Most modelers and aircraft enthusiasts are aware of the Coanda 1910, and if they aren't, then they should acquaint themselves with it, because it was the very first jet aircraft, built in France in 1910. It wasn't powered by a jet as we have come to know them, but rather by an inline petrol engine driving, instead of a propeller, a ducted fan on the nose, which compressed the air behind it. This was then mixed with petrol vapour and ignited, resulting in a jet efflux which was largely flame and not very thrusting.

Accounts vary as to whether it actually became airborne. At the time it was thought not. But the designer Henri Coanda, much later in life, claimed that he thought that it had, he just didn't notice at the time. This is understandable. Were I trying to control a primitive flying machine with only two side wheels as controls, and then noted that flames were licking around the fuselage just ahead of the cockpit, a fuselage which incidentally had just been constructed from wood, I do not think I would notice something as trivial as whether the beast had left the ground or not.

A replica of the 1910 aircraft is on display at the Henri Coanda airport, which is the main airport of his native Romania. There is a 1/72 resin kit of it available from Fan Kit, a Romanian company. And a very nice scratch built version on the internet by Gabriel Stern, which I might well try to emulate one day, once I have got a lot better at scratch building.

Nothing daunted, Coanda constructed another machine a year later, very different from the 1910, and using such materials as he could salvage from the burnt wreck of the first machine. This time he also  scored a first in aviation history, by building the first two engined aircraft.  The two engines are of the rotary kind and arranged on either side of the nose, in line with the fuselage, driving the single propeller through a gearbox. I assume that the engines were 'handed', so that they rotated in the same direction, thus eliminating the torque effects of rotary engines. What it would also have done though is increase the gyroscopic effect, which would have a strong and unpredictable effect on the handling, especially in turns. 

Coanda's main area of expertise was in fluid mechanics, especially how a jet of air behaves close to a curved surface, and the “Coanda effect” is with us to this day in the design of blown flaps on aircraft. It is also the phenomenon which enables flying saucers such as the Avrocar to fly. And even Grand Prix cars use it now, by routing the exhaust gasses over parts of the body to increase aerodynamic efficiency. While Coanda was undoubtedly a genius in this field, one cannot escape the suspicion that mechanical engineering was not his forte.

I studied the few pictures of the 1911, and was baffled because there seemed to be no struts connecting the fuselage to the wing, only rigging. One can easily imagine the weakness of this setup.  Then I slowly came to think that what look like rigging wires between fuselage and wing could only be very thin metal struts. Even so there are few of them, and only fastened to the single main spar of the wing. The torsional forces on the few junction points must have been huge. So I took a few liberties by increasing the width of the struts, which are mainly cabanes, and adding a couple which were necessary to hold body and soul together.  

Some plans were found on the excellent Russian website Their Flying Machines, adjusted to scale and several photocopies made so that one or two could be cut up for templates.

I began with the wing since that seemed simplest, and used my favoured method, borrowed from the famous Harry Woodman, who used to scratch build biplanes and wrote a book about it long ago which is revered as the Bible of scratch builders.

The bottom surface was cut from 20 thou plastic card and the upper surface from 10 thou, heavily scored on the inside with a biro to represent ribs. The leading edges were glued, then a plastic rod inserted at about 1/3 the chord back from the leading edge. Then the rear skins were glued together, and sanded to fit.

So far so good, but then I was undecided about the fuselage. So instead I turned to those quaint wheel spats, which are just one unique distinguishing feature of the aircraft. It looks like it is trailing two dead umbrellas, turned inside out by the wind. Why exactly Henri chose that shape for what was a simple undercarriage is a mystery but I suspect he had a whimsical streak.

One old photo reveals that the skirts could in fact be rolled up over the frame and they look like they are made of thin tarpaulin. I cut four triangles to shape, glued their edges, scored a few ribs and put spacers in the middle while they set.

I began eyeing some balsa planks for the complex fuselage, which is circular at the rear end, and tapers to flat sides at the front, with a stepped upper nose. But then I bit the bullet, and with a loud cry of  “We are Plastic, not Wooden, Modellers”, glued together six strips of plastic card, cut from the plan. The four inner ones had a cutout for the cockpit, the two outer ones did not. I now had a square box section with the right sideview. It was then but a matter of only weeks to sand the thing down to the right shape, while distracting the mind through advanced yogic techniques.  Or what others call staring out the window while not thinking.  

Once it was in shape, a seat, a stick, and an instrument panel taken from a suitable etched set were put in place. I doubt that the original pilot, a stout-hearted soul called Bountry-le-Soin, had much else in his workplace. I also wonder what possessed him to climb into the cockpit in the first place.

The 1910 Coanda is always shown in a coat of brick-red paint. Since there was only one, I imagine that Henri would have had some spare tins of the paint lying around the hangar, and so opted for that colour for the wing and forward fuselage. Black and white pictures showed a marked difference with the rear of the fuselage and so that was painted in linen, for which I used Vallejo Buff. The red was also from the Vallejo range.

Most photos show that the 1911 was in fact a sesquiplane with a small wing between the spats. But there is one picture which shows it as a biplane with extensions to this on the outer side of the spats. Taking the path of least resistance, I opted for the sesquiplane and made one up in the same method as the wing and painted it red. Staunch struts were attached to the top of the spats, and the lower axle-wing joined to the two, and then the struts were glued in place onto the lower surface of the wing, to form a neat box.

Now came what the Spanish call “the moment of truth”. Or the moment when the matador must plunge his sword into the bull and hope he hits the right spot. Otherwise it is “the moment of disembowelment”. I offered up the fuselage into the box and wondered how on earth it could be connected. By close scrutiny of the photos, I managed to locate most of what seemed to be rigging but could only be struts. And duly replicated them using slightly over-thick rod. After it had set, it was still a flimsy arrangement, and was handled with with my breath held and hands made steady by abstinence from strong coffee.

Then came the engines. Two rotaries were chosen from the Box of Dead Engines, and glued one on either side of the nose. Murky old photos show a rat's nest of wiring and small bits of machinery surrounding the engines, but fortunately I found a close-up of the engines from an air show in Paris, and these show that a cage was made to frame the engines, which allowed them to rotate, but also formed part of the fuselage structure, to which struts and rigging were then added. There was also what looked like exhaust pipes emerging through the frames. This was all rigged together from plastic rod with two sets of reading glasses on my nose, and a thesaurus to hand so that I could find variants of strong oaths and curses. One photo shows a mechanic standing on one cage, so they must have been a strong affair.

The cruciform tailplanes were cut from 10 thou card, and glued. Once again the photos are deceiving. They show the tailplanes just clear of the ground, but no reason for them to be so.  And so I formed a tail skid in the same pattern as the 1910 Coanda, reasoning that it would probably have been a survivor of the early crash, and so could be recycled. It is a paperclip, bent to suitable curves with needle nosed pliers. Four wheels came from the Big Bag of Wheels, two small, two medium, and were thrust into their funny trousers with glue.

When making scratch built models the main thing that plagues the modeler is problems of alignment. You soon find yourself ignoring the plans, just to get things to fit correctly without looking awful. But there is one great consolation from the few pictures of the Coanda 1911. Which is the fact that he too had problems of alignment. The two rigging support king-posts on the upper wing have a distinct lean to them, and are not in line with the undercarriage struts. There may have been a good reason for this. Or it might have been, as I suggested, that mechanical engineering was not Monsieur Coanda's strong suit. But, it allows you, the modeler, a little leeway. As a matter of fact I lined up the struts, because alignment is more aesthetically pleasing than crookedness, but still, the wiggle-room is there if you want it.

Finally, a little rigging with elastic thread, coloured silver with a gel pen and held in place with small drops of superglue gel, put in place with a sharpened toothpick.

I was once in Romania just after the fall of their dictator Ceaucescu, and a fine country it is, with a Mediterranean people who are hospitable and amusing.  And the countryside around Transylvania looks like the last remaining rural landscape which is unchanged since Medieval times. It is a place of mountain meadows, castles, and ancient forests, and it is very beautiful.

The Romanian for 'Yes' is 'Dah'. I don't know what the crowd shouted in triumph as they dragged the wretched Ceaucescu from his balcony and rang the Army for a  firing squad, but perhaps it was a loud “DAH”.

I repeated it, as I settled back with a long sigh and a single malt. For there in front of me was the only known model of a rare aircraft built by a master of aviation. If there is another out there, it has left no footprint on the internet. Coanda went on to design even more strange and wonderful machines, before having a long career with Bristol aircraft in the UK. He finally settled in the US and his legacy in the shape of blown flaps is the main reason why your airliner is so safe when flying slowly in to land.

http://www.the-blueprints.com/blueprints/modernplanes/modern-c/18093/view/coanda_(1911)/

http://flyingmachines.ru/Site2/Crafts/Craft28597.htm

http://www.asoublies1418.fr/default.asp?367332D3741663E62643384331D36D47269331233D166E6236233D077462386331233DE6

http://www.newfluidtechnology.com.au/wp-content/uploads/Henri_Coanda_The_facts.pdf

http://www.notrefamille.com/cartes-postales-photos/cartes-postales-photos-Concours-Militaire-Reims-Octobre-1911.-Boutiny-sur-Biplan--Coanda--s-alimentant-d-HUILE-D.-F.-et-AUTOMOBILINE-51100-REIMS-51-marne-522217-70261-detail.html 

Chris Peachment

April 2014

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