Workshop at the OSC Wasserkuppe
This is a question we also asked ourselves. For a long time, we have already been reading carefully reports and experiences. We had samples in our hands, at the AERO we looked at aircraft covered with ORATEX.
Such a modern material on our historical Schulgleiter – “no, this does not fit”, some „traditionalists“ in the OSC-Wasserkuppe thought.
The Ka8 from our member Jörg from Hannover was the test flight aircraft for the certification of ORATEX UL 600 for all gliders and motor gliders, like the Motorfalke SF25. Finally, on 9 March 2017 ORATEX UL 600 was certified for gliders by the EASA. Now, we had to make an appointment for the covering. We had not yet worked with the material – and afterwards, I can definitely confirm that the Application Manual and the descriptions on the homepage of Lanitz Aviation help in understanding the covering technique with ORATEX, but nothing is better than practical advices which the covering technician Fred gave us on site.
The preparation of the parts to be covered was finished within the last weeks: old adhesive was completely removed; different smaller repairs were made and the aircraft was presented to the examiner.
On Thursday afternoon the workshop began. Fred and Roman came with all required materials and tools. Everything was quickly prepared for the covering and the first layers of adhesive (watery, two component high-tech glue) were applied.
The covering also had to receive a thin, even layer of adhesive. The glued covering dried and in the evening the first strips of the covering were attached to the underside of the wing.
Heat gun, felt blade and a lot of talent were needed for a successful work. Admittedly, the covering takes more time than with traditional material. Furthermore, you always need one helping hand more, but if the material is ironed on and tightened, the work is really FINISHED. No dope, no further coating, simply finished. (OK, we had to stitch the undersides, but with 6 people helping, we were very fast.)
For me Josef (Seppl) was a real sensation. With his 90 years he was certainly the oldest participant of the ORATEX-Workshop. Open-minded for the technical evolution, he always stood on our side with a huge own initiative and interest in all the working steps which were shown by Fred and he also worked tirelessly to cover the aircraft.
Yes, we worked from 8 o’clock in the morning till 18/19 o’clock in the evening – and Seppl was always there. Therefore he gained my honest respect. And when he saw the result, Josef was also convinced of the new covering technology.
Everybody who looks at the SG38 from a distance of 3 metres will think that it is cotton covering of which the dope has already gone yellowish after a few years. Fred told us that the weather and UV conditions have been simulated with a life span of 30 years. This makes me curious. This would be brilliant. The resistance and stability could be tested impressively on a test frame and a micro light tail unit.
The “Bergfalke” also needs a new covering with ORATEX. The experience shows that a double seated aircraft like the ASK13 lost between 17 and 19 kg of weight. Some weight-losing would be good for the “Bergfalke”. The Udet Flamingo could also be covered with the robust aircraft fabric ORATEX 6000.
Conclusion: an impressive seminar, intensive exchange of experiences, materials which are good to work with, many mechanical advantages compared with traditional covering materials – highly recommended. And yes – ORATEX and SG38 fits!
We are very thankful to Frank Thies of the OSC Wasserkuppe for his report