AERODYNAMIC
ANALYSIS
OF
THE
CARBON
DRAGON AIRFOILS
About the author:
Alejandro Ramirez-Pineiro (30) has the degree of
Bachelor of Science in Mechanical Engineering, earned at the Universidad
Tecnologica Metropolitana of Santiago, Chile. At this moments he is working as
a Composite Materials Engineer at ENAER, building a 100% composite JAR 23
airplane (visit www.euro-enaer.com ).
Also he is building a modified Carbon Dragon, planned to fly during the first
quarter of 2000. You can reach him at alejo@netline.cl
.
Introduction:
The Carbon Dragon is an ultralight, high
performance glider. This glider was conceived by Jim Maupin who also
designed the famous Woodstock sailplane and the Windrose motorglider.
With encouragement from Irv Culver, who promised to "run the
numbers", Jim Maupin finished the design and built the prototype. As
a result, Jim Maupin with an assist from co-designer Irv Culver, produced an exciting
sailplane.
Scope of the study:
The proposal of this study is getting aerodynamic data
that can be used for the structural modifications of the original Carbon
Dragon. This data will be used also
on the study of the longitudinal static
stability of the modified glider. All the aerodynamic values presented here can
be useful to actual or future builders for helping their own studies.
For preliminary design,
the values presented in this report are excelent, but must to keep in mind that
the data presented here was developed by a computer software, so, to get more
“real” values, the reader will have to do wind tunnel testing.
Getting the coordinates:
To get the coordinates
of the wing root and wing tip airfoils, the original drawings of the ribs
number 1 and number 13 where divided on 88 stations on the root and 58 stations
on the tip. The mesures where taken with an accuracy of + - 0.5 mm. The job was done by my building
partner Miguel Eyquem.
With the coordinates
obtained in milimiters, the next step was to convert them in fractions of
chord. For this task I used an electronic spreadsheet.
(values on fraction of chord)
|
Coord |
x |
Yu |
Yl |
|
Coord |
X |
Yu |
Yl |
|
0 |
0 |
0 |
0 |
|
51 |
0.361367 |
0.116951 |
-0.07819 |
|
1 |
0.001314 |
0.00657 |
-0.00591 |
|
52 |
0.374507 |
0.115966 |
-0.07819 |
|
2 |
0.003285 |
0.010184 |
-0.00828 |
|
53 |
0.387648 |
0.114652 |
-0.07806 |
|
3 |
0.00657 |
0.014783 |
-0.0115 |
|
54 |
0.400788 |
0.113338 |
-0.07779 |
|
4 |
0.009855 |
0.018725 |
-0.0138 |
|
55 |
0.413929 |
0.111695 |
-0.0772 |
|
5 |
0.013141 |
0.022339 |
-0.01577 |
|
56 |
0.42707 |
0.110381 |
-0.07668 |
|
6 |
0.016426 |
0.026281 |
-0.01774 |
|
57 |
0.44021 |
0.108541 |
-0.07615 |
|
7 |
0.019711 |
0.029566 |
-0.01971 |
|
58 |
0.453351 |
0.106767 |
-0.0753 |
|
8 |
0.022996 |
0.032852 |
-0.02102 |
|
59 |
0.466491 |
0.105125 |
-0.07424 |
|
9 |
0.026281 |
0.035808 |
-0.02234 |
|
60 |
0.479632 |
0.103154 |
-0.07326 |
|
10 |
0.029566 |
0.038765 |
-0.02431 |
|
61 |
0.492773 |
0.101183 |
-0.07194 |
|
11 |
0.032852 |
0.041393 |
-0.02562 |
|
62 |
0.505913 |
0.099212 |
-0.0707 |
|
12 |
0.036137 |
0.044678 |
-0.02727 |
|
63 |
0.519054 |
0.096912 |
-0.06932 |
|
13 |
0.039422 |
0.047306 |
-0.02858 |
|
64 |
0.532194 |
0.094941 |
-0.06754 |
|
14 |
0.042707 |
0.049934 |
-0.02989 |
|
65 |
0.545335 |
0.092576 |
-0.06597 |
|
15 |
0.045992 |
0.052562 |
-0.03121 |
|
66 |
0.565046 |
0.08883 |
-0.06334 |
|
16 |
0.049277 |
0.054534 |
-0.03252 |
|
67 |
0.584757 |
0.085414 |
-0.06064 |
|
17 |
0.052562 |
0.056505 |
-0.03351 |
|
68 |
0.604468 |
0.08134 |
-0.05782 |
|
18 |
0.055848 |
0.059133 |
-0.03463 |
|
69 |
0.624179 |
0.076938 |
-0.05519 |
|
19 |
0.059133 |
0.061104 |
-0.03581 |
|
70 |
0.64389 |
0.07293 |
-0.05256 |
|
20 |
0.062418 |
0.063403 |
-0.03679 |
|
71 |
0.663601 |
0.06866 |
-0.04961 |
|
21 |
0.065703 |
0.065703 |
-0.03784 |
|
72 |
0.683311 |
0.064389 |
-0.04652 |
|
22 |
0.072273 |
0.068988 |
-0.04008 |
|
73 |
0.703022 |
0.05979 |
-0.04336 |
|
23 |
0.078844 |
0.072273 |
-0.04172 |
|
74 |
0.722733 |
0.055191 |
-0.04074 |
|
24 |
0.085414 |
0.075558 |
-0.04382 |
|
75 |
0.742444 |
0.050591 |
-0.03752 |
|
25 |
0.091984 |
0.078844 |
-0.04534 |
|
76 |
0.762155 |
0.047306 |
-0.03476 |
|
26 |
0.098555 |
0.0818 |
-0.04731 |
|
77 |
0.781866 |
0.043364 |
-0.03187 |
|
27 |
0.105125 |
0.084757 |
-0.04901 |
|
78 |
0.801577 |
0.039093 |
-0.02891 |
|
28 |
0.111695 |
0.087385 |
-0.05099 |
|
79 |
0.821288 |
0.035085 |