Comments, notes, corrections and questions for the

Carbon Dragon Builders Manual

by Steve Adkins


Davis, Brian <This email address is being protected from spambots. You need JavaScript enabled to view it.> has created a Microsoft Word Document or an "electronic manual" which is an exact copy of the manual that is delivered with your plans.

The electronic manual is very easy to read in both electronic and printed version ... but, it allows for electronic searches for a specific item!  Each page is full size 8.5 by 11 inches rather than a reduce size with 4 pages on one page as provided Maupin, ltd.

Many of the comments below have been factored into the electronic version.

Jim Maupin is able to describe a fairly complex procedure very succinctly.  When I attempt to write a process, the text becomes overwhelmed by minutia.   To be honest, I was dissappointed by the builders manual and extremely pleased by the drawings.  On the other hand, much of the instructions are contained directly on the drawings.  EAA, Chapter 25 holds a plans night about once a year and Maupin's plans (drawings) are much better than most plans sets (which are in a few cases ... one large sheet!).  The drawings and handbook coupled with membership in the SHA are sufficient to enable one to create a Carbon Dragon.

The builder's manual appears to have been a preliminary rough draft; perhaps, with parts dictated to a tape recorder and transcribed by a typist ... or typed from handwritting ... thus, many errors are in the transcription process, not made by the designer.  Organization leaves much to be desired ... at least one section is repeated with slightly different instructions; perhaps an updated version was slotted in without removing the first version.  In any case, these errors are fairly easy to reason out and should not lead to building errors.  The purpose of this section is to get new builders a fast start and to provide an exchange of information regarding corrections and comments.

Below is what I have noticed so far ... mostly nits.  Much of the "changes" are adding merely clarification and headers to faciliate finding sections.  In the few cases where there is a serious problem, I will highlight the text with red and a graphic like this [tbd]  ... being, I'm glad we found it!  One final note:  The stuff below is one man's interpretation, subject to error ... if you have a better interpretation ... This email address is being protected from spambots. You need JavaScript enabled to view it. 

Light red, an assumption I have made ... 3 instance
Dark red, warning about critical error ...  0 (first 16 pages)
Dark yellow, warning about known changes being made by another builder which I deem wrong ... 1 instance
Green, a question I have that is unanswered ...   2
  ... seem to be rather low numbers.

Page 3, 5th line:
Replace "wear tight" with "near right" of "near one" ... to read, "Staple ... near one edge".

Page 4, 1st line:
What part of the stabilizer is place flat on the table?

Page 4, mid page just below first drawing
Place a dividing line with the heading "Elevator" just below the line.

Page 5, mid page:
Replace "8 to 18" with "8 to 8"

Just below the "6 to 16", etc. ... I made a drawing of the tow "layers"  to clarify the text description
36"                               24"                               16"                                  8"                                 C/L
|               2 tows            |                4 tows            |                6 tows             |               8 tows          |

With each line representing 2 pulls of 12k carbon fiber tows (or yarn).  This drawing represents the tow pattern for the center table of values.  As you can see, from the root section or CenterLine to the 8" point, the tows are 8 deep.

Page 6, second illustration:
After counting the layer ... I decided there is a total of 7 pieces of cloth required.

Page 6, 7th line:
I might replace "Squeeze off" with "Squeege off".  A nit.

Page 6, last line:
A hole for only one retention cotter pin ... I guess that is comparable to other sailplanes.  Which bolt?
How do you put the cotter pin in place? ... those bolts are deep in a nicely rounded nose D-section.

Page 7, Above the title "Female Hinges", I drew a dividing line.  No big deal.

Page 7, under 4th paragraph (ending with the word, " ... place"):
Draw a dividing line and add the title below the line, "Elevator Horn".

Page 10, the rudder horn
This item has puzzled many people.  Jonathon Pitts wrote a dynamite article with photos and detailed decription on how to perform this construction.  See Sailplane builder, September 1995, page 6.  Back issues are available from SHA.

Page 11, drawings of "plug" 2/3rds down the page with labels "top view" and "side view"
After I puzzled out what these parts are ... I have had arguments with other plans holders who disagree.
The first reaction, is that these are two views of the spruce "box" (see first line of text). But, they are really the drawing of the "plug"  that goes inside the box.  I assume the plug is made from balsa wood.  Also, be sure to note that the plug has rounded edges (see last line in first paragraph).  The intent is to have a portion of the carbon spar cap to be a hollow carbon square tube.  Structural engineers will attest to the stiffness of a hollow square tube ... much better than a round tube (and more resistant to denting (as when steel square tubes are used in fuselages in place of round tubes).

One builder is leaving out the plug.[tbd]  I totally disagree with this change unless some other compensating change is made coupled with design analysis.  A flat ribbon in this area may not be stiff enough to resist buckling under high G forces.

Also, note the upper-right most figure shows a vertical line in the spruce box cross-section.  This line represent the tip of the balsa plug.

Page 12, first row of fractions:
Replace "3/5" with "3/8" ... yes, I know this is obvious!

Page 12, second row of numbers:
There should be a drawing of square under 5/16 x 5/16  similar to the two drawing to the right.

Page 12, second paragraph:
Change "larger piece" to read, "larger plug piece".  ... well that's my guess ... what's yours?
Do the same in the spruce box sides?

Page 12, 3rd paragraph, 5th line:
Change "nails are" to read "nails in the plug are".

 .... Time to take a break ... having fun yet?  If not, wait for the carbon "pulls" for the spar cap! ....

Page 13, mid-way down the page on the right
I would replace the word "Ribs" with "Rib Numbers"

Page 13, bottom row of numbers:
Replace "14" with "15" ... also, between "23" and "19", you might want to place the total, "21"

Note:  The bottom row is the total number of tows at the corresponding position in the spruce box (don't add the Rib Number into the total!).

Page 13, second figure from the bottom:
I drew a side view of the carbon material which is a long wedge shape of carbon.

Page 14, immediately under the second paragraphs ending with the word, "...curves".
Draw a dividing line.  Below the line, write the heading, "Wing Ribs".

Page 14, to the left of the third paragraph:
Write "Nose" for nose ribs.

Page 14, to the left of the fourth paragraph and illustration:
Write "Center Ribs".

Page 14, draw a dividing line under the figure followed by the heading "Wing Main Spar Shear Web"