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- .\" plotfoil.1l 2/17/92
- .TH plotfoil 1l "Feb. 1992"
- .SH NAME
- \fBplotfoil\fP \- generate a PostScript plot of airfoil data.
- .br
- \fBeditfoil\fP \- modify camber and thickness of airfoil data.
- .br
- \fBmixfoils\fP \- interpolate between two airfoil sections.
- .SH SYNTAX
- \fBplotfoil\fP [\fIoptions\fP] [\fIfilename...\fP]
- .br
- \fBeditfoil\fP [\fIoptions\fP] [\fIfilename\fP]
- .br
- \fBmixfoils\fP [\fIoptions\fP] \fIsection1\fP \fIsection2\fP
- .SH DESCRIPTION
- \fBplotfoil\fP plots (in PostScript) airfoil sections
- (well, actually any section
- that is not smoothly closed). It can also allow for spars,
- sheeting, and prints registration marks that are aligned with the L.E. and T.E.
- It uses Bezier splines to interpolate between
- data points, with an option to use straight lines instead.
- .PP
- The other two programs, \fBeditfoil\fP and \fBmixfoils\fP, modify airfoil
- data. By default they send the data to standard output, so they can be used
- in a pipe to \fBplotfoil\fP to plot the results. (Unix only.)
- .SH OVERVIEW
- Plotfoil reads airfoil data and generates PostScript code that when printed on
- a PostScript printer will deliver a plot of the airfoil section along with
- spars (if any). The bounds of
- the section are also drawn, with crosses, and these can be used for
- registration of the ribs or templates. If the plot is going to be larger than
- one page, it will automatically be spread over as many pages as are required.
- .PP
- PostScript is a printer language for describing printed pages. Printers that
- accept PostScript include the Apple LaserWriters, QMS PS- series printers,
- DataProducts LZR-2665 and 2660 and the Linotronic 100 and 300 typesetters.
- PostScript is a trademark of Adobe Systems Incorporated. The ghostscript
- program can convert PostScript to a variety of printer formats if a PS
- printer is not available. (Ghostscript can also be used to preview plots on
- the display.)
- .PP
- Bezier splines are used to calculate interpolating curves between the points.
- In some case the process may not deliver a smooth curve, and you will
- have to use the straight-line plot option (\fB\-s\fP).
- .PP
- \fBplotfoil\fP can also account
- for sheeting. If the wing you are building is to
- be sheeted, the ribs or templates need to be inset from the required surface
- by the thickness of the sheet. The airfoil
- outline is plotted with a dotted line, and the template line is drawn with a
- solid line.
- .SH OPTIONS
- Under MS-DOS, the ``/'' can be used as the option character instead of the
- ``\-''.
- .IP \fB\-c\fR
- Sets the chord of the section to plot. The argument is the chord, in units of
- either mm, cm or inches. The units are specified by a
- trailing `m', `c', or `i',
- with the default of mm being used if unspecified.
- .IP \fB\-s\fR
- This flag indicates that for \fIx\fP values of greater than 2.5%,
- straight lines
- should be used to join the points. This results in a PostScript file which is
- probably just as good but should print in less time. The limit (2.5%) can be
- changed with the \fB-l\fP option.
- .IP \fB\-l\fR
- This option changes the limit used with the \fB-s\fP option. It takes the
- percentage-chord as argument.
- .IP \fB\-p\fR
- This invokes the interactive mode where plotfoil will prompt you for all the
- paramters of the plot. If plotfoil is invoked without an arguments it
- automatically enters prompt mode.
- .IP \fB\-i\fR
- This option draws the section inset by the specified amount, which is what you
- would use if the wing you are building is sheeted. The units default to those
- used for the chord.
- .IP \fB\-sp\fP
- This option adds a spar to the plot. It takes two arguments, the offset
- (expressed as a percentage of the chord) and the thickness of the spar
- (default units:
- same as used for the chord). This option can be used multiple times to
- draw more than one spar. Also, 0-thickness spars can be used to draw vertical
- lines on the plot.
- .IP \fB\-th\fR
- This option sets the height of the template outline, measured from the chord
- line. The default is 0.
- .IP \fB\-tl\fR
- .IP \fB\-tt\fR
- These options set the horizontal extents of the template. The value specified
- is the distance of the edge of the template from the {leading, trailing} edge.
- The units default to those specified while setting the chord. The default
- value is 0.
- .IP
- If any of \fB\-th\fR, \fB\-tl\fR or \fB\-tt\fR is used, a template will be
- drawn.
- .IP \fB\-a\fR
- Turns the section by this many degrees. This useful for adding washout or
- washin. A positive number is a rotation in the counter-clockwise direction;
- negative is clockwise.
- .IP \fB\-h\fR
- Prints some help information.
- .IP \fB\-o\fR
- Writes the output to the specified file.
- .IP \fB\-x\fR
- This option moves the drawing on the page to the right. Some printers (or
- ghostscript drivers) have different ideas about what constitutes
- centered. This option can be used for fine-tuning.
- .IP \fB\-y\fR
- Same as \fB\-x\fR except that it moves the drawing up.
- .SH editfoil
- .IP \fB\-c\fR
- Modifies the camber to this value (expressed as percent. chord). 0 is valid.
- .IP \fB\-t\fR
- Modifies the thickness to this value (expressed as percent. chord).
- .IP \fB\-o\fR
- Writes the output to the specified file.
- .SH mixfoils
- .IP \fB\-r\fR
- The interpolation ratio. The generated section will be \fIr\fP of the second
- section and \fI(100-r)\fP of the first. If you have one section at the root
- and another at the tip, to find the section at 70% semi-span out you
- would use 70.
- .IP \fB\-o\fR
- Writes the output to the specified file.
- .SH INPUT FORMATS
- There are two formats for \fBplotfoil\fP input data,
- distinguished by how coordinates are
- specified. The first line of the file is taken to be the name of the section
- and is printed along with the plot.
- .PP
- The smallest \fIx\fR value (usually 0.0) is the L.E. and the largest
- (usually 1.0) is the T.E.
- .PP
- This is the first format:
- \fC
- SD-8020
- 1.0 0
- 0.9 0.011
- 0.85 0.02
- ...
- 1.0 0
- \fR
- .br
- Note: it starts at \fIx\fP=1.0 (the trailing edge), goes around
- and ends again at the
- T.E. This is the format used by the sections in Soartech 8.
- .PP
- This is the second format:
- \fC
- Clark YH
- 0 0 0
- 0.0125 0.0409 -0.0183
- 0.025 .0529 -.0271
- ...
- 1.0 0 0
- \fR
- .br
- This starts at the L.E. and ends at the T.E., with the columns being the upper
- and lower ordinate values. This is the format that most of the NACA sections
- were published in.
- .LP
- \fBeditfoil\fP and \fBmixfoils\fP both print data in the first format.
- .SH EXAMPLES
- This command:
- .IP
- \fC\s-2plotfoil -c 20c -i 2m -sp 32 0.2 sd8020 | lpr\s+2\fR
- .LP
- will plot the SD-8020 section with a chord of 20cm, with a sheeting allowance
- of 2mm, and a spar 2mm wide at 32% chord. The name of the section and the
- sheeting allowance are also printed.
- .IP
- \fC\s-2plotfoil -c 8.5i -i 0.125 -s -l 10 -o clarkYH.ps clarkYH\s+2\fR
- .LP
- will plot the Clark YH with a chord of 8.5 inches. Only the area from the L.E.
- to 10% back will interpolated with splines, and from 10% to the T.E.; straight
- lines will be used to connect the points. A sheeting allowance of 0.125" (1/8")
- will also be drawn. The PostScript will be left in "clarkYH.ps".
- .IP
- \fC\s-2plotfoil -c 450m -i 1 -sp 5 0.5 -sp 30 2.5 -th 70 -tt 10 -tl 10 -x -1.5c -o rg15.ps RG-15\s+2\fR
- .LP
- This plots the RG-15 airfoil with a chord of 450mm. Since this is too large
- to fit on one page it will be automatically split across two pages. A
- sheeting allowance of 1mm is printed, and there are two spars: one at 30%
- that's 2.5mm thick, and another at 5% that's very narrow, i.e. a LE marking.
- A rectangular template
- is drawn around the plot; and all the graphics are moved to the \fIleft\fR
- by 1.5cm, i.e. negative numbers can be used in the positioning. The
- PostScript is saved in "rg15.ps".
- .IP
- \fC\s-2editfoil -c 0 -o symmetric.airfoil SD-7037 \s+2\fR
- .LP
- Construct a symmetric airfoil from the SD-7037 and save as "symmetric.airfoil".
- .IP
- \fC\s-2editfoil -t 7 -c 1.5 RG-15 | plotfoil -c 400m -i 1 -sp 30 1.5 | lpr\s+2\fR
- .LP
- Plot a thinned down (7%) de-cambered (1.5%) RG-15.
- .IP
- \fC\s-2mixfoils -r 75 -o mixed-airfoil SD-7037 SD-7032\s+2\fR
- .LP
- Generate a section that is 25% SD-7037 and 75% SD-7032.
- .SH DISTRIBUTION
- \fBplotfoil\fP, \fBeditfoil\fP and \fBmixfoils\fP are free;
- anyone may redistribute copies of it to anyone
- under the terms stated in the Gnu General Public License version 2, a
- copy of which should accompany each copy of plotfoil. See the file ``COPYING''
- in the source area. If you do not have this file, a copy may be obtained from
- the author, or from:
- Free Software Foundation
- 1000 Mass Ave.
- Cambridge, MA 02138
- .br
- or from the author.
- .LP
- Also, if you make any changes to these programs and re-distribute them,
- the same
- conditions apply to the modified version so that we can all benefit from
- it. And please send me those changes!
- .SH AUTHOR
- Shamim Mohamed (shamim@math.isu.edu)
- .br
- Dept of Mathematics
- .br
- Idaho State University
- .br
- Pocatello, ID 83209
- .SH BUGS
- On some printers, there may be a stack overflow if the plot is on more than one
- page and there are more than a certain number of coordinate values. If this
- happens, try
- .IP
- a) finding another printer, or
- .IP
- b) removing some of the airfoil data.
- .LP
- In the latter case you may still get satisfactory results because of the
- smooth interpolation used.
- .PP
- Since the program doesn't know how big the printer page size is, it can get
- confused. This should only err conservatively, like producing an extra blank
- page on a multi-page plot. As long as the page is higher than about 11 inches
- (27 cm) everything should be fine. If you have a compiler, adjust the values
- in \fC\s-1plotfoil.h\s+1\fP and recompile.
- .PP
- I don't know of any other bugs right now,
- but please send all bug reports to me. Include
- version number and the exact details (input files, command-line options etc.),
- please.
-