Pilatus B-4

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B4-PC11
Pilatus B4-PC11 AF D-3993.jpg
Role Club-class sailplane
National origin Switzerland
Manufacturer Pilatus
Designer Manfred Herbst and Rudolf Kueppers
First flight 7 November 1966
Number built 322

The Pilatus B4-PC11 (also known as the PC-11 in the Pilatus numbering sequence) is an all-metal intermediate sailplane built by Pilatus Aircraft of Switzerland.

The B4-PC11 is designed to Standard Class specifications, which means that it has a 15 metre wingspan and no flaps. Air brakes are provided on the top surface of each wing for glidepath control. Construction is aluminium, with foam ribs in the mainplane, fin and tailplane.

Development[edit]

The design of this glider originated in the 1960s, when the company Firma Rheintalwerke G. Basten (from which the "B" in the original designation is derived) manufactured the first two prototypes. The designers were Manfred Herbst and Rudolf Kueppers. The first flight of the first prototype took place on 7 November 1966. However, no series production was started.

In 1972 Pilatus bought the manufacturing licence for the B-4 and renamed it the B4-PC11. In the spring of the same year the first production example (numbered HB-1100) undertook its first flight.

A total of 322 B4-PC11s of all versions were built by Pilatus by 1980, when the license to manufacture the craft was sold to Nippi Aircraft of Japan, who only built 13 examples, plus a two-seater designated the Nippi B4T.[1]

Subsequently, in 1994, EWMS Technomanagement bought the rights to produce and service the B4-PC11. This company also specializes in renovating and upgrading older B4-PC11 craft. In addition, it manufactures a motorized B4-PC11.

Variants[edit]

While the original B4-PC11 was permitted to fly a number of aerobatic maneuvers, it was not permitted to do inverted loops or flick/snap/quick maneuvers. Consequently, the B4-PC11A was developed, which was permitted to perform inverted loops and was also able to handle higher g-forces. In 1975 the B4-PC11AF version was released, which had full aerobatic capabilities. The B4-PC11 was available with either fixed or retractable landing gear.

The changes in construction from B4-PC11 through A and AF variants were to add extra ribs through the fuselage section (increasing torsional rigidity), and to modify the control column stops and shorten the rudder giving greater control surface deflection.

Specifications[edit]

General characteristics

  • Crew: One pilot
  • Length: 6.57 m (21 ft 8 in)
  • Wingspan: 15.00 m (49 ft 3 in)
  • Height: 1.57 m (4 ft 2 in)
  • Wing area: 14.0 m2 (151 ft2)
  • Aspect ratio: 16
  • Empty weight: ca. 230 kg (508 lb)
  • Gross weight: 350 kg (770 lb)

Performance

  • Maximum speed: 240 km/h (150 mph)
  • Maximum glide ratio: ca. 35 according to Pilatus. Measurements performed by Idaflieg suggest 30.
  • Rate of sink: 0.63 m/s (126 ft/min)

Airfoil used for main wings NACA 64(3)-618.
Wing twist on main wings None(unofficial).
Airfoil used for horizontal tailplane NACA 0009(unofficial).
Max g-load
PC-11: +5,3g/-3g.
PC-11A: +6,5g/-4g.
PC-11AF: +7g/-5g.

See also[edit]

Aircraft of comparable role, configuration and era
Related lists

References[edit]

  1. ^ http://www.nippi.co.jp/history/history1980.html B4T in History of Nippi company (in Japanese:Click PHOTO icon after word B4T to see the photo)
  • Hardy, M. Gliders & Sailplanes of the World. Ian Allan, 1982