Conventional wisdom says that technology has tamed the elements and removed risk from almost every human activity. In early 2007 Rotron Founder and Chief Technology Officer, Gilo Cardozo, turned conventional wisdom on its head in the pursuit of a childhood dream; to fly a paramotor (a foot-launched powered paraglider) over the summit of Everest. The dream grew to become a worthy adversary of all he had learnt as an engineer.
For this endeavour Gilo teamed up with friend Bear Grylls, arguably one of the world’s most famous TV personalities in the world of adventure sports. Coming from the military, and with a successful ascent of Everest behind him, Bear’s energy and connections gave a platform for the expedition to take shape, giving Gilo just seven months to build two paramotors that could fly above Mt Everest.
The odds seemed stacked against Gilo and the team. The flying and engineering world said he couldn’t do it; even getting a paramotor off the ground at 4,500m (14,500ft) was deemed impossible, never mind then climbing to 9,000m (29,500ft). The designer and builder of three ‘Round the World’ balloon projects gave the mission less than a 30% chance of success and it’s even rumoured that a world record-breaking microlight pilot told a UK newspaper to cease coverage of the project before it was hopelessly abandoned.
The Everest Engine
The most powerful paramotor engine available was barely producing 30hp and was far too heavy to launch at the desired altitude, so the biggest challenge Gilo faced was designing and manufacturing an engine powerful enough to fly to 30,000ft, yet small and lightweight enough to be worn on the pilot’s back; an entire aircraft that could be foot-launched at 14,500ft high in the hills beneath Mount Everest.
At such high altitude there is 0.3 times the amount of air - an engine which uses oxygen in the air to produce it’s power now has only a third of the amount to combust. The result is engine that in theory produces one third of the power, in practice when one takes into account the mechanical losses, this becomes around 1 tenth of the power. In addition, a propeller when driven at 30,000ft will only produce 0.6 times the thrust, so to compensate the engine needs to drive the propeller 1.7 times faster.
The answer to the problem was to design and build a revolutionary 4-stroke rotary engine that was more compact and fifty percent lighter than a piston engine equivalent and almost twice the reliable power output for its cubic capacity. The basis of the Everest engine was a 294cc single rotor engine producing 4hp as a standard normally aspirated engine. To make this standard engine block capable of delivering the required 100hp a huge amount of research and engineering work was carried out.
If the engine could be made powerful enough, it also needed to be made capable of automatically compensating the fuel delivery for high altitude. The only solution was to develop a computer managed fuel injection system which could measure the altitude every tenth of a second and compensate the fuel delivery accordingly. Once the altitude compensating problem was solved it was now a question of how to get the extra power…. This was eventually achieved by using a miniature centrifugal supercharger fitted with a miniature intercooler to ensure the air was as cold and dense as possible when entering the combustion chamber. The supercharger which had been designed to spin at a maximum of 150,000rpm was modified to be spun at up to 200,000rpm in order to simulate sea level atmospheric pressure of 1 bar at 30,000ft.
Another problem to overcome was icing occurring in the inlet manifold, potentially blocking the fuel/air flow as is common with all light aircraft engines even at low altitude, let alone 30,000ft. To eliminate this problem the supercharger was placed before the fuel delivery system. The heated and supercharged air was then sent through an intercooler before passing the injector at an average of 25 degrees celsius thus preventing any chance of icing. The engine also equipped with an extremely high pressure submersible fuel pump, to create up to 8 bar of pressure at the fuel injector in order to achieve optimum atomization of the fuel into the inlet manifold.
To run the ECU, the ignition system, fuel pump and liquid cooling pump required nearly 14 amps. Gilo developed a miniature, ultra lightweight 3 phase generator that ran direct off the engine drive shaft to power all the onboard electronics.
After 4 months of design, development, testing and manufacturing, the engine was finally ready. With just two days before departure, the second engine was completed.
Reaching the ‘Ceiling of the Impossible’
On the 14 May 2007 Gilo and Bear took off from the foothills of the high Himalaya, some 20 miles south of Everest in eastern Nepal.
Alongside the everest engine, both pilots were kitted out wearing three thermal suits, the top one made of goose down and designed for -80C temperatures; a helmet with camera; boots and gloves; a radio; lightweight crampons fastened to their calves; oxygen systems with a six-hour capacity and a survival grab-bag containing food, water, mini-flares, emergency locator beacons; and a sky-diving rig - total weight of around 120kg.
Once airborne, the intrepid pair flew north, over glaciers, towards Mount Everest. Once south of the infamous Nuptse Wall, a sheer ice and rock face that soars eight thousand feet high, Gilo and Bear began to circle and ascend towards their target altitude.
At 28,000 feet, a fault in Gilo’s machine ended his mission just 1,000 feet below the summit, forcing him to glide back to safety. Luckily, Bear was able to continue to ascend until, at around 9.30 am, he reached the height of 29,500ft to claim a world record!
The expedition raised $1million for Global Angels projects in Uganda, Sierra Leone, Kenya and Mozambique; 100% of which went towards providing water, food, education, medicine and housing for kids and their communities.