WW2 USAAF Blue Recce Aircraft Camouflage

USAAF Camouflage Reference Contents:

The Blue Recce WW2 Aircraft Camouflage of The US Army Air Force (1942-1945)

For nearly six decades, the story of Haze Paint remained a hidden, uncharted terrain that, figuratively speaking, slipped off the mainstream radar. Its absence from official technical orders and its removal from production before the appropriate changes were in place made it a subject of intrigue. The unique properties of this paint, combined with the impracticality of creating samples, led to the lack of common color chips. Although this camouflage scheme served as the standard for high-altitude photographic scouts from March through October 1942, most are still unaware of its existence and use on the nearly 130 photographic Lockheed Lightnings. In the field of camouflage, if any pattern came close to achieving real invisibility, it was Haze paint.

In the wake of the United States' entry into World War II, a pivotal juncture emerged when the US Army Air Forces (USAAF) engaged in discourse with Samuel Cabot, a distinguished paint manufacturer hailing from Boston. Cabot's audacious proposition unveiled a groundbreaking white Haze paint, purportedly capable of rendering aircraft nearly invisible by exploiting the Tyndall Effect - the same optical phenomenon underpinning the blue appearance of the sky. This very phenomenon paints our skies blue and graces our landscapes with majestic violet hues.

Cabot's paint, which is a colloidal solution of zinc oxide in oil, was originally designated L 31340. The essence of its uniqueness lay in the pigment particles, whose diameter was smaller than the wavelength of blue or violet light. Cabot's theory was based on the fact that when this pigment was applied to a dark blue or black base, only the blue and violet colors were selectively reflected, while the base absorbed the other colors. As the angle of reflection changes, the rate of absorption will change dynamically, theoretically matching the shade of the surrounding sky. While not guaranteeing absolute invisibility, such a scheme was promising under certain weather and lighting conditions. The Tyndall effect was to be achieved by applying layers of Haze paint over a black base, creating complex segments of varying degrees of brightness, especially on the underside of the aircraft. Cabot's theory hinged on the notion that applying this pigment over a dark blue or black base would selectively reflect only blue and violet, while the base coat would absorb other colors. Varying angles of reflection would dynamically alter the rate of absorption, theoretically aligning with the ambient sky hue. While not promising absolute invisibility, this scheme held promise under specific weather and lighting conditions.

Cabot's theories found resonance within the scientific circles of the Massachusetts Institute of Technology (MIT), an institution deeply engaged in military-related scientific endeavors. MIT's engineers validated Cabot's hypotheses, propelling the Materiel Division of the Army Air Corps into large-scale testing. However, these comprehensive trials didn't materialize until late December 1941.

Initial tests, conducted in December, employed a Republic P-43 aircraft as the canvas for Cabot's innovative paint scheme. The outcome of these preliminary trials was encouraging, foreshadowing the potential of this groundbreaking pigment. By March 1942, Lockheed received the mandate from the U.S. Army Air Force to envelop all F-4 and early F-5 (the photo-reconnaissance variant of the P-38) Lightnings in the cloak of Haze Paint.

Haze Paint's essence resides in its graded system, orchestrating shadow shading or countershading through distinct layers of Haze paint to conjure varying shades. The process commenced with a foundational black coat encompassing the entire aircraft. Subsequently, a light layer of Haze Paint was delicately sprayed onto upper surfaces, yielding an intense, almost obsidian hue. The nether surfaces bore the brunt of a generous Haze paint application, especially within shaded regions. This strategic layering birthed a graduated spectrum, spanning from ethereal light blue to nearly pristine white. The fuselage sides, booms, and vertical stabilizers were adorned with a medley of pigmentation, a result of a moderate coating. Haze paint's non-solid color camouflage essence, coupled with the absence of mechanisms to regulate precise layer application, rested on the "artistic" discernment of the aircraft painter. This subjective approach yielded variations in layer thickness and, by extension, reflectance, resulting in aircraft with distinct visual signatures. With only a loose guideline to govern Haze paint application, numerous early airframes fell short of U.S. Army Air Force inspectors' stringent criteria.

The application of Haze Paint was intrinsically tethered to daylight, as nocturnal endeavors were marred by the absence of adequate light for judging relative thickness. The oil-based nature of Haze Paint demanded a protracted twelve-hour drying period. Consequently, an additional two to four man-hours were dedicated to meticulously expunge accumulated particles from the finish. The paint's fumes exacted a toll, causing illness in some painting crews, occasionally resulting in hospitalization after an arduous eight-hour painting session. The endeavor of retouching chipped paint proved an uphill task, rendered even more challenging by the inevitability of paint finish weathering, progressively darkening to its base hue over time, consequently eroding the benefits derived from the Haze layer.

In a bid to surmount these technical impediments, Lockheed ventured into alternatives. Notably, the introduction of Cloudmist, a lacquer-based paint, and Ken-Haze, an enamel base, aimed at circumventing the issues surrounding Haze Paint. Regrettably, both ventures proved futile. The U.S. Army Air Force's rejection of Cloudmist stemmed from its coarse finish, deeming it unsuitable. Similarly, Ken-Haze, the enamel-based endeavor, met the same fate, denied by the Materiel Command. Faced with the dearth of appropriate paint for their F-5s, Lockheed secured permission in October 1942 to embellish their reconnaissance Lockheed Lightnings with the conventional Dark Olive Drab No. 41 / Neutral Gray No. 43, pending a resolution to the Haze Paint quandary. A mere week later, the Proving Ground Command issued a conclusive report on Haze Paint, concluding its marginally superior efficacy under slight haze conditions, while asserting the parity of the standard Dark Olive Drab / Neutral Gray in other scenarios. On this basis, the Materiel Command recommended discontinuing Haze Paint's use on PR Lightnings.

Despite the verdict, the AAF Director of Photography wielded compelling evidence in support of the Haze scheme's advantages. Field units, embarking on combat missions with Haze-clad aircraft, extolled the camouflage's attributes, deeming it exceptionally desirable. The slightest advantage bestowed upon unarmed reconnaissance pilots was perceived as an asset. The legacy of Haze paint, however, bore its share of challenges. Over time, Haze paint exhibited a tendency to darken considerably, posed a labor-intensive application process, and proved unsuitable for nocturnal endeavors. Consequently, it faced a brief hiatus between October and January of the ensuing year. Thus, in January 1943, following an internal policy debate, a directive was issued, mandating the application of Haze paint "until such a time as a more suitable type of haze paint is developed." This very replacement was at the cusp of realization, developed and vetted at Lockheed under the banner of Synthetic Haze paint.

Anticipating the eventual resurgence of Haze Paint's necessity, Lockheed's engineers pivoted toward unearthing a viable replacement. In January 1943, a rendezvous transpired between the U.S. Army Air Force/Lockheed factory representative, a Sherwin-Williams engineer, and Lockheed Vega engineers, collectively shaping the path to innovation. Astonishingly, flight tests involving aircraft cloaked in oil-based Haze Paint unveiled their luminosity at altitudes exceeding 20,000 feet. Given that all Haze scheme tests were hitherto executed at lower altitudes, absent the accompaniment of a chase plane, the overlooked phenomenon of heightened luminescence comes as no surprise.

Innovative thinking manifested as the birth of a deep blue base named Sky Base Blue. Subsequently, the synthesis of the synthetic haze enamel with Flight White yielded a hue named as Flight Blue. The maiden beneficiary of this groundbreaking transformation was an F-5A Lightning, adorned with coats of Flight Blue to accentuate shadow domains, counterpoised by lighter applications on upper surfaces and flanks. The resultant shading was an epitome of subtlety, granting the aircraft an impression of homogeneity at first glance.

This haze variant became the hallmark color for the later F-5 Lightnings from March 1943 onward. The closest approximations to the original Flight Blue hue include FS 35190 and, to a lesser extent, ANA 501 (Light Blue). The intensified base color likely imbued Synthetic Haze with a deeper visual impact compared to its predecessor.

The culmination of Synthetic Haze Paint's formulation resided in an imperative flight test. The F-5A, soaring to 30,000 feet, embarked on a mission of validation, maneuvering within a thousand feet of a Boeing B-17 Flying Fortress adorned with six observers. Astonishingly, the Synthetic Haze Lightning remained concealed until this close encounter. This triumph deemed a resounding success, garnered an endorsement from both the Director of Photography and Materiel Command. By March 1943, Lockheed had enshrined the Synthetic Haze Paint formula and application scheme as the standard for all F-5A/B Lightnings.

The prevalence of synthetic smoky paint is not known. Clues suggest that Synthetic Haze Paint's usage waned post-mid-1944. And despite sought to address its predecessor's complexities, the mid-1940s ushered in a strategic shift. To overcome the challenges inherent in Synthetic Haze's application, most USAAF photo-reconnaissance aircraft transitioned towards harmonizing their appearance with their RAF counterparts. This shift manifested in the adoption of the PRU Blue scheme, characterized by a darker blue-gray palette, applied uniformly as a single shade. Following this juncture, PR Lightnings, subject to painting, adopted RAF stocks' PRU Blue as their cloak of choice, especially evident across Europe, the Mediterranean, and regions endowed with accessible RAF paint stocks.

The USAAF's engagement with British photo-reconnaissance aircraft via Reverse Lend-Lease deepened the narrative's complexity. This collaboration encompassed PR versions of iconic aircraft like Spitfires and Mosquitoes, adorned in factory-applied PRU Blue camouflage. This convergence not only mirrored the evolution of camouflage strategies but also bore testimony to intercontinental cooperation in the art of aerial concealment.

The tale of aviation camouflage is etched with remarkable ingenuity, strategic adaptation, and a seamless blend of scientific theory and artistic intuition. From Samuel Cabot's audacious vision of Haze Paint to Lockheed's unyielding quest for camouflage perfection, this narrative traverses uncharted skies, revealing the complexities and triumphs of concealing aircraft within the realm of the azure expanse.

Color Guide to The WW2 USAAF Blue Recon Aircraft Camouflage

• Haze / Synthetic Haze: Any deep sky blue color will work for Synthetic Haze, with a gradient to sky blue for the bottoms. For Haze, a lighter, less blue color would work best, receding into white on the sides and under surfaces.
• PRU Blue: A grayish-blue color which clostest equivalent is the modern BS 381C 636 PRU Blue color. As for US colors, the most applicable analogues are ANA 608 Intermediate Blue or its successor FS 35164.

Photo Reference on WW2 USAAF Blue Recon Aircraft

References:

• Archer, Robert D. and Archer, Victor G., USAAF Aircraft Markings and Camouflage 1941-1947, Schiffer Publishing (1997)
• Bell, Dana, Air Force Colors Volume 1 1926-1942, Squadron/Signal Publications (1995)
• Elliot, John M., The Official Monogram US Navy & Marine Corps Aircraft Color Guide Vol 2 1940-1949, Monogram Aviation Publications (1989)
• Paul Budzik, paulbudzik.com
• Rodrigo Aguilera, The World Wars.net

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