The Polikarpov PM-1 was a passenger aircraft created by

Polikarpov Polikarpov Design Bureau was a Soviet OKB (design bureau) for aircraft, led by Nikolai Nikolaevich Polikarpov. Dux Factory was acquired by the USSR and became part of Polikarpov. After the death of Polikarpov on 30 July 1944 at the age of ...

in the 1920s.

Design and development

The PM-1 (PM - ''Passazhirskii Maybach'' – passenger transport Maybach engine) was a wooden biplane with a monocoque fuselage built up from glued ply veneer sheets (known as ''Sphon''), including the integral tail-fin. The two-spar wings were skinned in plywood forward of the main spars and covered in fabric aft of the main-spars. All control surfaces were built in a similar fashion with ply-skinned structural members and built-up wooden structure covered in fabric. Large I-type inter-plane struts, canted at about 30°, and steel cables braced the wings, which were attached to the fuselage at the top and bottom of the main fuselage frames. The undercarriage consisted of 2 main-wheels on a live axle supported by V-stuts with bungee springing. The Maybach Mb.IVa engine was mounted conventionally in the nose and had a retractable radiator forward of the undercarriage.

Operational history

First flown on 10 June 1925 the PM-1 flew a public demonstration flight on 26 July 1925 and started a scheduled

Moscow Moscow ( , US chiefly ; rus, links=no, Москва, r=Moskva, p=mɐskˈva, a=Москва.ogg) is the capital and largest city of Russia. The city stands on the Moskva River in Central Russia, with a population estimated at 13.0 million ...

Berlin Berlin is Capital of Germany, the capital and largest city of Germany, both by area and List of cities in Germany by population, by population. Its more than 3.85 million inhabitants make it the European Union's List of cities in the European U ...

service in August 1925. On one of the early flights the aircraft crashed due to engine failure, or engine bearer failure, and was not repaired as the Maybach engine was considered obsolete and the new

Kalinin Kalinin may refer to: * Mikhail Kalinin (1875–1946), Bolshevik revolutionary and Soviet functionary * Kalinin (surname) Places *Kalinin, former name of Noramarg, Armenia *Kalinin, former name of Tashir, Armenia *Kalinin, former name of Burunqo ...

monoplanes promised better performance.

Specifications

References

{{Soviet transport designations 1920s Soviet and Russian civil aircraft PM-1 Single-engined tractor aircraft High-wing aircraft Aircraft first flown in 1925