The Brochocki BKB-1 was a Canadian

mid-wing A monoplane is a fixed-wing aircraft configuration with a single mainplane, in contrast to a biplane or other types of multiplanes, which have multiple planes. A monoplane has inherently the highest efficiency and lowest drag of any wing con ...

, single-seat,

experimental An experiment is a procedure carried out to support or refute a hypothesis, or determine the efficacy or likelihood of something previously untried. Experiments provide insight into cause-and-effect by demonstrating what outcome occurs when a ...

tailless

glider Glider may refer to: Aircraft and transport Aircraft * Glider (aircraft), heavier-than-air aircraft primarily intended for unpowered flight ** Glider (sailplane), a rigid-winged glider aircraft with an undercarriage, used in the sport of glidin ...

that was designed and constructed by Stefan Brochocki with assistance from Witold Kasper and A. Bodek. The designation indicated the contributions of all three men. The aircraft was intended to study flight above the

stall angle In fluid dynamics, a stall is a reduction in the lift coefficient generated by a foil (fluid mechanics), foil as angle of attack increases.Crane, Dale: ''Dictionary of Aeronautical Terms, third edition'', p. 486. Aviation Supplies & Academics, 199 ...

.Rogers, Bennett: ''1974 Sailplane Directory, Soaring Magazine'', page 94. Soaring Society of America, August 1974. USPS 499-920

Design and development

The BKB-1 was constructed in 1959 and built entirely from wood. The wing was swept, had a 9.5:1 aspect ratio and employed a

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8-H-12 airfoil. The aircraft had a very high wing area of which resulted in a light wing loading of just 3.81 lb/sq ft (18.6 kg/m²). The prototype BKB-1 was originally registered in Canada as CF-ZDK-X. Later it was moved to the

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, owned by Kasper and registered as N2991G. As a

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the aircraft went through several modification states. The modifications included aerodynamic devices to improve aircraft control above the stalling angle. These reduced the

stall speed In fluid dynamics, a stall is a reduction in the lift coefficient generated by a foil as angle of attack increases.Crane, Dale: ''Dictionary of Aeronautical Terms, third edition'', p. 486. Aviation Supplies & Academics, 1997. This occurs when t ...

to and resulted in a 200 ft/min (1.0 m/s) rate of descent while stalled. This allowed stalled landings with no ground roll. As a result of these and other design changes the aircraft was designated as the BKB-1A, the "A" indicating

aerobatics Aerobatics is the practice of flying maneuvers involving aircraft attitudes that are not used in conventional passenger-carrying flights. The term is a portmanteau of "aerial" and "acrobatics". Aerobatics are performed in aeroplanes and glide ...

. The aircraft was intended to be fully aerobatic, including tumbling maneuvers. Kasper had a plan to produce the aircraft and the developmental derivative Kasper Bekas, which mount different wings to a common fuselage, as a single kit, with the choice of wings, but it seems none was actually produced.

Operational history

The sole BKB-1A was destroyed on 6 November 1971 near

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, when a pilot conducted unauthorized aerobatics in the aircraft, subjecting it to an estimated negative 30 g during a high-speed inverted descent. The 31-year-old commercial pilot, who had a total of 3000 flying hours and five hours on type, was wearing a parachute, but did not bail out and was killed in the accident. The National Transportation Safety Board cited as cause factors that the pilot misjudged the aircraft's speed and overstressed the airframe to failure.

Variants

;BKB-1 :Early configuration of the aircraft ;BKB-1A :Later configuration of the same aircraft with modifications for parachute flight above the stalling angle and also aerobatics.

Specifications (BKB-1)

Notes

References