Templates for Fly Baby Parts

February 2009
Rib Template
Fly Baby rib template by Marco Pinto (Color added)

The photocopier is one of the more ubiquitous items in the modern world, but most folks don't know their dirty little secret:  They distort the images they copy.

For the most part, this distortion consists of a proportionate enlargement or reduction of the item they're copying.  In plain English, the image is slightly bigger or smaller than the original.

This doesn't make much of a difference if you're copying page 293 of  a physics textbook.  It does make a difference if you're making a copy of a template of a Fly Baby part!

Pete included a lot of templates in the plans, but he always included the actual dimensions of the part the template represents.  If you slap a ruler on the template, you may well find that the template dimensions aren't quite right.

This gets worse the larger the part.  The largest part templates in the plans are the ribs...and they can get quite far off.  Here's a picture Tim Roska took of one of the plans' rib templates laid against Marco Pinto's CAD rib template.  I've "colorized" the CAD template equivalent of the plans template.  Note how the plans template is definitely smaller than it is supposed to be.

You should always check the template dimensions prior to cutting out the part.

Several Fly Baby builders have drawn Computer-Aided Design (CAD) templates of key Fly Baby parts, and have passed them to me for use by others.  If you follow the special instructions below, you'll find that these will be a lot more accurate than what is contained in the plans set.  Plus, you won't have to cut up your plans to make parts, since you can print these on your own printer and just run another set if you botch the part.

First off, let me establish a disclaimer, and give you the special instructions needed to use these.


These templates were not drawn by professionals, nor have they been checked and verified to the degree an aviation manufacturer would require.  It is the responsibility of the builder to check the dimensions of the templates prior to making parts from them.  No claim of suitability nor accuracy is made.

Special Instructions

There is a key factor that has to be considered when you print these templates:  Your computer printer may not necessarily print them at the proper size.

printer settingsPrinters usually automatically adjust the size of the printed image to match some internal standard.  If you allow your computer to do this, the template will not be the proper dimensions.

Prior to printing, you need to either bypass this automatic adjustment.  You'll usually find it in the "Page Setup" menu.  You may have to then click the "Printer" button (and probably the "Properities" button) to get to the page that lets you adjust the print size.

The appearance of that page differs between printer brands.  You can see the adjustment page for my Epson printer on the right.  I have clicked the "Reduce/Enlarge Document" button, and set the percentage to 100%.

If I hadn't done that...the printer prints at 97%, EVEN if the "Reduce/Enlarge" control isn't checked.

Once the template prints out, check the dimensions.  If it's too small, you'll have to increase the percentage, and vice-versa.

The setting holds throughout your print session, so if you're printing rib template sections, you shouldn't have to re-set this for each page.  UNLESS you exit, and re-start the program, of course.

Many of these templates require that you print multiple pages and tape the results together.  Index marks are provided to help you align the pages.


The templates are all in Adobe Acrobat (e.g., .PDF) format.  Unless your computer really dates from the stone age, you should have Acrobat Reader already.

Best approach is to RIGHT-click the links, then save the files somewhere on your hard disk.  If you do a normal left-click, it'll probably open inside your web browser.  Don't print it from the web browser!  But you'll probably be given the option to save it to your disk at that point.

Wing Ribs

The wing ribs are the largest templates in the plans set, and the one most vulnerable to dimension errors.  Plus, in the most-recent printing of the plans, the templates are actually reduced to fit on a single 8x10 page rather than the 11x17 fold-out.

Marco Pinto's rib CAD files are great.  They're for the main ribs in the wing (ribs 3-11) and include the alterations for the false ribs that only exist in front of the spars.  On each page, he includes a little map that shows where, on each rib, the template goes.  Here's a sample:
Rib sample
One thing you'll notice is that Marco providee a set of horizontal and vertical indexes on each page, 10 centimeters apart.  Check these measurements to ensure that the drawings printed out the proper size, then tape them together.

Now, I know the plans are in English measurements.  I'm as addicted to the inch-foot -miles system as any American.  But using 10 centimeters as the index makes things a lot easier, because you won't have to do any decimal conversions of fractions of inches to adjust your printer.  Say your ruler measures the 10cm index marks as 10.1 cm apart.  Your printer's printing large, so you need to set your size percent to 10/10.1 or 99%.  If the index marks were four inches apart (for example), and you'd measured 4 3/32",  you'd have to convert that fraction first.

Marco generated two types of rib drawings.   The first outputs the ribs on standard 8.5x11 paper, and consists of six files.  I've packed them into a single ZIP file:

Standard Paper Rib Template

He generate the second on my request.  Many printers can print on what is called "Banner feed" paper...and endless string of  standard paper attached end-to-end with perforations between sheets.  He built this file based on using two banner sheets (e.g., 8.5 x 22 inches).  With this method, you only have one taping to do (two separate banner sheets for the middle ribs).  You can buy banner paper at any office-supply store.

Banner-Paper Rib Template

Note that each of the two files above individually has all the templates to build the entire rib.  You don't need to download both (though they're only about 200 kb in size).

Marco also drew up a layout showing where to drill the ribs to clear the internal bracing wires.

Airfoil Shape in Excel

I've taken the airfoil ordinates that Pete included in the Sport Aviation articles and plotted them in an Excel spreadsheet, along with the stock 4412 airfoil.

Steel Parts

Ted Cannaday took the time to draw up layout diagrams for the steel parts.  These show how you could arrange all the 4130 steel parts of a Fly Baby on 4130 sheet to maximize efficiency when you cut them out.  The file is 36 pages long, including several pages of instructions at the start.

Within the PDF file are full-size layout drawings for all the .063”, .093” and 3/16” fittings for the Fly Baby as shown in Pete Bowers’ plans book, along with one of the 1/4" parts. They are arranged to fit the standard available sheets in sizes 9” x 18” and 9” x 9”, and 1¼” strips in the case of the 1/4" material. Since these sizes cannot be printed on commonly available printers, each layout sheet is divided up into two or three printed pages which should be ‘assembled’ before use. To this end, registration marks and dashed assembly lines are provided at the 6” and 12” points, along with rulers along two edges of each sheet and strip.

Also, Jim Katz has generated a set of Autocad files for both the steel parts and many wood parts.  You should be able to take these to a laser cutting/water jet/plasma cutting shop and have them cut out parts automatically.  However, it's important to CHECK the dimensions youself... there's no guarantee there aren't any errors in there, nor that the various computer systems haven't distorted some of the dimensions.  You might also want to change the hole size to small pilot-size holes, too.

List of Materials

Materials List.  An Excel spreadsheet with a stab at the total materials list for building a Fly Baby

Questions?  Email Ron Wanttaja .

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