Click here to download Letters and Numbers
By the Numbers
Getting the markings right
By: Marv Hoppenworth
Everyone who builds or restores an airplane is hit with the task of laying out registration identification numbers. Over the last 60 years they have gone from 24 inches to 20 inches to 12 inches and whatever on classic and amateur-built aircraft. May I suggest a current copy of Federal Aviation Regulation (FAR) Section 45.1, Subpart C, Nationality and Registration Marks. The FAA-mandated markings can be traced back to a 1919 international agreement that detailed the type of markings for aircraft around the world.
I painted my first set of numbers on my J-3 Cub in 1948: NC9245H in black on yellow. I did quite a few in those early years. You must hear about this one set of numbers in particular. A friend was having me re-cover the wings of his 1939 Aeronca Chief. One day we were alerted to two new cute little yellow airplanes at the gas pit. Come to find out, they were the new Piper PA-15 Vagabonds. My friend drew my attention to the new little 18-inch numbers on the wings and asked if I could paint his wings like that. My answer was, “I don’t know why not.” So I proceeded to lay out the set of numbers. Maroon on white. Two days after I pulled the tape, we got an advisory circular in the mail announcing the new minimum size of registration numbers on the wing was 20 inches!
There was no way I could correct that except to do it over. I spent the next two evenings on my own time, with a sharp knife, peeling the maroon letters down to the silver dope and reworking the white base color. Then the new size 20-inch numbers were masked and repainted maroon.
Now you know why I recommend a current copy of FAR Section 45.1, Subpart C. There are so many combinations of size, speed, age, etc. that it is too hard to commit to memory.
Here’s another story I have to credit to experience. Sometime around 1960, my Taylorcraft was due for re-cover. At that time the FAA was requesting registration numbers be put on the side so that recognizing these numbers would be easier for fighter pilots. I did not argue with that. Since my T-Craft had split colors on the fuselage, I masked and painted black numbers, black above the split-line and yellow numbers below the line, surrounded by the black trim color. This set of numbers, although contrasting in color, washed out to be unrecognizable at 200 feet. I then had to lower my trim line about 8 inches and redo the letters in black-on-yellow on the lower half. You cannot believe what a difference that made. We learn by our mistakes. So we call it experience. Wisdom comes from learning from someone else’s experience.
Over the years I have observed many sets of N numbers. I have seen “4s” and “7s” that would tip if you looked at them long enough. Included is a layout of what, I think, numbers should look like. The FAR calls for “Roman Block.” Many print shops do not even recognize Roman Block. As you will note, the numeral “8” is the “frame” for many of the numbers and is used in directing many of the letters of the alphabet in Roman Block. There is one exception in width of the letters “M” and “W”. These will be as wide as they are tall and the center intersecting bars will join with a “B” width just like on the letter “N”.
In laying out the numbers, they should be in a straight line and the vertical edges should be 90 degrees to the top and bottom. You can use the 3-4-5 triangle or multiples of that, such as 9-12-15 to verify your verticals. Decide where you want to put your row of numbers. If it is a rectangular wing, I suggest you take your measurements from the trailing edge. The distance between each letter or number is to be one half the width of the letters. Do not use a ballpoint pen to make any marks. A soft lead pencil should be used if you need to make marks. You may also use short pieces of tape.
Pull the masking tape to the full length of the registration numbers. Bring the tape down to your marks and be cautious not to curve the tape. Do the same for the lower edge. Now mark on the tape where the vertical guides will go. Verify that you are still 90 degrees when you get to the last number. It is suggested that you identify each number and letter and mark it on the tape. Check it against your registration certificate. An error from here on would be hard to correct.
We all know that masking tape never tears where you wish it to, so I recommend a putty knife about an inch and a half wide. Place the putty knife over the spot you want the tape to tear and pull up. This leaves a sharp edge with accuracy within about 1/64th of an inch. Where two pieces of tape converge on an angle of less than 90 degrees, just lay them down, sticking one on top of another. Lift the two ends together, slip a small piece of metal under the intersection and cut on the lines formed by the masking tape using an Exacto knife or a sharp utility knife. Then lay the tapes back down. Do not cut directly onto your painted surface. There are vinyl tapes that give a nice sharp edge, and these may be worth the extra cost. 3M “Fineline” masking tape is also a great product for producing sharp, clean masked paint edges.
Double-check each number, making sure you have closed in and masked all the corners that should be treated that way. It is easy to overlook. Before painting the numbers, remember to check all the edges by rubbing down with your thumbnail and use a lower air pressure when painting the trim and numbers.
A simple way to put numbers on the vertical fin and rudder is to lay out your small numbers using masking tape sized to match the width of the bar (
B). Example: One-inch masking tape will give you a letter or number 6 inches tall. Then mask a horizontal line above and below the numbers. This will present you with a horizontal bar about 12 inches to 15 inches with 6-inch contrasting numbers. It looks nice and it is much simpler to make than masking around little numbers.
Remember upper right wing and lower left wing. Yes, it can happen. I hope that this has given you a bit of a heads-up on laying out registration numbers.
Aviation Roman Block Type
By H.G. Frautschy
The downloadable font is based upon the letter guide published in the December 2002 issue of Vintage Airplane, as originally published in Brimm and Boggess’ Aircraft Maintenance for the Airplane Mechanic. In my research on this subject, at no time have I turned up an FAA or Civil Aviation Authority (CAA) document that actually depicted the letters. Only a description in the regulations has been seen in official documents.
I have created alternative versions of some of the letters (the 2 and 7) as seen in material submitted by Marv Hoppenworth and in period photos of aircraft built in the 1930s and 1940s. If members have others they’d like to see depicted, please let us know.
The letters were created in Adobe Illustrator and can be downloaded as .eps files. You can download only the letters you need, or all of them if you wish. Typically, sign shops specializing in computer-generated graphics can work with vector graphic artwork such as Adobe Illustrator, CorelDRAW, FreeHand, etc. Thanks to being created in vector-based computer artwork, these characters are scalable to very large sizes. The sign shop can adjust the artwork to your required size with no problem, whether you’re asking them to make a mask for the numbers or are looking for the entire character to apply to the airframe.
In addition to the scalable artwork provided on our website, there are computer type fonts available for use in marking aircraft. The closest version to the style used on pre-World War II and postwar aircraft is commonly designated “AmarilloUSAF.” It is the font used by the U.S. Air Force to mark its aircraft. The font is available from TLai Enterprises at www.TLai.com/med_des/amusaf.html. It is available as a free download on a trial basis and is fairly inexpensive ($15) if you want to buy the full letter set.
This font is very close to that used on civil aircraft in the 1940s, but there are differences. Research of your aircraft type will disclose changes you may need to make. For example, the “7” used on Waco aircraft has the upper right corner of the numeral trimmed at an angle, where other aircraft manufacturers used a “7” that featured a sharp corner at that point. The regulatory requirement for the font’s thickness to be 1/6 of the height of the character notwithstanding, variations in thickness seemed to abound as well.
Another option, for those who would prefer to have their artwork generated by a specialist, is to employ the services of a company such as Aerographics of Loveland, Colorado. They can generate graphics in a variety of styles and outputs. Aerographics can be reached at 800-336-9633 or www.Aerographics.com. Be sure to clearly explain your needs, particularly with regard to the exact configuration of the letters. As you can see, even for a marking defined by regulation, there’s plenty of variation!