitual for engineers, I fired up Excel and created a spreadsheet for calculating material requirements and down fills for underquilts based on the cross-sectional area of the baffles.

The sheet allows you to specify your finished quilt dimensions and baffle design, and will return material dimensions for construction and the amount of down (for an input fill power) required to fill it. Down fill can be adjusted via the Over/Understuff field or by directly altering the "Total Oz. of Down" field.

Two experimental features are also included:
- An approximation of the quilt's overall weight (minus suspension) based on the material sizes, fabric weights, and down, with 15% allowance for stitching and seams.
- A VERY experimental calculation of the quilt's theoretical temperature rating, based on the published design specs for some Underground and HammockGear quilts.

I've attached the sheet for the community's perusal, please give it a look and feel free to suggest any improvements to be made. If you want to un-protect the sheet to play with the formulas, the password is "hammockforums".


-Trevor

Thanks a lot for making that! I used it to help calculate mine! Worked out really well.

[bikerbobber]

I realize this is an old thread but,
Can anyone tell me if any of the calculators were accurate for a winter rated UQ?
I'm looking to make a -20 ish UQ and have seen some serious differences in ratings and finished weight.
I'm thinking 4.5" baffles on a 45" wide with 8 or 9 baffles.
Also wondering if anyone knows the difference in horizontal vs longitudinal baffles?

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[Cruiser51]

It works, I have made a few -20C quilts ....

Also, when you are using taller baffles like that, having a few more is likely better, because it tends to stay vertical, as they get wider baffles can sort of "smush". There is actually a thread that posted a suggested aspect ratio between height and width ... maybe some one else will remember and post that.


Brian

[bikerbobber]

Thanks Brian!
I've started my own build thread.
How many baffles do you think? Vertical or horizontal?


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