Engineering Insight: The Albatros Warbird
The Vintage Aviator doesn’t just make planes: it recreates them in a process somewhat akin to modern archaeology.
“Many of the airplanes that we build – and have reproduced from scratch – don’t exist anywhere in the world, not even in museums. Some, of course, haven’t been flown for 100 years,” Vintage Aviator Production Manager, Gene DeMarco, says.
Based in the Wellington suburb of Kilbirnie, the company employs 52 people to reproduce airplanes, mainly those flown during World War I (WWI). One such plane is the Albatros DVA, a German fighter aircraft produced in 1917. Built by Albatros-Flugzeugwerke GmbH, a German aircraft manufacturer best known for supplying the Luftstreitkräfte (airforce) throughout WWI, the Albatros series were single-seat flying scouts. Originally 4,600 Albatros D series airplanes were manufactured, but only two planes have survived, both Albatros DVAs.
“It’s a really beautiful design, a very sleek looking airplane, a unique construction,” Mr DeMarco says. “It was the one that really appealed to us because it was so different.”
A biplane, the Albatros’ airframe is made from formed plywood to create a monocoque structure. Similar to an eggshell, a monocoque structure is where the outer skin carries most of the stresses.
While reproductions of the Albatros have been completed in the past, there are no original drawings left, and information about the airplane is not necessarily reliable. To get around this problem, Vintage Aviator staff Michelle Crosbie and Warren Rangi undertook an initial study of one of the two surviving planes housed in the Australian War Memorial in Canberra.
“It was at the most opportune time for us because the good people at the museum over there were restoring their airplane to put it on display, so it was all apart and it was in a warehouse,” Mr DeMarco says.
Using a 3-D scanning tool called a FaroArm, Uli Beck and Charlotte Key from WETA workshop measured the co-ordinates of the plane, while the Vintage Aviator staff researched the other parts and assemblies.
The FaroArm is of an articulated arm fitted with either a digital probe or a laser scanner. With several “joints” enabling it to follow the shape of any surface, it reaches several metres in any direction and can obtain accuracies of 0.002 centimetres without touching an object.
“The co-ordinate measuring machine gave us every curve, every dimension, [and showed] where all the nails were. The machine is so accurate that even when we scanned the plywood surface, you could read the thickness of the paint in the digital scan,” Mr DeMarco says.
From the scans, a 3-D model of the entire airframe could be created, so the team could go back and make drawings of the individual parts.
The Vintage Aviator also had access to the research and notebooks from the National Air and Space Museum, part of the Smithsonian Institution in Washington DC, from when the Museum restored the other surviving Albatros. “That was a big help as well,” Mr DeMarco says.
Using parts from a crashed Albatros, the team was able to reverse engineer the radiator, applying regular materials analysis to determine which materials were used in its construction.
Original samples from the fabric covering the wooden frames of the Albatros’s wings were also collected. Dyed with a distinctive five-coloured lozenge pattern, the samples were copied onto bolts of Irish linen to ensure the reconstructed Albatros was exactly the same as the original version.
To find the Albatros parts, Mr DeMarco checked auctions, eBay, Trade Me and talked to collectors. Original data is sourced from period-type magazines, technical documents or reports on aircraft captured by the Allies. Museums also often have artefacts in storage, which can sometimes be borrowed, restored or just referenced. “We’re like a sponge: any bit that we can collect is extremely helpful,” Mr DeMarco says.
He notes that with German aircraft like the Albatros, instruments like fuel gauges, tachometers and air speed indicators, as well as wheels or tyres, are often common types. “So the minute you have a reference for one, you can use those parts on other airplanes.”
Even so, all of the parts for the Albatros needed to be built, except for the Mercedes D.III engine, which was overhauled, although it took several years to find a suitable example. To ensure the technology is available for future Albatros reproductions, the entire engine has been copied.
The plywood for the fuselage bulk-heads also had to be made. This required the Vintage Aviator to perfect a way to bend ash, which is a hardwood, as until the Albatros reconstruction they had only worked with the softwood spruce used in British aircraft.
The Vintage Aviator’s workshop is well equipped to take on this type of work with just about everything from a Computer Numerical Control (CNC) router, CNC lathes, and CNC milling machines to a rapid prototyping machine, as well as milling and honing machines. There are also giant woodworking tools like joiners, planers and spindle moulders.
Any parts designed by the Vintage Aviator need to be certified by a Civil Aviation Authority (CAA) Part 146 Ap-proved Design Organisation, like NTech. “A 146 company will go over the design, check the loads, check the materials and certify that the parts that we’ve designed, or the parts that we have replaced, will be okay,” Mr DeMarco says. “They will do this mathematically, or in a computer, or they can specify that load testing needs to be done, so we can test the individual parts or test a component like the assembly of a whole wing.”
Once the 146 company has issued a Certificate of Design, either for the original drawings or parts that have been reverse engineered, work to produce a plane where every single part conforms to the drawing can begin. Given that it does conform to the drawings, the CAA will inspect it and issue a Certificate of Airworthiness so it can be test flown.
Mr DeMarco says it’s one of the bonuses of his job that he gets to test fly every one of the Vintage Aviator airplanes. “That encompasses finding out what the stall speed is. We set a ‘never-exceed’ speed based on historic documents typically, making sure it handles sufficiently well so I can turn it over to other pilots.”
Flight testing can last anywhere from two to 25 hours, depending on the engine needed, the propeller or the airframe. Once it is successfully test flown and any problems rectified, the CAA may carry out another inspection before issuing a permanent airworthiness certificate.
In cases where there is a complete set of drawings for a plane, not much testing is done. Mr DeMarco says as the Albatros’s were built in sufficient quantities and flown 100 years ago during the war, they’ve already been tested and proven. “The problem comes when we don’t have a complete set of drawings.”
Engines are also test run, with new built engines being tested for 20 to 25 hours, pulled apart, checked internally, then put back together and run for another two hours. While destructive testing is done for items like buckles, cables and bolts to determine their ultimate strength, this is generally frowned upon by Vintage Aviator. Non-destructive testing, on the other hand, such as X-ray analysis, magnetic particle inspection and dye penetrant testing, is something the company has invested heavily in.
According to Mr DeMarco, the planes will perform as well or better than the original models. “They fly just like they did in the First World War. They sound, smell, handle and perform in the same way as the originals. We’re essentially an extension of the original production line, although the exception is safety, where new seat belts and shoulder harnesses will sometimes be installed.”
The new planes have all the original idiosyncrasies as the original models. For example, a pilot flying the Albatros needs to constantly twist the greaser handle during flight to force fresh grease to the water pump to make sure the water is separated from the engine oil, as there is not a proper seal between the two. Some have primitive controls, primitive instrumentation and no brakes, so are very difficult to steer on the ground in some cases. Some also have rotary engines, where the whole engine spins with the propeller, introducing a gyroscopic force that makes the handling characteristics of the airplane quite different. “They’re not always straightforward – they’re a bit cantankerous,” Mr DeMarco notes. This uniqueness appeals to a small group of aviators and collectors, or to museums who want to fill a gap in their collection.
The Albatros has a price tag of around $750,000. While the Vintage Aviator owns all the intellectual property relating to the planes it creates, the amount of time it takes to make a set of drawings means that three or four planes have to be produced just to amortise the costs.
“It’s very expensive,” Mr DeMarco comments. “I’ll have two or three CAD [computer-aided design] draughtsmen working for a year or two just to develop the set of drawings – a tremendous amount of work. With digital models and plans, though, the planes can be made again as needed.”
He says the process of recreating the Albatros was like a cross between a great mystery and a jigsaw puzzle with a dash of history thrown in. “But this is absolutely fantastic. Building these kinds of airplanes is phenomenal.”
The Red Baron
Probably the most famous Albatros D-series pilot was Freiherr (Baron) Manfred von Richthofen (1882–1918), who is credited with 80 combat victories. Nicknamed “The Red Baron”, the German flying ace had his Albatros painted red – a move copied by other members of his squadron to make him a less conspicuous target.