Akaflieg Berlin B12

Akaflieg Berlin B12
Type:	Glider
Design country:	BR Germany
Manufacturer:	Akaflieg Berlin
First flight:	July 27, 1977 ; August 11, 1987 with T-tail
Number of pieces:	1

The B12 is a two-seater glider of the Academic Aviation Group of the Technical University of Berlin with a wingspan of 18.20 meters and flaps . The first flight with a cross tail took place on July 27, 1977, another after conversion to a T-tail on August 11, 1987. The glider index is 106, the aircraft registration D-7612 and the competition registration CB .

History and construction

Originally, a tubular steel frame construction with exchangeable GRP hull boat shells to investigate the aerodynamic effects of the outer contour and a self-developed wing with a span of 22 meters were planned for the two-seater project.

The design finally built in the early 1970s aimed to minimize the air resistance of the fuselage. The shape of the fuselage was derived from a streamlined rotating body developed at the Institute for Aircraft Construction at the TU Berlin, with its longitudinal axis bent and a double-elliptical cross-section selected. The fuselage is strongly constricted in the area of the wings. In order to limit the effort of the student project, the wings of the Schempp-Hirth Janus , which is being developed at the same time, were used slightly adapted. The fuselage is formed by a load-bearing GRP shell in positive construction with a large one-piece acrylic glass hood. The GRP chassis swing arm, initially moved by an electric motor, has a very large swivel range. The extended wheel is in front of the aircraft's center of gravity so that there is no need for a nose wheel.

B12 with cross tail

The aircraft flew for the first time on July 27, 1977 in Ehlershausen with a cross tail in GRP full sandwich construction. Its horizontal stabilizer had a very thin NACA profile and spar webs made of carbon fibers , the 1.80 meter high vertical stabilizer had the specially designed Wortmann FX 71-L-150/30 for the profile. In August 1978, was at the summer meeting Idaflieg on the airfield Aalen-Elchingen the flight performance of the aircraft flight compared with the reference plane of the DLR , a Schempp-Hirth Cirrus B determined.

After a traffic accident in the summer of 1986, in which this tail unit was destroyed, the aircraft was fitted with a new vertical tail made from the shapes of the B13 that was just being built and the damped horizontal tail was mounted with the contour of the glass wing 604 upwards. The renewed flight test began on August 11, 1987 at the summer meeting of the interest group of German academic flying groups (Idaflieg) in Elchingen . There was also another performance measurement - this time in comparison to the DG-300/17 of the DLR.

During an outland landing on the first valuation day of the prototype comparison flight of the Idaflieg 2012 in Kammermark , the aircraft was significantly damaged, so that it had to be extensively repaired with a new tail unit and landing gear.

B12 with T-tail (from 1987)

Technical specifications

Parameter	B12 with T-tail
crew	1 + 1 ( double tax )
length	8.67 m
span	18.20 m
height
Wing area	16.58 m²
Wing extension	19.97
Wing profile	FX 67-K-170 inside FX 67-K-150 outside
Payload
Empty mass	438 kg
Max. Takeoff mass	620 kg
Glide ratio	40.5 at 110 km / h
Slightest sinking	0.68 m / s at 90 km / h
Top speed

Trivia

The construction of the aircraft was delayed by a construction freeze imposed by the British command , since according to occupation law no gliders were allowed to be built in Berlin.

Comparable types

Schempp-Hirth Janus B.

Web links

Commons : Akaflieg Berlin B12 - Collection of images, videos and audio files

B12 in the J2mcL Planeurs glider database

Individual evidence

↑ ^a ^b ^c ^d Berlin B12 . In: Flugrevue + Flugwelt . 10year = 1976, p. 70 .
↑ ^a ^b Ralf Schneider: 75 years of idaflieg . Ed .: Idaflieg . 1st edition. M. Wehle, Witterschlick / Bonn 1997, ISBN 3-89573-045-9 , p. 201 .
↑ ^a ^b Carsten Karge: crash landing of the B12 . In: Akademische Fliegergruppe (Ed.): Annual Report 2013/2014 . Berlin 2015, DNB 013347667 , p. 27-31 .
^ Dietmar Geistmann: Gliders in Germany . 2nd Edition. Motorbuch Verlag, Stuttgart 1994, ISBN 3-613-01449-1 , p. 18th ff .

[Flugrevue1976-1] Berlin B12 . In: Flugrevue + Flugwelt . 10year = 1976, p. 70 .

[Schneider1997-2] Ralf Schneider: 75 years of idaflieg . Ed .: Idaflieg . 1st edition. M. Wehle, Witterschlick / Bonn 1997, ISBN 3-89573-045-9 , p. 201 .

[Karge2015-3] Carsten Karge: crash landing of the B12 . In: Akademische Fliegergruppe (Ed.): Annual Report 2013/2014 . Berlin 2015, DNB 013347667 , p. 27-31 .

[4] Dietmar Geistmann: Gliders in Germany . 2nd Edition. Motorbuch Verlag, Stuttgart 1994, ISBN 3-613-01449-1 , p. 18th ff .