Akaflieg Munich Mü 27

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Akaflieg Munich Mü 27
The Mü 27
Type: Glider
Design country:

Germany Federal RepublicFederal Republic of Germany BR Germany

Manufacturer:

Akaflieg Munich

First flight:

1979

Number of pieces:

1

The Akaflieg Munich Mü 27 is a glider of the student flight group Akaflieg Munich , in which the so-called Wortmann flap  - a wing geometry that can be changed in flight - was tested. With a maximum takeoff weight of 900 kg, the aircraft is considered to be the heaviest glider in the world and is now in the Schleissheim aircraft yard , a branch of the Deutsches Museum in Munich .

history

One of the problems for high-performance gliders is that two different wing profiles are required for climbing in thermals and for high-speed flight between two updraft areas: on the one hand, for slow circling in thermals, a wing with a large wing area and large curvature and, on the other hand, for For high-speed flight, a thin wing with little drag. In the 1970s, several Akaflieg groups were working on aircraft with variable wing geometry to solve this problem. While Akaflieg Stuttgart was working on a project with a variable span with the fs 29, students from Braunschweig with the SB 11 and Akaflieg Munich took the path of adapting the wing area by changing the wing depth.

Since it was the first fiber composite aircraft built by the Munich students and the two-seater had a wingspan of 22 meters and four-part wings, the complex project dragged on through the entire decade. The successful first flight could be carried out on January 24, 1979, which was followed by many modifications to improve the glider's flight characteristics.

The prototype turned out to be only partially suitable for daily flight operations and competitions, as both the setup and dismantling as well as the maintenance were significantly more difficult than with normal aircraft. In 2009, Akaflieg Munich decided to make the aircraft available to the Deutsches Museum .

construction

A gapless Wortmann flap was installed along the entire length of the wing, which can be fully retracted or extended by an electric motor within ten seconds. This changes the wing area by 36 percent and at the same time increases the curvature of the profile. In order to implement this system, it was necessary to construct a riveted box spar made of aluminum that absorbs all bending and torsion moments of the wing. This must make the wing sufficiently rigid to prevent the flap mechanism from tilting due to excessive flexing of the surfaces. Another problem that arises from the complex flap mechanism is the ailerons, which, due to the design, have to be integrated into the Wortmann flap.

The changes that resulted after the first flight tests included the replacement of the previously steerable tail wheel with a rigid one and the enlargement of the braking parachute, which is used for landing. Very high rudder forces were also found during the first flight, which could be significantly reduced by constructive measures at the control.

Technical specifications

Parameter Data Flaps extended
crew 1
Passengers 1
length 10.3 m
span 22 m
height
Wing area 17.6 m² 23.9 m²
Wing extension 27.5 20.2
Glide ratio 47
Slightest sinking 0.65 m / s at 108 km / h 0.66 m / s at 77 km / h
Empty mass 712 kg
Max. Takeoff mass 900 kg
Top speed 230 km / h 149 km / h

See also

literature

  • Charles Gray, Jane's Information Group , Leonard Bridgman, Leonard Howard-Flanders: Jane's All the World's Aircraft . S. Low, Marston & Company, Ltd., 1980.
  • Renate Linke-Haas, Matthias Gogl, Matthias Weinzierl, Johannes Achleitner, Hannes Röpling: 85 years of Akaflieg Munich eV - anniversary publication for the 85th anniversary . Munich 2009.

Web links

Commons : Akaflieg München Mü27  - Collection of images, videos and audio files

Individual evidence

  1. ↑ fs 29 on the Akaflieg Stuttgart website , accessed on October 13, 2015
  2. ↑ The Mü 27 on the website of Flugwerft Schleißheim , accessed on June 18, 2012
  3. ↑ a b c The Mü 27 on the Akaflieg Munich website , accessed on June 18, 2012