Adolf Saurer, a vehicle manufacturer, was also involved in building aircraft engines, mainly for those of the SAF, or Swiss Air Force.

-He used licenses from Hispano Suiza. For example, the AG-SLM model engine was an 860 HP HS77.

-Already in 1939 he made the 1000 HP 12Y-51A for the Swiss D-3801 fighters (Morane-Saulnier MS-412).

“Saurer YS”

-The YS were the most prolific.

-They were all derived from the HS-12Z starting with the YS-2 of 1943 for the D-3802 fighter. It gave 1,250/1,300 HP.

-The YS-3 gave 1,500 HP, and the YS-4 delivered 1,600 HP.

-Two more models are now known, the 12Y-51A, like the one shown below, with six Hispano Solex 56 SVG fanned carburetors with automatic height control (AMC) and the 12Y-51B.

“Saurer 12Y-51A”

-Both being of similar power, the A version maintained it up to 3,250 meters altitude and the B up to 3,750 meters.

From Appendix 6: A collaborator has passed us the information that Saurer (Adolph Saurer Ltd) developed a 15 HP APU.

-It was a small turboshaft called GT-15 to supply ventilation and D.C. current to the Hansa HFB-320 aircraft, around the 1960s.

-At the Zurich Museum we can admire the Saurer YS-2 that is mentioned in the main text.

-It is said that it is based on the 12Z.

-Its gearbox is longer at the front than the one on the 12Y. We can see that there are 5 bolts joining the two half parts, while a 12Y has 3 bolts. See arrow in the photo of the YS-2.

“Saurer YS-2”

-This specific model gives 1,250 HP of power.

“The Saurer YS-2, from the other side”

-The upper part of the reduction box is curved instead of straight as in the original Hispano Suiza engines.

-It has a mechanical supercharger, and we can see that the fuel injector and gasoline pump pipes appear above the engine.

"YS-2, side view, photos by JGB”

From Appendix 9: This important factory created by Adolf Saurer Arbon, made aviation engines based on Hispano Suiza, generally on the 12 Y model (Brs and Crs), reaching the YS-2 and YS-3. See main text.

-Possibly they also built the HS-61 or 12Nb and the 12Mb (HS-300).

“HS-12 Ycrs engine plate, Made under License”

“Hispano-Suiza engine 12Mb in Dübendorf”

“Hispano-Suiza 12Y -300-”

“The same engine showing the gun through it”

“Saurer YS-2, in Dübendorf”

-The YS-2 model, more powerful, also has an extension on the propeller shaft, making the gearbox more easily identifiable.

-As stated in the main text, they have curved-shape ribs on the gearbox and five bolts on each side instead of three.

-As a comparison we show a classic 12Y gearbox.

“12Y gearbox”

“Saurer YS-2 from behind”

-In the main text there is a series of engines manufactured under license from Hispano-Suiza.

“View of the factory. Blocks and benches

-Photo received to insert in the Saurer chapter of the main text.

-Adolf Saurer Ltd. made DH jet engines for the Swiss Vampire (see main text) but also other small auxiliary turbines.

“Saurer logo”

-Interestingly, when the author of this A-Z edition was a mechanic's apprentice (when 15 years old) at the Tradisa company in Barcelona, one of the first jobs was to make a Saurer logo from a plate, for one of the trucks. I think it was somewhat irregular.

“The Saurer GT-15, with starter-generator”

“Simple interior of the GT-15”