When the Armistice between the Allied and Axis forces was signed on 11 November 1918, the document identified just one aeroplane for surrender to the Allies out of the expansive German arsenal – the Fokker D.VII. Today, Mikael Carlson offers his impressions of manufacturing, flying and maintaining his immaculate reproduction Fokker.
For an aeroplane that entered service during the final months of the Great War, the Fokker D.VII certainly created a furore during its short life on the front line. Designed by Reinhold Platz and manufactured in large numbers, the D.VII was initially delivered to Jasta 10 in May 1918, immediately demonstrating its potent capabilities as a highly manoeuvrable fighter superior to many of the biplanes it superseded in the skies over northern Europe. By the war’s end, the D.VII had earned a fearsome reputation as one of Germany’s finest birds of prey.
Mikael’s Fokker D.VII (SE-XVO) is one of only a handful of airworthy reproduction D.VIIs flying in the world. In many ways, this Fokker’s story stretches back to Mikael’s childhood in his native Sweden. His interest in aviation started at a very young age with plastic model kits, spurring a passion to craft and create that evolved into building balsa wood and then radio controlled model aeroplanes from the age of 10. A gliding licence came naturally at the age of 14, followed by his Private Pilot’s Licence at 19 and his airline qualifications five years hence, funded in part by his commissioned build of several 1/6-scale model aeroplanes for the Swedish Air Force Museum. Mikael’s enthusiasm for building vintage aeroplanes was never far away, even as his career as an ATP pilot progressed. Having flirted with a 3/4-scale SE5 replica that he deemed wholly unsatisfactory, he set about building his first aeroplane, a full-scale FVM Ö1 Tummelisa reproduction manufactured to original specifications, when he was 19.
This labour of love took nine years to complete, with Mikael exercising a stunning attention to detail reflected throughout his subsequent projects. As soon as he could drive, he was travelling to the Swedish Air Force Museum where he set about creating the technical drawings that would form the basis of the Tummelisa’s build. With little money or support, Mikael was completely self-sufficient by necessity; he chopped down and crafted the aircraft’s woodwork from pine trees in his family’s ranch, and spent four months hand making the 110 metric turnbuckles the Tummelisa required. Any parts that could not be sourced were machined or made by hand.
He was also taught the art of drawing, measuring and building wooden propellers by Eric Bratt, one of the SAAB engineers responsible for designing the J35 Draken. “You must be a bit naïve to start a project like that when you’re 19”, Mikael now says, “but it worked!” Welding, woodworking, fabrication, machine working – all these techniques and more were learned and honed during those formative years of Mikael’s life as a restorer and builder of vintage aeroplanes, giving him invaluable expertise that he would apply to his two Thulin As, a Fokker Dr.1 and, of course, the Fokker D.VII.
The D.VII project began in earnest in 1994, when Mikael discovered a 200hp six-cylinder Daimler D.IIIaü high compression engine by pure coincidence in Norway. Over the next 12 months, he sought out as much information as he could find on the aircraft from as far afield as America and Switzerland to prepare himself for the build, before going about restoring the D.IIIaü power plant to airworthy condition.
“All aircraft engines from that time, even if you find them boxed new and never used, require the same amount of work as a used engine would”, he says. “You will have corrosion in the cylinders, bearings may have become brittle, you need to clean all the channels, and I chose to modify the pistons from cast iron to aluminum. It’s a big process.” Any parts that needed replacing were manufactured or overhauled by foreign and domestic companies – a painstaking but vital undertaking.
Besides the engine and cockpit instruments, very few original D.VII parts could be utilised in an airworthy aeroplane and the vast majority of components were manufactured either in-house by Mikael or by specialist companies, including prominent names such as Volvo. Mikael crafted all of the D.VII’s woodwork himself, using locally sourced pine and plywood. “You start by building the large pieces, the wings, and it takes a lot of time but you don’t spend as much money in the beginning as you’re using natural materials”, Mikael explains. “Once you have built the wing structure and fuselage frame, you can mate them to one another and from there, you begin to add to the structure.” He almost makes it sound easy!
With the help of the Deutsches Technikmuseum Berlin, Mikael negotiated with a Swedish tyre manufacturer over three years to produce the 760mm x 100mm tyres originally used on the Fokker D.VII. Once the mould had been created, both Mikael and the manufacturer’s resident students produced an initial batch of ten tyres for the D.VII and around 100 more for aviation museums across the globe.
“I also managed to buy the five-colour lozenge camouflaged fabric from a museum in Berlin, which they had produced for their Halberstadt aircraft 20 years ago”, Mikael adds. “I chose my D.VII’s markings because I have a late high compression engine, a late exhaust pipe, a late cowling and the five-colour lozenge. That means my D.VII represents a late-production aircraft built by the Fokker factory. I wanted to have the aircraft in the most authentic appearance, in the standard factory delivery markings rather than a special, more colourful scheme like those you see on a lot of Fokkers.”
No expense was spared when reproducing the D.VII to factory standard, with Mikael going as far as to build ten exact replicas of the aircraft’s machine guns, powered by propane to produce an authentic sound when fired during mock-dogfights (as demonstrated in the D.VII’s tangles with the Tummelisa at some recent European airshows). The attention to detail even extends to the linen seat belt in the cockpit, built and attached as per the original.
Once the build neared completion, Mikael registered the D.VII under a homebuilt experimental licence on the Swedish civil register. “As long as I could prove the quality of the material I used and the quality of the construction of the aircraft, the authorities let me build it to the original specifications”, he explains. “I manufactured the D.VII using the same materials and methods that were used during production, using designs that worked 100 years ago – those designs worked, so why build it stronger than it was when I know that no D.VII ever had a structural failure, and those tested in America in the 1920s only suffered failures at 13G?”
The D.VII first flew in Mikael’s hands on Sunday, 10 April 2011. It has since made numerous appearances at prominent airshows across Europe, including displays at Gothenburg Airshow, Sweden, Hahnweide Oldtimer-Fliegertreffen, Germany, and AIR14, Switzerland, with its custom-built fixtures, transport gear and trailer allowing Mikael to ferry the D.VII around Europe by road with minimal difficulty. Indeed, with a team of just two or three people, the aircraft can be reassembled at an airshow venue in less than four hours. “To fly for ten minutes at an airshow takes roughly 14 days of work”, says Mikael, “including taking apart the aircraft, transporting it, building it up, flying it in the show, cleaning it and taking it home. All for one weekend!”
Mikael describes the D.VII’s extensive maintenance regime as a “full-time job”, with the engine requiring “a thorough post-flight inspection each time it flies” – a likely reason, he ponders, why so few First World War aircraft fly at air displays away from their home bases. With Mikael’s sole restored D.IIIaü engine mated to the D.VII, the level of care and maintenance is only amplified and each flight requires around an hour of preparation to ensure that the engine runs smoothly and there are no issues, however minor, that might cause problems during or after the flight.
The process itself is meticulous. Depending on the temperature, the water and oil will be heated before being injected into the engine. Water levels are then checked, valves oiled with a small hand pump, the oil system levelled out and gasoline checked. “I check the engine very carefully after each flight too – for example, to be sure that there are no metal chips in the oil, I change it maybe every ten hours’ flying time to be on the safe side, and check for metal chips every three hours. I also lift the cam rocker housing every second flight to look at the cams.
“My only problem is the temperature. These high compression engines are not built to fly at high power and low-level, they’re built to climb fast to 3,000 metres and shoot down the terrible Englishman!” he jests. “I’m guessing that I’m overdoing it a bit with the amount of maintenance, but that’s only to be on the safe side – I don’t want to damage my engines.”
The Fokker D.VII is a wonderfully stable aircraft both on the ground and in the air, with no vices to speak of. The aeroplane can operate from a small grass strip, albeit it needs to be nursed within the confines of smaller fields, particularly during public air displays where space is at a premium. “In an airshow environment, wing walkers are important to have with you. They’re your eyes at an airshow, because there is no radio in the Fokker. They can look for you and give you signals to show it’s clear around you. That’s particularly important at small airfields; if you have a field like they had in the old days, it’s no problem to make a large turning circle on the ground, but you can’t do it without wing walkers if the field is only 40 metres wide. Ideally the wind would be coming from no more than 20 degrees to the left or right of you on take-off, in order for the aircraft to get airborne without swinging in any direction. You hold the stick in the centre and give it full power, maybe give it a little nose-down to get the tail up, and you’re airborne in 50 metres.
“It’s not a pilot friendly environment”, he says of the D.VII’s cockpit. “It’s terribly noisy, which has nothing to do with the engine. In the Fokker, you’re sitting behind the machine guns more or less without a windscreen in a 160 to 200kph slipstream, and the air is so turbulent that the noise is tremendous. If you don’t have double earplugs, you’ll be deaf for an hour after landing!” During the flight, Mikael is mentally focused on “driving the engine”, monitoring only the engine rpm and water temperatures in the cockpit. In-flight use of the wing strut-mounted airspeed indicator and the other limited instrumentation is negated by terrific experience and sensory knowledge of the aircraft. “With these aircraft, the flying should come naturally. Your real focus should be the engine – if you have to think about flying, you shouldn’t be in the aircraft”, he says.
Once out of the take-off pattern, the Fokker cruises comfortably at low power around the 140kph mark, with higher power bringing it up to 180kph in level flight and a maximum speed of 200-210kph achievable in the right conditions, placing it broadly alongside the Royal Flying Corps fighters of the day. Mikael praises the D.VII’s docile handling and the terrific rate of turn afforded by its large elevator and broad wing surface. As with all World War One aircraft, the D.VII is tail heavy and must be flown with consistent positive pressure on the stick; indeed, a bungee chord can be attached to the control column to reduce the pressure the pilot must exert in order to prevent the aircraft from pitching into a climb.
Mikael went as far as re-rigging the D.VII and altering the angle of the top wing by five degrees in an effort to trim it into more level flight, to no avail. “Maybe it’s built like that to allow quick turning in combat”, he muses. “But with a small bungee chord, it’s beautiful. The longest flight I’ve had is one hour and 20 minutes and it was no problem at all. You just cannot let go of the stick and must be fully engaged for the entire flight!”
The Fokker D.VII’s docility extends to its low-speed handling, with the stall – the characteristics of which Mikael describes as being “more like a parachute” – occurring between 60 and 70kph in level flight. “If you try and stall it with power on, it will hang right on the edge of the stall”, he says, drawing to mind the accounts of D.VIIs hanging on their propellers whilst firing vertically in combat. “There’s no flick of the wing because it has a large airfoil, unlike the SE5a and SPAD which have sharp, thin airfoils and [consequently] a more abrupt stall. The D.VII stalls gently with a drop of the nose, and it enters a falling leaf type manouevre.”
Those who have seen Mikael displaying the Fokker D.VII in an airshow environment will appreciate just how vigorously the aircraft can be flown. The sequence is conducted with near constant pitching and turning, with the aeroplane rarely flying straight and level for more than a few moments. It is, perhaps, amongst the very finest demonstrations of Great War fighting machines one could witness. “If you fly maneuvers in the right sequence, starting high and using the speed working down, the D.VII is a fantastic aircraft. You don’t even have to dive it to gain speed, you can fly high-power at low-level and fly a loop, and continue to loop it, quite comfortably. It’s beautiful to fly, a very forgiving aircraft in the air with better stability than the Dreidecker.” In the air display environment, this allows Mikael to keep this routine low and close to the crowd, demonstrating mostly vertical figures – “they’re not built for rolling, so you have to work with it” – including loops, cubans and split-S dives, never exceeding 4G.
Much of the concern during an air display is with the water temperature in the high compression D.IIIaü engine, which generates more heat than a normal 160hp engine and reaches the 75 degree threshold very quickly during a sortie on a warm day. This is constantly monitored in-flight, and influences the sequence of manouevres Mikael flies during his routine; flying high-power, low-level aerobatics at an airshow typically keeps the Fokker at a lower speed when carrying out aerobatics, which in turn reduces the air flow through the radiator. “If I reach 75 degrees, and I can do that easily in a display, I will fly some diving figures at idle and some low-level flypasts to cool the engine down immediately”, Mikael recounts. “If the engine hits 85 degrees, the book says to land immediately, so the margins are quite small.”
As such, Mikael’s display profile typically sees him climbing rapidly for height in front of the crowd immediately after take-off, demonstrating the aircraft’s famed rate of climb, before diving into a series of ad hoc loops and half rolls to cool off the engine. “I don’t have a set routine”, he explains. “Generally I fly a standard three or four manouevres and adapt the display depending on water temperature, wind and the venue, which influences the order of the figures. I can enter a vertical climb or a loop comfortably at 200ft, and still have sufficient speed to exit the manouevre if I lose the engine, for example. Typically I enter aerobatics at 500ft to give myself more than sufficient altitude to recover the aircraft if I experience any engine issues.
“If you have the inertia, you can continue to fly vertical looping aerobatics,” he continues, “and when the speed drops off, you can fly half rolls to dive out – it’s largely about energy and engine management.” Mikael cites the aircraft’s turning characteristics as excellent for its era with a very sensitive elevator that facilitates tight turns and vertical figures, whilst the rate of roll is “limited but not disastrous”. The key, Mikael says, is to utilise the Fokker’s turning characteristics to keep the aircraft directly in front of the crowd at all times. A 500 metre display line is more than sufficient for Mikael to fly a full aerobatic routine “without the audience having to turn their head”, with the whole sequence, from take-off to landing, taking place within the display box.
Display complete, Mikael will cool the engine in the downwind leg before three-pointing the Fokker on the grass. At a damp grass airfield, the aircraft will comfortably stop within 70 metres, but care must be taken when operating from a dry, hard surface, as the D.VII has a tendency to roll out for a considerable distance before drawing to a halt. After a minute or so of idling the engine, Mikael will shut the D.IIIaü engine down using the magnetos (the D.VII does not have any in-cockpit mixture control) and begin the post-flight engine maintenance regime described earlier.
“The D.VII is very pleasing to fly”, Mikael summarises. “I think that’s why it had a good reputation at the end of the war, but the development of combat aircraft was so fast in World War One that it would’ve been superseded by a superior fighter within months, had the war not ended.” Mikael’s experiences flying the D.VII have given him an appreciation of just how the aircraft garnered its reputation as one of the conflict’s finest fighters. Its speed, rate of climb and docile handling characteristics made it the perfect aircraft for young, inexperienced German pilots to enter the war in. “If you’re above your enemy, you will win the fight, so the key was to climb above”, Mikael continues. “Climbing and turning, that’s the most important thing. Most dogfights were ‘hit and runs’ – if you enter a dogfight, it’s like a Western duel. If you’re duelling every day, eventually somebody will be faster than you and you’ll lose in the end. Dogfighting is the most stupid thing you can do.”
“You couldn’t take a graduate pilot with seven hours’ training and put him in the Dreidecker, he would ground loop and crash it on landing” says Mikael. “But the D.VII will make a mediocre pilot a good pilot. If I had to go out and fight, I would pick the Dreidecker before the D.VII because it’s a better fighting aircraft, but you need experience to fly it.
“The D.VII was an exceptional aircraft for its time. There were many exceptional aircraft developed during the First World War, but it’s the ones flown by the ‘aces’ that people remember.”