Coupled or joined engines

[PMN1]

Did anyone manage to get a coupled or joined engine to work reliably and if so how long did it take them to do this?

What are the advantages of making a coupled or joined engine over sizing up an existing engine and building it as a standard single engine?

[PMN1]

Fairey seemed to have managed this with its H16 Prince and P24 Monarch (see posts on these).

According to Norman Friedman in his book 'British Carrier Aviation - the evolution of the ships and their aircraft' they also proposed a tandem Merlin instalation for their Spearfish in place of the Centaurus.

'The pilot wopuld sit above the one, with the other between him and the observer. Each Merlin would drive an independant (though concentric) propeller, each having its own throttle and its own fuel system, though the fuel systems would b einterconnected so that the aircrfat could cruise for most of the time on one engine. The oil systems were completely seperate'

Fairey exppected the aircrfat to have a speed of 350/360mph and a range the same as the Centaurus Spearfish.

http://www.fleetairarmarchive.net/Aircraft/Spearfish.htm

[GregP]

Coupled engines are usually a source of mechanical failure. The engine described in the Spearfish above seems to NOT be a coupled engine since there was no gearing linking the crankshafts.

If you proposed a linked engine, then what you were really saying was, "We can't design that in the time avilable, but CAN offer something based on a current production engine that might work for you."

No coupled engines I am aware of were successful except in marine operations, rail, or other, non-aviation endeavors. In these cases, there was not a need for aerodynamic streamlining, so the engines could be coupled at 90° or even 180° if necessary to make servicing easier. In airfraft, that was not the case. They needed to be more or less inline and near the center of gravity.