On Mark Engineering

On Mark Engineering was an American aircraft remanufacturing company established in 1954 at Van Nuys Airport in California. Its most significant products were rebuilding military surplus A-26 Invaders into executive transports—the Marketeer with an unpressurized fuselage and the Marksman with fuselage pressurization. On Mark converted a single B-26 into the YB-26K Prototype. After successful tests, that prototype was reconfigured with 39 other planes into the B-26K Counter-Invaders (later redesignated A-26A) for counterinsurgency missions with the US Air Force. A total of 40 of the planes were produced. On Mark also undertook conversion work of a Boeing 377 Stratocruiser into the prototype Pregnant Guppy for Aero Spacelines.

An A-26A Counter-Invader on display at Hurlburt Field, Florida

On Mark Marksman C N60XX fitted with deepened pressurised fuselage, R-2800 engines and wing tip tanks

Products

• On Mark Executive
• On Mark Marketeer
• On Mark Marksman
• B-26K Counter-Invader
• Aero Spacelines Pregnant Guppy—prototype only