Compounded Engines

[krieghund]

I ran across these and though I'd put them here for a discussion on the final push on reciprocating engines before moving on to jets. Enjoy

 

[fastmongrel]

Another attempt to prevent the demise of the piston engine the Napier Nomad half diesel engine and half gas turbine.

 

[wuzak]

Another attempt to prevent the demise of the piston engine the Napier Nomad half diesel engine and half gas turbine.

That was also a turbo compound - but with an axial flow compressor connected to the turbine.

The MkI drove one of its co-axial props from the main engine and the other using the power from the turbine. The MkII had the power from teh turbine fed directly back into the engine. Fuel could be injected and burned in the exhaust to get more power from the turbine.

 

[Piper106]

Allison also was in the game. Dan Whitney's "Vees for Victory" has the 'best desciption I have seen of the V-1710 E27 turbo-compound engine. It was a E22 mechanical supercharged two stage engine (no turbo) with a GE CT-1 exhaust gas power recovery turbine feeding power back to the crankshaft. Plenty of power - 2800 HP at war emergency conditions. Sticking point was the exhaust gas turbine was only good for 1725 deg F and that temerature was 'easily' exceeded at full power. Rather than working into 1946 or 1947 to develop an air cooled turbine that could handle exhaust from 115/145 fueled 6.0:1 compression 100" manifold pressure cylinders, they decided to turn their efforts toward pure jet and tuboprop gas turbines.

Piper106

 

[wuzak]

Allison also was in the game. Dan Whitney's "Vees for Victory" has the 'best desciption I have seen of the V-1710 E27 turbo-compound engine. It was a E22 mechanical supercharged two stage engine (no turbo) with a GE CT-1 exhaust gas power recovery turbine feeding power back to the crankshaft. Plenty of power - 2800 HP at war emergency conditions. Sticking point was the exhaust gas turbine was only good for 1725 deg F and that temerature was 'easily' exceeded at full power. Rather than working into 1946 or 1947 to develop an air cooled turbine that could handle exhaust from 115/145 fueled 6.0:1 compression 100" manifold pressure cylinders, they decided to turn their efforts toward pure jet and tuboprop gas turbines.

Piper106

Allison were also reluctant to develop an engine version without firm orders or development funds from interested parties (ie the military).

 

[PWR4360-59B]

Fuel economy wise, I'd bet something on the lines of the Nomad could compete with some of the jets.