Swedish license production of the DB 605 B inverted V12 piston engine

[blockhaj]

I thought we should have a thread dedicated to this.

Short story: The Swedish Air Force needed a modern inline engine for the SAAB 21 fighter aircraft and other future projects. Due to WWII and the allied embargo on Sweden, they went to Germany for stuff like the DB 601 or Jumo 211. Some effort was made to make a pirate copy of the DB 605B in August 1941 but it took time and after much trouble, Sweden eventually got a license for the DB 605B and even allowed to buy German production examples. The German engines were made for war time and thus were unreliable and broke down after a couple houndred hours. For Swedish production, several thousand changes had to be made to make the engine reliable for peace time. A total of 800 engines were produced in Sweden (SFA: Svenska Flygmotor AB + Muntell) until 1948 with the number series 2001 - 2800. Due to the quality difference, Swedish engines were prioritized for the single-engined SAAB 21. Once more engines became available, the twin-engined SAAB 18B was required to have at least one Swedish engine installed for safety reasons. The first DB605B engine came for overhaul to CVA in May 1946. The last DB605B engine was delivered in June 1955 (no clue how that happened with production wrapping up in 1948). Post-war, Swedish DB 605 engines were sought after to keep surviving Bf 109s airworthy, some even being installed in Spanish Ha-1112's to make immitation 109s.

Basic data i had in a document, no clue how accurate it is:
Engine type: supercharged, inverted V12, four-stroke , liquid-cooled inline engine
Power: 1475 hp at 2800 rpm
Length: 2305 mm
Height: 1050 mm
Width: 762 mm
Cylinder diameter: 154 mm
Stroke: 160 mm
Engine displacement: 2,99 liter per cylinder
Total cylinder volyme: 35,7 liter
Cruising speed fuel consumption: 320 liter/h at 2300 rpm
Propeller direction (pusher config): right to left
Propeller gear ratio: 8:15
Compression ratio: 7,5:1
Weight: 720 kg

 

[blockhaj]

Muntell, if my memory serves me right, made a modification in like 1947 for 1700 hp. This hp is confirmed in SAF documents from around 1948 (not sharing the entire document). A T 18B pilot said that they used 147 octane fuel in the engines in 1953.

 

[airsky]

Muntell, if my memory serves me right, made a modification in like 1947 for 1700 hp. This hp is confirmed in SAF documents from around 1948 (not sharing the entire document). A T 18B pilot said that they used 147 octane fuel in the engines in 1953.

Really interesting, can i please have a source for the T18B pilot saying they use 147 octane fuel?

 

[F119Doctor]

Would this be the same fuel as the 115/150 PN fuel introduced by the US near the end of WW2? It would likely be readily available in the early 1950s with the large population of high power piston engines at that time.

 

[Apophenia]

Would this be the same fuel as the 115/150 PN fuel introduced by the US near the end of WW2? It would likely be readily available in the early 1950s with the large population of high power piston engines at that time.

Probably, AB Bolinder-Munktell was one of the Swedish engine-maker so those 1947/48 experiments were likely about establishing just how much power could be safely added to an aero-engine designed around 87 octane fuel.

 

[blockhaj]

Really interesting, can i please have a source for the T18B pilot saying they use 147 octane fuel?

https://www.f8kamratforening.nu/bredakrabladet nr 2 2016.pdf
"Lukten av kall aluminium, hydraulolja, motorolja, läder och 147-oktanig flygbensin var som parfym för en 18-års kille som bestämt sig för att bli flygare redan i koltåldern."

"The smell of cold aluminium, hydraulic oil, motor oil, leather, and 147-octane aviation fuel, was like parfyme for an 18 year old lad who had decided to become a flyer already in the school years."

 

[blockhaj]

Would this be the same fuel as the 115/150 PN fuel introduced by the US near the end of WW2? It would likely be readily available in the early 1950s with the large population of high power piston engines at that time.

147 octane is a rare number ive only ever heard in this Swedish case. Conventional historical numbers around thw world are otherwise 87, 95, 100 and 150 octane. Im guessing 147 refers to the same style of fuel as 150 octane, but specified for some reason, or maybe it is a unique Swedish production.

 

[blockhaj]

Probably, AB Bolinder-Munktell was one of the Swedish engine-maker so those 1947/48 experiments were likely about establishing just how much power could be safely added to an aero-engine designed around 87 octane fuel.

Ye. Unfortunately my research has gotten cold since long ago. They moved the archive further away from where i live (not a big deal), i had to focus on life (still), so i havent looked into the archive for more fuel information yet.

 

[arc3371]

Do you have any information on how much the Swedish DB 605 did cost?