R2800 vs R3350

[Piper106]

I don't have first hand knowledge, but I would start the betting on the Wright R-3350 Power Recovery Turbine (PRT) problems were related to on metallurgy. The exhaust gas of a high powered spark ignition (gasoline) piston engine is very hot, close to 1000 deg C / 1800 deg F. The Wright PRT used air cooled turbine blades but even so the temperature and stress was on the ragged edge for the metallurgy available at the time. It is interesting to me that gas turbine engines of the era operated at lower temperatures because of the metallurgy issues.

The Detroit Diesel PRT reliability is the result of the lower exhaust gas temperature of diesels (around 775 deg C / 1400 deg F at full load) plus 50 years plus worth of metallurgy advancements since the Wright PRT.

Piper106

 

[wuzak]

I know that the turbine used in the V-1710-127 turbocompound (basically a turbine from the C-series turbochargers used in the P-47) could not cope with the temperatures of teh V-1710 at full WEP, even with copious amounts of ADI. Allison wanted to develop an air cooled turbine, but without customers for the engine they did not want to fund is development.

I wonder if the problem with the R-3350 PRTs was the turbines themselves, or the drivetrain used to feed power back to the crank - which included fluid couplings/torque converters.

 

[jellydonut]

I know that the turbine used in the V-1710-127 turbocompound (basically a turbine from the C-series turbochargers used in the P-47) could not cope with the temperatures of teh V-1710 at full WEP, even with copious amounts of ADI. Allison wanted to develop an air cooled turbine, but without customers for the engine they did not want to fund is development.

I wonder if the problem with the R-3350 PRTs was the turbines themselves, or the drivetrain used to feed power back to the crank - which included fluid couplings/torque converters.

That's exactly what I am wondering about too. I am hoping it was a problem with the turbines themselves, and not the arrangement.

I have a project in mind, using some turbines salvaged from DD15s (if I can find them) and I'm currently searching for more information about this whole concept. It's not easy.