Design Innovation
Jim Maupin revolutionized homebuilt glider construction with the Windrose's groundbreaking sparless wing design. Rather than using traditional wooden spars or metal frameworks, Maupin carved the entire 41.5-foot wing from solid foam, then covered it with fiberglass skin reinforced by unidirectional roving bands epoxied underneath. Vertical dowels handled compression loads, eliminating the complex internal structures that typically challenged amateur builders. This innovative approach, developed with assistance from renowned airfoil designer Irv Culver, made high-performance soaring accessible to homebuilders lacking advanced woodworking skills.
Contest-Winning Engineering
Maupin designed the Windrose specifically for the Sailplane Homebuilders Association Design Contest, targeting six key objectives: ease of construction, safety, self-launching capability, low cost, aesthetic appeal, and dual-mode operation as either a pure glider or motorglider. The aircraft's mixed construction combined the foam wing with a hollow plywood box fuselage and fiberglass cockpit. A single triangular spoiler mounted on the fuselage provided speed control, while all-flying stabilizers enhanced pitch authority. The inboard aileron placement eliminated wing-internal control runs, further simplifying construction.
Performance Excellence
The 315-pound glider achieved impressive performance figures that rivaled factory-built sailplanes. At its optimal speed of 48 mph, the Windrose delivered a maximum glide ratio of 30:1, meaning it could travel 30 feet forward for every foot of altitude lost. Its minimum sink rate of 126 feet per minute occurred at 40.5 mph, enabling pilots to exploit weak thermals effectively. The high aspect ratio of 18.25:1 and wing loading of just 5.5 pounds per square foot contributed to its soaring efficiency. An optional extended wingspan of 49.2 feet was available for builders seeking even better performance.
Motorglider Variant
The powered version, first flown in 1984, incorporated a 33-horsepower Cuyuna 430 two-stroke engine for self-launching capability. This eliminated the need for ground crews, winches, or tow aircraft that pure gliders required. The motorglider variant could take off in just 500 feet and climbed at 500 feet per minute initially, though the additional 75 pounds of engine and fuel increased empty weight to 390 pounds and gross weight to 600 pounds. The Cuyuna engine, manufactured in the United States during the 1970s and 1980s, was specifically designed for ultralight and sailplane applications.
Limited Production Success
Jim Maupin Ltd. marketed construction plans through the 1980s, complete with over 200 square feet of detailed drawings and comprehensive instruction booklets. Plans cost $175 in the United States and Canada, or $195 for overseas airmail delivery. At least 14 aircraft were completed by homebuilders across the United States, all registered in the Experimental Amateur-built category. By July 2011, five Windroses remained on the FAA registry—four gliders and one motorglider still owned by designer Jim Maupin himself.
Lasting Impact
The Windrose influenced subsequent homebuilt glider designs and demonstrated that innovative construction methods could make high-performance soaring affordable for amateur builders. Maupin continued developing the concept with the related Windrose II and later the Carbon Dragon, building on lessons learned from the original design. The aircraft exemplified 1980s innovation in composite construction techniques that would eventually become standard in both homebuilt and production aircraft. While few remain airworthy today due to their age and homebuilt nature, the Windrose fostered a small but dedicated community of builders who proved that contest-winning performance could emerge from garage workshops rather than factory production lines.