The Grob Strato 2C was a German experimental high altitude research aircraft. Powered by two turbocharged

piston engine A reciprocating engine, also often known as a piston engine, is typically a heat engine that uses one or more reciprocating pistons to convert high temperature and high pressure into a rotating motion. This article describes the common featu ...

s and featuring an extremely long span wing of

composite Composite or compositing may refer to: Materials * Composite material, a material that is made from several different substances ** Metal matrix composite, composed of metal and other parts ** Cermet, a composite of ceramic and metallic materials ...

construction, one aircraft was built in the 1990s, but was abandoned despite setting a world altitude record for piston-engined aircraft on its last flight.

Development and design

In April 1992, the

German Aerospace Center The German Aerospace Center (german: Deutsches Zentrum für Luft- und Raumfahrt e.V., abbreviated DLR, literally ''German Center for Air- and Space-flight'') is the national center for aerospace, energy and transportation research of Germany ...

(''Deutsches Zentrum für Luft- und Raumfahrt e.V'' - DLR) commenced a programme to develop an aircraft to carry out

atmospheric An atmosphere () is a layer of gas or layers of gases that envelop a planet, and is held in place by the gravity of the planetary body. A planet retains an atmosphere when the gravity is great and the temperature of the atmosphere is low. A s ...

, stratospheric and

climatic Climate is the long-term weather pattern in an area, typically averaged over 30 years. More rigorously, it is the mean and variability of meteorological variables over a time spanning from months to millions of years. Some of the meteorologic ...

research.Taylor, 1996, p.173. It chose Grob Aerospace to design and build an aircraft to meet these requirements, based both on its experience in use of

composite material A composite material (also called a composition material or shortened to composite, which is the common name) is a material which is produced from two or more constituent materials. These constituent materials have notably dissimilar chemical or ...

in aircraft structures together with its successful development of the Egrett surveillance aircraft, with the aircraft expected to be operational by 1996.Jeziorski ''Flight International'' 31 January - 6 February 1996, p.66. In order to meet the requirement to operate at an altitude of 24,000 m (78,700 ft) for 48 hours,Galleithner 2004, p.552. Grob designed a twin-engined aircraft with a straight, very high aspect ratio wing of 56.5 m (185 ft 4½ in) span.Bents et al. 1998, p.4. The wings featured

winglets Wingtip devices are intended to improve the efficiency of fixed-wing aircraft by reducing drag. Although there are several types of wing tip devices which function in different manners, their intended effect is always to reduce an aircraft' ...

, and were mounted across the top of the

fuselage The fuselage (; from the French ''fuselé'' "spindle-shaped") is an aircraft's main body section. It holds crew, passengers, or cargo. In single-engine aircraft, it will usually contain an engine as well, although in some amphibious aircraft t ...

which terminated in a

T-tail A T-tail is an empennage configuration in which the tailplane is mounted to the top of the fin. The arrangement looks like the capital letter T, hence the name. The T-tail differs from the standard configuration in which the tailplane is ...

configuration. The aircraft was designed to be crewed by two pilots, and could accommodate two scientists and associated mission equipment in a pressurised cabin. A galley, rest facilities and a toilet were provided. Unlike the Egrett, which was powered by a single

turboprop engine A turboprop is a turbine engine that drives an aircraft propeller. A turboprop consists of an intake, reduction gearbox, compressor, combustor, turbine, and a propelling nozzle. Air enters the intake and is compressed by the compressor. Fuel ...

, the Strato was powered by two wing-mounted pusher compound engines consisting of a turbocharged piston engine with the Gas Generator from a PW127 turboprop engine to provide a constant supply of pressurised air to the piston engine at high altitude. This had the advantage of maintaining power at high altitudes. Each engine drove a 6 m (19 ft 8 in) diameter five-bladed propeller. Construction of the airframe moulds started mid-November 1992, with airframe construction beginning in April the following year, starting with the tailplane. The airframe was completed in 1994 and engine installation commenced.

Operational history

The prototype first flew on 31 March 1995.Jeziorski ''Flight International'' 12–18 April 1995, p.16. Costs overran, however, and the prototype, which was intended as a Proof of Concept aircraft with off the shelf equipment and a heavier wing structure than planned for the production aircraft,Taylor, 1999, p.152. was late and did not deliver the expected performance.Jeziorski, ''Flight International'' 31 January - 6 February 1996, p.67. Despite setting a world altitude record for manned piston-engined aircraft of 18,552 m (60,897 ft) on 4 August 1995,Taylor, 1999, p.151. on its 29th and what turned out to be final flight, the programme was cancelled by the DLR in 1996.Jeziorski, ''Flight International'' 10–16 July 1996, p.4.

Specifications (Strato 2C)

References

*Estimated performance.

Bibliography

* Bents David J., Mockler, Ted, Maldonado, Jaime, Harp, James L.Jr., King, Joseph F. and Schmitz. Paul C.
Propulsion System for Very High Altitude Subsonic Unmanned Aircraft
' . NASA/TM—1998-206636. Cleveland, Ohio: NASA Lewis Research Centre, April 1998 *Galleithner, Hans.
High Altitude Research Aircraft as Further Examples of the Application of the Fibre Composite Technology
. ''Aeronautical Research in Germany: From Lilienthal Until Today ''. Ernst-Heinrich Hirschel, Horst Prem, Gero Madelung. New York: Springer-Verlag, 2004. . *Jeziorski, Andrzej.

. ''

Flight International ''Flight International'' is a monthly magazine focused on aerospace. Published in the United Kingdom and founded in 1909 as "A Journal devoted to the Interests, Practice, and Progress of Aerial Locomotion and Transport", it is the world's oldes ...

''. 12–18 April 1995. *Jeziorski, Andrzej.
High and Dry
. ''

''. 31 January - 6 February 1996. pp. 66–67. *Jeziorski, Andrzej.
DLR cancels Strato 2C contract
. ''

''. 10–16 July 1996, p. 4. *Taylor, M.J.H. ''Brassey's World Aircraft & Systems Directory: 1995/1997 Edition''. London: Brassey's, 1996. . *Taylor, M.J.H. ''Brassey's World Aircraft & Systems Directory: 1999/2000 Edition''. London: Brassey's, 1999. .

External links

Homepage of Grob AircraftDLR - Institut für Flugsystemtechnik - History – Road Map of Events: 1992-1994
{{Grob aircraft 1990s German experimental aircraft Grob aircraft Twin-engined pusher aircraft Aircraft first flown in 1995 High-wing aircraft