Fischer and Jacobs began their work in Philadelphia in 1927 immediately moving to Camden, NJ., as Aircraft Engine Corp. Later it became known as Jacobs in Pottstown, Pennsylvania. At the end of WWII it became a Division of the Republic Ind. Inc. (Republic Aircraft).

-The first engine that was built seems to be the one with two horizontally opposed cylinders known as B-1, a 2-stroke, air-cooled engine with single ignition. It gave 20 hp at 2,500 rpm and 25 hp at 3,000 rpm. It was built around 1929-1930.

-Below we show a picture of the B-1 engine that is mentioned in the text.

“Jacobs B-1, rear view”

-This small engine works with the two-stroke cycle.

“Jacobs B-1, front view”

-After that, Jacobs focused on radial engines. In fact, they were the best known of the brand.

-It seems that the first radial one was the LA-1, a seven-cylinder air-cooled engine from 1929 that gave 140 hp.

“Jacobs LA-1”

-In 1930 the L-3 three-cylinder radial appears. It gave 55 hp and obtained the ATC-75 Type Certificate.

“Jacobs L-3”

-In 1931, the LA-1 already delivered 170 hp and obtained the ATC-31.

-The 1933 L-4 engine (ATC-121) had two categories, the 589 cu. in. with 225 hp.

-And the one with 757 cu.in. which gave 245 hp with 7 air-cooled radial cylinders.

-The latter was officially known as R-755. (The R-755E with 275 hp, and the R-755S with 350 hp).

“Jacobs L-4 (R-755)”

-The R-755 was one of the successes of the brand, built in its version A, B, S, etc. like Jacobs-Page.

-There were other versions of the basic L-4, such as the L-4MA that gave 225 hp at 2,000 rpm and varied with the L-4MB increasing its power to 245 hp, just like the L-4MP. it was achieved at 2,200 rpm. (On a Cessna T-50).

-The L-5 is from 1935, with 285 hp displacing 831 cu in and with 7 air-cooled radial cylinders.

-The L-5 was made in several versions such as the one shown, which is an L-5MB.

-The L-6 was officially the R-915 engine, the brand's success engine.

-It obtained the Type Certificate with the number 195.

-It had a total displacement of 914 cu in with 7 radial cylinders.

“Jacobs L-5MB”

-The power was between 300 and 330 hp depending on the version.

-Like the L6M, -MB, -MBA, ... (Seen on the Beech 18).

“Jacobs L-6MB”

-After the WW2 Jacobs entered the general aviation market making four-stroke engines with horizontally-opposed cylinders.

- Between 1946 and 1947 they made the O-200A that gave 85 hp at 2,350 rpm. It was air-cooled, and had four horizontally opposed cylinders.

-The O-240A was also cooled by air and had 4 horizontally opposed cylinders giving a power of 100 hp at 2,300 rpm. It was manufactured between 1946 and 1950.

-The same engine,but liquid-cooled was the O-240L with the same power. Only the first version was marketed for aviation.

-However, liquid-cooled engines were offered as O-240EG for land and marine use.

“Jacobs O-360L”

-The O-360 and OL-360 were the largest horizontally-opposed cylinder engines with 6 cylinders.

-The air-cooled O-360A gave 165 hp at 2,400 rpm and was manufactured between 1946 and 1950.

-The O-360L was liquid cooled and had the same power as its air-cooled brother. No application is known.

From Appendix 6: Curiously in 1914, an extraordinary Jacobs engine appears. The author of this publication has not yet been able to relate this engine to the famous Jacobs brand that began its activity in 1927 becoming known for its radial engines as a result of the union of Jacobs and Fisher (See Jacobs).

-The supposed new Jacobs brand is mentioned here separately. However, there is not enough data of its power, etc.

-What calls our attention is the number and arrangement of the cylinders. We guess there are seven cylinders arranged in an irregular fan-shape and difficult to study. If not, one of the cylinders has been disassembled.

-We also see that the cylinder fins are spiral and those of the head are horizontal and parallel.

-The cylinder heads seem to be interchangeable for the angles they have. They have two spark plugs in each of them.

-The magnetos are also arranged in an original way. I wish one day I could see the engine and study it.

“The extraordinary Jacobs”

-Below we insert a couple of ads of the time.

-They are inserted because it is possibly the same designer of the important radial engines built a couple of decades later.

-In the first ad, the Jacobs L-6 engine and in the second, the feat carried out by O.J. Whitney on his Beechcraft with a Jacobs 225 hp engine.

“Jacobs L-6 ad”

“Commemorative flight ad”