We have already reported here about the LS 4 Jet - now the EASA has issued the STC!
Potential customers please book your slot!

On the 18th of July the EASA has issued the type certificate for the JS-MD 3.
With the JS-MD 1 already certified we are happy to provide our customers with a further EASA certified aircraft!

Exactly ten years ago, on 12 December 2006, the JS1 flew for the first time.

A small team of three engineers and three technicians combined all their knowledge to design an aircraft that wins competitions and flies beautifully. That was the beginning of a success story. Today, 16 qualified engineers and over 110 employees work at the Jonker factory, with M+D Flugzeugbau in Germany strengthening the team in the areas of development, propulsion and certification. The JS1 is an established and integral part of the scene.

Early on, the designers Atti Jonker and Johan Bosman thought about a new development with a 15 metre wingspan, but with more performance than usual for the class. The two saw the key to achieving significantly more performance primarily in the realisation of a new fuselage. The usual wind tunnel tests were replaced by highly effective CFD analysis (computational fluid dynamics). This enables fast and efficient simulation of flows in order to calculate the forces at work and thus understand the effects on the aircraft's performance. The results achieved are extremely impressive. In addition to a significantly optimised glide ratio, uncomplicated flight behaviour (independent of the load condition), a high maximum wing loading, crash safety and cockpit ergonomics were also on the agenda.

The JS3 was not only newly developed and designed by an experienced team over many thousands of hours. A new and integrated development approach also breaks new ground in production. Every aspect, every component, every function of a large or small part, the manufacturing process, the optimum material thickness and the required mould were defined and developed together. This approach is somewhat slower during the initial phase, but ultimately saves time in production and significantly increases precision. This made it possible to significantly reduce the mass of the aircraft without having to compromise on safety. Thanks to the high level of manufacturing precision, it is now possible to interchange wings, stabilisers or fuselages from different aircraft for the first time without any further adjustments. A novelty in sailplane construction.

The development goal was clearly defined: The JS3 will be an aircraft with a performance above the usual 15 metre class, combined with maximum wing loading and the proven jet system from M+D Flugzeugbau. Last but not least, a very characteristic and dynamic design was created.

Well done Atti, Uys, Johan, and Team!

Further information and pictures at www.jonkersailplanes.de

High-tech at its best - Tim Markwald presents the jet drive.

Flashback: On 21 September 2009, M&D Flugzeugbau applies for the TC (Type Certificate) for the MDTJ-42 jet engine designed and manufactured in-house. It took six years to get the MDTJ-42 jet engine approved for use in gliders.

If you want to certify an engine with an EASA TC (Type Certificate) for aeroplanes today, there are many details to consider. The standards for safety, reliability and consistent performance are extremely high. The underlying documentation is extensive. The M&D team received active support from aerospace engineer Stefan Hilbenz from Kasaero GmbH in preparing the documentation.

A few figures: Around 50 engines were deliberately pushed to and beyond their limits during tests and on the test benches at M&D. During the prescribed endurance and cycle tests, the engines were run for over 100 hours in a simulation between take-off, idling, full throttle and back again and were subjected to a maximum load of 16 hours at full throttle (!).

A good 180 test flights were carried out by M&D test pilot Sören Pedersen and his colleagues, and the engines flew for around 300 hours in various aircraft types during field testing.

The cooperation between M&D Flugzeugbau and Jonker Sailplanes and the construction of 50 JS1s with jet engines provided further insights for development. Intensive testing, flying and refinement also took place in South Africa. The density altitude and temperatures in Africa also contributed important findings for development. Over 80 engines have now been delivered to non-EASA countries. But the MDTJ-42 has now also passed all tests in Europe and has the EASA-TC.

And: The engine has its own electric starter and is fuelled with simple diesel instead of special and therefore expensive aviation fuel.
What happens now: The MDTJ-42 will not only continue to be installed in the JS1. M&D is focussing on other aircraft types, and nothing stands in the way of a retrofit using an installation kit.
And of course the engine will be further developed and adapted to the profile of the aircraft type.

A flight report on the jet in the MD-JS 1 Revelation can be found in the Jet flight report.

The M&D website http://www.md-flugzeugbau.de will provide information on questions and answers about the engine and the options for installation in various aircraft types in the near future.