Aluminum B-17s bomber vs Camouflaged B-17s bomber

To paint or not to paint? That was the question for US Army and Navy Air Forces in World War II.

In late 1943, the Army and Navy both decided to stop painting their fighters and bombers in camouflage colors.

From January 1944, all new B-17s, B-24s, P-38s, P-47s, and other aircraft, apart from specialized airplanes like the P-61 Black Widow, were sent into combat buffed in their original fresh-off-the-assembly-line aluminum shine.

The reason behind the change was straightforward: not painting airplanes was cheaper, faster, and less resource intensive than painting them. The Allies needed more planes in the sky right away, regardless of how they looked.

The military had originally camouflaged its aircraft with variations on a two-toned theme: olive drab on the upper surfaces, and flat gray on the lower. The scheme was designed to make the planes blend into the sky from below and the ground from above.

In February 1944, the first glimmering silver bombers began arriving to squadrons in the Eighth Air Force in England. Crews weren’t happy with the change.

They worried that the new planes would stand out from the older ones, making them more obvious targets for the enemy.

Air Force brass tried to reassure the bomber crews and fighter pilots. Camouflage, they said, mostly helped when planes were on the ground. In the air, the planes gained little protection from the paint jobs. The loud engines and contrails were dead giveaways, regardless of how shiny the planes were. Plus, the Germans used radar to track aircraft. Fancy paint schemes were a senseless waste of resources.

Still, the US military conducted studies to compare whether painted or unpainted airplanes performed better in combat.

The results were startling, if seemingly contradictory.

According to a fine 2014 article by Dwight Jon Zimmerman on the Defense Media Network, the tests showed that unpainted airplanes performed better than painted ones.

The issue, Zimmerman explains, was weight. The 35 gallons of paints needed to coast a B-17 weighed a whopping 300 pounds after it dried. Leaving a Fighting Fortress unpainted thus increased capacity for extra ordnance and added some zip in flight.

Keith Mann of the excellent WWII US Bombers YouTube channel, however, draws slightly different conclusions from the evidence. His in-depth video focuses on the case of the B-17.

The Air Force conducted flight tests in March 1944 comparing painted and unpainted B-17s. The results showed that painted B-17s flew 2.5 to 4.5 miles per hour faster than unpainted ones at the same engine power.

The difference in weight, he says, was negligible (75 pounds, not 300). The key, rather, was surface drag.

The paint, it turned out, helped to fill small gaps around rivets and seams, improving aerodynamics and reducing drag.

Closeup of B-17s bomber rivets and lap joints

Still from WWII US Bombers, “B-17 Bomber Paint Vs No Paint, Unexpected Results”

Under combat flight conditions, a painted B-17 would maintain the same airspeed as an unpainted B-17 with a 3 percent increase in engine power. The unpainted B-17 consumed 3 percent more fuel than the painted B-17 for the same mission range. The weight of the extra fuel required by the unpainted B-17 offset any advantage it had gained from the lack of paint.

When it came to performance, the painted surface had the advantage, at least with the B-17.

But that wasn’t the case, Keith Mann points out, with the more modern B-29. B-29 bombers boasted cleaner surfaces with flush fasteners and skin butt joints. The result was minimal drag. These large bombers, used in the Pacific War, didn’t need paint to improve their aerodynamics.

Closeup of B-29 bomber rivets and butt joints

Still from WWII US Bombers, “B-17 Bomber Paint Vs No Paint, Unexpected Results”

In all cases, the key to performance was a smooth, polished surface.

Combat tactical commands knew that from the beginning.

In early 1943, the War Department in Washington, DC, asked commanders overseeing air operations in Europe and the Pacific whether they preferred painted or unpainted planes.

“We don’t care,” they responded as if with one voice. “So long as they airplane skins are smooth.”

Either keep them painted or smooth the bodies some other way, they said.

So, in January 1944, one last step was introduced into the production process for war planes. Each plane received not paint, but a wax coating or a lightweight clear coat.

This final step filled the gaps and saved the time, weight, and cost of giving aircraft two-toned color schemes.

There also seems to have been an intangible benefit from sending crews up in gleaming silver airplanes rather than olive drab ones. Anecdotal reports suggested air crews eventually experienced a morale boost from the shiny planes. The glimmering fuselages became a mark of Allied air superiority.

“Here we are. Come and get us,” they seemed to say.

Top image: Airwolfhound, CC BY-SA 2.0, via Wikimedia Commons