Akaflieg Berlin B12
| Akaflieg Berlin B12 | |
|---|---|
 |
|
| The B12T rolling for a winch launch | |
| Role | Two place glider aircraft |
| 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. 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 Schemp-Hirth Janus B, shortened to 18.2m (59.71 feet), allowing the students to concentrate their efforts and budget on improving the fuselage.
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.
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.
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 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.
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.
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