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<\/p>\nLatest news: Like the rest of the SolarStratos team, HB-SXA had been eager to return to the skies. Since 19 May, the aircraft has been flight-ready \u2014 and keen to make itself heard, its new variable-pitch propeller bringing a noticeable change in tone, with a deeper, more resonant sound! With the official Permit to Fly from the Federal Office of Civil Aviation in hand, Rapha\u00ebl Domjan and our test pilot remained on standby, awaiting the first favourable weather window.<\/p>\n
That window finally opened on Friday 23 May, when the first flight of the year was successfully completed \u2014 just ahead of an approaching thunderstorm. This 107th flight took place under the attentive gaze of a special guest: Mark Rocket, space enthusiast and CEO of Kea Aerospace, who is soon to become the first New Zealander in space as part of Blue Origin\u2019s next mission. The result of this inaugural flight of 2025? Several performance enhancements \u2014 a promising beginning as the team looks ahead to the planned 10,000-metre flight this summer.<\/p>\n
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Optimisation. Since 13 May, our home base in Payerne has been alive with activity. One major advantage of ground-based thrust testing? It can continue regardless of the weather \u2014 grey skies and rain included. A full sequence of tests was conducted according to a precise protocol, including fine-tuning the pitch of the variable propeller to optimise climb rate in relation to energy consumption.<\/p>\n
The outcome confirmed the aircraft\u2019s impressive performance: with HB-SXA securely anchored to the ground, the dynamometer recorded nearly 200 kilograms of thrust. And yes \u2014\u00a0thrust\u00a0is the technically correct term, even if, like one of our online followers who raised the question, we tend to picture the propeller as \u2018pulling\u2019 the aircraft. Propeller thrust even has its own equation \u2014\u00a0in newtons,\u00a0thrust (N) = mass (kg) \u00d7 acceleration (m\/s\u00b2).<\/p>\n
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Almost completely silent.\u00a0One of the standout benefits of a solar-electric aircraft like SolarStratos \u2014 though several of you have rightly noted it isn\u2019t entirely noise free \u2014 is just how much quieter it is compared to conventional aircraft (especially when set against the roar of FA\/18 jets ripping through the skies above Payerne). While reviewing footage from recent ground tests, we were delighted to hear birdsong in the background \u2014 a gentle reminder of the aircraft\u2019s near-silent operation.<\/p>\n
Beyond offering a decarbonised way to experience the joy of flight, SolarStratos brings with it the added advantage of remarkably low noise emissions.<\/p>\n
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