Thoughts on Panel Design by Amit Dagin   (amitdagan at comcast.net)
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One of the most pleasurable parts of building your own aircraft must be designing the instrument panel. It is also the first thing people look at when you are parked at a fly-in, after the paint scheme of course.

Apart from being a sight of beauty to those of us infected with the aviation virus, and forgetting for a second the $$$ issues involved in that part of the project, the panel serves a very important function, and as such should be designed with it’s functionality in mind.

I don’t know if Wilbur and Orville gave any thought to the subject, but GAMA – the General Aviation Manufacturers Association has. In its Publication No. 10 - Recommended Practices & Guidelines for Part 23 Cockpit/Flight Deck Design, they go into the human factor issues related to cockpit/flight deck design. It includes a compilation of industry "best practices" for addressing the critical interface between humans and aviation systems. A great reading, you can download it for free from their website: http://www.gama.aero/   Go to Publications, Online catalog, Certification & Technical, and click on the link to download it. You can also order it for $12.

The part I found most useful and interesting, is the optimal field of view that the pilot has on her panel. Just how far away off from “straight ahead” can we really have useful information on our panel?

Here is a figure right out of that paper:


The dimensions are given in degrees, so we must measure the distance between the pilot’s eyes and the panel itself in order to find the area of the field of view.
I sat in my RV-7 fuselage and measured approximately 20 inches between the eyes and panel. I then took a calculator to find the trigonometric tangent value for 15, 20, 35 and 40 degrees, and multiplied them by 20.
I got the following: for 15 degrees, use 5.36 inches. For 20 degrees, 7.28 inches, and for 35 and 40 degrees 14.0 and 16.8 inches respectively (If you use a different distance between your eyes and the panel, you will need to re-calculate).

I then copied a drawing of the RV-7 panel (from Bill Von Dane’s great tool, the epanelbuilder), and superimposed two ovals over it, centered more or less in the pilots field of vision. I tried to make all parts of the drawing the same scale of course:

The smaller circle represents the optimum filed of view, and the large oval – the maximum. Please forgive any inaccuracies, this is for demonstration only.

I find this drawing very illuminating when figuring out the placement of instruments in the panel. There are of course other constraints that needed to be addressed, such as the support structure for the panel, the size of the instruments and so on, but you get the idea.

Interesting to note too, is the fact that the panel on tandem RVs and the RV-3, while smaller in area, has more of it in the optimum and maximum field of view.

 


Labeling the Instrument Panel

After the design of the instrument panel, comes the inevitable part of actually manufacturing it. Today there are several ways to go about it. The easiest and least challenging of all is to have someone else do it for you. Indeed, Vans Aircraft will sell you a pre-punched panel that even eliminates the design from your part! But if you have more time than money, and are not afraid of the fly cutter or the Greenly punch, you shouldn’t have any problems creating what is arguably the crown of your project. The RV home wing even has an instrument screw template tool for your use (Now available to any Chapter 105 member).

More challenging is cutting the square holes for the radio stack (jig saw!), and the corner cuts for the altimeter setting knob for example. A rotary file on your die grinder is a good tool for the job, provided you take care.

After all your holes are cut or drilled, and you are so happy and relieved you didn’t have to order a new blank panel from Vans because you didn’t screw anything up (imagine that!), you will want to finish the panel with your choice of color.

Most panels seem to be painted in either the same interior gray, or in black. Black will reduce the reflections and enhance instrument readability at night. Either way, you are still left with labeling your switches and the required placards.

A common way is to use small label printers, such as the Brother P-touch, which comes in several sizes and can print in many color-on-color combinations.

You can also use your ink-jet printer and a special AVERY kit for printing clear labels available from Office Depot and the likes.

If however, you want to have a silk-screen effect (and actually, you can have your panel silk screened), you might want to look into using color transfers.

Color transfer is an old technology, very popular with graphical designers in the 80’s, before computer graphics became mainstream. Letraset was the big company, and they made rub-on letters in several fonts sizes and colors, that the graphical artist could transfer on to her project quickly and easily. Today only very few designers still use this technique, but it is a viable option for us, panel labelers.

Start by using your favorite word processor to make a page of all the labels you will use on your panel. If you use Windows Excel, you can also easily have your words framed. You are not limited to words only; any graphic symbol you can print is par for the cause. You can use any font you like, but try to keep it simple and readable. I found that Arial 10 points worked well for most labels. I also made the “Passenger warning” placard and the call sign for my RV on the same page, in a larger font size and Bold.

I believe you will find you don’t need the entire page, so go ahead and make some doubles of your labels. “On” and “Off” appear many times, so have a few extra of those too. On my page I managed to cram 2 of each label, sometimes more. Print your page on a laser printer. You want quality printing so your letters are crisp and beautiful.

How do you turn your printed page into a color transfer?
There are very few places that still do this. In Portland, I found Camera Graphics, located in SE Portland. Telephone: (503) 234-1967. Cost is about $35-$40 for a single 8.5” X 11” page in one color.

Rubbing your rub-on labels is easily done with a burnishing tool made out of a rounded wooden chopstick, but be VERY CAREFULL to align your labels so they come out straight and level, not crooked. Use whatever means you have to ensure they are level. After you peel off the special sheet the labels are printed on, use the non-stick sheet (which resembles a cookie sheet) and give the label another rub-over with your burnishing tool.

To finish it off, apply several light coats of Krylon clear coat spray. This will protect your panel and if you use the satin version, will also cut down on the glare.

PS: For your labels, character height-to-width ratio, stroke width, spacing between characters, spacing between words, spacing between lines and viewing angle should also be considered. Recommendations for these values are contained in Section 7 of DOT/FAA/CT-96-1.

Or just use whatever you like….
Note: The idea to try this technique came from an article by Patrick Fanning, EAA Chapter 448, originally re-published in the Chapter 1000 newsletter May 1992, available to read at http://www.eaa1000.av.org/technicl/details/details.htm  .
So I take no credit for it.