Douglas A-26 / B-26 Invader — Original Airframe Engineering Drawings Archive

Douglas Aircraft Company — A-26 Series · T.O. No. 01-40A-59 · November 1944 Revision

Why This Archive Matters

Warbird restoration and re-engineering depends entirely on access to original factory blueprints, loft drawings, and technical construction drawings. Because exact-fit components for the A-26 Invader are no longer manufactured, serious restorers combine original engineering drawings with reverse engineering to accurately replicate historically airworthy parts. With only approximately 23 to 24 airworthy examples surviving worldwide from an original production run of roughly 2,500 aircraft, this primary-source drawing archive represents one of the most authoritative dimensional and structural references available to the restoration community.

The Aircraft

The Douglas A-26 Invader was one of the most aerodynamically refined twin-engine light bombers of the Second World War — and one of the few American combat aircraft to serve in three consecutive conflicts: World War II, Korea, and Vietnam. Designed around the then-revolutionary NACA 65-215 laminar flow airfoil by project aerodynamicist A.M.O. Smith, the Invader combined a remarkably narrow fuselage, tight low-drag engine nacelles, and fighter-like handling into a platform that outperformed many single-engine fighters of its era.

Early Langley pressure tunnel wind-tunnel testing on the XA-26 prototype validated its low-drag configuration. The production wing was intentionally designed with pronounced root stall to provide safer, more predictable low-speed characteristics. Prototype testing revealed severe engine overheating, forcing engineers to completely redesign the cowlings and delete the original propeller spinners. The nose wheel structure collapsed repeatedly under high-load handling tests, prompting a major structural redesign of the entire gear assembly.

A December 1944 production engineering bulletin replaced the heavily framed flat-top canopy with a raised single-piece clamshell canopy to improve pilot visibility over the wide engine nacelles. A standardised modular nose attachment allowed ground crews to swap between a solid strafing nose carrying up to eight .50 calibre machine guns and an ungunned glass nose for bombardiers. Defensive armament was revised to low-profile remote-controlled dorsal and ventral turrets operated by a single gunner via periscopic sight.

Technical Data — A-26B / B-26B

• Powerplant: 2 × Pratt & Whitney R-2800 Double Wasp 18-cylinder radial · R-2800-27 (2,000 hp) early · R-2800-79 water-injected (2,350 hp) late
• Maximum Speed: 355–373 mph depending on altitude and armament configuration
• Cruise Speed: 247–284 mph
• Initial Climb Rate: 1,250 ft/min
• Combat Range: 1,400 nm · up to 3,200 nm with external tanks
• Airfoil: NACA 65-215 laminar flow
• Handling: Fighter-like roll rates · strong single-engine performance · NACA-verified longitudinal and directional stability

Surviving Examples

Of approximately 2,500 A-26 / B-26 Invaders built, only an estimated 23–24 remain airworthy worldwide. Notable flying examples include Sexy Sue operated by warbird groups out of Medina, Washington; Tina operated by Tina Fly GmbH in Europe — a rare On Mark converted A-26B, one of only two in the world with that specific engine modification; and several examples maintained by the Commemorative Air Force across the United States. The extreme rarity of surviving airworthy examples makes original factory engineering drawings an irreplaceable resource for any serious restoration or licensed reproduction project.

The Archive — What This Collection Contains

This is a primary-source engineering archive drawn directly from Douglas Aircraft Company’s original manufacturing drawings, converted first to microfilm and now to high-resolution electronic format.

• 10,795+ engineering drawing sheets
• 19 microfilm rolls — Rolls A, B, C, D, E, F, G, H, J, K, L, M, N, P, Q, R, S, T, U
• Total archive size: 33.3 GB
• Formats: TIFF (archival) and Adobe PDF
• Includes: Drawing number index · T.O. No. 01-40A-59 · November 1944 revision
• Published by authority of: Commanding General, Army Air Forces
• Index correct to: 1 August 1944

Drawing Groups Covered

• General Assembly
• Wing
• Empennage
• Fuselage
• Power Plant
• Landing Gear
• Special Equipment
• Armament

Index Structure

• Section I: Introduction — microfilm use, associated equipment, interchangeability, revisions
• Section II: Numerical Index — Contractor’s Standard Parts · Numerical List of Drawings
• Section III: Alphabetical Index — Contractor’s Standard Parts · Alphabetical List of Drawings by Group

Note: This set of drawings is not exhaustive of all documents ever produced for the A-26 series. A full index of drawing numbers (T.O. No. 01-40A-59) is included with the collection.

⚠️ Regulatory Notice: Under FAA 14 CFR § 43.13 and EASA Part-M, any mechanic performing maintenance on an active aircraft must use current, manufacturer-approved revision-controlled data. This archival document does not satisfy that requirement.

This is an archival, static-copy edition fixed at its original publication date. Intended for historical reference, restoration support, re-engineering, and educational use. Not approved for active airworthiness maintenance under FAA 14 CFR § 43.13, EASA Part-M, or equivalent international regulations. Operators of active aircraft must use current, revision-controlled publications from the Type Certificate holder or an authorised distributor.

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