Hirtenberg HS.9
# Hirtenberg HS.9

The Hirtenberg HS.9 was an Austrian two-seat touring or training aircraft of the early 1930s.

## Design and development

A derivative of the Hopfner HS-5/28 via the Hopfner HS-8/29, the HS.9 was a parasol wing monoplane with a fixed tailskid landing gear and room for two occupants in tandem open cockpits, and first flew as the Hopfner HS-9/32 in 1932, powered by a de Havilland Gipsy I engine. Production versions had Siemens Sh 14 engines with NACA cowlings. A single example of a refined version with an uncowled Siemens engine was flown in 1935 as the Hopfner HS-9/35, shortly before the Hopfner company went bankrupt.

When Hopfner's assets were purchased by Otto Eberhardt Patronenfabrik, production continued of both de Havilland- and Siemens-powered aircraft under the Hirtenberg brand.

## Variants

* HS-9/32 - Original version by Hopfner
* HS-9/35 - developed version of HS-9/32
* HS.9 - Production aircraft with a Siemens Sh 14a piston engine.
   * HS.9A - Production aircraft with a de Havilland Gipsy Major piston engine.
* HS.16 - military trainer version of HS.9

## Operators

### Austria

* Austrian Air Force (1927-1938)

## Specifications (HS.9A)

Data from British Civil Aircraft since 1919 Volume 3.

General characteristics

* Crew: 2
* Length: 8.05 m (26 ft 5 in)
* Wingspan: 10.972 m (36 ft 0 in)
* Empty weight: 568.8 kg (1,254 lb)
* Gross weight: 948 kg (2,090 lb)
* Powerplant: 1 × de Havilland Gipsy Major , 90 kW (120 hp)

Performance

* Maximum speed: 190 km/h (118 mph, 103 kn)
