Aircraft Wiki

Fibera KK-1e Utu (Mist) is a Finnish 1960s single-seat fibreglass glider. It was one of the first (possibly even the first) fibreglass gliders in the world. KK stands for either KuituKone (Fibre Plane) or Kalja & Kuitu (Beer & Fibre).


Ahto Anttila designed the Utu in 1961 as his thesis. The prototype, OH-LKX, flew for the first time on 14 August 1964. Between 1965 and 1968 the Oy Fibera Ab built 21 Utus, and two more were built by independent builders in the 1970s. All Fibera-built Utus had the letters LK (Lasikuitu, Fibreglass) in their original Finnish registration codes.

The Utu has a sandwich construction of polyurethane foam (PVC foam in the last two Utus) between two layers of fibreglass. The undesirable features of polyurethane and a flaw in the construction process caused structural problems to many Utus, and they had to be repaired several times. A potentially dangerous flaw in the wings was detected in the early 1980s. Because of this, most Utus were retired relatively soon.

One Utu was sold to USA in 1967. It had to be registered as an experimental aircraft, since the Utu never received a type certification. Its registration code was N1070, and it was de-registered in 2013.

Aircraft on display[]

  • OH-368 and the fuselage of OH-355 are at the Finnish Aviation Museum in Vantaa, Finland.
  • OH-LKF is at the Karhulan Ilmailukerho Aviation Museum in Kotka, Finland.
  • OH-364X was mounted on a pole in Hausjärvi, Finland in 2007.
  • N1070 is at the Southwest Soaring Museum in Moriarty, New Mexico, USA.
  • OY-XCJ is at the Danmarks Flyvemuseum in Skjern, Denmark.


  • Crew: 1
  • Length: 6.5 m (21 ft 4 in)
  • Wingspan: 15.0 m (49 ft 3 in)
  • Wing area: 11.2 m2 (121 sq ft)
  • Aspect ratio: 20:1
  • Airfoil: wing root: NACA 63-618, wing tip: NACA 63-612
  • Empty weight: 187 kg (412 lb)
  • Gross weight: 310 kg (684 lb)
  • Never exceed speed: 249 km/h (155 mph, 135 kn)
  • Maximum glide ratio: 35:1 at 50 mph (80 km/h)
  • Rate of sink: 0.61 m/s (120 ft/min) at 46 mph (74 km/h)
  • Wing loading: 27.6 kg/m2 (5.65 lb/sq ft)