On Monday, December 19, 2016 at 9:41:33 PM UTC-7, wrote:
Hi
Some interesting speculations. Here are a few facts:

The JS3 wing is in essence the same as that of the JS1 Evo except for the inner 1m were the transition to fuselage starts. The evo wingtip was designed for the JS3 but was used on the JS1 as the JS3 fuse was not yet ready 3 years ago. The evo wingtip proved to be very good in terms of performance and handling improvement. That served to confirm the new wingtip airfoil and 3rd generation winglet design methodology.

The fuselage is the result of a huge basic research effort. We took 2 year to learn how to design a modern glider fuselage. The fuselage was just about ready when we discovered a fundamental problem inherent to most high wing configurations that will offset any gains due to the high wing. We then had to redesign the fuse to remove that problem. That took about 2 years. We use CFD analysis exclusively for this development work. Bossie (Johan Bosman) spent 3 years (PhD) to properly calibrate the software for our flow regime. A lot of effort went into the wing fuse junction. This is still a very difficult area to design properly.

The moulds for the wings was started in Feb 2016 and completed in June 2016. (we used the mould-plug-mould route to composite moulds). The detail design on the JS3 was started in March 2016 and was basically completed in beginning of NOv 2016. The total design effort(not building of anything, just design) took approx 25000 man hours( 16 engineers)

The fuselage mould was started on 4 Aug 2016. We stated building the fuse in Oct 2016 and the wings in Nov 2016. An integrated design approach was used where everything was designed simultaneously, ie airframe, moulds, tooling and manufacturing method. So when the design was completed, so was most of moulds, tooling and jigging. The prototype were therefore really built as close to as is possible to a production aircraft. We tried to use as many JS1 parts as possible but most systems and parts are completely new.

The first prototype as accumulated 20 h over the week since the test flight and the envelope is opened to full wing loading (60 kg/sqm) and 270 kph. The stall speed matches the calculated value perfectly. The handling is really good, JS1++. The performance.. well we are satisfied.

Regards
Attie Jonker

Thanks so much for taking the time to explain the process to us. I had to double check the number of man hours spent in the design effort. 25k hours?!?!? Wow! Congrats on another beautiful ship and I can't wait to fly one..

Bruno - B4