A photo of the Fiat S.76 racing car (above), surfaced recently that we have not seen before, courtesy of Chamon Vincent. This photo gives you a new perspective into the size of the 28 litre engine, which was installed into the “The Beast of Turin” as it was called.
Duncan Pittaway, from the UK who owns the S.76 car that he is working on (follow these two links to see the progress. Link one….. Link two). He has provided us with all of the differences here between the racing motors and the airship motors:
The car engines were made at the end of 1910/very early 1911. The airship engines for Forlanini were not made until 1912 and were supplied in left and right hand rotating pairs. The airship engines only shared the same bore and stroke. The crankcases were cast iron with no “legs” to mount into a chassis, a big square oil sump, the cam and mag drive was at the opposite end, not the flywheel end like the car, the block had 8 valves instead of 12, the oil pump was driven from the nose of the crank instead of the cam drive, the compression ratio was very low and, as the airship engines had compressed air start, they didn’t need a complicated sliding decompression cam like the car, which was started on a handle from the front of the crank.
Fiat has a “clockwise” airship engine at Centro Storica, and Politechnico di Torino have an “anti clock” version…. I’ve been lucky enough to look at both. They’re both dated 1912, are slightly different and I don’t think they have any interchangeable parts with the car engine whatsoever.
These engines if the specifications we found are correct, turn out to have a bore and stroke of very close to 7 1/2″ x 9 27/32″ (19.0 cm x 25.0 cm ). That works out to 1729 c.i. total or 432 c.i. per cylinder which is bigger than most big V-8 engines in total. You can take a quick look back on previous coverage here on The Old Motor showing many S.76 photos and other information, including an incredible ongoing effort to reconstruct a Fiat S.76 from an S.76 racing engine that came from Fiat and other parts that have survived.
Above are two of the S.76 engines mounted side-by-side and set up to drive right-angle gearboxes. They powered a Forlanini F.5 dirigible, seen in the (bottom) photo. From what we were able to find out about them, a few of these dirigibles were used in the war between Italy and Turkey between 1911-1912. Later air ships appear to have been powered by smaller Fiat engines. Photos of the engines (above) and the craft at the (bottom) courtesy of jn.passieux.free.fr
The photo just below is from The New York Times Mid-Week Pictorial, dated Jan. 31, 1918. It shows what they call “the car” of one of the period Forlanini airships were the power plant above was located. Full details of the craft can be found in the periodical.