It was the main establishment for aviation engines in recent times, based on the old Walter factory in Prague-Jinonice, known for its piston engines. Lately Walter's name only continues as a brand used by Motorlet.

-In 1952, they began manufacturing the RR Nene in the Russian version RD-45 for the Mig-15 aircraft. It was renamed M-05.

-The Russian AI-25TL engine built under license from A. Ivchenko also changed its name as “Titan”.

“Titan”

-The Titan is a small turbofan with 3,795 lbf of thrust and was used by the Czech L-39 training aircraft.

-Motorlet's best known products have been the M-601, M-602 turboprops and the M-701 turbojet.

-It has a very curious coincidence in general architecture with the P & W-Canada PT-6. The M-601 has been the second turbine built in Czechoslovakia. It had a free turbine and delivered 700 nominal CV to the shaft.

“M-601”

-The M-601A gave 730 CV. The -B gave 691 CV. The -D, 724 CV and the -E, 751 CV.

“M-601B”

“M-601E”

-However, the first gave only 550 CV. Furthermore, the M-601E model, clearly "derated" delivered 483 CV. All M-601s are reverse flow, rear to front.

“M-602”

-Completely different has been the M-602, with a double single-sided centrifugal compressor. It had a reverse-flow annular chamber and three turbines: one for the gas generator and two for power. It had an important gearbox.

-The delivered power is higher, 1,824 CV to the shaft at takeoff. The first of these engines was manufactured in 1994.

“M-701”

-However, a very nice engine has always been the Motorlet M-701, in the style of the early English RR engines.

-It had a single-sided centrifugal compressor and separate and thick combustion chambers. it had a single turbine and delivered 890 Kgf of thrust.

-This engine had a pressure ratio of 4.3: 1 with an air flow of 16.9 Kg/sec. at 15,400 rpm. It weighed 330 Kgs.

-The dimensions were as follows: about 900 mm in diameter by a length of 2,000 mm. It was mounted on the first L-39 "Dolfin" aircraft.

“M-701, cutaway”

From Appendix 9: Between 1946 and 1956 the following piston engines are known.

-The Walter A, (1946) giving 22 CV at 2,500 rpm.
-The Mikron III, (1946) giving 65 CV at 2,600 rpm.
-The Minor III, (1946) giving 105 CV at 2,500 rpm.
-The Minor M-4-IIIS (1946) giving 120 CV. at 2,600 rpm.
-The M-332, (1956) giving 140 CV at 2,700 rpm.
-The Minor M-6-III (1946) giving 160 CV at 2,500 rpm.
-The M-6-IIIS (1947) giving 180 CV at 2,600 rpm.
-The M-208B (1954) giving 220 CV at 3,000 rpm.
-The M-208C (1954) giving 235 CV at 3,300 rpm.

“Ing. Simunka's Mikron III”

“Minor M4-IIIS”

-The letter "S" comes from the "Supercharger". Note that it is mechanical and a duct carries the compressed air to the carburetor and from there to the intake manifold. Therefore it is a "blown" carburetor.

“A Motorlet M-332”

“Minor M-6-III”

From Appendix 12: Originally it was Walter that in 1946 was required as LET and in 1948 it was nationalized as Letecke Zavody.

-In 1949 it passed to the Motorlet group to facilitate marketing. Finally Walter got its name back.

“Motorlet logo”