Rutan VariEze
The Rutan VariEze is a lightweight, two-seat, homebuilt aircraft designed by American aerospace engineer Burt Rutan, featuring a canard foreplane configuration, pusher propeller, and composite construction using foam core covered with fiberglass for efficient, stall-resistant flight.[1][2] Development began in 1974 as a proof-of-concept prototype (designated Model 31, registration N7EZ), which first flew in May 1975 powered by a 62-horsepower Volkswagen engine conversion, though it was later deemed unsuitable for production due to vibration issues.[1] A refined version with a 100-horsepower Continental O-200 engine followed, achieving its first flight in March 1976, after which detailed plans were released to amateur builders in June 1976 by Rutan's Rutan Aircraft Factory in Mojave, California.[1][2] The design emphasized safety through natural stall-limiting characteristics, ease of construction for non-professional builders, and high performance, including a cruise speed of 180 mph (290 km/h) and a range of 700 miles (1,127 km) while carrying two adults.[2][3] Key specifications include a wingspan of 22 feet 2.5 inches (6.8 m), length of 14 feet 2 inches (4.3 m), empty weight of 585 pounds (263 kg), and maximum takeoff weight of 1,050 pounds (476 kg), with a service ceiling around 25,000 feet (7,620 m).[2] The aircraft's innovative use of molded composite structures reduced build time and cost compared to traditional wooden or metal kits, while wingtip devices derived from NASA research minimized drag for better fuel efficiency.[1][3] The VariEze significantly advanced the homebuilt aircraft movement, with over 3,000 plan sets sold by 1979 and approximately 200 flying examples by 1980, with over 400 examples ultimately completed, popularizing canard designs and composite techniques that influenced later Rutan models like the Long-EZ.[2] Plans were discontinued in 1985 following a lawsuit brought by relatives of a passenger killed in the crash of a Long-EZ, another Rutan canard design, but the type amassed hundreds of thousands of flight hours worldwide, demonstrating a strong safety record when properly constructed.[2][1]Development
Origins and Design Goals
Burt Rutan, an aeronautical engineer specializing in experimental aircraft, established the Rutan Aircraft Factory (RAF) in Mojave, California, in 1968 as a part-time venture while working at Edwards Air Force Base and later at Bede Aircraft Corporation. By June 1974, following his resignation from Bede, Rutan transitioned RAF into a full-time operation dedicated to innovative homebuilt designs, leveraging his experience in wind tunnel testing and radio-controlled models dating back to his college years at California Polytechnic State University.[1] The VariEze concept evolved from Rutan's earlier Model 27 VariViggen, a wooden canard pusher introduced in 1972, and a subsequent planned smaller version known as the Mini-Viggen, which was not pursued due to production challenges. Incorporating lessons from the wooden VariViggen's build process—particularly the challenges of precise joinery—Rutan pivoted to a moldless composite construction method for the new aircraft, aiming to streamline assembly for amateur builders while maintaining structural integrity.[2][4] Design initiation occurred in early 1974, with Rutan sketching the basic configuration initially dubbed the "Mini-Viggen" before renaming it VariEze to emphasize its "very easy" homebuilt nature. The primary goals centered on delivering a high-performance, economical two-seat aircraft: straightforward construction accessible to non-experts, a total build cost under $10,000 in 1970s dollars, a cruise speed of approximately 200 mph, a 1,000-mile range, and tandem seating for pilot and passenger to optimize aerodynamics and weight distribution.[4][5] Central to the design was the adoption of a canard configuration, selected to inherently limit stalls by unloading the main wing first and enhance overall efficiency through better lift distribution, building directly on Rutan's VariViggen research. This approach was further informed by his studies of winglets—endplate devices inspired by NASA aerodynamicist Richard Whitcomb's work on drag reduction—and pusher propulsion systems, which positioned the propeller behind the wing to minimize interference and noise.[1][4] For affordability and low weight, the initial engine choice was a 65 hp Volkswagen automotive conversion, modified for aircraft use, reflecting Rutan's focus on accessible components that could keep the prototype's empty weight around 400 pounds.[5]Prototype Construction and First Flight
The prototype of the Rutan VariEze, registered as N7EZ and designated Model 31, began construction in early 1975 at Mojave Airport in California. Burt Rutan led a small team in employing moldless composite construction techniques, utilizing a foam core sandwich structure with fiberglass skins to form the airframe. This approach enabled efficient shaping without traditional molds, drawing on Rutan's prior experience with composites in experimental aircraft. The build process took approximately three months, reflecting the design's emphasis on simplicity for potential homebuilders.[5][2] N7EZ achieved its first flight on May 21, 1975, piloted by Burt Rutan from Mojave Airport. Powered by a modified Volkswagen 1834 cc engine producing 62 horsepower, the aircraft demonstrated promising handling from the outset. The initial flight test program, conducted over subsequent weeks, encompassed approximately 50 hours of evaluation, including stall behavior assessments, spin avoidance maneuvers, and performance trials that verified a cruise speed of 175 mph. These tests validated the canard configuration's stability and efficiency, with no major issues reported during the phase.[6][7][5] The prototype's public debut occurred at the Experimental Aircraft Association (EAA) Oshkosh fly-in in July 1975, where it captivated attendees and sparked widespread interest in composite homebuilt designs. Piloted by Dick Rutan, N7EZ set a Fédération Aéronautique Internationale (FAI) world record for closed-course distance in its weight class (under 500 kg), covering 1,629 miles (2,621 km) in 13 hours, 8 minutes, and 45 seconds on 40 gallons of fuel. This achievement highlighted the aircraft's range and economy. Early flight data from the test program prompted refinements, including adjustments to canard incidence angles and winglet geometry to further optimize pitch stability and reduce drag.[8][5][1][9]Design
Airframe and Materials
The Rutan VariEze employs a moldless composite construction method to create its lightweight monocoque airframe, utilizing foam cores shaped into structural forms and laminated with epoxy-resin-impregnated fiberglass for a strong, efficient structure. This approach eliminates the need for expensive molds or jigs, making it accessible for amateur builders.[10][1] The primary materials include polystyrene or polyurethane foam for the core, which is contoured using hot-wire cutters to define the airframe's contours, followed by layers of E-glass fiberglass cloth bonded with epoxy resin to form sandwich panels that distribute loads effectively across the outer skins. This results in a durable structure resistant to corrosion, unlike aluminum or metal designs, while the foam core enhances shear strength and overall rigidity without adding significant weight. The empty weight of the completed airframe is approximately 585 pounds.[10][2][1] Key airframe components feature a tandem cockpit for two occupants, enclosed by a transparent bubble canopy for improved visibility; a swept main wing incorporating winglets for stability; a forward canard foreplane; and a rear-mounted pusher propeller configuration integrated into the fuselage tail boom. The fuselage itself spans 14 feet 2 inches in length with a narrow, streamlined cross-section to minimize drag, and includes integral fuel tanks within the wings totaling 24 gallons capacity, supplemented by a 2-gallon reserve tank in the fuselage.[2][11][12] Designed specifically for home construction, the VariEze's plans provide detailed, step-by-step instructions in a 153-page bound manual, covering all aspects of assembly except engine installation and emphasizing precise layup techniques with specified fiberglass plies and foam integration. This guidance supports an estimated build time of around 600 man-hours for experienced builders working in spare time, focusing on safety-critical elements like continuous layups for structural integrity.[13][12][1]Aerodynamic Configuration
The Rutan VariEze features a canard aerodynamic configuration characterized by an unswept foreplane with a span of 13 feet 2.5 inches and a reflexed GU25-5(11)8 airfoil designed to produce zero lift at typical cruise angles of attack. This setup provides primary pitch control while ensuring the canard stalls before the main wing during high angles of attack, thereby preventing deep stalls and enhancing overall safety.[14][15] The main wing incorporates a backward sweep of 25.7 degrees at the quarter-chord, a span of 22 feet 2.5 inches, and a reference area of 53.6 square feet, yielding an aspect ratio of approximately 9.2 for favorable lift-to-drag characteristics and efficiency in cruise. The wing employs a modified GA(W)-1 airfoil section and includes winglets at the tips that serve dual purposes as vertical stabilizers and yaw control surfaces, reducing induced drag by an estimated 15 to 20 percent compared to untapered tips.[15][2][16] A rear-mounted pusher propeller, supported by a composite pylon, positions the propwash behind the lifting surfaces to maintain undisturbed laminar airflow over the canard and main wing, minimizing turbulence and supporting the aircraft's low-drag profile. The configuration imparts positive longitudinal stability through the canard's forward placement and reflex, while the elevated main wing position promotes spin resistance by limiting post-stall descent modes; the resulting best glide ratio is 9:1 at 85 mph with the propeller windmilling.[15][17] Flight controls consist of full-span elevators on the canard trailing edge for pitch authority, inboard ailerons spanning the inner halves of the main wing panels for roll control, and dual rudders integrated into the winglets for yaw, eschewing a conventional empennage to streamline construction and reduce weight.[18][19]Operational History
Production and Adoption
The Rutan Aircraft Factory (RAF) began offering plans for the VariEze to amateur builders in the summer of 1976. The first amateur-built example achieved flight in March 1977. Priced at $113 per set, the plans emphasized a straightforward moldless composite construction method that enabled rapid assembly by individuals with average mechanical skills. By the end of 1979, RAF had sold more than 3,000 sets, fueling a surge in homebuilt activity that saw approximately 200 VariEzes flying by 1980. This early adoption marked a pivotal expansion from the prototype phase, transforming the design into a cornerstone of the experimental aviation movement. The VariEze's production was supported by a vibrant builder community, bolstered by the Experimental Ida Aircraft Association (EAA) through events like Oshkosh fly-ins and technical resources. RAF further nurtured this network with its Canard Pusher newsletters, which provided ongoing updates, construction tips, and modification guidance from 1976 onward, fostering collaboration among builders in the U.S. and abroad. Growth extended internationally, with examples appearing in Europe and Australia. By the 2020s, around 800 aircraft had been completed worldwide as of 2022, reflecting sustained interest despite the design's age.[7] Economically, the VariEze revitalized the homebuilt aircraft sector by offering high performance at a fraction of certified aircraft costs, with average build expenses ranging from $10,000 to $15,000 in the late 1970s and 1980s—primarily due to affordable materials like foam and fiberglass alongside converted Volkswagen engines. This accessibility appealed to pilots seeking efficient cross-country travel without the burdens of type certification and regulatory overhead. Classified under the FAA's experimental amateur-built category, the aircraft required at least 51% of fabrication by non-professionals for certification, eschewing type certification to permit owner modifications while maintaining operational flexibility. Key milestones included reaching 400 to 500 flying examples by 1987, underscoring the design's reliability and appeal. The VariEze's success pioneered the use of composite materials in kitplanes, influencing subsequent trends toward lightweight, efficient homebuilts and inspiring derivatives that expanded the canard configuration's popularity in amateur aviation.Flight Characteristics and Usage
The Rutan VariEze is renowned for its responsive handling characteristics, particularly in pitch, where the sensitive elevator provides precise control for maneuvering during flight. The aircraft's swept-wing design with wingtip rudders contributes to effective yaw control, though ailerons can feel heavy at lower speeds below 110 knots, improving with higher airspeeds. The pusher propeller and canard foreplane configuration offer superb all-around visibility, especially during turns, enhancing situational awareness for pilots, although the canard partially obstructs the direct forward and downward view. Pilots must maintain awareness of the canard's stall limits, as it is engineered to stall before the main wing—typically at angles around 15-18 degrees—to avert a full aircraft stall, resulting in a gentle pitch drop without wing drop.[20][21] Takeoff and landing distances are relatively short for a high-performance homebuilt, with a typical ground roll of approximately 600 yards (about 1,800 feet) to reach 70 knots liftoff in calm conditions at moderate weights, and landing rolls of around 1,500 yards (4,500 feet) from a 70-knot touchdown, reducible with headwinds. This performance supports operations from smaller airfields suitable for personal use. The VariEze's stability is solid across all axes, with a glide ratio of about 10:1 at 80 knots, making it forgiving in engine-out scenarios when handled properly.[20] In typical operations, the VariEze excels in cross-country touring and personal transport missions, accommodating two occupants with a range of roughly 700 miles at an economical cruise speed of 165 mph using its standard 100-hp Continental O-200 engine. Fuel efficiency stands at approximately 37 miles per gallon during economical cruise, derived from a burn rate of 4.4 gallons per hour.[22][23][20] Common modifications among owners include engine upgrades to 115-160 hp units, such as the Lycoming O-235, to enhance climb rates beyond the stock 1,600 feet per minute and overall performance, though these can increase propeller noise and vibration levels in the pusher configuration. Due to its non-standard canard layout and experimental nature, pilot training emphasizes structured transition courses with qualified instructors familiar with the type, as recommended by FAA guidelines to mitigate higher accident risks associated with unfamiliar configurations. With proficient handling, the VariEze demonstrates a low incident rate among experienced operators. Notable endurance examples include a 1975 world closed-course distance record of 1,638 miles covered in 13 hours by Dick Rutan in the prototype, showcasing its suitability for extended flights.[24][7]Variants and Derivatives
Engine and Configuration Options
The Rutan VariEze prototype was initially powered by a 62-horsepower Volkswagen 1834 cc air-cooled flat-four engine conversion, selected for its lightweight design and affordability for homebuilders. However, due to vibration issues, this configuration was not used for production plans. The plans instead specified the 100-horsepower Continental O-200 air-cooled flat-four engine for the refined Model 33 prototype, optimizing the aircraft's pusher-propeller setup while keeping overall weight low.[2] For greater reliability and performance, many builders installed the 115-horsepower Lycoming O-235 air-cooled flat-four, which integrated well with the VariEze's rear-mounted installation.[25][26] This alternative, approved in the original plans, provided smoother operation and better parts availability, though it added approximately 50 pounds to the empty weight compared to the O-200, influencing center-of-gravity placement and requiring minor firewall adjustments during construction.[26] Volkswagen conversions in the 75- to 100-horsepower range were also used by some builders, though less common due to reliability concerns.[20] Configuration options for the VariEze included modifications to the landing gear and propeller to suit builder preferences and operational needs. The standard setup featured fixed main landing gear mounted beneath the wings and a retractable nose gear for tricycle configuration, with the nose leg designed to retract rearward into the fuselage for prop clearance during flight and parking.[7] Some builders opted for an extended nose gear, adding up to 3 inches of length to improve ground attitudes, reduce prop strikes on rough fields, and enhance propeller ground clearance without altering the retractable mechanism.[27] Propeller choices typically involved fixed-pitch wooden or composite units tailored to the engine, with diameters around 60 to 64 inches and pitches varying from 66 to 72 inches to balance climb and cruise performance. Variable-pitch propellers, such as electrically actuated models, were available as upgrades for better optimization between takeoff/climb and high-speed cruise, allowing in-flight adjustments to maintain engine efficiency across altitudes.[28] The fuel system consisted of integral wing strake tanks feeding a forward header tank via gravity and electric pumps, ensuring positive fuel flow in all attitudes. Standard capacity was 26 gallons usable, providing about 700 miles of range at cruise, though builders could configure up to 52 gallons by extending the strakes for longer missions, at the cost of added weight and reduced payload.[22] Engine selection directly impacted the build process and aircraft handling; for instance, switching to a Lycoming O-235 increased cruise speeds by 20 to 30 mph over the standard O-200 setup but necessitated reinforced engine mounts and ballast adjustments to maintain stability.[26] These options allowed customization while preserving the VariEze's emphasis on lightweight, efficient construction. As of 2025, interest in new VariEze builds persists among homebuilders, with modern materials and avionics adaptations.[29]Related Rutan Designs
The Long-EZ, introduced in 1979, represents a direct evolution of the VariEze with a stretched fuselage to accommodate side-by-side seating for two, a 26 ft 1 in (7.95 m) wingspan, and a gross weight of approximately 1,400 pounds (635 kg), thereby enhancing range and payload capabilities compared to its predecessor.[30][31] Over 2,000 Long-EZ aircraft have been constructed from plans, making it one of the most prolific homebuilt designs in aviation history.[32] The Cozy series, developed in the 1980s by Nat Puffer as a derivative of the Long-EZ, expands the configuration to a four-seat arrangement suitable for family transport, incorporating a Roncz-designed canard for improved low-speed handling and incorporating composite construction techniques pioneered in the VariEze lineage.[33][34] In the 1980s, Rutan developed the Defiant as a twin-engine pusher configuration with a forward tractor propeller and rear pusher for enhanced redundancy and balanced thrust, maintaining the canard layout while providing seating for four; production remained limited, with approximately 20 aircraft completed.[35][36] The VariEze's emphasis on canard aerodynamics and moldless composite construction popularized these features among homebuilders, inspiring the development of thousands of Rutan-influenced aircraft across various designs, though none achieved FAA certification as production models.[37] Key evolutionary differences in these derivatives include increased overall size and seating capacity, addressing the VariEze's limitations in tandem-only accommodation for passengers.[38]Specifications
General Characteristics
The Rutan VariEze is a lightweight, two-place homebuilt aircraft featuring tandem seating for one pilot and one passenger.[2] Its compact design emphasizes efficiency and ease of construction using composite materials.[39] Key physical specifications include a length of 14 ft 2 in (4.32 m), wingspan of 22 ft 2.5 in (6.77 m), height of 4 ft 11 in (1.50 m), and wing area of 53.6 sq ft (5.0 m²).[2] The aircraft has an empty weight of 580 lb (263 kg) and a maximum gross weight of 1,050 lb (476 kg), providing a useful load of approximately 470 lb.[39]| Category | Specification |
|---|---|
| Powerplant | 1 × Continental O-200 air-cooled flat-four piston engine, 100 hp (75 kW); alternative options include the Lycoming O-235-L2C (115 hp) or original 65 hp Volkswagen conversion; 2-blade wooden fixed-pitch propeller |
| Fuel Capacity | 52 US gal (197 L) maximum (with optional auxiliary tanks); 26 US gal (98 L) standard in wing tanks plus 2-gal header tank |
| Avionics | Basic VFR instrumentation (engine gauges, airspeed indicator, altimeter, attitude indicator, and turn coordinator); optional IFR upgrades such as GPS and transponder limited by panel space |
Performance
The Rutan VariEze demonstrates impressive performance for a homebuilt aircraft, particularly in speed and efficiency, thanks to its lightweight composite construction and pusher-propeller configuration powered by a 100 hp Continental O-200 engine in the standard setup.[40] It achieves a maximum speed of 200 mph (322 km/h) and a cruise speed of 180 mph (290 km/h) at 75% power, enabling rapid cross-country travel while maintaining low fuel burn.[40] The stall speed is 59 mph (95 km/h) with the canard, contributing to its stall-resistant characteristics without flaps.[17] Key performance metrics for the standard VariEze configuration are summarized below:| Parameter | Value | Notes/Source |
|---|---|---|
| Range | 700 mi (1,127 km) with reserves | At economy cruise with two adults; usable fuel 26 gal.[2] |
| Endurance | 6-8 hours | Dependent on power setting.[40] |
| Rate of climb | 1,200 ft/min (6.1 m/s) | At sea level, gross weight.[39] |
| Service ceiling | 25,000 ft (7,620 m) | Practical operational limit.[2] |
| Glide ratio | 9:1 | Best glide at 92 mph (148 km/h).[17] |
| Takeoff ground roll | 750 ft (229 m) | Sea level, standard conditions.[39] |
| Landing distance over 50 ft obstacle | 600 ft (180 m) | With proper technique.[39] |