Beech 18 (Turbo)

Overview

The Beech 18-Turbo is a turboprop conversion of the Beech 18 airframe, most commonly associated with Volpar Aircraft’s Super Turbo 18 program. Volpar replaced the original Pratt & Whitney R-985 radials with two 705 hp Garrett AiResearch TPE-331-1-101B turboprops, flat-rated to 605 hp, and added the Volpar MkIV tricycle landing gear conversion. The result preserved the Twin Beech’s heavy-hauling cabin while modernising powerplant, ground handling, and dispatch reliability.

Key Features for GA Buyers

• Turbine reliability on a vintage cabin. Garrett TPE-331 turboprops eliminate the magneto, carb-ice, and cylinder-temperature complexity of the R-985 radials, while the cabin retains the Twin Beech’s 6-8 seat utility configuration.
• Tricycle gear handling. The Volpar MkIV nosewheel conversion removes the demanding ground-handling profile of the original taildragger, opening the type to a wider pilot population.
• Operational pedigree. Air America operated 14 Volpar conversions during the Vietnam War; civilian freight operators kept Volpar Turbo 18s in revenue service through the 1980s, demonstrating durability under hard utility use.

Trade-offs

• Conversion-population type. Volpar built a finite number of conversions; airframe availability is limited and parts support depends on a small specialist community.
• Fuel burn vs payload. Turboprop performance comes at higher fuel-flow than modern equivalents; the 318-gallon fuel system is needed to deliver the published 1,000 nm range, leaving useful load constrained at full fuel.
• Period airframe. The underlying structure remains a 1937-design Beech 18: spar inspections, corrosion management, and parts that depend on a vintage supply chain are part of the ownership profile, even with the modern powerplant.

See Also

• Beechcraft Beech 18 – the unconverted radial-piston Twin Beech the conversion is built on; classic appeal at lower acquisition and operating cost. Compare
• Beechcraft 50 Twin Bonanza – Beech’s heavy piston twin successor; comparable utility-twin mission, contemporary lineage. Compare
• Beechcraft 65 Queen Air – cabin-class piston twin in the same Beech utility lineage; comparable cabin, piston economics. Compare
• Beechcraft King Air 90 – the factory-turboprop heir to the cabin-twin lineage; modern systems, comparable cabin, much wider parts and training support. Compare