EFW was a Swiss engine factory that made engines under license and from own design. As they also built aircraft cells, this company was remarkably independent.

-For the EFW N-20 aircraft, it manufactured the "AS Mamba" renamed "Swiss Mamba" and with reference SM-01.

-The turbofan SM-05 gave 1,500 Kgs of thrust. We are waiting for more documentation.

From Appendix 6: During a visit to the Transport Museum in Luzern in 2008, the "Swiss-Mamba" was found, which was developed from the English AS Mamba, but instead of being a turboprop, a Fan was adapted.

-It was the first double-flow reactor that was made at the EFW workshops (also known as F + W).

-Situated in Emmen near Luzern, (Lucerne).

-Due to the Swiss characteristic of having three official languages, it was known as "Fabrique Fedérale d'Avions", as "Fabbrica Federale d'Aeroplani" and in the local language -Emmen-, in German "Eidgenössisches FlugzeugWerk".

"Swiss-Mamba for the N-20"

-Destined to the Swiss N-20 "Aiguillón" aircraft, of the flying wing type.

"One of the two fan outlets"

-As we can see, the engine accessories are not upon or under the engine but on both sides, due to the aircraft design.

"Side outlet and combustion chambers"

"Exhaust nozzle with afterburner"

-It was calculated to deliver 1,700 Kgs of thrust with additional combustion in the exhaust (Afterburner).

-The development of this project was canceled in 1952. As well as those of the engines SM-03, SM-04 and SM-05, in favor of buying foreign material from the East and the West, considering the Czech Mig-15, the Saab J-29 or the French Mystere IV.

-Finally the main acquisition was 100 English Hunters in 1958.

-The SM-01 that was bound for the Swiss indigenous N-20 Aiguillón fighter plane built by EFW itself, had four of these engines. Taking advantage of the excess air of the compressor to create a post-combustion in the nozzle and the cold air of the fan for a high-lift and reverse as directed by different channels.

"Swiss-Mamba SM-01"

-The SM-03 was an improved SM-01 but insufficient. It had a compressor designed by Brown-Boveri & Cie.

-The next version in this project was the SM-04 and like the previous one, the LP compressor had gear. The LP compressor provided both primary and secondary air at the same time.

-The SM-05 had the characteristic of having two shafts or contra-rotating turbines: the HP had one stage and the LP had two stages.

"Swiss-Mamba SM-05"

-There was still an SM-06, similar to the SM-04, for which we have no details at the moment.

-We located another SM-01 at the Zurich Museum, interesting turbofan based on the English turboprop Mamba.

"Swiss-Mamba SM-01"