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EAA AirVenture Oshkosh RSS Feed Shipshape Flight: The slam-dunk rigors of sea service impose adaptations

By FREDERICK A. JOHNSEN
Helldiver
A blue undersurface on the folding panel of the Helldiver wing diminished the aircraft's visibility when stowed on deck of aircraft carriers. Photo by Frederick A. Johnsen
Skyhawk
This Douglas A-4 Skyhawk at AirVenture 2011 prominently wears its navy tailhook for aircraft carrier landings. Photo by Darrell Brooks
Wildcat
Grumman aircraft of World War II, like this Wildcat, folded their wings back with the leading edge down to minimize space on aircraft carriers. Photo by Frederick A. Johnsen

S-3 Viking

NASA's Navy - NASA flies a number of former U.S. Navy aircraft for research purposes, including this folding-wing Lockheed S-3 Viking, parked on ConocoPhillips Plaza for AirVenture 2011. Photo by Frederick A. Johnsen
Corsair
A combination of tailhook and tail wheel retracts into the Corsair fuselage with an exposed hook nested in its recess. Photo by Frederick A. Johnsen

Aviation occurs in defiance of gravity’s laws.

But aviation in turn demands respect physics’ laws.

When the U.S. Navy grappled with the physics of landing airplanes on ships, something had to give.

Sometimes physical constraints drove the adaptation; other times the issue was more of a kinetic-energy issue.

Take tail wheel tires.

Those small air-filled rubber doughnuts could pop from the heavy vertical slamming they received in arrested carrier landings. 

On some fighters like the F4U Corsair, pneumatic tires were inflated to 85 pounds per square inch (psi) for ground operations, and as much as 115 psi in an effort to resist carrier deck impacts.

Still they blew.

So, many Navy carrier aircraft swapped tail wheels to match their surroundings: a solid rubber roller that couldn't deflate for shipboard wear, pneumatic tires for ground-based ops. Some vintage shipboard Navy planes parked at AirVenture may thus be expected to have pneumatic tail wheel tires.

The rigors of carrier landings also necessitated appropriately strong main landing gear. Shorter gear legs were desirable, but propeller arc clearance often dictated otherwise.

Designers at Vought Aircraft came up with a remarkable solution, giving their Corsair its characteristic inverted gull wing that allowed short gear legs to attach at the lowest point on the wing.

The resulting right-angle intersection between the wing root and the fuselage gave another bonus in its inherent aerodynamic cleanliness.

An arresting development
Tailhooks were a clever stopping mechanism for the first Navy airplane, and they became even more in vogue between the wars, and remain still vital today.

A series of cables stretched across the carrier deck gives a pilot more than one chance to get it right by snagging one. That cable then relaxes just enough to bring the airplane to an abrupt, but not violent, halt. Today that’s called a “trap.”

Take a look at Navy warbirds at AirVenture and you may see the hook-and-tailwheel combo of the F4U, which is largely faired behind tail wheel doors in flight, and the extending tailhook stinger style of the various Grumman warbirds.

And though considered an aircraft-carrier appliance, tailhooks gained a latter-day following in the Air Force when that service appreciated the value of hooks to snag high-speed jet fighters that had lost their brakes.

Know when to fold ’em
Folding wings are an accommodation to the limited acreage of an aircraft carrier. 

In the 1920s, biplane wings that simply pivoted aft made more room on deck.

Grumman fighters and torpedo bombers of World War II relied on a knuckle pivot that swung the wings aft while dropping the leading edge down, giving the aircraft an even smaller footprint when stowed.

The simplest, yet bulkiest, wing stowage was an overhead reach, accomplished hydraulically.

The Corsairs and the big Curtiss Helldiver at AirVenture 2011 use that option.

Not all aircraft carriers are equal; when the Royal Navy acquired Corsairs for its carriers, clearance to the hangar-deck overhead was a few inches shy of its American counterpart.

Engineers solved the problem by giving British Corsairs a natty clipped-wing look that fit the lower headroom.

Overhead-folding-wing airplanes stowed on deck gave aircraft carriers another problem to solve in the era of multi-color camouflage paint.

Now you see me…
Rationale of the day said white undersides and dark blue upper surfaces made Navy aircraft harder to see.

A three-tone coat of blues and white did the job in flight, but when wings folded overhead, aircraft carrier decks would be instantly emblazoned with billboard-sized white markers from the wings' upturned surfaces.

Not good.

The low-tech answer was to paint the hinged outer portions of the wings blue on both upper and lower surfaces so with wings folded the blue hue matched the neighboring blue sea.

In flight, the aircraft lost only a portion of its white underbelly camouflaging, and the appearance of blue outer panels may even have contributed to camouflaging effectiveness by making it more difficult to judge size and distance from the visible blobs of color. Check out the Helldiver in the warbirds area for an example.

At AirVenture, the ex-Navy (now NASA) S-3 Viking folds its wings like a circus contortionist until they lie nearly flush with the top of its fuselage. Other postwar carrier planes simply raise their outer wingtips to the vertical, like a football referee signaling a touchdown from the elbows only.

A stroll among the Navy warbirds at AirVenture reveals ingenuity and adaptation that did so much to win wars and advance aviation.

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