Comments by "" (@neutronalchemist3241) on "The Piaggio P.119; A Fighter with A Unique Engine Set Up" video.

  1. The Piaggio P.XV was already a very good 1700hp engine. The only advantage of the P.XXII was that it would have provided that power using standard 87 octane fuel, while the P.XV needed 97 octane.
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  2. Italians produced 1000 hp radials since the mid '30s (1000 hp Piaggio P.XI and 1030 hp Fiat A.80. Also the 960 hp Fiat A.74 and the 950 hp Alfa Romeo 128 were close). In 1939 had been omologated the 1500 hp Piaggio P.XII and the 1600 hp Alfa Romeo 135 (the second never reached a sufficeint reliability, but the first one had probably been the best radial that used standard 87 octane fuel of the war). In 1941 had been homologated the 1700hp Piaggio P.XV (97 octane fuelled version of the P.XII).
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  3.  @paoloviti6156  "modification" in VERY broad terms, since it had double the row and more than double the power. "Hence" means nothing when the engines are so different. The reliability problems were on the first engines produced. Those of well known engines like the BMW 801 or the P&W R2800 lasted for longer before being ironed out. It has to be taken into account that, due to the different productive capability, the "first engines that gave problems" (a common occurrence in WWII era) were an higher percentage of the total production for the Italians, even if they were numerically fewer. The TBO of Italian licenced DB engines was of 60 hours. Packard Merlins rarely lasted 100 hours (and, due to the different mission profiles, most of those hours were at military/emergency power for Italian engines and at cruise speed for Packard Merlins). The P&W R-2800 started service with an expected life of 25 hours (then the 5 cylinders in top rear position had to be replaced without even checking them, while, for the DBs, at the overhaul the cylinders were checked and rebored only if needed). Only some thousands engines later it became of several hundreds hours, then of thousands. The difference between the outstanding P&W R-2800 and the unreliable Alfa Romeo 135 was that the US could afford to put in service an engine that required to toss 5 cylinders every 25 hours of functioning. The RR Merlin had nominally a 240 hours TBO but according to Rolls-Royce, if 30% of engines were reaching overhaul life and, no single cause made-up more than 30% of rejections, then it was time for an increase of maximum engine life.That means that 70% of the RR Merlins didn't even reach TBO, and that was late in the war when, again, much of the time the engine was at cruise speed.
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