Re: PT boats

Posted by Dave Kenney On 2011/12/8 20:39:12

The American PT boat and the British and Canadian MTB's (one of which my father served on during WW2) were powered by the 4M-2500, four-stroke, 60-degree V-12 with an aluminum block with a bore of 6.04 inches and a 6.50-inch stroke, which brought it to 2,490 cubic inches. Weighing 2,900 pounds, the 4M-2500 had four valves per cylinder, a 6.4:1 compression ratio, and a centrifugal supercharger, later models were also fitted with an intercooler. A Holley 1685F aircraft carburetor supplied the fuel, 100-octane gasoline, fired by two spark plugs per cylinder. The first engines developed 1,200hp, but improved versions with higher boost levels nominally made 1,500hp.

John, I looked at that video 3 times and the photograph of the aircraft. It does appear that it has radial engines if you look close at the engine cowling so I am thinking it is not a Lancaster but the similar appearing Handley-Page Halifax many of which used the Bristol Hercules 14 cylinder 2 row radial engines. A few hundred Lanc's did have radial Bristol Hercules engines but many more Halifax bombers used them. A better photograph of the tops sides would make identification easy but from below it is hard for me to say if it is a Lancaster or Halifax since both shared that twin boom rudder but the rounded wing tips may be a clue it is a Halifax. Just my .02 Cents.