Reviving history: the meticulous restoration of the Birdcage Corsair

Located aboard the historic Naval Air Station (NAS) in Pensacola, Florida, the National Naval Aviation Museum is the largest naval aviation museum in the world. Established in 1962 and opened in 1963, the museum has grown from a small building and a handful of aircraft to 350,000ft2 of exhibit space on a 60-acre campus.

The museum displays as many as 150 aircraft at any given time – and the museum is also responsible for managing more than 1,000 planes displayed in airports, foreign countries, and other museums worldwide. The eclectic collection includes planes deployed in multiple conflicts: both World Wars, the Korean War, Vietnam, and others. There are also countless artifacts including uniforms, medals, and personal letters. Not all the exhibits are military; they even feature a moon rock brought back to Earth by Eugene Cernan, the last man on the moon.

Straight out of the skies

But the aircraft are inarguably the star attraction, arriving at the museum from multiple sources. “Some of the planes come to us directly from military service – straight out of the skies and through the doors,” explains Hill Goodspeed, deputy director of the museum. “Others were procured by civilians, then donated. Many were just sitting in storage until they were discovered.”

According to Goodspeed, the most unique form of acquisition is underwater recovery. While many planes were sitting on the ocean floor, the majority were pulled from a much smaller body of water.

“Most underwater planes have been recovered from Lake Michigan,” Goodspeed says. “A sizable number of planes crashed there in the early 1940s during World War II carrier qualification. There were plenty of neophytes training in these aircraft, so unfortunately, quite a few went down. There were about 150-to-200 wrecks in the lake, and so far, we’ve supervised the extraction of about 30.”

Restoring the aircraft is essential for preparing them for exhibit. All require some level of refurbishment, especially the ones fished out of the water. For Mike Allen, department head of aircraft preservation and maintenance, this long and arduous process starts with documentation.

“Documentation is the foundation of all our aircraft restoration efforts,” Allen says. “We document everything on the plane and photograph every inch of the interior and exterior to ensure we can put everything back together properly after it’s been removed and refurbished. We strive to ensure our airplanes remain true to their original construction and design. Our job is to refurbish them to look the way they looked when they were being flown.”

Allen and his team take out the removable components to reconstruct them. The bulk of these components involve the plane’s avionics: instrumentation, gauges, radio, and navigational equipment. But it can also include larger subassemblies such as landing gear struts. Although some portions of the airframe are too difficult to disassemble or don’t require any restoration, just about every component coming off the airframe will work its way through the blasting cabinet the museum acquired from Titan Abrasive Systems. The cabinet is used to eliminate corrosion, rust, and paint covering many of the components. There are two purposes behind this process:

• Removing the debris helps restore the component as closely as possible to its original condition, playing a vital role in making the plane exhibit-worthy.
  
• Once the extraneous material has been blasted away, Allen and his team will have a better idea of whether the part itself needs repair – or whether it’s unusable and needs to be fabricated from scratch in their in-house machine shop.

While the museum’s renovation team has tried multiple media for the blasting application, they find aluminum oxide is the most effective material for their purposes. “Aluminum oxide is suitable for virtually all metallic applications,” Allen explains. “It does a very thorough job without causing damage to the component.”

No part too large

Allen’s team has yet to encounter any part too large for the cabinet to accommodate. But that’s partly because the aluminum fuselage never sees the inside of the cabinet – and never will. The blasting process creates heat, which is the enemy of aluminum frames; in fact, the restoration team will never put components in the cabinet with even the slightest potential of being deformed in the blasting process. Should a fuselage require attention, the team employs an orbital sander equipped with a HEPA filter, an important addition for protection against the lead paint used on most of these aircraft. The Titan blasting cabinet also has a reclaimer on it, meaning the aluminum oxide can be collected and reused multiple times.

Allen is actively involved in the actual restoration, along with seven volunteers. Their involvement applies to the blasting process as well. And the expertise they’ve gained from this hands-on approach has served them well.

“We’ve been using abrasive blasting for decades,” Allen says. “We know where the equilibrium point is for these components. If you go beyond that, you put the quality of the components at risk. We know exactly when and where to stop.”

The Titan blast cabinet plays a key role in the museum’s refurbishment operation. But there are myriad other processes involved, and when you combine them all – and throw in some manpower considerations – you end up with a procedure that’s beyond time-consuming.

“Restoring the aircraft to display condition is not a quick operation,” Allen says. “It’s an extreme case, but we’ve been working on the Vought F4U-1 – a rare Birdcage Corsair, with a cockpit canopy featuring framed panels rather than the bubble canopies of later versions – for 14 years. It’s been an arduous job, plus we used to have more employees in the department, but even with more hands on deck, it still would have taken seven or eight years. Remember, we usually have to reconstruct and refabricate a ton of components, each of which can take considerable time. You can’t just go to the local auto parts dealer and buy these parts. But one upside is that we don’t have to make the plane flight ready. It just needs to look good and project as much authenticity as we can provide.”

Given the complexity of the job, as well as the litany of restoration issues and problems needing to be creatively solved daily, what’s the driving force behind Allen’s and Goodspeed’s passion?

“Of course, we enjoy working on the aircraft and preserving these extraordinary pieces of history,” Goodspeed says. “But the museum is about much more than the artifacts housed inside. We’re connecting people – especially the younger generation – with the courageous actions of their parents, grandparents, and great-grandparents who served our country so bravely. We certainly want people to appreciate the aircraft and the artifacts, but we’re just as enthusiastic about presenting the human side of naval aviation.”

The Titan blast cabinet is a small part of a much bigger picture at the National Naval Aviation Museum. Yet it’s a role the company performs with a deep sense of pride.

National Naval Aviation Museum
https://navalaviationmuseum.org

Titan Abrasive Systems
https://www.titanabrasive.com