Another Radial Engine Option... The Jacobs R-755 Better Known as the Shaky Jake
Dale, from the biplaneforum, is one of those round engine guys, just like myself.
A few posted messages and a few private messages and he's telling me how great the "Shaky Jake" is. Said his will be pushing out over 320 hp.
Real close to what I want to have pulling my Skybolt around. Knowing that, I began to do a little research on the Jake.
The Jacobs Engine Company started life in Philadelphia, PA under the name of Fischer and Jacobs. The year was 1927. Their first atempt at manufacturing was a four cylinder, two-cycle radial engine. It's been said that it was designed to be a replacement to the OX-5 engine which was popular at the time. Weight was somewhere under 250 pounds and they claimed it would produce approximately the same power, which was 90 hp. It appears that they abandoned the development of this
engine because it was never relased for market sales.
From Philadelphia they moved their operations to Central Airport (since closed... now the Airport Circle)in Camden, NJ, a place not more than a stone's throw from my house, and changed their name to Fischer and Jacobs Aircraft Engine Corporation. It was at this location that they began to market the radial engines that they started developing at their Philadelphia offices in 1927. It's first engines were a 55 hp F-head three and a 150 hp seven. While the F-head didn't stick around too long, the seven cylinder engine (model number LA-1) was the start of a very long line of engines. Orignally he LA-1 produced 140 hp at 1800 rpm. The power was later increased to 170 hp at 2125 rpm.
A refinement of the LA-1 was the LA-2. This received it's Type Certificate on May 6, 1932. A larger engine, displacing 589.2 cubic inches, it was rated at 195 hp at 2075 rpm.
In 1934, Jacobs came out with the L-4 (or R-755,) which would develop 225 hp from 757 cu in. The L-5, produced 2 years later, would put out 285 hp from 831 cu in.
Although the Jacob engine was used throughout the 30's in various aircraft; the Spartan Executive and the Beech Staggerwing. It didn't see real use until the Second World War. Cessna ended up using them on their two-engined UC-78 (Bamboo Bomber.) After the war, Cessna would power their famous line of 195s with the Jacobs.
After World War II, Jacobs beacame a division of Republic Industries (not Republic Aircraft.) The type certificates are currently held by Air Repair, Inc.
The "Shaky Jake," got it's name from it's coil ignition and distributor caps' set-up. They were prone to cracking. The cracking lead to the spark being delivered to the wrong cylinder, resulting in a rough, or shaky, running engine. The fix was to put the cap through a bakeout, in a vacuum oven, then impregnate the
crack with insulating varnish. Having done this, the cap would run forever without any further trouble. Just one caveat, it was illegal and the government, in all their wisdom, said that the fix was to replace it with a new crack-prone distributor cap. That was/is the wisdom of our government.
No of Cylinders: 7
Displacement: 757 cu in.
Weight: 505 lbs
Fuel Consumption: 15 gph
No of Cylinders: 7
Displacement: 914 cu in.
Weight: 557 lbs