Il y a 25 ans, en décembre 1986, le bimoteur Voyager conçu par Burt Rutan réalisait le premier tour du monde sans escale ni ravitaillement en vol. L’équipage était constitué de Dick Rutan, son frère, et de Jeana Yeager.
Il y eut quelques moments tendus… dès le décollage de la piste de 4.500 m de la base d’Edwards AFB, non loin de Mojave où furent réalisés tous les essais du prototype. Chargé pour la première fois de tout son carburant, les extrémités de voilure ont frotté le sol durant toute l’accélération initiale. Dick Rutan ayant enfoncé l’alternat de la VHF pour annoncer ses vitesses, personne n’a pu le prévenir. Ce n’est qu’à la rotation que les ailes de 33,80 m d’envergure ont consenti a se courber vers le haut… Le Beech Duchess de la Rutan Aircraft Factory (RAF) est allé voir les dégâts – un winglet arraché – et Dick Rutan a effectué ensuite des attaques obliques pour faire «partir» l’autre winglet.
Puis le trimaran des airs, construit par des bénévoles durant cinq ans, a pris son cap vers Edwards pour un tour du monde sans escale. A pleine charge, l’appareil était totalement instable longitudinalement, imposant un pilotage constant. Le contrôle fut presque perdu en passant aux marges d’un orage près du Japon. Lors du survol de l’Afrique, Burt Rutan est venu inspecter en vol le bimoteur, à partir d’un autre avion, pour évaluer également la quantité de carburant encore à bord car une incertitude demeurait sur l’autonomie du Voyager après avoir consommé plus que prévu lors de détours pour raisons météo ou non-autorisation de survol de certains pays.
Si le moteur avant (Continental IO-240) avait été utilisé pour décoller à pleine masse, seul le Continental arrière était en fonctionnement en vol de croisière mais il est arrivé, sur problème de gestion carburant, qu’il s’arrête, transformant le bimoteur en planeur le temps de faire repartir le GMP arrière, un Continental OL-200 à refroidissement liquide.
Au final, après 9 jours, 3 mn et 44 secondes, le Voyager s’est reposé à Edwards à l’issue d’un tour du monde de 42.432 km dont 40.212 km seront homologués par la FAI. Si à masse à vide, l’appareil en composites (fibres de verre, de carbone et Kevlar) affichait un peu plus de 1.000 kg, la masse maximale atteignait 4.400 kg. Une bonne partie du périple autour du globe s’est fait à une vitesse de moins de 200 km/h, pour travailler au plus près de la vitesse de finesse maximale, estimée à 27.
Par la suite, l’équipage reçut le Collier Trophy tandis que le Voyager rejoignait le National Air & Space Museum à Washington, survolant désormais l’accueil du musée.
Vous l’avez encore lu sur www.pilotermag.com !

The damaged left wingtip of Voyager

Extrait de Wikipedia (version EN)

The aircraft was first imagined by Jeana Yeager, Dick and his brother Burt Rutan as they were at lunch in 1981. The initial idea was first sketched out on the back of a napkin. Voyager was built in Mojave, California, over a period of 5 years. The Voyager was built mainly by a group of volunteers working under both the Rutan Aircraft Factory and an organization set up under the name Voyager Aircraft.
The airframe, largely made of fiberglass, carbon fiber and Kevlar, weighed 939 pounds (426 kg) when empty. With the engines included, the unladen weight of the plane was 2250 lb (1020.6 kg). However, when it was fully loaded before the historic flight, it weighed 9,694.5 pounds (4,397 kg) due to the large amount of fuel required for the long-distance flight.[2] The aircraft had an estimated lift to drag ratio (L/D) of 27.[3]
Voyager had front and rear propellers, powered by separate engines. The rear engine, a water-cooled Teledyne Continental IOL-200, was planned to be operated throughout the flight. The front engine, an air-cooled Teledyne Continental O-240, was operated to provide additional power for takeoff and the initial part of the flight at heavy weights.
Operational history
Voyager’s take off took place on the longest runway at Edwards AFB at 8:01 am local time with 3,500 of the world’s press in attendance. As the plane accelerated, the tips of the wings, which were heavily loaded with fuel, were damaged as they scraped against the runway (the pilot wanted to gain enough speed that the inner wings would lift the plane, not the fragile outer wings – in 67 test flights, the plane had never been loaded to capacity before), ultimately causing pieces (winglets) to break off at both ends. The aircraft accelerated very slowly and needed approximately 14,200 feet (2.7 mi)(4.3 km) of the runway to gain enough speed to lift from the ground, the wings arching up dramatically just before take-off. During the flight, the two pilots had to deal with extremely cramped quarters. To reduce stress, the two had originally intended to fly the plane in three-hour shifts, but flight handling characteristics prevented routine changeovers and they became very fatigued.

The plane also continuously reminded the pilots of its pitch instability and fragility. They had to maneuver around bad weather numerous times, most perilously around the 600-mile-wide (1,000 km) Typhoon Marge.[4] Libya denied access to the country’s airspace, forcing precious fuel to be used. As they neared California to land, a fuel pump failed and had to be replaced with its twin pumping fuel from the other side of the aircraft.
In front of 55,000 spectators and a large press contingent, including 23 live feeds breaking into scheduled broadcasting across Europe and North America, the plane safely came back to earth, touching down at 8:06 am at the same airfield 9 days after take-off. The average speed for the flight was 116 miles per hour (187 km/h). There were 106 lb (48 kg) of fuel remaining in the tanks[2], only about 1.5% of the fuel that had been loaded.
Sanctioned by the FAI and the AOPA, the flight was the first successful circumnavigation of the planet, passing the equator twice, non-stop, non-refueled. This has since been accomplished only one other time, by Steve Fossett in the Global Flyer. For the feat, Yeager, the Rutans, and crew chief/builder Bruce Evans received the 1986 Collier Trophy.[5]
Voyager is now on display at the Smithsonian Institution’s National Air and Space Museum in Washington, DC.