Topic
Exact Quilt Fill Quantity
Forum Posting
A Membership is required to post in the forums. Login or become a member to post in the member forums!
Home › Forums › Gear Forums › Make Your Own Gear › Exact Quilt Fill Quantity
- This topic is empty.
-
AuthorPosts
-
Nov 13, 2006 at 3:11 pm #1220208
Here is a way to find out the exact quantity of down needed to fill a quilt. The formulation shown below is good for a 2 inch thick layer revolved around a 2 foot radius.
The basic idea is to determine the area between the two lines I used to construct a basic quilt shape and revolve that area halfway around the x-axis.
QUILT EQUATIONS
Foot:
y=x^(.5)+1
y=x^(.5)+1.167Body:
y=0.0283x+1.83
y=0.283x+2Area/Volume Calcuation
(S will be used as integral sign)Volume =
=(3.14/2) { S (x^(.5)+1.167)^2-(x^(.5)+1)^2 + S (0.283x+2)^2-(0.0283x+1.83)^2}The first integral is evaluated from 0 to 0.723 and the second is from 0.723 to 6.
Volume = (3.14/2)(0.3985 + 3.60654) = 6.29109 ft^2
Fill Calculation
6.29109(12^3) = 10871 cubic inches
10871 / 800 = 13.6 oz
It should be simple to replace thickness layer with another thickness(like 1 inch or 1.5 inches), or to make the sleeping bag longer or shorter than 6 feet(just change the linear slope so that it intersects that point).
I hope this is useful for you guys.
-
AuthorPosts
- You must be logged in to reply to this topic.
Forum Posting
A Membership is required to post in the forums. Login or become a member to post in the member forums!
Our Community Posts are Moderated
Backpacking Light community posts are moderated and here to foster helpful and positive discussions about lightweight backpacking. Please be mindful of our values and boundaries and review our Community Guidelines prior to posting.
Get the Newsletter
Gear Research & Discovery Tools
- Browse our curated Gear Shop
- See the latest Gear Deals and Sales
- Our Recommendations
- Search for Gear on Sale with the Gear Finder
- Used Gear Swap
- Member Gear Reviews and BPL Gear Review Articles
- Browse by Gear Type or Brand.