Limited Production History
The Mirage Marathon represents one of the most exclusive designs in homebuilt aviation, with only ten kits sold by 1998 and a single example registered with the Federal Aviation Administration as of January 2014. This extraordinarily limited production reflects the specialized nature of the amateur-built aircraft market and the technical challenges of constructing composite aircraft from plans.
Despite minimal sales, Mirage Aircraft Corporation continued listing the Marathon as "in production" through 2014, meaning kits remained available to determined amateur builders willing to undertake the complex construction process involving wood, foam, and fiberglass materials.
Designer and Development
Larry Burton conceived the Marathon as a fixed-gear variant of his acclaimed Mirage Celerity, which earned him an Oshkosh workmanship award in 1985. Burton's design philosophy centered on achieving maximum cross-country performance while minimizing operating costs through innovative powerplant selection and efficient aerodynamics.
The designer's sudden death from a heart attack in 1994 marked a significant transition for the Marathon program. Burton had established the technical foundation for both aircraft designs, but never witnessed the full development of his fixed-gear concept into a marketed kit.
Innovative Powerplant Strategy
The Marathon's most distinctive feature lies in its acceptance of automotive engine conversions, particularly the standard 160-horsepower Chevrolet V-6 powerplant. This approach represented a radical departure from traditional aircraft engines, offering builders substantial cost savings compared to certified Lycoming alternatives.
Beyond the Chevrolet installation, approved powerplants include Subaru, Mazda, and Ford V-6 automotive engines, all modified for aircraft service within the 150 to 180 horsepower range. This flexibility allowed builders to select engines based on availability, cost, and personal preference while maintaining performance parameters.
The automotive engine strategy reflected broader trends in the homebuilt movement toward reducing construction and operating costs. Traditional aircraft engines often cost three to four times more than equivalent automotive powerplants, making the Marathon's approach particularly attractive to budget-conscious builders.
Performance and Specifications
With its 160-horsepower Chevrolet V-6, the Marathon achieves a maximum speed of 200 mph and cruise speed of 185 mph, performance figures competitive with certified aircraft costing significantly more to operate. The 55 mph stall speed with flaps provides reasonable low-speed handling characteristics for a high-performance design.
The aircraft's 800-mile range with 50 gallons of fuel capacity delivers genuine cross-country capability, while the 20,000-foot service ceiling and 1,500 feet-per-minute climb rate provide operational flexibility for mountain flying and weather avoidance.
Weight distribution proves challenging with full fuel loads. The 1,825-pound gross weight allows only 406 pounds for pilot, passenger, and baggage when carrying maximum fuel, requiring careful mission planning for longer flights with two occupants.
Manufacturing and Support
Mirage Aircraft Corporation relocated from Tucson to Prescott Valley, Arizona, during the Marathon's development period, continuing to support both the Celerity and Marathon designs following Burton's death. The company maintained relationships with Aircraft Spruce & Specialty Co. and Wicks Aircraft Supply for materials distribution.
As a plans-built design rather than a traditional kit, the Marathon required extensive builder fabrication of components. This approach reduced initial costs but demanded considerable woodworking, composite construction, and systems installation expertise from amateur builders.
Legacy and Current Status
The Mirage Marathon's legacy rests not in production numbers but in demonstrating viable alternatives to expensive certified aircraft for personal transportation. The single registered example proves the design's technical feasibility while highlighting the challenges facing complex homebuilt projects.
The Marathon's automotive engine integration anticipated later developments in experimental aviation, where engine conversions became increasingly sophisticated and reliable. Burton's vision of affordable high-performance flying through innovative powerplant selection influenced subsequent homebuilt designs.
Today, the Marathon remains available to builders willing to invest the estimated 2,000 to 3,000 hours required for completion. The design serves primarily as a technical exercise for experienced builders rather than a practical alternative to certified aircraft, given the extensive construction time and specialized skills required.
The aircraft's extremely limited population makes it one of the rarest flying machines in American aviation, with its single registered example representing a unique achievement in amateur construction and automotive engine conversion technology.