Jodel D11 ZS UEK-a Labour of Love
By Willie Bodenstein
Stewart Clegg started his career in aviation at Comair where he did his apprenticeship as an aircraft mechanic. At the time he had been looking around for an aircraft to build. Initially he looked at the KR2 but that was just too marginal and after doing some research he decided on the Jodel and acquired a partially built one that he kept in the back of the hangar at Comair. In 1979 he got his PPL at Oribi, Pietermaritzburg and today has besides the Jodel got the Tiger Moth, Whisper, Cessna 140, 172, 182 Gruman Traveller, Cherokee 140,160 and 181.
The Jodel followed him when he moved to Celair where he assisted with the design of the CelStar aerobatic glider. He left Celair a year later and the Jodel went with to Resitex where he worked on the cowlings for the turbine conversions on the DC3/C-47's. When Resitex went insolvent Stewart joined Episilon Engineering with the partially completed Jodel in tow. Then UEK came on the market. By then Stewart had realised that he would probably never finished the partially built one and he took a loan from a bank and bought UEK.
Based at Zyferfontein she needed some work to get into flying condition and Stewart spent the next six months traveling between Pretoria and Zyferfontein to get her ready for her ferry flight to Fly-in Estate. Jeff Birch flew her to her new home and then later gave Stewart his conversion. Whilst at Fly-in Estate UEK got a new cowling and bubble canopy that Stewart had designed. John Mcsher did the test flying and Stewart took her to a couple of the EAA Fly-ins at Margate. After a couple of scary moments and engine failures Stewart saved up, took another loan and bought a O 235 l2C Lycoming refurbished for UEK by Fanie Viljoen.
With the engine fitted, part of the engine run in flight was a cross country trip down to Paradise Beach, Jeffreys bay. Stewart and family had moved down to Paradise beach to start developing and manufacturing the Whisper motorglider kits. They would remain there for ten years. Whilst there, a broken wing rib was noticed whilst flying. Upon landing the wing fabric was cut open and indeed there was a broken rib. The broken rib was repaired and before recovering, the wings were load tested to 3.5Gs. In the 10 full recovering and a new coat of paint as well as a new reshaped cowling and an extra 45 litre fuel tank behind the seat.
In 2010, Gregory, Stewarts son was in matric. Greg had ambitions to become a commercial pilot and did not plan on getting a university degree. However, the school of engineering at Nelson Mandela Metropolitan University (NMMU) had a design competition for grade 12 scholars to win a bursary to study in the field of engineering at NMMU. The competition was to design, document and build a RC sized electric car. The car was to be powered by a 9v battery, it had to race down a 1.2 m track, hit a wall and race back. The cars were to race against each other to determine the fastest car.
Greg spent the lengthy school holidays, due to the soccer world cup, building his car. The race happened after the school holidays at the university. Greg ended up coming first and winning himself a full tuition bursary to study and Greg chose to study Mechanical engineering. Later that year, Greg under the guidance of Stewart, started fitting dual controls to the Jodel. The Jodel needed a throttle and brakes on the instructor's side.
In 2011 Greg started his first year at university and later that same year he started his PPL at Algoa Flight Centre on the Jodel. Greg worked as a waiter on weekends and holidays to fund his PPL and was sent solo on UEK at around 8 hours. Because of his studies and lack of funds it took him over one and a half years before he got his PPL in 2013. He currently has about 190 hours on the Jodel and also rated on the Sling.
In 2013 the family relocated back to the big smoke. Stewart returned to Episilon Engineering and UEK found her way back to Fly inn. Greg, with his studies mostly completed, joined the family in Gauteng to complete his practical at the same company where Stewart is working. UEK in the meantime got a new set of undercarriage as there was quite a bit of corrosion on the old set. In 2014 she also got a set of spats that both Stewart and Greg made. The final task, which they eventually got around to doing, was making the fairings to fair in the spat and gear leg interface.
The Jodel was designed by Societe Avions in response to a requirement by the French government for a low-wing aircraft for use by the nation's many emerging flying clubs. Designers Édouard Joly and Jean Délémontez based the design on two of their earlier projects; they combined the wing of the projected D.10 with a lengthened and widened version of the D.9 fuselage. The aircraft uses all-wood construction with a single piece box-spar and the first example flew on 4 April 1950.
The Clegg's D11 weighs just under 440kgs, can take 2 medium sized adults, 30kgs of baggage and 110 litres of fuel. She will still take off in 400 meters on a warm day and climb at 600 fpm. UEK, like most Jodels, doesn't have flaps. "Flaps", Stewart says, "would be a nice to have just for the landing phase. Landing with any excess speed she floats forever. Approach speed is 55 mph where she will land within 300 to 400 meters. We cruise around at 115 knots indicated burning 18 LPH on average. At the coast at full power we will do 135 knots."
"She will stall at about 45 mph, where she gently mushes down. She would drop a wing in the past but this has been corrected by the inboard stall strips as well as the Vortex Generators (VGs). The VGs were first fitted in a quest to tame the stall but they weren't the magic that they claimed to be. Stall strips were later fitted at the root of the wing to pre stall the inboard section of the wing first, while the tips keep flying"
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