Editing Advanced Soaring Concepts Apex (section)

== Design and development ==

The Apex was based on a modified [[Schweizer SGS 1-36]] sailplane, extensively redesigned to withstand the rigors of high-altitude flight. The airframe incorporated graphite/epoxy and boron/epoxy composites to achieve the necessary strength-to-weight ratio.<ref name="Greer1999">{{cite report |last=Greer |first=Donald |author2=Hamory, Phil |author3=Krake, Keith |author4=Drela, Mark |title=Design and Predictions for a High-Altitude (Low-Reynolds-Number) Aerodynamic Flight Experiment |publisher=NASA Dryden Flight Research Center |date=July 1999 |url=https://ntrs.nasa.gov/api/citations/19990049398/downloads/19990049398.pdf |access-date=2025-04-16}}</ref>

A distinctive feature of the Apex was its custom-designed wing, utilizing the "APEX-16" airfoil developed by Dr. [[Mark Drela]] of the [[Massachusetts Institute of Technology]]. This airfoil was optimized for stable flight in the low-density, low-[[Reynolds number|Reynolds-number]] conditions of the upper atmosphere.<ref name="Greer1999" />

The sailplane measured approximately 22.7 feet (6.9 meters) in length with a wingspan of 41.2 feet (12.6 meters) and a wing aspect ratio of 13.6. It was designed for a target gross weight of 600 pounds (272 kilograms) and a 5-g maneuver load factor.<ref name="Greer1999" />