Bruni 3V-1 Eolo

The Bruni 3V-1 Eolo, sometimes known as the SIAI-Marchetti Eolo 3V-1, was a high performance sailplane designed by Giovanni Bruni in Italy in the early 1950s. The 3V-1 was built by a collaboration between SIAI-Marchetti and the Alessandro Passeleva Soaring Sports Club of Vergiate. The high performance sailplane, intended for competitions and record breaking, was an all wooden cantilever mid-wing aircraft, with a high aspect ratio, single spar wing which was sharply tapered in plan and mounted with 3° of dihedral.[1][2] The wing was covered with unusually thick plywood to maintain the laminar profile[3] and its tips carried "salmons", small streamlined bodies intended to minimise induced drag. Narrow slotted control surfaces filled the whole trailing edge, each occupying about a third of the span; the outermost were conventional ailerons, followed by a second set of ailerons which drooped when the flaps on the inboard third of the wing were lowered.[1][2] The Eolo had a pair of mid-chord airbrakes mounted just behind the wing spar, each with sixteen blades deployed above and below the wing surfaces.[1] In the initial version there were inboard leading edge tanks that could hold 32 kg (71 lb) of water ballast.[1]

The Eolo's fuselage was a wood framed, ply skinned semi-monocoque of elliptical cross-section. Behind a pointed nose the pilot sat under a long, one piece canopy which extended rearwards almost to the wing leading edge where it was smoothly blended into the fuselage. It had a straight tapered V-tail with surfaces at 110°, ending in salmons, like the wings.[1] The elevators were equipped with trim tabs.[4] The glider had a monowheel undercarriage, equipped with a brake, which retracted behind two doors. There was also a sprung tailskid and a small protective nose skid.[1]

The Eolo first flew in August 1955.[1] A year later it competed in the World Gliding Championships held at Saint-Yan but had to retire after an accident on the third day.[5]

Data from The World's Sailplanes - Die Segelflugzeuge der Welt - Les Planeurs de le Monde (1958)[4]

General characteristics

• Capacity: One
• Length: 8.55 m (28 ft 1 in)
• Wingspan: 20.00 m (65 ft 7 in)
• Wing area: 16.00 m² (172.2 sq ft)
• Aspect ratio: 25
• Airfoil: root : NACA 65₃618 ; tip : NACA 65₁612
• Empty weight: 329.5 kg (726 lb)
  

365 kg (805 lb) equipped

• Max takeoff weight: 450 kg (992 lb)

Performance

• Stall speed: 40 km/h (25 mph, 22 kn) with full flaps (50°)

60 km/h (37 mph; 32 kn) no flaps

• Never exceed speed: 230 km/h (140 mph, 120 kn)
  
• Airbrake limiting speed: 160 km/h (99 mph; 86 kn)
• Aerotow speed: 100–130 km/h (62–81 mph; 54–70 kn)
• Maximum glide ratio: 32.8:1 at 96.5 km/h (60.0 mph)
• Rate of sink: 0.79 m/s (156 ft/min) at 92 km/h (57 mph)
• Wing loading: 28.1 kg/m² (5.8 lb/sq ft)

• Bridgman, Leonard, ed. (1958). Jane's All the World's Aircraft 1958-59. London: Jane's All the World's Aircraft Publishing Co. Ltd. pp. 199–200.