Style Guide

The Man and the Work

Dan Somers is a Purdue-educated aeronautical engineer who spent 15 years at NASA Langley Research Center before founding Airfoils Incorporated in 1980. He co-developed the Eppler Airfoil Design and Analysis Code with Richard Eppler of Universität Stuttgart—a tool that allows airfoils to be designed for almost all subcritical applications. He has designed dozens of named airfoil families: the S-series for wind turbines and fans, the NASA NLF series for general aviation, airfoils for cruise missiles, business jets, gyroplanes, sailplanes, and unmanned aerial vehicles. His resume lists him as an "internationally recognized expert in airfoil design, analysis, and testing."

His tagline—Only The Best Is Good Enough—is not marketing. It is a statement of professional identity from someone whose airfoils are spinning on wind turbines and flying on aircraft around the world.

The Audience

Dan's clients are the National Renewable Energy Laboratory, the Naval Air Warfare Center, NASA, and private aerospace companies. His audience is engineers—people who read AIAA Journal papers and NASA Technical Memorandums, who evaluate consultants on technical depth, and who distrust anything that looks like it's trying too hard. They hire Dan because he is one of the best in the world at what he does, and they expect his presentation to reflect that substance.

Why Serif Headings

The world Dan inhabits—NASA technical reports, AIAA conference proceedings, university research publications—is a world of serif type. When his audience sees "Subsonic Airfoil Design" set in a transitional serif, it registers as a journal article title, a technical memorandum, a publication of substance. In a sans-serif, the same words read as a blog post or a product page.

We chose Source Serif 4, a transitional serif designed by Frank Griesshammer at Adobe. Its letterforms are precise without being cold—the subtle contrast in stroke weight and the clean, open counters echo the kind of careful, methodical craft that defines Dan's approach to airfoil design. It is a modern typeface with roots in the tradition of technical publishing. It does not call attention to itself. It simply looks right.

Why Sans-Serif Body

Dan's content is dense technical prose: Reynolds numbers, boundary-layer characteristics, NACA designations, performance percentages. Paragraphs are long and information-rich. For sustained reading of this kind of material on screen, a humanist sans-serif outperforms a serif at body sizes—it handles the mix of acronyms, numerals, and technical abbreviations more cleanly, and it provides better legibility at the smaller sizes where body text lives.

The system font stack also honors the legacy site's use of Arial and Helvetica while delivering modern refinements: San Francisco on macOS, Segoe UI on Windows, Roboto on Android. Zero loading cost. Instant rendering. The body text gets out of the way so the reader can focus on the content—which is, after all, what Dan's clients came for.

Why Monospace for Technical Identifiers

Airfoil designations like S801, NLF(1)-0416, and SM701 are not words—they are identifiers. Setting them in monospace distinguishes them from the surrounding prose instantly, just as they would appear in a data table or a wind-tunnel report. This is how engineers expect to see these designations in documentation.

Why 17px Body Text

The default web body size of 16px was established when screens were lower resolution and reading distances were shorter. Dan's content demands sustained attention—paragraphs explaining boundary-layer development, pressure distributions, and Reynolds-number ranges. At 17px with a 1.7 line height, the text has room to breathe. The slightly larger size and more generous leading reduce eye strain and improve comprehension for the kind of careful, technical reading this content requires.

The Overall Effect

The combination—serif headings, sans body, monospace technical text—creates a site that looks like it belongs to someone who publishes in journals, works with NASA, and conducts wind-tunnel investigations. Not a startup. Not a blog. A serious technical practice with institutional depth, presented with modern craft. Dan should recognize his site. An engineer should trust it. A typographer should approve of it.