Smilin Ed.
The Allison engines in the P-38 Lightning were identical but were installed facing different directions to get the props to rotate in opposite directions. This was simpler than building the engines differently by using different valve camshafts and simplified the supply problem. Does anyone know if the Merlins and Griffons were capable of being installed "backwards"?
Probably not. The Allison engines in the P38 were
turbocharged, the Merlin and Griffon were
supercharged ie; the supercharger was driven through a two or three speed gearbox from the aft end of the crankshaft. A glance at either engine shows the entire rear end is full of supercharger, gear boxe and the carburetor/aneroid assembly.
27/09
My understanding re the use of contra-rotating props was the need to be able to absorb the horsepower of the more power full engines. They were used on the Spifires and the Shakletons and other piston types as well no doubt. The Russians used contra-rotating props on some of their turbo-props.
Absolutely. The Spitfire had quite short legs and even after the mighty Dowty three blade prop was fitted, the Merlin power output just kept on going up. If you remember, the Griffon Spits had five blade props and the contra rotating prop was mostly needed for the
Seafires, because they tended to 'peck' with even the five blade prop.
Look at the F4U Corsair. 4000hp available and it had whacking great long legs to clear that windmill of a four blade prop. Apparently they were called 'widow makers', because of their tendency to 'torque flip' on short finals, if an incautious driver was tempted to 'give her a little nudge' to slow the sink rate.
Roger.