A microlight helicopter?

It’s 8pm on a Friday night, and in the golden evening light, under a cloudless Italian sky, I’m strapping myself into a very exciting helicopter indeed. The Zefhir is the first of its kind. A two-seat, ultralight helicopter with a turbine engine and a ballistic parachute. Developed and built by Curti Aerospace, it has the potential to revolutionise helicopter safety – and a whole lot more besides. Only three have been built so far, and I’m flying one of them with Curti’s chief test pilot, Matteo Pozzoli.

 The story so far…

In the moments leading up to the point that I get my hands on the controls of this beautiful little helicopter, I chat with Mirco Cantelli, Curti’s delightful Chief Marketing and Business Development Officer, about the Zefhir’s journey so far. Curti Aerospace, part of 70-year-old Curti Industries, is a family company based in Italy’s renowned ‘Motor Valley’, an area also home to the likes of Ferrari, Lamborghini and Maserati. They’ve been making parts for Leonardo Helicopters (which now make the AgustaWestland 109, among others) for more than 40 years, and the owner – Mr Curti himself – is a big fan of helicopters.

Having decided he wanted to make his own, and having established that Leonardo wasn’t interested in building a small helicopter, Mr Curti did some market research and hired, to supervise his engineers, someone who knew a thing or two about designing helicopters… none other than the (retired) Chief Product Engineer of the AW109.

“From the beginning, the Curti Zefhir was very unconventional, because first, we proposed to make a very beautiful external design,” says Mirco. “Three designers from the Bugatti team designed it. Then, we went inside and thought about how to make it very well stabilised and high performance. We also went to the Czech Republic to get the PBS TS100 turboshaft engine.”

The result is an elegant, meticulously designed turbine helicopter with a maximum take-off weight of 600kg (1,322lb), making it an ultralight – a category seen elsewhere in Europe but not, as yet, in the UK.

So, about that parachute. 

“After researching helicopter accidents, we discovered that around 90% of fatal accidents were because for different reasons, the pilot was not able to make an autorotation,” Mirco explains. “So, we developed the idea of a parachute and finally, in 2018, we were the first in the world to test a helicopter with a parachute.”

If you’d been, as I was, at the Zefhir’s debut at Aero Friedrichshafen in 2018, you’d have noticed the parachute in a pod on top of the rotor head, but the helicopter in front of me now is missing this. That’s because it created too much vibration, resulting in it being relocated into the airframe. When the parachute is deployed (minimum deployment altitude: 450ft), an impressively efficient brake halts the rotors in an astonishing 0.7 seconds, which stops the spin in the event of loss of tail rotor authority, and also makes the landing safer for both the occupants and anyone who happens to be nearby on the ground. A rocket then pushes the parachute out and the helicopter falls gracefully to the ground at 7.5 metres per second (the same descent rate, apparently, as a parachute worn by a human).

Mirco tells me that it’s there to save the pilot’s life, but not necessarily the airframe (which perhaps explains why the sleek marketing video showcasing the parachute demo cuts just as the helicopter is about to touch the ground). 

If the engine fails and you can enter autorotation, you should. If you can’t – for example due to panic, incapacitation, flight control failure, loss of manoeuvrability or in the event that there are no suitable landing sites – then the parachute is your ‘get out of jail free’ card.

“If you’re a pilot flying 200 or more hours a year, you could enter autorotation blind,” Mirco points out. “If you’re a pilot who flies 40 hours a year, you could panic. This way, you save your life.”

Still, I for one hoped I wouldn’t be needing it.

Meeting the Zefhir

Looking over the helicopter with Curti engineer Brando Tuberosa before my flight, the quality of every component is immediately obvious. The airframe is made from carbon fibre, and Brando tells me that everything I can see in front of me, except the doors and engine cowlings, weighs just 72kg. Carbon fibre is also used for the main and tail rotor blades, along with fibreglass, and their profiles have been designed to minimise noise emissions.

Curti makes every part of the helicopter itself, with the exception of the engine (and the parachute, which is developed in collaboration with Junkers Profly). 

“In our factory we have a series of fatigue test benches where we test all critical groups, for example the main and tail rotor transmission,” Brando explains. “We have an electric engine that simulates the power and torque of the turbine, and we have reached more than 3,000 hours without simple maintenance like oil change and so on.”

Full Authority Digital Engine Control (FADEC) keeps the rotor rpm constant by itself, so there’s no throttle on the collective, reducing the workload for the pilot. For planning purposes, it’s a fuel burn of one litre a minute, so 60 litres an hour, with an endurance of 2hr 15min.

Taking to the skies

The helicopter’s name comes from the word ‘zephyr’, which means ‘a gentle breeze’, and the motionless windsock reveals there isn’t even one of those this evening, which is just as well. Clambering into the cockpit, watched by six members of the Curti team, I feel a certain sense of occasion; I am to be the first female pilot to fly the Zefhir.

Inside, it’s spacious, with comfortable yet crashworthy seats, and the visibility is fantastic. The glass cockpit soon lights up in red, yellow and green as the turbine comes to life, a wonderful sound and smell that feels somewhat incongruous in such a small helicopter.

The FADEC means the start couldn’t be quicker or simpler – at 20°C, you can be collective up in two minutes. You simply switch the avionics on, activate the fuel pump and turn the knob to ‘Idle 1’ for one minute. Then you switch it into flight mode for another minute, and that’s it. You’re ready to go!

It’s not long, then, before Matteo lifts us into a hover and repositions us from the concrete to the grass, where, to my surprise, he immediately gives me control and free rein to do what I like with the Zefhir. Maintaining a steady hover is the first challenge. It feels as though every small control input puts me out of balance, and initially I’m wallowing around like an ab initio student. Matteo puts it down to the teetering rotor head.

I decided to transition into forward flight and try some upper air work to get the hang of flying it away from the airfield (and cameras!) first. The marketing blurb describes the Zefhir as ‘pure performance at your command’, and I can immediately see what it means. It climbs effortlessly at 1,400ft per minute, with an incredible amount of power available. Indeed, its power-to-weight ratio is impressive; with a maximum power of 105 kW (141shp), there’s plenty more than is necessary given how little it weighs. The engine’s actual max power is 241shp but, like many helicopter engines, it’s derated to ensure reliability.

The cruise speed is a respectable 87kt, with a VNE of 102kt. Out of the hover it still feels a struggle to keep it in balance, the yaw string continually wandering off centre, but Matteo reassures me that it takes an hour or two to get used to flying it. With the sun already sinking towards the horizon, we don’t have an hour or two to play with, but I’m keen to see what the helicopter is capable of in the hands of an experienced test pilot. I hand control back to him and ask him to show me what it can do.

First, he demonstrates an out of ground effect hover at 1,000ft, a manoeuvre that uses only around 70% of the available power (at the maximum take-off weight of 600kg, the OGE hover ceiling is 13,100ft). Next, Matteo shows me some tight turns and then an autorotation, which surprises me in that it seems to have a better glide performance than the Robinsons I’m used to flying.

A couple of exhilarating approaches into the airfield later, practically pirouetting along the deserted runway, Matteo lets me do a few approaches of my own. By the end of the flight I’m taxying and hovering steadily enough to complete my first take-offs and landings, before handing it back to Matteo to position back on the helipad.

The shutdown procedure is as simple as the start was – essentially the same but in reverse. There’s a cooling sequence down to 100°, and then the avionics can be turned off. There’s no rotor brake (yet), so we wait for the blades to come to a stop before getting out.

Future of the Zefhir

As I mentioned, microlight helicopters are an established category elsewhere in Europe, but not yet in the UK – so will the Zefhir be the one to change that?

“The commitment from the beginning was to develop a helicopter that was 100% compliant with EASA CS-27, but at the same time it should be within the new ultralight European regulation 1139,” says Mirco. “That was very difficult to manage, and we are still on the limits. The result is that the helicopter is compliant with CS-27, and with tough attention to the weight, it can fit the ultralight classification. The Zefhir recently got the ultralight approval in Italy, so now we can fly and sell it as an ultralight. But each country in Europe has its own rules.”

Curti aims to start production this month, having already received interest from around the world, focusing initially on three markets: the US, the UK and Italy. While any two-seat helicopter is likely to be of interest to training organisations – this one especially, thanks to its turbine engine – it’s law enforcement and defence that Mirco identifies as key markets for the Zefhir. That’s because the potential cost savings per hour are significant, with operational running costs of €280 per hour compared with €1,300 for the H135/145 or €1,800 for the AW139/169.

Not only are the cost savings compelling, but the parachute doesn’t just protect the pilot and people on the ground – it also has the potential to save all the expensive specialist equipment with which law enforcement and defence helicopters are fitted. The same benefit is true for another interesting potential use for the Zefhir: it can be operated unmanned to fill a gap in the UAV market, capable of taking a payload seven times that of commercially available drones and fitted with the same instruments as for law enforcement, or even with technology such as LIDAR.

Private owners will, of course, be another market – and they’re sure to appreciate the 320 litres of luggage space in its rear bay. In terms of maintenance, the overhaul is at 2,500 hours, with the limit being the turbine rather than the helicopter itself. Once it’s approved here, sales and maintenance will be via the UK dealer, Savback Helicopters at Nottingham Heliport, where those interested in a potential purchase can register an interest.

I thoroughly enjoyed my flight in the Zefhir and have been continually impressed, throughout my communications with Curti, with the obvious passion the team have for the fantastic little machine they’ve created. Once they’ve secured that coveted CAA approval, look out for a Zefhir coming to a hangar near you in the not-too-distant future – they’re definitely going to be one to watch.