Carbon Dragon - spreadsheet for parts in wing

Carbon Dragon Wing

A spreadsheet containing a complete list of all parts and materials with their dimensions and weight SEE WARNING BELOW

Most Carbon Dragons exceed the design weight. This is true for all homebuilts. The Carbon Dragon was designed and built to be a proof-of-concept ... not to be a production glider. Maupin's theory about additional parts for the glider are, "... But remeber, when you think of adding anything, the basic principal is ... go out in the yard and throw it up in the air. If it comes down ... it's too heavy." [Builder's Manual, page 9]. The prototype has almost no finish coat to save weight. According to Gary Osoba, most of the additional weight in newer Carbon Dragons comes from building a stronger wing. Also, some additional weight comes from better weather-proofing.

I have developed an Excel spreadsheet (download is 49, 152 Bytes) which contains the mass balance of all the parts for one wing panel for the Carbon Dragon.
Note: to download this Excel file Using Microsoft Internet Explorer
- click the right button and a pull-down menu will appear
- click on Save Target As ...
Note: to download this Excel file Using Netscape Navigator
- click the left button, a notice should appear to either download the file or open it (in Excel or Works)
- if Netscape attempts to open the file as a *.htm window, you need to change your preferences
(Email me for help)
I will be re-editing the spreadsheet soon, so you might want to download later after this line is removed.

The intent of this spreadsheet is to provide the foundation for analyzing design changes.

For example, suppose design considerations for building a stronger wing lead you to consider doubling the spar web or adding more spar web vertical stiffeners. What is the weight penalty as contrasted to the improvement in strength and torsional stiffness. My spreadsheet answers the first question.
Suppose you decide to eliminate the doors for foot launch ... how much weight is saved? How can I best put that weight saved into a stronger wing?

Also, the spreadsheet provides a "parts locator" for most of the parts by referencing the applicable drawing and location on the drawing. [Note: For locating a part the following convention is used, so a part may be found on Dwg 9B1

    A    B    C    D    E
1        xxx
2                                    So look on Drawing 9 about part way across on the top (see xxx)
3
4
5

Sample information found on the spreadsheet:

One wing panel (including aileron)	704 parts	34.3 pounds	.
Design information for wing panel	.	37.5 pounds	.
1/32nd plywood Spar Web	.	27.2 oz	.
Vertical Stiffeners	7 parts	0.5 oz	Dwg 7 - B3
Sparcap carbon tows	.	1 pound	.
One aileron	.	7.6 pounds	.
Aileron lead balance weight (ref: page 17 of builder's manual)	.	.	11.85 oz (calculated) 0.75 # (manual)

Note: parts weights are based either on calculation based on the density and dimension of the part and/or actually weighing finished parts. Also, I have compared weights from Johnathon Pitts, H.F. Blanton, Mark Crist and others. Accounting for the epoxy between joints is the most difficult number to estimate. I have bought a precision scale and will be improving this estimate. Absolute accuracy is not so important as the relative weights in making design decisions.

If you have trouble down loading the file, send me a Email and I will forward the spreadsheet as an attachment. S. Steve Adkins

WARNING: Do not make design changes without proper design analysis. See Irv Culver's analysis for the Windrose to develop an appreciation for the effort required. In EAA Experimenter, there was a photo of a busted wing on an acrobatic homebuilt ... the owner had added a stiffening plate behind the spar ... the wing broke just outside of the plate. The point is, adding strength in one area may move the forces to an area not design to carry the stress.

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