Fournier Resurrection Part 3
Fournier Resurrection Part 3: re-covering the fuselage
With the aircraft back together it was time to re-cover the fuselage
Ihad wanted to replace the ageing fabric and shabby paintwork on my wooden Fournier RF4D ‘Wagon’s fuselage. I specified and collected fabric and paint of the Polyfiber system from Aircraft Coverings at Henstridge because it’s flameproof, stays flexible for a very long time, and that’s what I have on my Australian Fournier and Maule. Now the materials had disappeared (see Part 1) so, having repaired and prepared the Fournier’s airframe, I repeated the selection process… but this time I would be doing the work myself.
I don’t have a spray gun, compressor or booth, nor the appropriate skills for spray painting, and I was concerned
about achieving a reasonable finish. I had also been pondering on the necessary elasticity of the paint coating for the flexible fabric it was going onto; many aircraft restorers use two-pack polyurethane paints now and I didn’t know if they would be sufficiently pliable. Importantly, most of today’s paint systems are classified as carcinogenic, so I would need protective clothing and breathing apparatus.
Then I learned about Oratex. I had vaguely heard of it before as ‘a German aircraft fabric using water-based adhesive’ but, being aware of Ceconite’s previously unsuccessful flirtation with water-based glues and paints, had dismissed Oratex from my mind. Now I heard something much more attractive about it: it comes ready-painted!
Paul Hendry-smith of The Light Aeroplane Company (TLAC) was the British importer of this innovative product. I phoned him for more details. He said a dozen or more British aircraft had already been finished with Oratex (this was 2015) including a big Robin and a Pitts Special, which
ought to testify to its strength, and insisted this fabric would be within my unskilled ability to apply. He told me Oratex was a polyester fabric, but its much finer filaments, threads and weave made it significantly lighter than Polyfiber, Ceconite or Diatex. He referred to this as ‘nano technology’. He confirmed it was ready-painted with seven layers of coatings: fabric sealant, primer, undercoat, three colour coats, and a urethane clear top coat, each coating having a combination of UV absorbers and blockers. Oratex also supplies Oracolour flexible paint which contains no plasticisers, so an aircraft can have a multi-colour scheme, and self-adhesive trim tapes of many shades (brand names Oraline for narrow tape and Oratrim for wider tape).
Today there are eleven primary fabric colour options. Paul did admit that it was expensive, but insisted that it was no more than the cost of a similar area of other polyester fabrics plus the required half-dozen or more layers of paint. He sent me samples of their white and red fabrics: Insignia White is a nice bright, titanium white, and by chance Fokker Red was precisely the same shade as my Fournier’s existing paint. Paul had cautioned me that the finish is not high gloss. The paint is actually quite shiny, but the layers are so thin that the very fine weave shows through imparting a satin-like sheen.
There being no substitute for hands-on experience, my friend John Watkins and I drove up to TLAC at Little Snoring for some practical instruction. Paul himself gave us a four-hour tutorial including some hands-on work, explaining the process step-bystep to re-cover a previously covered airframe.
The application of odourless water-based adhesive is pretty
simple. Ironing the fabric in place to activate the glue was just as easy. Shrinking it with a heat gun was a quick pleasure, although we learned that Oratex doesn’t shrink as much as Ceconite, Polyfiber or Diatex, so compound curves and corners can be a bit more difficult to cover without wrinkles. Paul showed us how to remove wrinkles and folds, saying, “Never try to shrink a wrinkle, shrink the area around it. Heat the glue to soften it and then shrink the fabric beside the blemish to pull it flat.” He showed us how the fabric can be warmed and stretched around the curves of fins and rudders, recounting that Oratex inventor Siegfried can cover an entire electric light bulb in the stuff without it wrinkling! The good thing was that I’ve never been interested in having a superb finish; what I wanted was an aeroplane that didn’t look as scruffy as when I bought it, and back in the air as soon as possible.
I soon realised the only significant disadvantage of Oratex is the price of everything. To do the job properly Paul insisted I needed a Steinel German digital heat gun and a Japanese Toko digital iron, because of their very accurate temperature control. Even the felt pad he recommended for pressing the fabric down into place after heating the glue was pricey. The paint only comes in one litre cans
Underside of the rudder pedal attachment, fully covered
... and the second, protecting the rear face
first stage in covering the rear edge of the firewall...
Complex shapes were covered with small sections of Oratex
ABOVE: ‘Wagon’s inverted fuselage, with detailed forward areas now covered
LEFT: further detail – covering the underfloor reinforcement for the hand starter lever
ABOVE: complex shapes under the cockpit floor, covered in Oratex
LEFT: sternpost covered in one piece, slit to wrap around the edges
RIGHT: paper templates were made for the difficult areas