Tag Archives: Museum

British engineers help to save WWII Dornier Do-17 German bomber from its last battle – Corrosion

Researchers from Imperial College London are working with the Royal Air Force Museum to clean the Dornier Do-17, known as The Flying Pencil (Fliegender Bleistift), and prevent further corrosion once it is removed from the water.

In 2010, shifting sands uncovered the aircraft, which lies off the Kent coast and was previously protected by layers of sediment, exposing it to the corrosive effects of seawater and threatening to destroy the aircraft entirely.

Dr Mary Ryan from Imperial’s Department of Materials, who is working on the project, said: ‘This is the last remaining intact Flying Pencil of its kind in the entire world, so the significance of this project to our history cannot be underestimated.”

‘We have been analyzing fragments already brought to the surface and it is absolutely fascinating to see how this bomber, which crash landed more than 70 years ago, has been so well preserved by the layers of sand.’

One of the challenges for the Imperial team is devising a method for cleaning and removing the corroded layers from the Flying Pencil’s aluminium fuselage, which contains large amounts of the corrosive agent chloride from the seawater.

The researchers are currently testing a solution based on citric acid, which is found in high concentrations in citrus fruit, to remove the surface layers of corrosion and sea deposits such as crustaceans from small pieces of wreckage already retrieved.

The aim is to develop a solution that is powerful enough to clean the bomber, but not so powerful that it damages any remaining paint and markings on the aircraft, which are of historical significance. Any remaining chloride on the metal surface could lead to further attacks of corrosion when the plane is on display.

The Imperial team will also help to work out the best environmental conditions for displaying the bomber in the museum. For example, too much humidity in the air could lead to condensation on the metal, which would activate further corrosion.

Once the research is complete, a team from the museum, working with specialist underwater archaeologists and recovery experts, will use a lifting cradle to support the weight of the fragile aircraft as it is brought to the surface, currently planned for spring 2012.

The Flying Pencil was brought down by the RAF on 26 August 1940, during the height of the Battle of Britain while en route to attack airfields in Essex with a large German formation.

It crashed into the shallows off Goodwin Sands killing two of the crew members, who were later recovered and buried in a military cemetery. The other two crewmen were taken prisoner.

Ian Thirsk, head of collections from the Royal Air Force Museum, said: ‘At the moment, we are attempting to trace the relatives of the crew members who survived this fateful mission, in order to help engage visitors to the museum about the human story behind this episode of the war.

‘As the last surviving example of the Dornier Do-17, this aircraft is truly unique. We think this old bomber has one last scrap left in her — the battle against corrosion.’

Once the aircraft is lifted from the seabed, it will then be transferred to the museum’s conservation facility at Cosford, and then placed on display in the planned Battle of Britain Beacon Wing at the museum’s London site.

SOURCE: http://www.theengineer.co.uk/sectors/aerospace/british-engineers-aid-attempt-to-save-german-bomber/1010776.article

Galveston’s tall ship Elissa no longer seaworthy…corrosion issue

GALVESTON, Texas — The official tall ship of Texas is in trouble.

The iron and steel bottom of the three-masted 1877 Elissa is nearly rusted through in places, prompting the U.S. Coast Guard to declare that the vessel is not seaworthy.

Officials at the Texas Seaport Museum in Galveston where the Elissa is berthed were astonished when a Coast Guard inspection earlier this year revealed the rotten hull.

The tall ship is inspected twice every five years, said John Schaumburg, museum assistant director. The latest inspection uncovered the worst rot since the tall ship was rebuilt in 1982, he said.

Very little corrosion was discovered during the previous dry dock in 2008, prompting surprise that the bottom could have deteriorated so quickly, Schaumburg said.

“Everyone’s jaw just dropped,” said Ed Green, one of about 100 volunteer crew members from Houston. About half of the volunteers are from Houston, as are most of the ship’s visitors, Schaumburg said.

No one knows for sure what caused the rapid deterioration, but officials suspect that Hurricane Ike might be the culprit. Elissa rode out the September 2008 storm at a special mooring designed for violent storms, losing a sail, a spar and suffering some other minor damage.

The worst damage was unseen, Schaumburg said. Sea water eats into any metal, so 15 zinc “anodes” are fastened to the hull to draw off the corrosion. Naturally occurring electrical currents draw the corrosion to the anodes, Schaumburg explained.

Officials believe that an electric current, possibly caused by an electric line dislodged by the storm, may have caused the rapid erosion, he said.

The series of inspections were conducted at the Bollinger Texas City LP ship yard. Enough repair was done to allow the Elissa to sail back to Galveston, where it will remain until it celebrates the 30th anniversary of its reconstruction at a Greek shipyard.

By then the museum hopes to have raised $3 million to replace the hull as well as do a long overdue replacement of the fir deck and deck furniture, such as the companionway and skylight.

Schaumburg said officials won’t know until refitting begins whether the entire hull below water will need replacement or only the 54 corroded steel plates, each 4 feet by 10-12 feet. If all goes according to plan, the Elissa will be sailing again in 2012, he said.

The museum is negotiating with a professional fundraiser and has established a system that allows $10 donations to be made by texting 50555.

Green, a 7-year volunteer, said it is vital that the Elissa keep sailing.

“The Elissa is indicative of the types of ships that brought commerce to Galveston and to Texas,” Green said. “I think it’s important to keep that part of history for everyone to see it.”

SOURCE: http://www.chron.com/disp/story.mpl/ap/tx/7650327.html