Development and Design Innovation
William H. Durand invested nearly four years developing his revolutionary biplane design, conducting extensive stress analysis and weight calculations to create an aircraft optimized for short-field operations at grass strips like his own Durand Sky Ranch. The prototype made its public debut at EAA Oshkosh in 1978, showcasing design features that challenged conventional biplane wisdom.
The Mk V's most distinctive characteristic was its large negative stagger configuration, where the lower wing was positioned ahead of the upper wing. This arrangement, validated by NACA reports from the 1920s, provided exceptional stall resistance and enabled the aircraft to achieve inherent flare-out characteristics during landing approaches. The negative stagger eliminated trim changes when deploying full-span flaps and contributed to the aircraft's reputation as virtually stall-proof.
Technical Innovation and Configuration
Durand's design departed from traditional biplane control systems by incorporating spoilers for lateral control instead of conventional ailerons. The single-bay wings were braced with I-struts, and both upper and lower wings featured full-span flaps that enhanced the aircraft's short-field capabilities. The tricycle landing gear utilized innovative Scotchply legs with steel carry-through structure.
The cockpit featured side-by-side seating under a forward-sliding canopy that provided expansive visibility and easy access. Durand incorporated a box-beam cockpit structure for both pilot protection and structural stiffness. Practical maintenance features included a swing-out tail for battery access and cowl-less oil drain systems that simplified routine servicing.
Powerplant and Performance
The Lycoming O-320 four-cylinder, horizontally-opposed engine provided 150 horsepower for the 1,840-pound gross weight aircraft. This reliable powerplant, which had been in continuous production since the 1950s, delivered a cruise speed of 135 mph and a service ceiling of 15,000 feet. The aircraft demonstrated impressive climb performance at 1,200 feet per minute and achieved a range of 400 miles.
To reduce noise levels, Durand mounted an automotive glasspack muffler between the landing gear legs. The prototype utilized government surplus instruments, reflecting the cost-conscious approach typical of homebuilt aircraft development in the late 1970s.
Production and Market Response
Durand Industries marketed the Mk V exclusively as plans for amateur builders rather than as a factory-built aircraft. Plans sales began in the late 1970s and continued through the 1990s, reaching 75 sets sold by 1987 and 91 by 1998. Despite relatively modest plans sales, actual construction numbers remained low, with only 12 aircraft built including the prototype.
By 1987, five examples were confirmed flying, increasing to nine by 1998. Builders in both the United States and Canada constructed the aircraft, with at least one Canadian example fitted with floats for water operations. The limited construction numbers reflected the complexity of amateur-built biplane projects and the specialized nature of the design.
Company Evolution and Revival
Durand Industries continued operations under William H. Durand's leadership through the late 1990s before becoming dormant. In 2017, Jim Swatosh acquired the rights and revived the company as Durand Industries LLC, creating detailed 3D CAD models using SolidWorks software. Swatosh, who owns two examples including the original 1978 prototype, has pursued development of quick-build kits to simplify construction for modern builders.
The revived company now markets plans through established suppliers like Aircraft Spruce, introducing the design to a new generation of homebuilders. This revival effort coincided with renewed interest in the type, exemplified by flying examples appearing at EAA AirVenture Oshkosh 2017.
Legacy and Influence
The Durand Mk V proved that innovative biplane configurations remained viable in the homebuilt market, successfully demonstrating how 1920s-era negative-stagger concepts could be adapted for amateur construction. The aircraft's stall-resistant characteristics and short-field performance validated Durand's design objectives of creating a safe, practical sports biplane for grass-strip operations.
While one example was formerly displayed at the Museum of Flight in Seattle, its current location remains unknown. The surviving flying examples represent an important chapter in experimental aviation history, proving that individual designers could still develop innovative aircraft configurations outside traditional manufacturing channels. The type's influence continues through the current revival efforts and its demonstration that unconventional design approaches can succeed in specialized aviation markets.