NewDeal Hot Tip 1200

[Hot Tips for...] NewDraw

NewDraw and NewCalc for Plotting Airfoils

NewDraw and NewCalc can cooperate to perform a task that's usually quite difficult, but important for model (or full-size) airplane designers and builders: plotting an airfoil.

Airfoil shapes are usually published as what are known as polars or coordinates -- and it's a lot of work to plot a fair curve through the specified points using traditional tools, while dedicated airfoil plotting programs cost between $40 and $100 -- as much, if not more, than NewDeal.

To get perfectly plotted foils from NewDeal, all you have to do is enter (or, preferably, import) the coordinates into NewCalc in a format with each ordered pair in vertically adjoining cells in the same column -- use as many columns as you need to get all the points in, and it's important to get all the upper coordinates in order from one edge to the other, then all the lowers going back -- you'll see why in a moment.

Now use NewCalc's graphing function to make an X-Y Graph of the points you've input. The resulting graph will have the X and Y axes as you've specified in your settings, and a neat graph of the airfoil you're looking for plotted onto the axes. If you click on the graph, you'll see that it selects like any other graphic object. Now comes the fun part. Copy the graph to the clipboard, and paste it into a NewDraw document. You'll notice that it ungroups as it pastes, so you can easily select and remove the axes and frame if you don't want them.

This next procedure is optional, and likely won't be needed on airfoil sizes small enough to pring on a single page: Select the spline tool (the rightmost drawing tool on the standard User Level 4 toolbar) and click anywhere on the airfoil itself -- you'll see one polyline handle appear for each coordinate you input into NewCalc. Now, select all the handles except the trailing edge, and click Transform, Polyline, Make Curve Point(s) to smooth the curve over the whole airfoil. You can also click Transform, Polyline, Close to close the curve at the trailing edge and let you fill it with a color or pattern, or paste a rib cross section inside it.

And there you have it -- NewCalc and NewDraw cooperating to plot airfoils like specialized software, and leaving you with a NewDraw polyline object you can manipulate afterward, at no extra charge! And, of course, the NewDeal print drivers will automatically print the resulting drawing on multiple pages if it won't fit on a single one, or let you output HPGL or PostScript to a file for a plotter or high resolution printer.

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Last Modified 2 Mar 1999