Back again..!... The GT6041 powered "Green Beast"..!
Jan 17, 2016 19:24:47 GMT -5
pitciblackscotland likes this
Post by smithy1 on Jan 17, 2016 19:24:47 GMT -5
Hi All,
Was supposed to do a little engine testing on Saturday morning but the weather was a tad "inclement"...however, later in the afternoon I was able to at least fire the beast up.
Sorry John, no usable video unfortunately, just a poor vid of me kneeling beside the beast while it makes a noise, nothing interesting to see really, much like your old vids in your shed up the mountains. When I get it sorted a bit better I might take some nicer video.
I had 3 different Allison/Rolls-Royce C20B fuel nozzles with me to test, a standard flow nozzle (which I knew would struggle at the pressures I was using), and two others of higher flow vs pressure which I have "Doctored" to suit my requirements. I fitted the standard C20B nozzle to start with...I was a bit wary of the start so I used propane to soften things a bit. As per usual if lit off easily and I slowly opened the fuel supply while increasing the blower... and she slowly started to spool up as normal, I had already increased the throttle idle stop to account for the low flow so I had half an idea of what was going to happen. With the flow tap fully open the engine only spooled up to ~ 14-15000rpm which is considerably less than idle so I increased throttle to help her along a bit...as I had thought, the flow wasn't really sufficient to allow a decent idle rpm so I shut down and had a wee think.
With the standard C20B nozzle a fuel pressure of @40 psi would normally see a flow of ~25lb/hr which is enough to light off but not much else, so I decided to fit my "Hi Flow" nozzle, this was a vast improvement with spool up to idle much better, in fact, the fuel flow is probably a bit too high at the same pressures, I had to knock the flow tap back slightly to allow a nice P2 of ~4-5psi...combustion sounded pretty good, a few flutters here and there but nothing silly and temps were in what I would call a normal range, even if a tad low...@~430C..! I might have to open the "primary" holes a few % as it's slightly lower in area than optimal, but this is reasonably easy to do.
My next run will be done with two 044 pumps in series and a slightly lower flow nozzle so I can keep the fuel pressure up a bit higher to help with fuel atomization and account for rises in P2 etc... hopefully all will be as it should be.
So John & Andrew....looks like it can be done...there's obviously a few things which need "tweaking" but she runs and I didn't break anything..!
Andrew...time to get your 6041 out and blow the cobwebs off it..!...or out of it as the case may be..!
Cheers,
Smithy.
PS: I "may" be on the Manspace TV show tonight on Channel 99-Go at 9:00pm...might be worth a giggle.
Was supposed to do a little engine testing on Saturday morning but the weather was a tad "inclement"...however, later in the afternoon I was able to at least fire the beast up.
Sorry John, no usable video unfortunately, just a poor vid of me kneeling beside the beast while it makes a noise, nothing interesting to see really, much like your old vids in your shed up the mountains. When I get it sorted a bit better I might take some nicer video.
I had 3 different Allison/Rolls-Royce C20B fuel nozzles with me to test, a standard flow nozzle (which I knew would struggle at the pressures I was using), and two others of higher flow vs pressure which I have "Doctored" to suit my requirements. I fitted the standard C20B nozzle to start with...I was a bit wary of the start so I used propane to soften things a bit. As per usual if lit off easily and I slowly opened the fuel supply while increasing the blower... and she slowly started to spool up as normal, I had already increased the throttle idle stop to account for the low flow so I had half an idea of what was going to happen. With the flow tap fully open the engine only spooled up to ~ 14-15000rpm which is considerably less than idle so I increased throttle to help her along a bit...as I had thought, the flow wasn't really sufficient to allow a decent idle rpm so I shut down and had a wee think.
With the standard C20B nozzle a fuel pressure of @40 psi would normally see a flow of ~25lb/hr which is enough to light off but not much else, so I decided to fit my "Hi Flow" nozzle, this was a vast improvement with spool up to idle much better, in fact, the fuel flow is probably a bit too high at the same pressures, I had to knock the flow tap back slightly to allow a nice P2 of ~4-5psi...combustion sounded pretty good, a few flutters here and there but nothing silly and temps were in what I would call a normal range, even if a tad low...@~430C..! I might have to open the "primary" holes a few % as it's slightly lower in area than optimal, but this is reasonably easy to do.
My next run will be done with two 044 pumps in series and a slightly lower flow nozzle so I can keep the fuel pressure up a bit higher to help with fuel atomization and account for rises in P2 etc... hopefully all will be as it should be.
So John & Andrew....looks like it can be done...there's obviously a few things which need "tweaking" but she runs and I didn't break anything..!
Andrew...time to get your 6041 out and blow the cobwebs off it..!...or out of it as the case may be..!
Cheers,
Smithy.
PS: I "may" be on the Manspace TV show tonight on Channel 99-Go at 9:00pm...might be worth a giggle.
...that's worth it's weight in rocking horse manure 
I like the drone.