Krisztián Dolhai, aeronautical engineer, glider and motor glider pilot, founded a glider club 18 years ago with his younger sister and friends, operating four gliders and a Falke. The motor glider for all year round use appealed to him at the time, but the Falke’s wooden wing, representing 1970s technology, was weather-sensitive and its speed and climbing ability were far below the ultralight aircraft then on the market. The Dimona, and especially the Grob 109 of the early 1980s, were heavy and although both could be used for thermalling with a stationary engine, their manoeuvrability made them less than ideal for that. Krisztián wanted a comfortable aircraft with side-by-side seating, a spacious baggage compartment, lower fuel consumption and noise pollution than a conventional powered aircraft, but also safe to fly with the engine running or stopped. Other considerations were good visibility both while taxiing and in flight, and a rigid landing gear to avoid lengthy and costly repairs after a possible belly landing. Although at first sight these criteria may not seem excessive, there was no aircraft on the market that met them. Some had small cabins, others did not provide good visibility when taxiing. The one that gave the best flight characteristics did not provide good visibility during thermalling because of the upper wing design.

So the decision was taken to build a variable wingspan aircraft of their own to meet these requirements. The launch and success of the project was greatly aided by Omikron Dokk Kft., the largest composite technology company in the region, and eCon Engineering Kft., a leader in aerodynamic and structural analysis. In 2014, the design of the new aircraft was started using a number of existing components and was completed by the end of 2017. The first flight took place on 20 June 2018 in Börgönd and it was already evident that it delivered the expected parameters – as Krisztián recalls, ‘it was love at first sight’. The first two prototypes of the Altus have now flown more than 1,250 hours and performed as well in cold alpine weather as they did in hot coastal or rainy conditions. In fact, during the testing process, Krisztián Dolhai flew five certified FAI world records with the aircraft. One of the key objectives set at the beginning of the development was safety, which the Altus also fully meets. It gently lowers its nose upon stalling and can be flown again within a short time. It is not susceptible to corkscrewing and can only be deliberately driven into it. Its glide ratio is below that of a glider, but a 15-metre wingspan, side-by-side seat spacing, rigid-gear aircraft cannot be expected to achieve more than a glide ratio of 25. The new wing of the Altus, also designed by aerodynamic genius Franco Orlando, was completed in spring 2023. Unfortunately, we now know that that was his last work.

The Altus project will make its fifth appearance in Friedrichshafen in 2025. The first two times the prototype fuselage was exhibited jointly with fuselage maker Omikron Dokk Kft., and in 2023 and 2024 the world record-breaking tail wheel plane and the nose wheel, Nr. 2 were on display to an audience of more than 30,000 people at AERO. The reception of the Altus has been very positive. The German, Swiss and Belgian sport pilots clearly seeing it as a possible alternative to the Dimona – just as Krisztián had planned when the project was launched. Based on the results and feedback so far, the development is going in the right direction, but there is still a lot of work to be done. The 600-kilogram DULV (Deutscher Ultraleichtflugverband, German Ultralight Flight Association) certification is just around the corner, and all the calculations, ground load tests and flight tests have been successfully completed. Altus Aero Kft. will exhibit the nose wheel Nr. 3 Altus at the Aero 2025 fair, which will take place between 9 and 12 April 2025.