| Akaflieg Berlin B12 | |
|---|---|
 | |
| The B12T rolling for a winch launch | |
| Role | Two place glider aircraft [1] |
| National origin | Germany |
| Manufacturer | Akaflieg Berlin |
| First flight | B12:27 July 1977; B12T:11 August 1987 |
| Primary user | Akaflieg Berlin |
| Number built | 1 |
The Akaflieg Berlin B12 is a high performance two-place glider aircraft that was designed and built in Germany. [1] Conceived as a research vehicle, only one unit was constructed.
The students at Akaflieg Berlin set out to improve the performance of modern gliders by reducing drag. To improve a modern glider's performance through modifying the aerofoil sections is time-consuming and very costly, so to reduce costs the group utilised production wings from a Schempp-Hirth Janus B, shortened to 18.2m (59.71 feet), allowing the students to concentrate their efforts and budget on improving the fuselage. [1]
The shape and profiles of the new fuselage were developed at the Institut für Luftfahrzeugbau (Institute for aircraft industry) and a new two-seat fuselage was constructed using contemporary GFRP (Glass-fibre Re-inforced Plastic) techniques in a monocoque shell. [1]
Built principally from GFRP the B12 uses monocoque construction, avoiding the use of a welded steel-tube core structure, maximising the volume available for crew accommodation and payloads such as research instrumentation. The cockpit seats two in tandem under large plexiglas canopies with the instructor seat, in the rear, set at a higher level to improve his forward view. [1]
The wings are standard 'Janus B' items built using identical construction methods. The empennage originally utilised a cruciform tail using an NACA 0009-64 aerofoil section [2] formed with ' Rohacell'/GFRP sandwich supported by CFRP (Carbon-Fibre Re-inforced Plastic) spars. After a trailer accident during road transport in 1986, which destroyed the rear fuselage and tail-unit, a T-tail was fitted during repairs. A thicker aerofoil section was used for the vertical tail of this revised unit, a specially developed Wortmann FX-71 L 150/30 profile. [3]
The single retractable main undercarriage wheel is supported on a tall leg assembly which was originally built with electric actuation, but after a field landing with a flat battery caused a wheels-up landing a manual system was fitted. A rubber tail skid, capped with hardened steel, under the rear fuselage completes the undercarriage. In the original fuselage a braking parachute, used for approach control, was housed at the extreme rear, but this feature was not carried through to the replacement tailcone during its rebuild. [1]
After the first flight of the B12 on 27 July 1977, piloted by Jürgen Ehlers Thorbeck, the B12 was used for research, cross country and competition flying until a trailer accident in 1986, whilst being transported by road, destroyed the tail section and twisted the rear fuselage. Repairs were carried out and the B12 was flying again on 1 August 1987 at the IDAFLIEG ( Interessengemeinschaft deutscher akademischer Fliegergruppen e.V. - interest group for academic flying groups) summer camp at Aalen-Elchingen, sporting a T-tail identical to that of the Akaflieg Berlin B13. The B12 continues to fly but rarely emerges from the hangar unless the soaring weather is good. [1]
Flying the B12 requires a certain amount of care, due to:
Once the quirks and foibles of the B12 are understood it is possible to compete effectively with other contemporary two-seaters. However the expected performance gains were only partly realised and the B12 does not rank with the highest performance gliders, as was hoped. One quirk is the B12 'sigh' which can be heard in certain flight conditions, the origin of which remains a mystery. Competition flying is carried out with the call-sign CB and a handicap index of 106 is applied. The aircraft carries registration 'D-7612'. [1]
Data from Jane's All the World's Aircraft 1988-89 [4] [5]
General characteristics
Performance
General characteristics
Performance
Related development
Aircraft of comparable role, configuration, and era
The Rolladen-Schneider LS1 is a Standard Class single-seat glider manufactured in Germany by Rolladen-Schneider from 1968 to 1977.
The Schempp-Hirth Nimbus-2 is an Open Class glider built by Schempp-Hirth during the 1970s. The Nimbus-2 first flew in April 1971 and a total of over 240 examples of all subtypes have been built until the beginning of the 1980s. It replaced the Schempp-Hirth Cirrus.
The Akaflieg Stuttgart fs24, nicknamed Phönix, was a glider designed and built in West Germany from 1951.
The VSO 10 Vosa is a Standard and Club-Class glider designed and manufactured in the Czechoslovak Republic from December 1978 as a replacement for the VT-116 Orlik II.
The ICA IS-28 is a two-seat sailplane produced in Romania in the 1970s. An all-metal aircraft of conventional design with a T-tail, it was originally produced with 15-metre wings, but in 1973, production shifted to the IS-28B with 17-metre wings and numerous aerodynamic refinements. These included a smaller tail with decreased dihedral, decreased dihedral on the wings, and redesigned fuselage contours. This version first flew on 26 April 1973 and was subsequently produced in versions with flaps (IS-28B2) and without (IS-28B1). Around 100 had been built by the early 1980s, with a substantial number sold for export. On April 7, 1979, Tom Knauff and R. Tawse set a world record with the IS-28 B2 glider, covering a distance of 829 kilometres on a predetermined out-and-return course from the Ridge Soaring Gliderport in Julian, Pennsylvania.
The ICA IS-32 is an open class high-performance metal two-seat sailplane produced in Romania in the 1970s. A refinement of the IS-28B, it shared most of that aircraft's fuselage, mated to new wings and empennage. This new wing had a span of 20 metres, featuring interconnected ailerons and flaps, Schempp-Hirth-type airbrakes. It had no provision for water ballast. The monowheel undercarriage differed from the IS-28 in being fully retractable.
The Mü-27 is a research glider aircraft that designed and built in Germany in 1979. Only one example was constructed.
The Torva 15 was a single-seat glider designed and built in United Kingdom from 1970.
The Akaflieg München Mü28 is a research glider aircraft that was designed and built in Germany in 1983. Only one example of the design was built.
The Akaflieg München Mü10 Milan is a two-seat glider aircraft that was designed in Germany in 1934. Only one copy of the design was built.
The Akaflieg München Mü15 was a two-seat glider designed and built in Germany in the late 1930s, loosely based on the Mü10. A longer span version, the Akaflieg München Mü20 was still in the design stages when further work was abandoned.
The Akaflieg Berlin B13 is a two-seat motor-glider designed and built in Germany.
Akaflieg Darmstadt is one of approximately twenty aviation groups attached to German universities. Akaflieg is an abbreviation for Akademische Fliegergruppe, an academic group of students and faculty from a German University.
The Akaflieg Darmstadt D-40 is an experimental variable geometry single seat sailplane, fitted with almost full span, camber changing flaps for optimum aerodynamics in weak thermals and integrated into the wing so as to minimise flap tip drag. One flew successfully but the D-40, like other variable geometry sailplanes, was not commercialised.
The Akaflieg Braunschweig SB-11 is an experimental, single seat, variable geometry sailplane designed by aeronautical students in Germany. It won the 15 m span class at the World Gliding Championships of 1978 but its advances over the best, more conventional, opposition were not sufficient to lead to widespread imitation.
The Akaflieg Darmstadt D-39 was a single-seat motor glider derived from the D-38 sailplane. Built in Germany in the late 1970s, it was not intended for production and only one was constructed.
The Akaflieg Braunschweig SB-7 Nimbus is a Standard class glider designed and built in Germany in the 1960s. It was one of a series of mixed glass fibre and wood designs from the students of Akaflieg Braunschweig.
The Akaflieg Braunschweig SB-8 is an experimental, single-seat, high performance glider built in Germany in the 1960s, constructed largely from glass fibre skin over built up balsa wood structure. Two were built; the second of which was later fitted with a high aspect ratio (30:1) wing, becoming the Akaflieg Braunschweig SB-9 Stratus.
The Nippi NP-100 Albatross was a Japanese two side-by-side seat motorized glider, powered by a ducted fan rather than the usual propeller. It did not go into production.
The Schleicher K 10 is a Standard class competition glider, designed by Rudolf Kaiser and built in Germany in 1963. Only a few were produced.