Bekas series
Role Glider
National origin United States
Designer Witold Kasper
First flight April 1968
Introduction 1968
Status No longer in production
Number built 3
Developed from Brochocki BKB-1

The Kasper Bekas is a family of American mid-wing, tailless gliders designed by Witold Kasper and derived from the earlier 1959 Brochocki BKB-1 design.[1][2]

Design and development

The Bekas series was an attempt by Kasper to create an experimental tailless glider with a higher glide ratio, better ground handling and rigging, using a flexible wing to study the effects of wing flexing on stability and controllability in flight.[1][2]

The Bekas is built from wood and covered in plywood. The wing uses a NACA 8-H-12 airfoil and has greater span and higher aspect ratio than the BKB-1 to achieve its goals. The wing features outboard trailing edge control surfaces that act both as elevator for pitch control and aileron for roll control. The wing is swept 15° and has a chord of 38 in (97 cm). The landing gear is a fixed monowheel.[1][2]

The design resulted in a high glide ratio for a 15 m (49.2 ft) wingspan of 45:1, along with a reasonably low sink rate of 2.0 feet per second.[1][2]

Operational history

The first Bekas, an "N" model, was built by Kasper in 1968. It was destroyed and removed from FAA records in 1977.[3]

Two others were completed. One model 1-A was started by Al Wilson of Seattle, Washington and completed by Clifford Johnson of Minneapolis, Minnesota in 1972, which features a wider chord wing. The final one was completed by Don Mattson of Seattle.[2][4]

Variants

Bekas N
The "N" (for narrow wing) was first flown in April 1968.[2]
Bekas 1-A
Variant with longer wing chord.[1][2]

Specifications (Bekas N)

Data from Sailplane Directory and Soaring[1][2]

General characteristics

  • Crew: one
  • Length: 12 ft 0 in (3.66 m)
  • Wingspan: 49 ft 3 in (15 m)
  • Wing area: 158 sq ft (14.7 m2)
  • Aspect ratio: 15.3
  • Airfoil: NACA 8-H-12
  • Empty weight: 350 lb (159 kg)
  • Gross weight: 550 lb (249 kg)

Performance

  • Maximum glide ratio: 45:1 at 66.5 mph (107 km/h)
  • Rate of sink: 120 ft/min (0.61 m/s) at 50 mph (80 km/h)
  • Wing loading: 3.48 lb/sq ft (17.0 kg/m2)

See also

References

  1. 1 2 3 4 5 6 Activate Media (2006). "Bekas 1-A Kasper". Archived from the original on August 19, 2012. Retrieved April 26, 2011.
  2. 1 2 3 4 5 6 7 8 Said, Bob: 1983 Sailplane Directory, Soaring Magazine, page 36. Soaring Society of America November 1983. USPS 499-920
  3. ↑ Federal Aviation Administration (April 2011). "Make / Model Inquiry Results". Retrieved April 26, 2011.
  4. ↑ Federal Aviation Administration (April 2011). "Make / Model Inquiry Results". Retrieved April 26, 2011.
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