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Online Magazine of the Missouri Historical Society


Spring 2008

Midnight Maintenance

Caring for Lindbergh's Monocoupe


A hydraulic crane puts workers within reach of the Monocoupe at Lambert Airport. Photograph © 2008, Missouri History Museum.  

Several times a year, travelers at Lambert-St. Louis International Airport who arrive on late evening flights may be surprised to see unusual activity going on over their heads as they emerge from one of the concourses into the Main Terminal. High on a hydraulic lift, parallel to the fuselage of an airplane that hangs from the ceiling, one or two workers sweep soft wool dusters over the wings and body of the small black and orange Monocoupe, creating clouds of dust that fall to the floor.

The plane, a 1934 Monocoupe D-145 once owned by Charles Lindbergh, has been on display at the airport since 1979 and is one of three airplanes in the Missouri History Museum’s permanent collection. Until 1998, the Lindbergh Monocoupe shared the spotlight at Lambert next to the Ryan B-1 Brougham, a replica of the Spirit of St. Louis, Lindbergh’s trans-Atlantic plane, which hung beside the Monocoupe. That plane now hangs in the MacDermott Grand Hall of the Missouri History Museum. The third plane, a red Monocoupe 110 Special, manufactured in St. Louis in 1931, hangs in the newer East Terminal at Lambert. It was completely restored by pilot John Glatz and donated to the Missouri History Museum (MHM) by him in 1983.

A replica of the Spirit of St. Louis hangs in the MacDermott Grand Hall of the Missouri History Museum. Photograph © 2000, Missouri History Museum.

Charles Lindbergh originally purchased the Monocoupe D-145 in 1934 from the Lambert Aircraft Corporation for use as his personal plane. He had several modifications made to the plane, including adding a 145-horsepower Warner engine (instead of a 90-horsepower Lambert engine), extra leg room, increased fuel capacity, a flat-panel windshield, a modified cowling, and a customized aileron arrangement that allowed them to be used as additional flaps in landing. After a cross-country flight with his wife, Anne, that year, Lindbergh used the plane very sparingly. He kept the plane in his possession until 1940, when he flew it to St. Louis to deliver it to the History Museum. He had written to MHM in 1938, offering the plane as a gift. “I do not intend to sell the plane,” he wrote, “because I am not well satisfied with its handling characteristics.”

The problem, he stated in his Wartime Journals, was that the factory had changed the wing curve from that which it had used on previous Monocoupes, and the new shape was less stable in the air. Lindbergh felt the plane could be dangerous to an inexperienced pilot. He also had the foresight to recognize that the plane would be an interesting piece for the museum to display 10 to 20 years down the road as an example of an early St. Louis–manufactured aircraft. When he flew the Monocoupe to St. Louis in 1940, he worked with Marjorie Douglas, an MHM curator, and Gregory Brandewiede, an officer of the Robertson Aircraft Corporation in St. Louis, to dismantle the plane and store it in the basement of the museum’s Jefferson Memorial Building. The plane remained in storage until 1962, when it was brought out and reassembled to display at a local air show. Over the next 15 years, Lindbergh’s Monocoupe D-145 was exhibited several times in the St. Louis area, including a number of years at the Museum of Transportation, and it appeared in a parade honoring the 50th anniversary of Lindbergh’s famous flight in 1977. After being moved, stored, and displayed several times, it was finally hoisted into its current position at Lambert Airport on April 17, 1979.


Thousands of travelers pass through the airport daily, bringing with them dust and dirt. Some of that debris gradually accumulates on the surface of the Monocoupe. In addition, the airport’s regular maintenance work and renovation projects around the plane can create construction dust that settles on the wings and fuselage. The dust needs to be removed on a regular basis, for both aesthetic and sanitary reasons.

Travelers pass under the Monocoupe as they line up for security screening. Photograph © 2003, Missouri History Museum.

The cleaning of the Lindbergh Monocoupe occurs late at night, when the number of people walking through the airport has dropped to a trickle. After 11:00 p.m., only a handful of travelers goes through the security checkpoint near the Monocoupe, and the area under the plane can be blocked off to keep gawkers a safe distance away from the falling dust.

MHM’s Lindbergh curator Sharon Smith has had a chance to observe numerous changes to the aircraft and to the airport and its environment. “The most evident change to the airport,” she noted, “is that the Lindbergh Monocoupe now hangs right over the entrance to the terminal’s main security screening area that leads into their busiest concourses.”

Prior to the increased security measures at Lambert, people were free to move all around that area of the terminal, often oblivious to the airplane above them. Now they encounter the plane as soon as they get in line to have their carry-on luggage checked, often passing under the plane numerous times as they walk back and forth through the maze of stanchions leading to the screening stations.

Lambswool dusters are used to gently remove dirt buildup from the aircraft. Photograph © 2008, Missouri History Museum.  

MHM Collections Manager Bob Mullen has been cleaning the airplane for all of his 20 years at the museum. “When I first came out to clean the planes in 1987, we had 8 to 10 staff members present, each taking turns to go up the lift to wipe off the planes,” Mullen recalled. “Someone would bring a cooler filled with refreshments, and we spent a good three hours cleaning the Monocoupe and the Spirit of St. Louis replica.” Now, with only a single plane in the Main Terminal since the Spirit of St. Louis replica was removed in 1998, the cleaning requires only one or two members of the MHM staff, and they can accomplish the job in an hour. An important member of the team is airport electrician John Meyer, who operates the hydraulic platform lift for the cleaning crew, a task he has been doing for many years. Meyer can recall helping with the planes when they were first placed at the airport in the late 1970s. The Monocoupe is also checked periodically by engineers to test the hanging hardware and strength of the cables that suspend the craft overhead.

The construction methods used on older, fabric-covered aircraft have unique issues that all museums with historic aircraft must confront. The old cotton fabrics are covered with several layers of airplane dope, a type of lacquer that is used to protect, waterproof, and make taut the cloth surfaces of airplanes. This is a standard procedure applied to the manufacture of all fabric-covered planes. As airplane dope dries, it tightens the material so that it fits snugly over the structure of the plane, eliminating wrinkles and any loosely fitting fabric. However, the dope never quite stops doing its job and continues its shrinking process slowly over the years, eventually stretching the cotton so tight that it can put pressure on the framework until the fabric either tears to relieve the stress or weaker parts of the interior structure snap. As the dope ages, it will begin to crack where the stress is greatest.

Just before Lindbergh’s plane was placed on display in the airport in 1979, MHM staff studied the plane and found that they had to deal with some of these issues. It was apparent that the plane needed some conservation work. They contacted the local Experimental Aircraft Association (EAA) Chapter 32, and with the help of the McDonnell Douglas Corporation, the plane was prepared for long-term display. MHM’s goal was to retain as much of the original fabric as possible. The EAA treated the doped fabric and patched some tears in the fuselage. The outer fabric of the right landing gear leg was torn so badly that it needed to be replaced. In addition, they found that one wing tip was damaged and needed new wood spliced in to repair it. They re-covered that repair with cotton fabric and dope. New tires were also placed on the landing gear, as the 41-year-old tires had outlived their ability to carry the weight of the plane as it was being moved.

Diligent regular maintenance has helped preserve the 74-year-old Lindbergh Monocoupe. Photograph © 2008, Missouri History Museum.

The Monocoupe D-145 has been hanging at Lambert Airport for 29 years now. Aside from the area on the landing gear leg and one wing tip, it still has most of its original cotton fabric from 1934. MHM staff members are keeping a constant watch on the aircraft for any recurrence of the inherent problems of an aging aircraft.

“Preservation is a continuing process,” says MHM objects conservator Linda Landry, who would like to have an assessment of the plane’s condition by a conservator who specializes in early aviation. “We want to preserve it in original, though not flyable, condition as much as possible. With an assessment, we can determine to what extent it will be preserved and when. Much of the plane’s original fabric remains intact, and we’d like to know what it will take to preserve it. We’ll also want to consider how to prevent further deterioration after it’s conserved.”

Most of the skin of the airplane is now over 70 years old, an amazing statistic for a fabric-covered aircraft. Of course, it has not been flown since 1940 and has been stored primarily indoors over those years, so the wear and tear has been minimal. Until the Monocoupe receives additional preservation treatment, it will remain hanging overhead at Lambert, greeting the airport’s visitors and employees. And, of course, MHM staff will continue to make periodic midnight journeys to the airport to do the work that few people witness in the wee hours of the night.


MHM Workshop


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