WW2 Earlier Turbo-compound aircraft engines

[Andras]

The V-1710TC engine seems to have some plumbing driving a turbine with exhaust gases, connected to what looks like a common supercharger with a big pipe to the intake for the integral mechanical supercharger common to all V-1710s from C-15 on. The turbo-compound appears to be still a supercharger of the turbo variety, fixed in position by its duty to drive the crankshaft. Vertical orientation would require some doing, without much advantage. Changing the air intake on the Lightning would be a big mistake, since it incorporates a nifty big air filter inside the nacelle which works when the gear is down. Just the thing for desert and rough field deployments in the Pacific. Okay for England though, since there's no dust there.

That looks like the turbine powers the 2nd stage blower (normally geared to the crankshaft), unloading the vampiric drain from the engine, and adding a certain amount back into the system. The blowers could consume ~400hp, though they add that much and more at higher altitudes.

 

[Draconis]

That looks like the turbine powers the 2nd stage blower (normally geared to the crankshaft), unloading the vampiric drain from the engine, and adding a certain amount back into the system. The blowers could consume ~400hp, though they add that much and more at higher altitudes.

I think I'm going to use my OP privileges to resurrect my old thread. There is an interesting discussion about the benefits and detriments of turbo-compound versus mechanical supercharging versus turbocharging in the P-38 thread I think it may need its own topical thread. I'm going to copy over your latest posting and mine from the P-38 thread to get things going.

 

[Draconis]

Developing some method of turbo-compounding early enough to be used in WW2 is an old topic of interest. Considering the performance improvements gained compared to mechanical supercharging and turbocharging, turbo-compounding offered some clear advantages. The thrust gained from the engine exhaust stacks is helpful but this must be weighed against the hundreds of horsepower consumed by the engine driven 2 stage superchargers at altitude. These were propeller engines operating at a speed range where all possible energy should be directed toward driving the propellers.

Here a link to an article that explores in some detail the energy available in the engine exhaust and a few other things as well. It includes a graphic illustrating the proportions of where the engines' energy is used or lost. https://www.enginehistory.org/members/articles/WasteHeat/WasteHeat.shtml

 

[Draconis]

Andras---"I'm gonna repost two videos by Greg. One is turbo vs Supercharging, and the other is power recovery turbines.

At 36 minutes is a direct comparison chart between the systems on a R2800.

turbocompounding

I lied, a third video on the best supercharging system on a Corsair" -- Andras.