Post by barnyard on Aug 14, 2019 23:38:11 GMT -5
It’s been a while since I have done much with the engine, other than start it up every once in a while. This week I had the chance to open the combustor and inspect the flame tube. Looks like the flame is burning in the top 1/3 of the tube, and offset close to the spark plug side. Not sure why it’s off to one side, maybe because of a swirl in the airflow coming from the compressor, or it could be the small gap around the spark plug hole in the fT is allowing additional air to mix with the fuel spray. Either way it runs decent I think.
I changed the fuel nozzle from a 7.5(gph?) to a 11, all while staying with my one Automotive fuel pump. I get around 70psi fuel pressure at full bore.
With the larger nozzle I’m not getting +20Psi from the compressor, a noticeable jump from the 15psi I was getting.
Lastly I’ve added a nozzle on the exhaust of the turbine. I felt it was running well enough to support one. I don’t remember the actual diameter of the outlet, but I tried to get it slightly larger than the turbo inlet diameter. I did have a EGT probe reading the temp, but it decided to burst after a short time, not confidence inspiring! I will get a functioning egt meter before I run the engine for long. I have seen no discolouration or glowing from the turbine wheel.
I’m quite happy with the latest progress, the exhaust nozzle has been something I’ve been looking forward to getting on. Now I need to make a way to test thrust, probably with a fish scale. My end goal is still to run a freepower turbine, either a st50, or possible a turbine stage from a Apu? There is a guy near me that has sold expired turbine wheels in the past, there is a small chance he will have something appropriate. However is there even a axial turbine wheel small enough for my engine (71mm turbo inducer)?
Thanks, James
I changed the fuel nozzle from a 7.5(gph?) to a 11, all while staying with my one Automotive fuel pump. I get around 70psi fuel pressure at full bore.
With the larger nozzle I’m not getting +20Psi from the compressor, a noticeable jump from the 15psi I was getting.
Lastly I’ve added a nozzle on the exhaust of the turbine. I felt it was running well enough to support one. I don’t remember the actual diameter of the outlet, but I tried to get it slightly larger than the turbo inlet diameter. I did have a EGT probe reading the temp, but it decided to burst after a short time, not confidence inspiring! I will get a functioning egt meter before I run the engine for long. I have seen no discolouration or glowing from the turbine wheel.
I’m quite happy with the latest progress, the exhaust nozzle has been something I’ve been looking forward to getting on. Now I need to make a way to test thrust, probably with a fish scale. My end goal is still to run a freepower turbine, either a st50, or possible a turbine stage from a Apu? There is a guy near me that has sold expired turbine wheels in the past, there is a small chance he will have something appropriate. However is there even a axial turbine wheel small enough for my engine (71mm turbo inducer)?
Thanks, James