The Importance of Wingspan Can't Be Underestimated

In the drive toward greater airplane efficiency, we must remember the wingspan's the thing.

Wednesday, February 28, 2024 at 10:58 AM ET

Verified

Increased wingspan—other things remaining the same—rewards you with better efficiency and climb rate, and improved high-altitude performance. [iStock]

Key Takeaways:

Modern aircraft design trends toward longer wingspans and higher aspect ratios to achieve greater aerodynamic efficiency, improved high-altitude performance, and better fuel economy.
The author's personal aircraft designs (Melmoth 1 vs. Melmoth 2) demonstrate that a significantly longer wingspan substantially enhances theoretical lift-to-drag ratio, range, and climb rate.
Despite significant theoretical gains, the practical fuel efficiency benefits of a longer wing are less pronounced at typical cruising speeds compared to theoretical "best range" conditions.
Achieving greater efficiency with an increased wingspan involves a trade-off, often resulting in a noticeable reduction in aircraft maneuverability, such as roll rate.

See a mistake? Contact us.

Unless you are the civilian owner of an F-14, you cannot change the wingspan of your airplane. If you’re a manufacturer, however, you can, and the same privilege extends to that miniature of a manufacturer, the amateur builder. Extending span requires adding strength to the spar or finding unnoticed extra strength in an existing spar. Or you can just start over and build a new wing from scratch.

Recent years have seen a general drift toward longer spans and higher aspect ratios. The Beechcraft Bonanza has a span of 33.5 feet and an aspect ratio of 6.2; the Cirrus SR22, which might be seen as today’s Bonanza, has a span of more than 38 feet and an aspect ratio of 10.1. The trend is generally toward greater aerodynamic efficiency, partly in response to fuel costs and partly because the increasing use of turbocharging leads to higher cruising altitudes, where longer wings are more at home.