I believe Oratex polyester fabric was originally designed for microlights, but is now certified. There are two different grades for different MTOMs. The new Robin factory uses it on the DR401, but I’ve never seen it – maybe @NealCS has it on his? It’s pre-coloured, so doesn’t need various coats of dope, primer, silver etc, saving many hours labour in the paint shop. Without paint, it’s lighter than conventional fabrics. I don’t have any figures, but apparently the weight savings are considerable. The glues are heat-bonding, so adhesive work can be done with a domestic iron. The US distributor has videos of the fabric being hit repeatedly with a hammer, but the dents come out in seconds with a heat gun.
I saw a plane that had been recovered in it, and my first impression was ‘looks good, but when are they going to paint it.’ Painting hides all the seams, extra glue, crinkles etc, and gives a gloss finish. It’s ok on a glider, bush plane or microlight, but I wouldn’t enter it into a ‘best restoration’ competition. Apparently it is a lot harder to work with than normal fabric, as it stretches less, and compound curves e.g. on the wing tips are very fiddly.
Does anyone have any experience with Oratex?
The glue is yellow
Daylight showing through
Here are some pictures from my overhaul. Covering is complete, just mounting all parts, renew perspex and radio 8.33. Silver and blue is with Oratex 6000 (cert. version). Not so bad.
Is that rubber matting on the wing for wiping the mud off your farmer boots before getting in the cockpit?
The rubber matting is only for protection while restoration is ongoing. (someone propose it as a vortex devise. Hihi) The nose of the wing is made from 3mm okume plywood. This is sufficient for aerodynamic shape, but not for walking on. The wing step is shown in the picture.
I looked at Oratex for the recovering of my Robin but decided to go for the conventional covering the reasons being I did not like the finish and I was less than sure about the chances of repairing any damage that I might encounter.
The wooden airframe structure is the normal limiting factor when it comes to heavy inspection of Robin aircraft with the covering requiring removal for structural inspecting.
In the last few years we have been re-building two Robin aircraft , one was last re-built in the early 80’s and spent a few years outside under covers before moving inside in the 90’s. While there have been no structural issues that would have caused structural failure in the immediate future quite a lot of work was required to bring the aircraft up to standard.
The other aircraft was re-built in the early 90’s and kept inside, only minor structural issues have been found but some poor repair issues had to be addressed .
My conclusion is that the condition covering is not the limiting factor with wooden airframe but cracks in paintwork or leaks from small holes in the fabric covering are detrimental to the wooden structure so the ability to ecomomicly repair minor damage to the covering is critical to airframe life.
May be I’m being a bit conservative but the conventional covering will outlast my projected flying and so I don’t intend to change to a technology that has yet to mature.
Your are right, you don,t get the glossy shine with Oratex. It is more classic. Repair is not a problem. Just apply a patch. But this is not unvisible.
During flight tests for EASA STC there were some aerodynamic benefit detected. Min speed was lower than before. Maybe the surface of the fabric works like a micro vortex generator.
From my impressions at Friedrichshafen (or maybe somewhere else, don’t remember), white Oratex was the least interesting – probably for lack of gloss; anyway, yellow and red were much more impressive. I wish it were also available in black.
Myself and a fellow Robin owners looked at the U.K. demonstrator in oratex a couple of years ago.We both agreed that the finish was not to the level we would expect from an aircraft costing over a £300k.Both of us felt that the original Dacron and paint finish which I believe is still an option had a much better appearance.Given the Robins enormous payload it does not need to save every last kilo of weight in its construction. Regards Stampe.
Apologies for delay replying @Capitaine I was in the process of selling my aircraft and didn’t want to risk ‘jinxing’ it with a public discussion – I was the eventual owner of the UK demonstrator mentioned by @Stampe above -a couple of things:
1 – I was told at the factory that this was the only airframe where they ever fully covered the wings in Oratex as it was so challenging to work with – they still use it for elevator/ailerons as an option.
2 – It was very easy to clean flies off- almost Teflon-like – it cleaned itself if I flew through a half-decent cloud
3 – In my opinion it worked very well with a Matt painted airframe with shiny metallic detailing- it would look odd if the rest of the plane was shiny – compared to shiny Robins the wings also loooked smoother,(less rippled) but the seams did not
3. – After 2 yrs a very faint grey-brown “stain” began to show through in stripes over where the ribs would be – presumably these parts had been subject to more heat reflection. Though not enough to show up in photos I t made the aircraft feel less-than-perfect, as I’d kept everything else in “brand new’ condition – while the airframe was in Dijon for warranty work they kindly re sprayed the white parts of the wings at cost – this looked in my opinion whiter and better it remained easy to clean, now by virtue of smoother seams – it made no measurable difference to speed/consumption and they re-weighed the plane to within, from memory, about 3kg of the original weight ?within margin of error?
In summary – in my case, Oratex provided a headache for the makers, and later a headache for the user. Though it certainly is very shiny and easy to clean.
*in last sentence above “shiny” should read “slippery”!