October 25, 2023

Soaring into the Blue

Smoke On Go

South Africans are renowned for their innovation and Jonker Sailplanes is a great example of that, starting from humbe beginnings and building on their passion to ultimately become an internationally-respected producer of high-quality gliders.

The story of Jonker Sailplanes is the story of a family business built on inspiration, passion and a love for one’s craft, passed down over the course of nearly 50 years to the next generation.

Origins

It starts with the birth in 1943 of Tienie Jonker on a farm in Christiana in the North West Province. Tienie’s love for aviation has its origins in him watching aircraft flying over the family farm and as a child he would run behind these aircraft until they disappeared over the distant horizon.

That desire led to young Tienie throwing himself into building and flying model aircraft, even going so far as to build and fly his very own radio-controlled aircraft.

Gliding first entered the lives of the Jonkers after Tienie saw a Tiger Moth towing a glider one afternoon. He followed the flight path on his motorcycle and ended up at the Air Force Gliding Club’s Summer Camp at the Potchefstroom airfield. His enthusiasm led to him being invited on his first flight in the then state-of-the-art Schleicher Ka-7 glider, a tandem two-seater. Tienie returned home that night with a huge smile on his face, along with the requisite bruises and scars that came with a stumble on his first wing-run attempt!

But the seeds were sown.

Tienie went on to join the Magalies Gliding Club in the mid-1960s, going solo on the same weekend that the club relocated to their current location, Orient Airfield, and thus becoming the first pupil to go solo on the airfield.

Passing of the Baton

1973 saw Tienie move to the small town of Bloemhof and ultimately help establish the Bloemhof Gliding Club, which gave him the opportunity to introduce his two young sons to the sport. Uys and Attie were barely five-years-old when they first joined their father at the club, taking every opportunity to accompany him. Tienie would strap his two boys together in the back of a Schleicher Ka-2 and go flying!

The Jonkers’ passion for gliding was further cemented in 1975 when Tienie started building a wooden Tern glider in the family’s backyard, getting Uys and Attie involved in the construction. The Tern was an American wood and fibreglass glider with a 15-metre wingspan, with Tienie eventually going on to test fly his Tern in 1980.

By the mid-1980s, Uys and Attie were regularly flying wooden gliders under the watchful eye of their father and both soloed shortly after their 16th birthdays, with the family going on to move to Potchefstroom in 1987, where the brothers became active members of the local gliding club.

After completing their studies, Uys took a job with Denel Aviation and Attie became a full-time lecturer at North West University, but by the end of the 1990s both brothers were lecturing at the university and soon got back into the full swing of gliding, flying rebuilt Cirrus sailplanes in competitions.

That led to both Jonker brothers being selected for the South African gliding team, but they were short of a competitive glider, as these types of gliders were unaffordable at the time.

Building the “Perfect” Glider

So, very much like their father nearly 30 years before, they decided to build their own sleek and fast glider, with Attie starting design on their “perfect” glider.

It was a real labour of love, with over 30,000 hours of painstaking work poured into this passion project, which ultimately resulted in the Jonkers’ very first JS1 prototype.

Its first flight took place on 12 December 2006 and a week later Attie entered the glider into the combined Open/18m Class at the South African National Championships in Bloemfontein. To everyone’s surprise, they won the competition, and the glider would go on to be known as the JS1 ‘Revelation’.

Originally, the Jonker brothers only intended building one or two gliders, but interest in their design led Uys and Attie to incorporate Jonker Sailplanes (Pty) Ltd.

Jonker Sailplanes

Uys now fills the role of project manager and Attie that of chief design engineer, whilst Johan Bosman, an aerodynamicist, and his team at the factory also contribute hugely to the success of the JS series and the company as a whole. All the executives are glider pilots.

Due to increased demand and production, Jonker Sailplanes has grown into a substantial business, with 16 qualified engineers and more than 140 permanent employees working in the Jonker Sailplanes factory in South Africa.

It’s a South African aviation success story, considering its humble beginnings and the fact that it was originally a small team of three engineers and three technicians who combined their knowledge to produce a sailplane that would go on to win competitions.

International Stage

Now that passion and expertise is on the international stage, with Jonker Sailplanes concluding a partnership agreement with M&D Flugzeugbau in Germany in 2019, with the goal to expand its activities in Europe by performing sales, purchases and other administration functions. M&D Flugzeugbau was founded in 1995 by a group of pilots and manufacturers light and sport aircraft, and Jonker Sailplanes GmbH has well and truly put this South African family business on the international map!

All JS gliders with an EASA-type certificate are produced under M&D’s production approval and European sales are now made directly through Jonker Sailplanes GmbH.

Jonker Sailplanes encourages all its employees to take part in the innovation process and this is just one of the many factors behind Jonker Sailplanes enjoying an edge over their European counterparts.

Range

The Jonker Sailplanes range currently consists of:

Jonker JS1 Revelation – 18m/21m flapped sailplane with jet sustainer
Jonker JS2 Revenant – 18m/21m flapped self-launcher
Jonker JS3 Rapture – 15m/18m flapped with jet sustainer or electric propulsion
Jonker JS4 Rengeti – 15m/18m standard class sailplane with jet sustainer or electric propulsion
Jonker JS5 Rey – Open class sailplane with jet sustainer or self-launcher

“The JS series of sailplanes is the top performer in its class and on a good day the JS1 can easily fly in excess of 1,000 kilometres. It comes as no surprise that the JS3 holds the world speed record for a triangle of 1,250 kilometres in an astonishing time of seven hours and 30 minutes,” says Uys Jonker.

Seventeen years after the first JS1 was launched, the Jonker brothers were able to celebrate delivering their 300th sailplane in 2023.

The JS series is now sought after by many competition pilots around the world and the results speak for themselves (see info box).

Between them, Attie and Uys Jonker have over 2,000 gliding hours and both have been crowned South African National Champion three times, whilst both have represented the South African gliding team in the world championships at various times.

And Tienie?

Well, he’s now a successful tour operator and enjoys life with his wife and grandchildren, often flying his Scheibe Falke touring motor glider, whilst remaining an inspiration for everyone at Jonker Sailplanes.

Jonker Sailplanes – a South African aviation success story, putting the country on the map as a premier supplier of competition sailplanes to the world soaring community.